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Technical Support Manual:
Waterbody Surveys and
Assessments for Conducting
Use Attainability Analyses
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Foreword
The Technical Support Manual: Water Body Surveys and Assessments for
Conducting Use Attainability Analyses contains technical guidance prepared
by EPA to assist States in implementing the revised Water Duality Standards
Regulation (48 FR 51400, November 8, 1983). EPA prepared this document
in response to requests by several States for additional guidance and
detail on conducting use attainability analyses beyond that which is
contained in Chapter 3 of the Water Quality Standards Handbook (December,
1983).
Consideration of the suitability of a water body for attaining a given
use is an integral part of the water quality standards review and revision
process. This guidance is intended to assist States in answering three
central questions:
(!) What are the aquatic protection uses currently being achieved in the
water body9
(2) What are the potential uses that can be attained based on the physical,
chemical and biological characteristics of the water body?; and,
(3) What are the causes of any impairment of the uses?
EPA will continue providing guidance and technical assistance to the
States in order to improve the scientific and technical basis of water
quality standards decisions. States are encouraged to consult with EPA at
the beginning of any standards revision project to agree on appropriate
methods before the analyses are initiated, and frequently as they are
conducted.
Any questions on this guidance may be directed to the water quality
standards coordinators located in each of the EPA Regional Offices or to:
Elliot Lomnitz
Criteria and Standards Division (WH-58S)
401 M Street, S.W.
Washington, D.C. 20460
Steven Schatzow, Director
Office of Water Regulations and Standards
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TECHNICAL SUPPORT MANUAL:
WATER BODY SURVEYS AND ASSESSMENTS
TABLE OE CONTENTS
0 Foreword
°Section I: Introduction
"Section II: Physical Evaluations
Chapter II-l
Chapter 11-2
Chapter II-3
Chapter 11-4
Chapter
Chapter
II-5
II-6
Flow
Suspended Solids and Sedimentation
Pools, Riffles and Substrate Composition
Channel Characteristics and Effects of
Channelization
Temperature
Riparian Evaluations
"Section III: Chemical Evaluations
Chapter III-l Water Quality Indices
Chapter III-? Hardness, Alkalinity, pH and Salinity
"Section IV:
Chapter IV
Chapter IV
Chapter IV-
Chapter IV-
Chapter IV-
Chapter IV-
Biological Evaluations
1 Habitat Suitability Indices
-2 Diversity Indices and Measures of
Community Structure
3 Recovery Index
4 Intolerant Species Analysis
5 Omnivore-Carnivore Analysis
fi Reference Reach Comparison
"Section V: Interpretation
"Section VI: References
'Appendix A-l:
'Appendix B-l:
'Appendix B-2:
'Appendix C:
Sample Habitat Suitability Index
List of Resident Omnivores Nationally
List of Resident Carnivores Nationally
List of Intolerant Species Nationally
Page
1-1
II-l-l
II-2-1
II-3-1
II-4-1
II-5-1
II-6-1
III-l-l
III-2-1
IV-1-1
IV-2-1
IV-3-1
IV-4-1
IV-5-1
IV-6-1
V-l
VI-1
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0 SECTION I: INTRODUCTION
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One of the major pieces of guidance discussed within the Water Quality
Standards Handbook (November, 1983) is the "Water Body Survey and
Assessment Guidance for Conducting Use Attainability Analyses" which
discusses the framework for determining the attainable aquatic protection
use. This guidance describes the framework and suggests parameters to be
examined In order to determine:
(1) What are the aquatic use(s) currently being achieved in the water body?
(2) What are the potential uses that can be attained based on the physical,
chemical and biological characteristics of the water body''; and,
(3) What are the causes of any impairment of the uses?
The purpose of the technical support manual 1s to highlight methods and
approaches which can be used to address these questions as related to the
aquatic life protection use. This document specifically addresses stream
and river systems. EPA is presently developing guidance for estuarine and
marine systems and plans to Issue such guidance in 1984.
Several case studies were performed to test the applicability of the "Water
Body Survey and Assessment" guidance. These case studies demonstrated that
the guidance could successfully be applied to determine attainable uses.
Several of the States involved 1n these studies suggested that it would be
helpful if EPA could provide a more detailed and technical explanation of
the procedures mentioned in the guidance. In response, EPA has prepared
this technical support manual. The methods and procedures offered in this
manual are optional and States may apply them selectively. States may also
use their own techniques or methods for conducting use attainability
analyses.
A State that intends to conduct a use attainability analysis is encouraged
to consult with EPA before the analyses are initiated and frequently as
they are carried out. EPA is striving to develop a partnership with the
States to improve the scientific and technical bases of the water quality
standards decision-making process. This consultation will allow for
greater scientific discussion and better planning to ensure that tre
analyses are technically valid.
Consideration of the suitability of a water body for attaining a given use
1s an Integral part of the water quality standards review and re ision
process. The data and Information collected from the water body ;urvey
provide a basis for evaluating whether the water body is suitable for a
particular use. It is not envisioned that each *ater body would
necessarily have a unique set of uses. Rather the characteristics
necessary to support a use could be identified so that water bodies having
those characteristics might be grouped together as likely to support
particular uses.
Since the complexity of an aquatic ecosystem does not lend itself to simple
evaluations, there is no single formula or model that will provide all the
answers. Thus, the professional judgment of the evaluator is key to the
Interpretation of data which is gathered.
1-1
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SECTION II: PHYSICAL EVALUATIONS
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OVERVIEW
The physical characteristics of a water body greatly Influence Its reaction
to pollution and Its natural purification processess. The physical
characteristics also play a great role 1n the availability of suitable
habitat for aquatic species. An understanding of the nature of these
characteristics and Influences Is Important to the Intelligent planning and
execution of a water body survey. Important physical factors Include flow,
temperature, substrate composition, suspended solids, depth, velocity and
modifications made to the water body. Effects of some of these factors are
so Interrelated that 1t Is difficult or even Impossible to assign more or
less Importance to one or the other of them. For example, slope and
roughness of channel Influence both depth and velocity of flow, which
together control turbulence. Turbulence, in turn, affects rates of mixing
of wastes and tributary streams, reaeratlon, sedimentation or scour of
solids, growths of attached biological forms and rates of purification
(FWPCA, 1969). Thus evaluating the factors which constitute the physical
environment cannot be done by just assessing one parameter but rather a
broader assessment and view is needed.
The purpose of this section is to amplify the methods and types of
assessments discussed in Chapter 3 of the Water Quality Standards Handbook
for evaluating the physical characteristics of a water body. The analyses
proposed in this section, as well as the other sections of this document,
do not constitute required analyses nor are these all the analyses
available or acceptable for conducting a use attainability analysis.
States should design and choose assessment methodologies based on the
site-specific considerations of the study area. The degree of complexity
of the water body in question will usually dictate the amount of data and
analysis needed. States should consult with EPA prior to conducting the
survey to facilitate greater scientific discussion and better planning of
the study.
CHAPTER II-l
FLOW ASSESSMENTS
The Instream flow requirement for fish and wildlife is the flow regime
necessary to maintain levels of fish, wildlife and other dependent
organisms. Numerous methodological approaches for quantifying the instream
flow requirements of fish, wildlife, recreation, and other Instream uses
exist. Each method has Inherent limitations which must be examined to
determine appropriate methods for recommending stream flow quantities on a
site-specific basis. The following describes in detail several of the more
commonly used and accepted methods.
TENNANT METHOD
One of the widely known examples of an Instream flow method is the Tennant
method (1976). Based on analyses conducted on 11 streams in Montana,
Wyoming and Nebraska, Tennant determined the following:
(1) Changes in aquatic habitat are remarkably similar among streams having
similar average flow regimes.
(2) An average stream depth of 0.3 meters and an average water velocity of
0.75 ft/sec were the critical minimum physical requirements for most
aquatic organisms.
II-l-l
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(3) Ten percent of the average annual flow would sustain short-term
survival for most fish species.
(4) To sustain good survival habitat, thirty percent of the average annual
flow was adequate since the depth and velocities generally would allow fish
migration.
(5) Sixty percent of flow provides outstanding habitat.
Using the above information, Tennant proposed a range of percentages of the
average annual flow regime needed to maintain desired flow conditions on a
semi-annual basis. These ranges are summarized by the following:
Recommended flow regime
Flow Description October-March April-September
Flushing 200% of the average annual flow
Optimum range 60%-100% of the average annual flow
Outstanding 40% 60%
Excellent 30% 50%
Good 20", 40*
Fair, Degrading 10% 30%
Poor, Minimum 10% 10%
Severe Degradation <10% <10%
The determination of average annual flow was conducted by Tennant by the
summation of the average monthly flow for a ten year period. After average
annual flows are determined, recommendations can be calculated by
multiplying the average annual flow by the percentages in the above table.
INSTREAM FLOW INCREMENTAL METHODOLOGY (IFIM)
The IFIM is a computerized water management tool developed by the U.S.
Fish and Wildlife Service for evaluating changes on aquatic life and
recreational activities resulting from alterations 1n channel roonphology,
water quality and hydraulic components. Bovee (1982) outlined the
underlying principles of IFIM as: (1 } each species exhibits preferences
within a range of habitat conditions that it can tolerate; (2) these ranges
can be defined for each species; and (3) the area of stream providing these
conditions can be quantified as a function of discharge and channel
structure. IFIM is designed to simulate hydraulic conditions and habitat
availability for a particular species and size class or usable waters for a
particular recreational activity. The hydraulic and channel
characteristics are simulated for IFIM by use of the Physical Habitat
Simulation Model (PHABSIM).
PHABSIM is a series of computer programs which relate changes in flow and
channel structure to changes in physical habitat availability. Hilgart
(1982) summarized the PHABSIM model as comprised of two parts: (1) a
hydraulic simulation program which will predict the values of hydraulic
II-1-2
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parameters for a range of flows from either a single measured flov. (WSP) r.>r
two or more measured flows (IFG4), -inn (2) a habitat assessment progran
called HARTAT, which rates the predicted hydraulic conditions for their
relative fisheries values. Rather than describing the stream reach as a
series of -lepth, velocity and substrate contours, PHABSIM is used o
describe the reach as a series of small cells (Figure ll-l-l).
Il-l-l
Conceptualization of Simulated Stream Reacn.
Subsections Have Similar Depth and Velocity Ranges.
Instead of summarizing average depth and velocity for a cross sect'.',,
PHA8SIM is used to predict the average depth and velocity for e
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STEP 3: Data Collection - Transects are selected to adequately
characterize the hydraulic and instream habitat conditions.
Data gathering must be compatible to IFIH computer models.
STEP 4: Computer Simulation - Involves reducing field data and
entering into programs described above.
STEP 5: Interpretation of Results - The output from the computer
programis expressedastne Weighted Usable Area (WUA), a
discrete value for each representative and critical study
reach, for each life stage and species, and for each flow
regime.
For further information on IFIM and PHABSIM the following publication
should be consulted: "A Guidance to Stream Habitat Analysis Using the
Instream Flow Incremental Methodology" U.S. FWS/OBS-82/26, June, 1982.
II-1-4
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CHAPTER 11-2
SUSPENDED SOLIDS AND SEDIMENTATION
The consideration of the potential effects of suspended sol Ids and
sedimentation on aquatic organisms may reveal important data and
information pertinent to a use attainability analysis. Suspended solids
generally may affect fish populations and fish in several major ways:
(1) "By acting directly on the fish swimming in water in which solids are
suspended, and either killing them or reducing their growth rates,
resistence to disease, etc.;
(2) By preventing the successful development of fish eggs and larvae;
(3) By modifying natural movements and migrations of fish; and
(4) By reducing the abundance of food available to the fish" (EIFAC,
1964).
(5) By hindering the foraging and mating abilities of visual feeders and
those with visual mating displays.
The effects of sedimentation on aquatic organisms were summarized by
Iwamoto et al. (197R). These effects Include:
(1) clogging and abrasion of respiratory surfaces, especially gills;
(2) adhering to the chorion of eggs;
(3) providing conditions conducive to the entry and persistence of
disease-related organisms;
(4) inducing behavioral modifications;
(5) entomb different life stages;
(6) altering water chemistry by the absorption and/or adsorption of
chemicals;
(7) affecting utilizable habitat by the scouring and filling of pools and
riffles and changing bedload composition;
(8) reducing photosynthetlc growth and primary production, and;
(9) affecting intragravel permeability and dissolved oxygen levels.
This chapter of the manual will explore these effects in detail. An
excellent review of the effects of suspended solids and sedimentation on
warmwater fishes was conducted by EPA in 1979 entitled "Effects of
Suspended Solids and Sediment on Reproduction and Early Life of Warmwater
Fishes" (EPA-600-3-79-042) and should be consulted.
GENERAL ECOSYSTEM EFFECTS
Suspended solids and sedimentation may affect several trophic levels and
components of the ecosystem. The interactions between components of the
II-2-1
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ecosystem are closely linked thus changes in one component can reverberate
throughout the system. The following examines changes in each component
resulting from suspended solids and sedimentation:
Influences on Primary Productivity
Increases in suspended solids can greatly alter primary productivity
because of decreasing light penetration and subsequently decreasing
photosynthetic activity. Cairns (1968) reviewed the literature on the
effects on primary producers. The decrease in light penetration can affect
the depth distribution of vascular aquatic plants and algae. Greatly
reduced light penetration may shift algal composition from green to
bluegreen since the latter are tolerant to higher levels of ultraviolet
light. Butler (1964) observed an inverse relationship between turbidity
and primary productivity; gross primary productivity in a clear pond was
three-fold greater than an adjacent turbid pond (with Permian red clay).
Benson and Cowel1 (1967) found that turbidity in Missouri River
impoundments was the strongest limiting factor to plankton abundance and
that plankton was of great importance to fish growth and survival.
Suspended solids can also alter the distribution of heat in a water body.
Butler (1963) reported that colloidal clay in central Oklahoma was altering
the heat distribution and consequently summer stratification was more
pronounced in turbid situations. This stratification causes greater
differences between the surface and bottom temperature in turbid water
bodies.
To protect against the deleterious effects of suspended solids on aquatic
life by decreasing photosynthetic activity, EPA (1976) developed the
following criteria: "Settleable and suspended solids should not reduce the
depth of the compensation point for photosynthetic activity by more than 10
percent from the seasonally established norm for aquatic life." The
compensation point is the point at which incident light penetration is
sufficient for plankton to photosynthetically produce enough oxygen to
balance their respiration requirements. To determine this compensation
point, a set of "light" bottle n.O. and "dark" bottle D.O. tests would be
needed (see "Standard Methods", APHA, 1979 for details).
Effect on Zooplankton and Benthos
Benthic macroinvertebrates and zooplankton are major sources of food for
fish which can be adversely affected by suspended matter and sediment.
Depopulation and mortality of benthic organisms occurs with smothering or
alteration of preferred habitats. Zooplankton populations may be reduced
via decreasing primary productivity resulting from decreased light
penetration. Ellis (1936) demonstrated that freshwater mussels were killed
in silt deposits of 6.3 to 25.4 mm of primarily adobe clay. Major
increases in stream suspended solids (25 ppm turbidity upstream vs. 390 ppm
downstream) caused smothering of bottom invertebrates, reducing organism
diversity to only 7.3 per square foot from 25.5 per square foot upstream
(Teho, 1955). Deposition of organic materials to bottom sediments can also
cause imbalances in stream biota by increasing bottom animal density,
principally oligochaete populations, and diversity is reduced as pollution
II-2-2
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sensitive forms disappear. Deposition of organic materials can also cause
oxygen depletion and a change in the composition of bottom organisms.
Increases in oligochaetes and midges may occur since certain species in
these groups are tolerant of severe oxygen depletion.
Sensitivity of Fish Populations to Suspended Solids and Sediment
Field and laboratory studies have shown that fish species vary considerably
in their population-level responses to suspended solids and sediment.
Atchison ana Menzel (1979) reviewed the population level effects on
warmwater species and categorized species as either tolerant or intolerant
based on their habitat preferences. This review also revealed species with
a preference for turbid systems. Tables 1 and 2 have been adapted from
this review and provide valuable information on population effects. As can
be seen from these tables, the intolerant assemblage is composed of a large
number of species with complex spawning behavior whereas the tolerant
fishes include a larger percentage of simple spawners and forms with
special early life adaptations for turbid waters.
Effects on Fish Reproduction
The impacts of suspended solids and sediments on fish reproduction vary
with the phases of the reproductive cycle. The following describes several
of the mechanisms of impairment:
(1) D i mi n1shed L i ght Penet rat i on
SwingTe(1956)provideddata which shows that suspended materials might
affect fish reproductive processes by reducing light penetration. He found
that largemouth bass spawning was delayed by as much as 30 days in muddy
ponds as compared to clear ponds.
(2) Visual Interference
Some species such as Mack bass and centrarchid sunfish have strong visual
components in their reproductive behavior. For example, Trautman (1957)
found that smallmouth bass populations in Lake Erie shunned potential
spawning areas that were highly turbid. Chew (1969) observed that in
turbid Lake Hoi 1ingsworth (Fla.) largemouth bass spawning was very limited
and that most females failed to shed their eggs and gradually resorbed
them.
(3) Loss of Spawning Habitat
Reproductivefailure among many species is attributable to direct loss of
spawning habitat through two pathways: (a) siltation of formerly clean
bottom and (b) loss of vegetation due to the reduction of the photic zone
by turbidity.
(4) Physiological Alterations
The major physiological alterations are:
(a) the failure of gonadal maturation at the appropriate time and (b)
stress incurred by the organism thus creating increased susceptability to
disease.
In general, laboratory bioassays indicate that larval stages of selected
species are less tolerant of suspended solids than eggs or adults.
Available evidence suggests that lethal levels for suspended solids are
determined by interaction between biotic factors, including age-specific
and species specific differences, and abiotic factors such as particle
size, shape, concentration and amount of turbulence in the system.
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TARLF 1: SELECTED MIDWESTERN WARMWATER FISHES WHICH ARE INTOLERANT OF
SUSPENDED SOLIDS (TURBIDITY) AND SEDIMENT
Species Effect
Spawning General
Ichthyomyzon - Chestnut lamprey
castaneus X
Acipenser - Lake Sturgeon
fulvescens X
Polyodon spathula - Paddlefish X
Lepisosteus - Shortnose gar
platostomus
Amia calva - Bowfin X
Hiodon tergisus - Mooneye
Esox lucius - Northern pike X
Esox masquinongy - Muskel lunge
Clinostomus - Redside dace
elongatus
Dionda nubila - Minnow
Exoglossum laurae - Tonguetied minnow
Exoglossum - Cutlips minnow
max ill ingua
Hybopsis amblops - Bigeye chub
Hybopsis dissimilis - Streamline chub
Hybopsis x-punctata - Gravel chub
Nocomis biguttatus - Horneyhead chub X
Noconis micropogon - River chub
Notropis amnis - Pallid shiner
Notropis boops - Bigeye shiner
Notropis cornutus - Common shiner
Notropis emiliae - Pugnose minnow
Notropis heterodon - Blacknose shiner
Notropis heterolepis - Blacknose shiner
Notropis hudsonius - Spottail shiner
Notropis rubellus - Rosyface shiner
Notropis stramineus - Sand shiner
Notropis texanus - Weed shiner
Notropis topeka - Topeka shiner
Notropis volucellus - Mimic shiner
Carpiodes velifer - Highfin carpsucker
Cycleptus elongatus - Blue sucker
Erimyzon obTongus - Creek chubsucker
Erimyzon sucetta - Lake chuhsucker
Hypentelium ni^jricans - Northernhog
sucker
Lagochila lacera - Harelip sucker
Minytrema melanops - Spotted sucker
Moxoxtoma carinatum - River redhorse
Moxostoma duquesnei - Black redhorse
Moxostoma valenciennesi - Greater redhorse
Ictalurus furcatus - Blue Catfish
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Impact
Suspended so
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
through
lids Sediment
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
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TABLF 1: SELECTED MIDWESTERN WARMWATER EISHES WHICH ARE INTOLERANT OF
SUSPENDED SOLIDS (TURBIDITY) AND SFDIMFNT (Cont'd)
Species
Etheostoma - Greenside darter
blennioides
Etheostoma exile - Iowa darter
Etheostoma tippecanoe - Tippe canoe
darter
Etheostoma zonal e - Banded darter
Perca flavescens - Yellow perch
Percina caprodes - Log perch
Percina copelandi - Channel darter
Percina evides - Gilt darter
Percina maculata - Rlackside darter
Percina phoxocephala - Slenderhead
darter
Noturus flavus - Stonecat
Noturus furiosus - Caroline madtom
Noturus gyrinus - Tadpole madtom
Nocturus mTurus - Brindled madtom
Nocturus trautmani - Scioto madtom
Pylodictis olivaris - Flathead catfish
Percopsis - Trout perch
omiscomaycus
Fundulus notatus - Blackstripe
toprninnow
Labidesthes sicculus - Brook silverside
Culaea inconstans - Brook stickleback
Ambloplites rupestris - Rock bass
Lepomis gibbosus - Pumpkin seed
Lepomis megalotus - Longear sunfish
Micropterus dolomieui - Smallmouth bass
Micropterus salmoides - Largemouth bass
Ammocrypta asprella - Crystal darter
Ammocrypta clara - Western sand darter
Ammocrypta pellucida - Eastern sand
darter
Effect
Spawning General
X
X
X
X
X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X X
X
X
X
X
Impact
Suspended so
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
through
lids Sediment
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
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TARLE ?: WARMWATER FISHES WHICH ARE TOLERANT OF SUSPENDED SOLIDS AND SEDIMENT
Species General Preference
tolerance for turbid systems
Scaphirhynchus albus - Pallid sturgeon X
nprpsoma cepedianum - Gizzard shad X
Hiodon alosoides - Goldeye X
Carasslus auratus - Goldfish X
Couesius~pVumbeus - Lake chub X
Cyprinus carpio - Common Carp X
Ericymba buccata - Silverjaw minnow X X
Hybopsis gelida - Sturgeon chub X
Hybopsfs' gracilis - Flathead chub X
Kotropis dorsal is - Bigmouth shiner X
Notropis lutrensi's - Red shiner X
Orthodon micrpTepTdotus - Sacramento blackfish X
Phenacobius mirabilis - Suckermouth minnow X
Phoxinus oreas - Mountain redbelly dace X
Pimephales promelas - Fathead minnow X X
Pimephale? vigil ax - Bullhead minnow X
PlagoptenJs argentissimus - Woundfin X
Semotilus atromaculatus - Creek chub X
Catpstomus commersoni - White sucker X
IctiobusTyprinellus - Bigmouth buffalo X
Moxostom'a erythrurym - Golden redhorse X
Ictalurus catus - White catfish X
Ictalurus melas - Black bullhead X X
Apnredooerus sayanus - Pirate perch X
Lepomis cyanellus - Green sunfish X
Lepomis humilis ~ Orangespotted sunfish X
Lepomis microlophus - Redear sunfish X
Micropterus trecuTi - Guadalupe bass X
Pomoxis annularis - White crappie X
Pomoxis nigromacUlatus - Black crappie X
Etheostoma graclle - Slough darter X
Etheostoma micriperca - Least darter X
EtheostomT mgrum - Johnny darter X
EtheostomT spectahile - Orangethroat darter X
StizosteHT'on canadense - Sauger X
Aplodinotus grunniens - Freshwater drum X
II-2-6
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CHAPTER 11-3.
POOLS, RIFFLES AND SUBSTRATE COMPOSITION
AQUATIC INVERTEBRATES
Many factors regulate the occurrence and distribution of stream-dwelling in-
vertebrates. The most Important of these are current speed, shelter, tempera-
ture, the substratum (including vegetation), and dissolved substances. Other
important factors are liability to drought and to floods, food and competition
between species. Many of these factors are interrelated - current, for
example, largely controls the type of substratum and consequently the amount
and type of food available. Of these, current speed, the substratum, and the
significance of riffle and pool areas will be discussed in greater detail in
the following paragraphs.
Current Speed
Many invertebrates have an inherent need for current, either because they rely
on it for feeding purposes or because their respiratory requirements demand
1t. However, persistently very rapid current may make life intolerable for
almost all species. At the other extreme, stagnant or very slow areas in
rivers which at time flow swiftly are often without much fauna. This is
because silt collects during periods of low discharge, and the conditions
become unsuitable for riverine animals. On the other hand, many common stream
creatures (e.g. flatworras, annelids, crustaceans, and a great number of the
Insects) persist In running water simply because they avoid the current by
living under stones or 1n the dead water behind obstructions. Still other
animals which are poor swimmers and lack attachment mechanisms and therefore
can only scuttle from one shelter to another select areas where the current is
tolerable, and move further out or back into shelter as the flow varies. This
applies to many genera of mayflies and to snails. Other animals actually bur-
row down into the substratum to avoid the current and require only to remain
burled. Many animals, such as the annelids and some Diptera larvae, have this
habit as a birthright; several other groups have acquired this habit, such as
several genera and species of stoneflies and mayflies. Similarly, as the
current changes from place to place in a stream at a given discharge so the
fauna changes.
In conclusion, current speed 1s a factor of major importance in running water.
It controls the occurrence and abundance of species and hence the whole struc-
ture of the animal community.
The Substratum and Its Effect On Aquatic Invertebrates
The substratum is the material (including vegetation) which makes up the
streambed. It is true of many river systems that the further down a river the
smaller the general size of the particles forming the bed. This is partly due
II-3-1
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to the fact that the shear stress on the bottom and hence the power to move
(and break up) particles decreases with Increasing discharge. In streams where
current speeds do not normally exceed about 40 cm/sec a streambed Is likely to
be sand, or even silt at still lower maximum currents of about 20 cm/sec. How-
ever, large amounts of silt occur only in backwaters and shallows or as a
temporary thin sheet over sand during periods of low flow; silt is certainly
not a major component of the substratum in the main channels of the great
majority of even base-level rivers. Where currents frequently exceed about 50
cm/sec on steep slopes the bed is likely to be stony and the animals which
live there must be able to maintain their position.
The substratum is the major factor controlling the occurrence of animals and
there 1s a fairly sharp distinction between the types of fauna found on hard
and on soft streambeds. In general, clean and shifting sand is the poorest
habitat with few specimens of few species. Bedrock, gravel and rubble on the
one hand and clay and mud on the other, especially when mixed with sand, sup-
port increasing biomasses. The fauna of hard substrata has its own typical
character, and it is here that most of the obviously specialized forms occur;
that of the soft substrata is more generally shared with still water, and it
shows much more geographical variety.
The fact that rubble supports more animals than does sand is almost certainly
correlated with the amount of living space (shelter) and with the greater pro-
bability that organic matter will lodge among stones and provide food.
Another factor affecting the occurrence of fauna in the substratum is the
temporary nature of some types of substratum themselves. For example, stony
areas can be alternately covered with silt or sand and then cleared away by
spring floods (spates). Streams that are more liable to spates or other
similar phenomena (which greatly and rapidly alter the faunal density) have
less abundant and less varied faunas than others. An interesting consequence
of this is that small tributaries, being less exposed to the effects of storms
covering limited areas, are richer than the larger streams into which they
flow. Another consequence is that as development increases the intensity of
runoff, the variety and abundance of stream fauna also decreases.
The presence of solid objects also affects the fauna, and the nature of the
solid object affects the animals which colonize it. As shelter is more impor-
tant, some animals prefer irregular stones as opposed to smooth ones. Still
other animals occur only on wood.
Other factors which may account for differences of invertebrate biomass in
streams or reaches of streams are the differences in plant detritus and in
vegetation on the banks, which, of course, supplies food to the biota. Both
the amounts and the nature of the deposits and the vegetation are important.
In any case there are more animals in moss, rooted plants, and filamentous
algae than there are on stones, and all plants are more heavily colonized than
the nonvegetated areas of substratum.
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Finally, the availability of food (whether 1t be organic detritus lodged
amongst stones, vegetation, wood. . . ) 1s an obvious factor controlling the
abundance of species. Generally speaking species occur, or are common, only
where their food is readily available, but 1t should not be forgotten that few
running water invertebrates are very specialized in their diets.
It seems appropriate at this time to restate the three ecological principles
of Thelsemann (Hynes, 1970) which summarize the implications of the foregoing
discussion. They are:
o The greater the diversity of the conditions in a locality the larger 1s
the number of species which make up the blotlc community.
o The more the conditions In a locality deviate from normal and hence
from the normal optima of most species, the smaller is the number of
individuals of each of the species which do occur.
o The longer a locality has been established in the same condition the
richer 1s Its biotlc community and the more stable 1t is.
In conclusion, it can be stated that the fauna of clean, stable, diverse stony
runs 1s richer than that of sllty reaches and pools both in number of species
and total blomass.
As previously discussed, certain species are confined to fairly well-defined
types of substraum, and others are at least more abundant on one type than
they are on others. The result of these preferences is that as the type of sub-
stratum varies from place to place so does the fauna. In general, the larger
the stones, and hence the more complex the substratum, the more diverse is the
invertebrate fauna.
The following groups of Invertebrates almost invariably provide the major con-
stituents of the fauna of stony streams:
o Parazoa
o Cn1dar1a
o Tricladida
o Oligochaeta
o Gastropoda
o Pelecypoda
o Peracarida
o Eurcarida
o Plecoptera
o Odonata
o Ephemeroptera
o Hemiptera
o Megaloptera
o Trichoptera
o Lepidoptera
o Coleoptera
o Diptera
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The fauna of the softer substrata In rivers Is much less evident than that of
the hard substrata. However, there are still many genera of Invertebrates such
as Limnaea, Chlronomus, Tublfex, and L1mnodi"l1us which can be found in rivers
in most continents,Bui the less-rigorous habitat of areas of slower current
which allows less-specialized species to occur also permits the local charac-
ter of the fauna to be dominant.
It is therefore difficult to generalize, but characteristic organisms of soft
riverine substrata are: Tublflcldae, Chironomldae, burrowing mayflies (Ephe-
meridae, Potomanthldae, Polymltarcidae), Prosobranchla, Unionidae, and Sphae-
riidae, and when plants are present a great variety of organisms may be added.
Riffle/Pool Areas
Natural streams tend to have alternating deep and shallow areas - pools and
riffles - especially where there are coarse constituents in the substratum.
Riffles tend to be spaced at more or less regular distances of five to seven
stream widths apart and to be most characteristic of gravel-bed streams. They
do not naturally form 1n sandy streams, since their presence seems to be con-
nected with some degree of heterogeneity of particle size. Riffles are formed
when the larger particles (boulders, stone and gravel) congregate on bars.
The reasons for the regular spacing of riffles is unknown; however, it is
known that riffles do not move, although the stones that compose them may mi-
grate downstream, being replaced by others. Furthermore, it has been estab-
lished that riffles are superficial features with the largest stones in the
upper layer.
Pools tend to be wider and deeper than the average stream course. In contrast
to the broken surface of riffles, the surface of a pool or backwater is
smooth. In pools, the current is reduced, a little siltation may occur, and
aquatic seed plants may form beds. The significance of riffle/pool areas to
the production potential of aquatic invertebrates has been alluded to in the
previous discussions of the current speed and the substratum. One result of
the complex interaction of local factors on faunal density is that in streams
with pool and riffle structure, the fauna is considerably denser on the lat-
ter. Similarly, aquatic invertebrates are most diverse in riffle areas with a
rubble substrate. As a consequence the amount of drift produced by riffles is
greater than that produced by pools.
FISHES
Like the invertebrates, there are many factors which regulate the occurrence
and distribution of running water fishes. The most important of these are the
substratum, food availability, cover, current speed, and the presence of a
suitable spawning habitat. All of these are directly related to the distribu-
tion of pool/riffle areas in a stream, and for most fishes a 1:1 ratio of pool
to riffle run areas Is sufficient for successful propagation and maintenance.
The significance of the substratum (type and amount), and the presence of both
pools and riffle areas will be discussed in greater detail in the following
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paragraphs. Finally, the specific habitat requirements of several fish species
(including black & white crappie, channel catfish, cutthroat trout, creek chub
and bluegill) will be discussed in order to illustrate the importance of the
substratum and the pool/riffle structure and to indicate the similarities and
differences in requirements between species.
The Substratum and Its Effect on Fishes
A few fishes, particularly small benthic species, are more or less confined to
rocky or stony substrata. These include all those with ventral suckers and
friction plates (e.g. some species of darters). Many others are also fairly
definitely associated with a specific type of substratum. For example, the gud-
geon is associated with gravel, the sand darter with sand, and the mudfish
with thick marginal vegetation.
For the great majority of fish species, however, the nature of the substratum
is apparently of little consequence except at times of breeding. Nearly all
species of fish have fairly well-defined breeding habits and requirements. The
great majority of freshwater fishes spawn on a solid surface (such as a flat
area under a large stone) in stoney or gravel substrata. Other species dig
pits in gravel (e.g. the stoneroller) in which the eggs are laid. This re-
quires that the gravel be a suitable size and be relatively free of silt and
sand. Still other species make piles of pebbles (e.g. some chubs and minnows)
through which water passes freely bringing oxygen to the buried eggs. Some
species of trout and Atlantic salmon select places for spawning where there is
a down-flow of water, say at the downstream end of pools, where the water
flows into riffles. In summary, species which construct nests (see Table
11-3-1) or redds are restricted not only in respect of the size of the mate-
rial of the substratum, which they must be able to move, but by the need to be
free of silt; and salmonids, and probably some other fishes, are also restric-
ted to places where there is a natural tntra-gravel flow of water.
On the other hand, there are a great many species (e.g. the whitefish, ster-
let, grayling, etc.) which breed on gravel or stones but build no nests. In
fact, this is probably the most common pattern of breeding among running-water
species. Table II-3-2 is a partial list of fish species (which build no nests)
along with their desired spawning habitat. The fishes which breed in this
manner move onto the clean gravel in swifter and shallower water than is their
normal adult habitat to spawn.
There are also those species which spawn on other substrata besides stones and
gravel, including sand (e.g. the log-perch), mud (e.g. the Murray cod), and
vegetation (e.g. some species of darters and most still-water species).
Finally, there are many riverine species (e.g. grass carp, some perch species)
which lay buoyant or semi-buoyant eggs which float in the water and are
carried downstream while they develop.
In conclusion, it can be seen from the previous discussion that breeding
habitat requirements for fishes can be very restrictive, and consequently, the
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TABLE II-3-1. EXAMPLES OF NEST-BUILDING FISH
Species Type of Nest
Sticklebacks (Gasterosteldae) Nest a circular
Largemouth Bass (Micropterus salmoldes) depression In mud,
Grapples (Pomoxls) silt, or sand and
Rock Basses (AmblopHtes) often in and among
Warmouth (Chaenobryttus) roots of aquatic
Bluegill (Lepomls macrochlrus) flowering plants
Most Bullheads (Ictalurus)
Small mouth Bass (Micropterus dolomieu) Nest a circular
Trouts (Salmo) depression in
Stoneroller (Campostoma anomalum) gravel
Brook Trout (Salvellnus font1nal1s)
Creek Chubs (Semotilus) Nest a pile of
Bluntnose 4 Fathead Minnows (Pimephales) pebbles
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TABLE 11-3-1. EXAMPLES OF FISH THAT DO NOT BUILD NESTS
Species Spawning Habitat
Northern Pike (Esox lucius) Scattering eggs over
Carp (Cyprinus carpio) aquatic plants, or
Goldfish (Carassium auratus) their roots or
Golden Shiner (Notemigonus crysoleucas) remains
Whitefishes (Coregonus) Scattering eggs over
Ciscos (Leucicthys) shoals of sand, gra-
Lake Trout (Salvelinus namaycush) vel, or boulders
Log Perch (Percina caprodes)
Suckers (Catostomus)
Walleyes (Stizosstedion)
Yellow Perch (Perca flavescens) Semi-buoyant or
White Perch (Morone americana) buoyant eggs
Grass Carp (Ctenopharyngodon idellus)
Brook Silverside (Labidesthes sicculus)
Alewife (Alosa pseudoharengus)
Siamese Fighting Fish (Betta)
Bitterling (Rhodeus) Eggs deposited in the
mantle cavity of a
freshwater mussel
Lumpsucker (Careproctus) Eggs deposited
beneath the carapace
of the Kamchatka crab
II-3-7
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suitable breeding sites can be extremely limited. Furthermore, the require-
ments can be extremely varied among species. However, the general breeding
habitat requirements fall into the following categories:
o Build a nest and breed on stone or gravel substrata.
o Breed on stone or gravpl substrata without building a nest.
o Breed on other substrata, including sand, mud, or vegetation.
o Lay buoyant or semi-buoyant drifting eggs and larvae.
Pool Areas
Pool areas in a stream are essential for providing shelter for both resting
and protection from predation. To a lesser extent pools are important as a
spawning habitat and for food production (although food production is lower in
pools than in riffles).
Even the streamlined species that are well adapted to fast-flowing water (e.g.
salmon and trout) need time to rest or seek shelter to avoid predators. As a
matter of fact all fishes spend most of their time resting in shelters in
lower velocity pool areas. Still other species (e.g. channel catfish, particu-
larly adults) reside primarily in pool areas and generally move only to riffle
areas at night to feed.
Therefore, based on the foregoing discussion, one must conclude that the exis-
tence of pools is critical to the well-being of all fish species, since they
provide resting cover and protection from predators.
Riffle/Run Areas
As discussed previously in the section on benthic invertebrates and again in
the section on the substratum and its affect on fishes, it is apparent that
riffle areas are most important due to their food producing capability (i.e.
benthic invertebrates) and their suitability as a fish spawning habitat (i.e.
it is in riffle areas where the silt-free stone or gravel exists and where oxy-
gen to the eggs is constantly being renewed). Without an abundant food supply
and the proper spawning habitat, propagation and maintenance of a fish species
would be impossible.
Species Examples
Bluegill (Lepomis macrochirus)
The bluegill is native from the Lake Champlain and southern Ontario region
through the Great Lakes to Minnesota, and south to northeastern Mexico, the
Gulf States, and the Carolinas.
Bluegills are most abundant in large low velocity (<10 cm/sec preferably)
streams. Abundance has been positively correlated to a high percentage (>60%)
of pool area and negatively correlated to a high percentage of riffle/run
areas.
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Cover in the form of submerged vegetation, logs, brush and other debris is uti-
lized by bluegllls. Excessive vegetation can Influence both feeding ability
and abundance of food by Inhibiting the utilization of prey by bluegills.
Bluegllls are guarding, nest building lithophils. Nests are usually found in
quiet shallow water over almost any substrate; however, fine gravel or sand is
preferred.
In summary, riffles and substrate play a small role in the life cycle of the
bluegill. In fact, excessive riffle/run areas have been negatively correlated
with an abundance of bluegllls. On the other hand, pools are significant as
the typical bluegill habitat for resting, feeding, and spawning.
Creek Chub (Semotilus atromaculatus)
The Creek Chub 1s a widely distributed cyprlnld ranging from the Rocky Moun-
tains to the Atlantic Coast and from the Gulf of Mexico to southern Manitoba
and Quebec. Within its range, it is one of the most characteristic and common
fishes of small, clear streams.
The optimum habitat for creek chubs Is small, clear, cool streams with mode-
rate to high gradients, gravel substrate, well-defined riffles and pools with
abundant food, and cover of cut-banks, roots, aquatic vegetation, brush, and
large rocks. Creek chubs are found over all types of substrate with abundance
correlated more with the amount of instream cover than with the substrate
type. It is assumed that stream reaches with 40-60% pools are optimum for pro-
viding riffle areas for spawning habitat and pools for cover.
Rubble substrate in riffles, abundant aquatic vegetation, and abundant stream-
bank vegetation are conditions associated with high production of food types
consumed by creek chubs.
Spawning occurs in gravel nests constructed by the male in shallow areas just
above and below riffles to insure a good water exchange rate through the creek
chub redds. Reproductive success of creek chubs varies with the type of spawn-
ing substrate available. Production is highest 1n clean gravel substrate in
riffle-run areas with velocities of 20-64 cm/sec. Production is negligible in
sand or silt.
In summary, pools, riffles and substrate are important to the creek chub in
the following manner.
1) Riffles - provide a suitable spawning habitat,
2) Substrate - a clean gravel substrate is required for spawning, and
3) Pools - provide resting cover and abundant food.
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White Crappie (Pomoxis annularis)
The white crappie is native to freshwater lakes and streams from the southern
Great Lakes, west to Nebraska, south to Texas and Alabama, east to North Caro-
lina, then west of the Appalachian Mountains to New York. It has been widely
introduced outside this range throughout North America.
White crappie are most numerous in base-level low gradient rivers preferring
low velocity areas commonly found in pools, overflow areas, and backwaters of
rivers. In these areas, cover is important for providing resting areas and pro-
tection from predation. Cover also provides habitat for insects and small for-
age fish, which are important food for the crappie. In addition, cover is
important during reproduction as the male white crappie constructs and guards
nests over a variety of substrates almost always near vegetation or around sub-
merged objects.
In summary, riffles and substrate composition are for the most part insignifi-
cant to the white crappie. However, pools are important for resting, feeding,
spawning and providing protection from predation.
Channel Catfish (Ictalurus punctatus)
The native range of channel catfish extends from the southern portions of the
Canadian prairie provinces south to the Gulf States, west to the Rocky Moun-
tains, and east to the Appalachian Mountains. They have been widely introduced
outside this range and occur in essentially all of the Pacific and Atlantic
drainages in the 48 contiguous states.
Optimum riverine habitat for the channel catfish is characterized by a diver-
sity of velocities, depths and structural features that provide cover and
food. Low velocity (<15 cm/sec) areas of deep pools and littoral areas and
backwaters of rivers with greater than 40 percent suitable cover are desir-
able. Riffle and run areas with rubble substrate, pools, and areas with debris
and aquatic vegetation are conditions associated with high production of aqua-
tic insects consumed by channel catfish. A riverine habitat with 40-60% pools
would be optimum for providing riffle habitat for food production and feeding
and pool habitat for spawning and resting cover.
Adult channel catfish in rivers are found in large, deep pools with cover.
They move to riffles and runs at night to feed. Catfish fry have strong
shelter-seeking tendencies and cover availability is important in determining
habitat suitability. However, dense aquatic vegetation generally does not pro-
vide optimum cover because predation on fry by centrarchids is high under
these conditions.
Dark and secluded areas are required for nesting. Males build and guard nests
in cavities, burrows, under rocks and in other protected sites.
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In summary, the presence of riffles and pools are equally important to the suc-
cessful propagation of channel catfish, with riffles providing a suitable
habitat for food production and feeding and with pools providing a suitable
habitat for spawning and resting. Additionally, channel catfish appear to be
relatively insensitive to variations in the substrate type.
Cutthroat Trout (Salmo clarki)
Cutthroat trout are a polytypic species consisting of several geographically
distinct forms with a broad distribution and a great amount of genetic diver-
sity.
Optimal cutthroat trout riverine habitat is characterized by clear, cold
water; a silt free rocky substrate 1n riffle-run areas; an approximately 1:1
pool/riffle ratio with areas of slow, deep water; well vegetated stream banks;
abundant instream cover; and relatively stable water flow, temperature regimes
and stream banks. A 1:1 ratio (40-60% pools) of pool to riffle area appears to
provide an optimal mix of trout food producing and rearing areas.
Cover is recognized as one of the essential components of trout streams. Cover
is provided by overhanging vegetation; submerged vegetation, undercut banks
and instream objects. The main use of this cover is predator avoidance and
resting.
Conditions for spawning require a gravel substrate with _< 5% fines. Greater
than 30% fines will result in a low survival rate of embryos. Optimal sub-
strate size averages 1.5 - 6.0 cm 1n diameter; however, gravel size as small
as 0.3 cm in diameter is suitable for incubation.
Black Crappie (Pomoxis nlgromaculatus)
The black crappie is native to freshwater lakes and streams from the Great
Lakes south to the Gulf of Mexico and the southern Atlantic States, north to
North Dakota and eastern Montana and east to the Appalachians.
Black crappie are common in base or low gradient streams of low velocities,
preferring quiet, sluggish rivers with a high percentage of pools, backwaters,
and cut-off areas. Black crappie prefer clear water and grow faster in areas
of low turbidity.
Abundant cover, particularly in the form of aquatic vegetation, is necessary
for growth and reproduction. Common daytime habitat is shallow water in dense
vegetation and around submerged trees, brush or other objects.
Conclusions
In conclusion, a review of the substratum and its effects on benthic inverte-
brates and fishes reveals that the Invertebrates are dependent on a suitable
substrata for growth, successful reproduction, and maintenance, and the fishes
are dependent on a suitable substrata primarily only during breeding. With the
II-3-11
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proper substrata, an adequate supply of benthie invertebrates is available as
food for the fishes.
Similarly, it is the proper balance between pools and riffles (approximately
1:1 ratio) that will insure an abundant food supply for both invertebrates and
fishes, the existence of the proper habitat for reproduction of both inverte-
brates and fishes, and adequate cover for resting and protection from pre-
datlon.
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CHAPTER II-4
CHANNEL CHARACTERISTICS AND
EFFECTS OF CHANNELIZATION
INTRODUCTION
Channelization can be defined as modification of a stream system - including
the stream channel, stream bank, and nearstream riparian areas - in order to
increase the rate of drainage from the land and conveyance of water down-
stream. Simpson et al. (1982) listed the common methods of channelization as:
1. Clearing and Snagging. Removal of obstructions from the streambed and
Banks to increase the capacity of a system to convey water. Such oper-
ations include removal of bedload material, debris, pilings, head walls,
or other mantnade materials.
2. Rip-rapping. Placement of rock or other material in critical areas to
minimize erosion.
3. Widening. Increase of channel width to improve the conveyance of water
and Increase the capacity of the system.
4. Deepening. Excavation of the channel bottom to a lower elevation so as
to increase the capacity to convey water or to promote drainage or lower-
ing of the water table, or to enhance navigation.
5. Realignment. Construction of a new channel or straightening of a channel
to increase the capacity to convey water.
6. LII ni nq. Placement of a nonvegetatlve lining on a portion of a channel to
minimize erosion or increase the capacity of a stream to convey or con-
serve water.
Channelization projects are classified according to their magnitude as either
short-reach or long-reach. Short-reach channelization is associated with road
and bridge construction and may entail 0.5 km of stream length within the vi-
cinity of the crossing. Although short-reach projects may adversely affect
stream biota, they should not produce significant long-term impacts with pro-
per mitigation (Bulkley et al. 1976). The comments in this chapter generally
refer to the effects of long-reach channelization; those impacts are greater
in duration, dimension, and severity. Simpson et al. (1982) listed the pur-
poses of (long-reach) channelization as:
1. Local flood control to prevent damage to homes, industrial areas, and
farms on the flood plain by Increased stream conveyance of water past
the protected areas;
II-4-1
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2. Increase of arable land for agriculture by channel straightening, deep-
ening, and widening to remove meanders, increase channel capacity, and
lower the channel bed. Straightening reduces the stream area and length
of bordering lands, Increases land area at cutoffs, and increases flow
velocity. Deepening and widening increases channel capacity and improves
drainage from adjacent lands;
3. Increased navigability of waterborne commerce and recreational boating,
usually performed in large streams; and
4. Restoration of hydraulic efficiency of streams following unusually se-
vere storms.
In the Interest of such goals, several thousand miles of streams in the United
States have been altered over the past 150 years (Simpson et al. 1982). Mow-
ever, In achieving these goals, detrimental effects are often incurred on
water quality and stream biota. This chapter addresses the effects of channel-
ization on stream characteristics and the associated biological Impacts.
CHARACTERISTICS OF THE STREAM SYSTEM
Stream Depth and Width
The depth and width of a stream are usually made uniform (generally by widen-
ing and deepening) by stream channelization 1n order to increase the hydraulic
efficiency of the system. This practice results 1n a monotony of habitats
throughout the modified reach. Gorman and Karr (1978) demonstrated the direct
relationship that exists between habitat diversity (considering depth, sub-
strate, and velocity) and fish species diversity. Alteration of stream depth
involves the disturbance and removal of natural bottom materials. Increasing
stream depth can lower the water table of the area. Probably the most signi-
ficant impact of depth modification 1s the disruption of the run-riffle-pool
sequence (See Chapter II-3: Pools, Riffles, and Substrate Composition). Wid-
ening a stream increases the surface area and often involves removal of stream-
side vegetation. These practices Increase the amount of light received by the
water column and can lead to changes in the productivity and trophic regime of
the system. Increasing and regularizing stream width also may reduce the pro-
portion of bank/water interface, which constitutes important wildlife habitat.
Stream Length
Stream channelization usually Involves realignment of the stream channel in
order to convey water more quickly out of the modified reach. By straightening
a stream Its overall length is decreased. Channelized streams have been short-
ened an average of 45 percent (ranging from 8 to 95 percent) in Iowa (Bulk ley
1975) and approximately 31 percent in Southcentral Oklahoma (Barclay 1980).
Shortening the linear distance between two points with a constant change in
elevation Increases the slope or gradient of the stream, causing a corre-
sponding increase in current velocity. Reducing the time required for a given
parcel of water to flow through a stream segment may lower the capacity of the
11-4-2
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stream to assimilate wastes and Increase the organic loading on downstream
reaches.
The obvious effect of reducing stream length is the loss of living space.
Stream segments that are isolated by channelization eventually become
eutrophic and fill with sediment (Winger et al. 1976), and their function is
severely impaired. In these eutrophic habitats, normal stream benthos,
especially mayflies, stoneflies, caddisflies, and helIgramites, are replaced
by tolerant chironomlds and oligochaetes (Hynes 1970).
In addition to the loss of total living space, the amount of valuable edge
habitat is decreased by stream straightening. Fish are habitat specialists
(Karr and Schlosser 1977) and are not found uniformly distributed throughout
the water column. Most fish and macroinvertebrate species utilize cover in
lotic systems, much of which Is associated with the sloping stream bank.
Channel Configuration
A stream is straightened by cutting a linear channel that eliminates natural
bends (meanders) from the main course of flow. Sinuosity is a measure of the
degree of meandering by a stream and is measured as the ratio of channel
length to linear length or down-valley distance (Leopold et al. 1964). Sinu-
osity index values may range from 1.0 for a straight conduit to as high as 3.5
for mature, winding rivers (Simpson et al. 1982). A high gradient mountain
stream may have a sinuosity Index of 1.1, while a value of 1.5 or greater jus-
tifies designation as a meandering stream (Leopold et al. 1964).
Channelization (straightening) decreases sinuosity. Reducing sinuosity de-
creases the total amount of habitat available to biota as well as the amount
of effective and unique habitat. Zimmer and Bachman (1976, 1978) found that
habitat diversity was directly related to the degree of meandering in natural
and channelized streams in Iowa, and that as sinuosity increased the biomass
and number of organisms in the macroinvertebrate drift increased. Drift of ben-
thic invertebrates is a major food source of fish.
The S-shaped meanders commonly observed in streams serve as a natural system
of dissipating the kinetic energy produced by water moving downstream (Leopold
and Langbein 1966). When a stream is straightened the energy is expended more
rapidly, resulting in increased scour during high-flow periods.
Bedform
Bedform, or vertical sinuosity, is a measure of riffle-pool periodicity and is
expressed in terms of the average distance between pools measured in average
stream widths for the section (Leopold et al. 1964). Leopold et al. (1964) re-
ported that natural streams have a riffle-pool periodicity of five to seven
stream widths. This is variable, however, and is dependent on gradient and
geology (as is horizontal sinuosity). Channelization eliminates or reduces
II-4-3
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riffle-pool periodicity (Muggins and Moss 1975, Lund 1976, Winger et al. 1976,
Bulkley et al. 1976. Griswold et al. 1978).
Disruption of the run-riffle-pool sequence has detrioental consequences on mac-
rolnvertebrate and fish populations. Creating a homogeneous bedform drasti-
cally reduces habitat diversity and leads to shifts in species composition.
Griswold et al. (1978) concluded that riffle species (heptageniids, hydro-
sychid, elmlds) in macroinvertebrate communities are replaced by slow water
forms (chironomids and tubifictds) after channelization of warmwater streams.
Riffles are commonly considered to be the most productive areas in the stream
in terms of macroinvertebrate density and diversity. Also, the benthic fauna
adapted to riffles are highly desirable fish food species. Pools can support
an abundant benthic fauna, but pool-adapted forms are not as heavily utilized
by fish. Habitat diversity provided by the run-riffle-pool sequence also con-
tributes greatly to species richness in the fish community.
Velocity and Discharge
Stream velocity is a function of stream gradient and channel roughness. Rough-
ness Is a measure of the Irregularity 1n a drainage channel, which will reduce
water velocity, and is affected by sinuosity, substrate size, instream vege-
tation, and other obstructions (Karr and Schlosser 1977).
Discharge or flow (Q) is the volume of water moving past a location per unit
time, and is related to velocity as follows:
Q « VA
where Q * discharge (ft /s)
V » velocity (ft/s) ~
A « cross-sectional area (ft ).
By increasing the slope and reducing roughness, channelization often increases
water velocity (King and Carlander 1976, Simpson et al. 1982); however, if the
cross-sectional area of the channel is sufficiently enlarged by widening and
deepening, the average velocity may be unchanged or decrease (Bulkley et al.
1976, Griswold et al. 1978). In either case, the velocity is usually made uni-
form by channelization.
The concept of unit stream power has been developed to predict the rate of sed-
iment transfer in streams. Unit stream power (USP) is defined as the rate of
potential energy expenditure per unit weight of water in a channel (Karr and
Schlosser 1977) and can be calculated by the following equation (Yang 1972):
dY dX dY
II-4-4
-------
where t a time (s)
V * average stream velocity (ft/s)
S * slope or gradient of the channel ' ft/100 ft)
Y = elevation above a given point and is equivalent to the potential
energy per unit weight of water (I.e., foot-pounds of energy per
pound of water)
X * longitudinal distance
USP » unit stream power, (foot-pounds of energy per pound of water per
second)
The USP is a measure of the amount of energy available for sediment transport;
however, a stream may carry less than the maximum load depending on the avail-
ability of sediment due to such factors as bank stability, substrate sta-
bility, vegetative cover, and surface erosion.
The effect of channelization on discharge is seasonally variable. During rainy
periods a natural stream tends to overflow its banks, Inundating adjacent low-
lying areas. This flood water is temporarily stored and slowly percolates to
the water table. Natural storage dampens runoff surges. Also, the roughness of
natural streams slows conveyance, lengthening the time of energy dissipation.
A variety of channelization practices designed to increase drainage and hydrau-
lic efficiency (e.g., straightening, removal of channel obstructions, removal
of instream and streamside vegetation, berming and leveeing) result in a sharp-
er flow hydrograph and a shorter flow period following rainfall events (Huish
and Pardue 1978). The hypothetical hydrographs shown in Figure 11-4-1 illus-
trate the hydrologic/hydraullc effects of channelization. Channelization is
designed to rapidly convey water off the land and downstream through the con-
duit. Properly-functioning channelized streams amplify the impact of high
flows. Increased flow velocity, discharge, and unit stream power result in ac-
centuated scour, erosion, bank cutting, sediment transport, and hydraulic
loading (flooding); especially below channelized segments. Because of in-
creased hydraulic efficiency, channelized streams return to base flow levels
following rainfall more rapidly than natural streams (see Figure II-4-1), and
can reduce water availability by lowering the water table. Griswold et al.
(1978) concluded that 1n small, well-drained, agricultural watersheds channel
alterations can lead to complete dewatering of long sections of the stream bed
during drought conditions. Simpson et al. (1982) summarized the seasonal im-
pacts of channelization as causing lower than natural base flows and higher
than normal high flows.
Instream vegetation can be reduced, eliminated, or prevented from reestablish-
ment by high stream velocity.
Current velocity has been cited as one of the most significant factors in de-
termining the composition of stream benthic communities (Cummins 1975). Hynes
(1970) suggested that many macrolnvertebrates are associated with specific vel-
ocities because of their method of feeding and respiration. Macrolnvertebrate
II-4-5
-------
Time
NATURAL STREAM
natural stream
i ime
CHANNELIZED STREAM
Figure 11-4-1.
Generalized hydrographs of natural and channelized strears
following a rainfall event or season (modified from Simpson
et al. 1982).
II-4-6
-------
drift has been found to Increase as discharge decreases (Mlnshall and Winger
1968) and as velocity increases (Walton 1977, Zimmer 1977).
By altering stream velocity, discharge, and unit stream power, channelization
modifies the natural substrate. Disruption of the streambed may produce shift-
ing substrates that are unstable habitats for macroinvertebrates. Scour and
erosion due to high velocity Increases stream turbidity and leads to siltation
of downstream reaches. High turbidity can damage macrolnvertebrate populations
via abrasive action on fragile species (Hynes 1970) and clogging the gills of
species without protective coverings (Cairns et al. 1971).
High turbidity and velocity in conjunction with a lack of cover is detrimental
to fish. Usually, a very high concentration of sediment is required to direct-
ly kill adult fish by clogging the opercular cavity and gill filaments (Wallen
1951), but detrimental behavioral effects occur at much lower levels (Swenson
et al. 1976). Turbid waters can also hinder the capture of prey by sight-
feeders. An obvious impact of channelization is the loss of habitat due to re-
duced flow and desslcatlon during drought conditions. Productive riffle areas
can be exposed by low flows, thereby directly affecting the benthos and reduc-
ing the food supply of fish. Low dissolved oxygen levels during summer low
flows can eliminate macroinvertebrates with high oxygen requirements (Hynes
1970), and can affect emergence (Nebeker 1971), drift (Lavandier and Caplancef
1975), and feeding and growth (Cummins 1974).The effects of reduced flow on
fish include a degraded food source, and interference with spawning. Concen-
trating fish into a greatly reduced volume can lead to increased competition,
predation, and disease.
Bulkley et al. (1976) found that gradient was a major factor affecting the dis-
tribution of fishes. Thus, modifications 1n gradient by channelization can
drastically alter the species composition of a fish community.
Substrate
The stream substrate is ultimately a product of climatic conditions and the
underlying geology of the watershed. It is specifically affected by factors
such as gradient, weathering, erosion, sedimentation, biological activity, and
land use. Channelization generally alters the substrate characteristics of a
stream; more often than not, average substrate particle size is reduced
(Etnier 1972, King 1973, Griswold et al. 1978).
The substrate of a stream is one of the most important factors controlling the
distribution and abundance of aquatic macroinvertebrates (Cummins and Lauff
1969, Minshall and Mlnshall 1977, Williams and Mundie 1978), and therefore,
the Impact of channelization on benthlc communities is directly related to the
degree to which the substrate 1s affected. Siltation is especially detrimental
to the benthos and can cause the following Impacts:
11-4-7
-------
1. Decreased habitat diversity due to filling of interstitial spaces
{Simpson et al. 1982)
2. Decreased standing crop (Tebo 1955)
3. Decreased density (Gammon 1970)
4. Decreased number of taxa (Simpson et al. 1982)
5. Decreased reproductive success by affecting eggs (Chutter 1969)
6. Decreased productivity (King and Ball 1967)
7. Species shifts from valuable species to burrowing insects and oligo-
chaetes (Morris et al. 1968)
Generally, the impact of channelization via substrate disruption is more sign-
ificant in high gradient headwater streams (where coarse substrates are essen-
tial for protection from a strong current) than in low gradient warmwater
streams. Little or no change in benthic communities has been observed in the
latter stream type following channelization (Wolf et al. 1972, King and
Carlander 1975, Possardt 1976), at least partially because the natural sub-
strate of these ecosystems was not drastically altered by channelization.
Shifting substrates are often a consequence of channelizing streams. The ab-
sence of a stable habitat leads to reductions in macroinvertebrate populations
(Arner et al. 1976). In some streams where channelization has not permanently
disturbed the substrate, rapid recoveries (within one year) in the benthic com-
munity have been observed (Meehan 1971, Possardt et al. 1976, King and
Carlander 1976, Whitaker et al. 1979); however, recovery of macrobenthos can
be very slow (Arner et al. 1976).
Changes in macroinvertebrate populations affect the fish community through the
food chain. Substrate composition is also important to fish reproduction. For
example: trout and salmon require a specific size of gravel in which to build
redds and spawn; pikes broadcast eggs over aquatic vegetation which requires
silt and mud to grow; sculpins require a slate-type substrate under which they
deposit adhesive eggs; and catfish prefer natural cavities for reproduction
(Pflieger 1975). Siltation can decrease reproductive success by smothering or
suffocating eggs. Channelization can also affect fish adversely by reducing
substrate heterogeneity, thereby decreasing habitat diversity.
Cover
Cover is anything that provides real or behavioral protection for an organism.
It can allow escape from predators, alleviate the need to expend energy to
maintain a position in the current, or provide a place to hide from potential
prey or to just be out of sight. Cover includes rocks, logs, brush, instream
and overhanging vegetation, snags, roots, undercut banks, crevices, inter-
stices, riffles, backwaters, pools, and shadows. Channelization generally de-
creases the amount of cover in a stream. Practices such as modification of the
11-4-8
-------
streambed (usually into a uniform trapezoidal shape), snagging and clearing,
and vegetation removal decrease the total amount and variety of cover, and re-
duce habitat diversity.
Cover such as logs, stumps, and snags provide valuable stable substrate for
macroinvertebrates - especially in streams with a shifting substratum. In-
stream vegetation serves macroinvertebrates as a substrate for attachment,
emergence, and egg deposition. Instream obstructions accumulate leaves, twigs,
and other detritus. This coarse particulate organic matter (CPOM) is used as a
food source by detritivorous invertebrates (shredders). Retention of CPOM re-
duces the organic loading on downstream reaches (Marzolf 1978).
Both fish and aquatic macroinvertebrates use cover for predator avoidance,
resting, and concealment. Simpson et al. (1982) stated that cover can be re-
garded as a behavioral habitat requirement for many fish species, and that re-
moval of cover adversely affects fish populations.
Inundation and Desiccation
The modified hydroperiod typical of channelized streams (illustrated in Figure
II-4-1) often causes downstream reaches to flood more frequently and more in-
tensely, altering floodplain soils and vegetation, and damaging land values
and personal property.
By augmenting land drainage and hydraulic efficiency, channelization has also
led to summer drying of streams and desiccation of adjacent and upstream land
areas. Nearstream riparian areas provide a number of valuable functions which
are often disrupted by channelization. Wetlands assimilate nutrients and trap
sediment from runoff and stream overflow, thereby acting as natural puri-
fication systems (Karr and Schlosser 1977, Brown et al. 1979). Rapid convey-
ance and accumulation of nutrients has led to eutrophication problems down-
stream (Montalbano et al. 1979). Natural fertilization of the floodplain is
prevented by restricting flow to the channel. In natural systems, detritus
entering the stream from backwaters constitutes an important food source for
benthic invertebrates (Wharton and Brinson 1977). Likewise, riparian areas are
often rich sources of macroinvertebrates (Wharton and Brinson 1977) that can
become available to stream fish during floods or serve as an epicenter for re-
populating stream benthos. Some fish (e.g., Esocidae, the pike family) use
swampy areas that are seasonally connected to a stream as spawning and nursery
habitat. Loss of wetlands due to dewatering precludes these functions.
When wetland areas are drained they become available for other types of land
use such as agriculture or development. Conversion of wetlands to pastures and
cropland has frequently occurred following channelization. Relative to wet-
lands, agricultural land uses accentuate runoff, sedimentation, nutrient en-
richment (from fertilizers and animal waste), and toxicant leaching (from
pesticides).
The response of the benthic community to nutrient enrichment (i.e., from agri-
cultural runoff) generally involves the demise of intolerant, "clean-water"
11-4-9
-------
taxa and an Increase 1n numbers and blomass of forms that are tolerant of or-
ganic pollution and low dissolved oxygen; a decrease in species diversity of-
ten occurs as well.
Land use changes can Increase the load of toxic chemicals reaching the stream.
Agricultural and urban runoff contribute a variety of toxicants. Saltwater in-
trusion may become a problem following drainage of coastal wetlands. (Although
sodium chloride Is generally not considered a toxic chemical 1t can be lethal
to freshwater organisms.) Potential impacts include lethal and chronic ef-
fects, blomagnification (via bioaccumulation and bioconcentration), and contam-
ination of human food and recreational resources.
The Impact of draining and dewaterlng riparian areas on terrestrial organisms
Is extensive. Vegetation (Including bottomland hardwoods) tends to undergo a
shift from water-tolerant to water-intolerant forms (i.e., hydric > mesic >
xerlc) (FredMckson 1979, Mak1 et al. 1980, Barclay 1980). These vegetative
changes along with land use changes and land drainage commonly cause the fol-
lowing Impacts on terrestrial fauna:
loss of habitat
loss of cover
loss of food sources
species composition changes
reduced diversity, density, and productivity
increased susceptibility to predation
increased exposure to toxic chemicals.
Streamside Vegetation
Channelization may Impact streamslde vegetation Indirectly through changes in
drainage as described above or directly by the clearing of stream banks and
the deposition of dredge spoils. Clearing, dredging, and spoil deposition typi-
cally result in reduced species diversity and vertical and horizontal struc-
tural diversity of streamslde vegetation. Tree removal is performed in many
channelization projects (FredMckson 1979, Barclay 1980). Removal of woody spe-
cies eliminates wildlife habitat, mast production, canopy cover, and shade.
Other detrimental Impacts of channelization on vegetation include dieback, sun-
scald, undercutting, and windthrow (Simpson et al. 1982). Spoils deposited on
the streambank from channel cutting, dredging, and bermlng generally make in-
fertile, sandy soils that are easily eroded. Subsequent channel maintenance
procedures hinder ecological succession and delay recovery of the stream sys-
tem.
Interception of rainfall by the vegetative canopy lessens the impact of rain-
drops on the soil, and bank stability is enhanced by the binding of soil by
plant roots. Loss of these functions permits the rate of erosion and the
stream sediment load to Increase.
II-4-10
-------
Remova'. of vegetation that shades the stream increases the intensity of sun-
light reaching the water column. A resultant increase in the rate of photo-
synthesis causes changes in the natural pathways of energy flow and nutrient
cycling (i.e., trophic structure). Increased primary production can lead to
amplification of the diurnal variation in pH and dissolved oxygen concen-
tration following channelization (O'Rear 1975, Huish and Pardue 1978, Parrish
et al. 1978). Increasing the incident sunlight raises water temperature. High-
er temperatures increase the rates of chemical reactions and biological pro-
cesses, decrease oxygen solubility, and can exceed the physiological tolerance
limits of some macroinvertebrates and fish - most notably trout (Schmal and
Sanders 1978, Parrish et al. 1978).
In natural stream systems, allochthonous input of organic matter from stream-
side vegetation constitutes the major energy source in low-order streams
(Cummins 1974). A functional group of benthic organisms called shredders uses
allochthonously-derlved detritus (CPOM) as a food source, and process it into
fine particulate organic matter (FPOM) which is utilized by another functional
group, the collectors. Removing streamside vegetation greatly reduces the in-
put of allochthonous detritus and allows primary productivity to increase be-
cause of greater light availability. These factors bring about a decline in
shredder populations and an increase in herbivorous grazers which take advan-
tage of increasing algae abundance. In headwater areas, species diversity is
likely to decrease due to the loss of detritivorous taxa, and macroinver-
tebrate density may decline because the swift current of those reaches is not
conducive to planktonic and some periphytic algae forms. Loss of allochthonous
material has less impact on intermediate-order streams because they are natu-
rally autotrophic (P/R>1), except that channelization of upstream reaches re-
duces the amount of FPOM that is received via nutrient spiraling. The liter-
ature contains excellent discussions of energy and materials transport in
streams (Cummins et al. 1973, Cummins 1974, Cummins 1975, Marzolf 1978, Van-
note et al. 1980).
Reductions and changes in the macroinvertebrate community affect the food
source of fishes. Changing availabilities of detritus and algae may skew the
fish community with respect to trophic levels that utilize those energy
sources. Clearing away nearstream vegetation also reduces the input of terres-
trial insects that are eaten by fish.
In addition, streamside vegetation provides cover in the form of shadows, root
masses, limbs, and trees which fall into the stream. Most game fish species
prefer shaded habitats near the streambank.
SUMMARY
The benefits realized by channelizing a stream are often obtained at the ex-
pense of such impacts as:
II-4-11
-------
1. Increased downstream flooding
2. Reduction of groundwater levels and stream dewatering
3. Increased bank erosion, turbidity, and sedimentation
4. Degradation of water quality
5. Promotion of wetland drainage and woodland destruction
6. Promotion of land development (agricultural, urban, residential,
industrial)
7. Loss of habitat and reduced habitat diversity
8. Adverse effects on aquatic and terrestrial communities (productivity,
diversity, species composition)
9 Lowered recreational values
The time required for a natural stream to return to a productive, visually-
appealing body of water is highly variable. Natural recovery of some channel-
ized streams requires better than 30 years. Restoration of the stream channel
and biota can be accelerated by mitigation practices.
The potential negative Impacts and time frame of recovery should weigh heavily
in the evaluation of any newly-proposed channelization project.
II-4-12
-------
CHAPTER 11-5
TEMPERATURE
Temperature exerts an Important Influence on the chemical and biological
processes in a water body. It determines the distribution of aquatic species;
controls spawning and hatching; regulates activity; and stimulates or
suppresses growth and development. The two most important causes of temper-
ature change in a water body are process and cooling water discharges, and
solar radiation. The consequences of temperature variation caused by thermal
discharges (thermal pollution) continue to receive considerable attention. An
excellent review on this subject may be found in the Thermal Effects section
of the annual literature review issue of the Journal of the Water Pollution
Control Federation. Discussion in this chapter is limited to the influence of
seasonal temperature variation on a water body.
PHYSICAL EFFECTS
Annual climatological cycles and precipitation patterns are controlled by the
annual cycle of solar radiation. Specific patterns of temperature and precipi-
tation, which vary geographically, determine annual patterns of flow to lakes
and streams. In general, winter precipitation in northern latitudes does not
reach a body of water until the spring snow melt. For this reason, streamflow
may be quite low in the winter but increase rapidly in the spring. Low flow
typically occurs in the summer throughout North America.
Changes in season cause changes in water temperature in lakes and streams. The
patterns of temperature change 1n lakes are well understood. Briefly, many
lakes tend to stratify in the summer, with a warm upper layer (the
epilimnion), a cold bottom layer (the hypolimnion) and a sharp temperature
difference between the two, known as the thermocline. The depth of the
thermocline is determined to large extent by the depth to which solar radia-
tion penetrates the water body. The epiHmnion tends to be well oxygenated,
through both algal photosynthesis, and through oxygen transfer from the atmo-
sphere. Surface wind shear forces help mix the epilimnion and keep it oxygen-
ated. The thermocline presents a physical barrier, in a sense, to mixing be-
tween the epilimnlon and the hypollmnion. If no photosynthesis takes place in
the hypollmnion, due to diminished solar radiation, and 1f there is no ex-
change with the epilimnion, dissolved oxygen levels (00) in the bottom layer
may drop to critical levels, or below. Often water released through the bottom
of a dam has no dissolved oxygen, and may severely jeopardize aquatic life
downstream of the impoundment.
Typical summer and annual lake temperature profiles are presented in Figures
II-5-1 and II-5-2, respectively. In the fall the thermocline disappears and
the lake undergoes turnover and becomes well mixed. The temperature becomes
fairly homogeneous in the winter (Figure 11-5-2), there is another wind in-
duced turnover in the spring and the cycle ends with the development of epi-
limnion, hypolimnion and thermocline in the summer.
II-5-1
-------
8 to 1? 14 16 18 20 22
Figure 11-5-1. Summer Temperature Conditions in a Typical
(Hypothetical) Temperate-Region Lake.
%!ARCH APRIL I MAY : JUN"! ' «ILY AUG. SEPT ' OCT. • NOV.
Figure 11-5-2. The Seasonal Cycle of Temperature and Oxygen
Conditions in Lake Mendota, Wisconsin, 1906,
(Reid and Wood).
II-5-Z
-------
Rivers and streams generally show a much more homogeneous temperature profile,
largely because turbulent stream flow assures good vertical mixing. Neverthe-
less, small streams may undergo temperature variation as flow passes through
shaded or sunny areas, as 1t is augmented by cool groundwater or warm agri-
cultural or other surface return flow, or as it becomes more turbid and cap-
tures solar radiation in the form of heat.
TEMPERATURE RELATED BIOLOGICAL EFFECTS
Warm blooded homeothermic animals, such as the mammals, have evolved a number
of methods by which to control body temperature. Cold blooded poikilothermic
animals, such as fish, have not evolved these mechanisms and are much more sus-
ceptible to variation in temperature than are warm blooded animals. Perhaps
the most important adaptation of fish to temperature variation is seen in the
timing of reproductive behavior.
Gradual seasonal changes in water temperature often trigger spawning, metamor-
phosis and migration. The eggs of some freshwater organisms must be chilled
before they will hatch properly. The tolerable temperature range for fish is
often more restrictive during the reproductive period than at other times dur-
ing maturity. The temperature range tolerated by many species may be narrow
during very early development but increases somewhat during maturity. Reproduc-
tion may be hindered significantly by increased temperature because this func-
tion takes place under restricted temperature ranges. Spawning may not occur
at all when temperatures are too high. Thus, a fish population may exist in a
heated area only because of continued immigration.
Because fish are cold-blooded, temperature is important in determining their
standard metabolic rate. As temperature increases, all standard metabolic func-
tions increase, including feeding rates. Water temperature need not reach
lethal levels to eliminate a species. Temperatures that favor competitors, pre-
dators, parasites and disease can destroy a species at levels far below those
that are lethal.
Since body temperature regulation is not possible in fish, any changes in am-
bient temperature are immediately communicated to blood circulating in the
gills and thereby to the rest of the fish. The increase in temperature causes
an increase in metabolic rates and the feeding activity of the fish must in-
crease to satisfy the requirements of these elevated levels. Elevated bio-
chemical rates facilitate the transport of toxic pollutants to the circulatory
system via the gill structure, and hasten the effect these toxicants might ex-
ert on the fish. Increased temperature will also raise the rate at which detox-
ification takes place through metabolic assimilation, or excretion. Despite
these mechanisms of detoxification, a rise in temperature increases the lethal
effect of compounds toxic to fish. A literature review on this subject will
also be found in the JWPCF annual literature review number.
The importance of temperature to fish may also be seen in Tables 11-5-1 and
II-5-2. The data in these tables were found in references by Carlander (1969,
1972) and Brungs and Jones (1977). Table II-5-1 shows the preferred tempera-
ture for a number of fish and Table 11-5-2 shows the range of temperatures
within which spawning may occur in several species of fish.
II-5-3
-------
Preferred temperatures usually are determined through controlled laboratory
experiments although some values published in the literature are based on
field observations. Determination of final temperature preferenda of fish in
the field is difficult because field environments cannot be controlled to
match laboratory studies (Cherry and Cairns, 1982). Temperature preference
studies are based on an acclimation temperature which is used as a reference
point against which to examine the response of fish to different temperature
levels. The acclimation temperature itself is critical for it affects the
range of temperatures within which fish prefer to live. This may be seen in
Figure II-5-3 which shows an .increase in preferred temperature and in the
upper threshold of avoidance with an increase in acclimation temperature. The
range between the acclimation and the upper avoidance temperatures is species
specific and is dependent on the acclimation temperature in which the fish
were tested. A greater variability in fish avoidance response is observed in
winter than in summer testing conditions (Cherry and Cairns, 1982).
Temperature preference/avoidance studies are important to an understanding of
the effect of thermal pollution on the biota of a water body. The literature
on temperature preference will be important to the water body survey in two
ways: when the stream reach of interest is affected by thermal pollution or
when ambient temperature patterns may be a contributing factor which deter-
mines the types of fish that might be expected to inhabit a water body under
different management schemes identified during the assessment.
Temperature is also important because it strongly influences self-purification
in streams. When a rise in temperature occurs in a stream polluted by organic
matter, an increased rate of utilization of dissolved oxygen by biochemical
processes is accompanied by a reduced availability of 00 due to the reduced
solubility of gases at higher temperatures. Because of this, many rivers which
have adequate DO in the winter may be devoid of DO in the summer.
Bacteria and other microorganisms which mediate the breakdown of organic mat-
ter in streams are strongly influenced by temperature changes and are more ac-
tive at higher than at lower temperatures. The rate of oxidation of organic
matter is therefore much greater during the summer than during the winter.
This means self purification will be more rapid, and the stream will recover
from the effects of organic pollution in a shorter distance during the warmer
months of the year than in the colder months of the year, provided there is an
adequate supply of dissolved oxygen.
Temperature is an important regulator of natural conditions. It has a profound
effect on habitat properties in lakes and streams; on the solubility of gases
such as oxygen, upon which most aquatic life is dependent; on the toxicity of
pollutants; on the rate and extent of chemical and biochemical reactions; and
on the life cycle of poikilothermlc aquatic life in general. Since in the con-
text of the water body survey uses are framed in reference to the presence and
11-5-4
-------
UJ
-------
the protection of aquatic life, those factors which support or jeopardize
aquatic life must be considered.
Perhaps the most critical element in the aquatic environment is dissolved oxy-
gen, whose solubility is a function of temperature. Oxygen is added to an aqua-
tic system by photosynthesis and by transfer from tfe atmosphere. Unfortu-
nately, the availability of dissolved oxygen is apt to be greatest when the
requirement for 00 is least, i.e., in the winter when metabolic activity has
been substantially reduced. Conversely, the availability may be lowest when
the demand 1s greatest.
Consideration of the relationship of temperature and availability of dissolved
oxygen is important to the water body survey, and will require a close examina-
tion of natural seasonal variation in 00 and its interaction with treatment
process efficiency, with the oxygen demand of the CBOO and NBOO in waste-
waters, and with the seasonal requirements of aquatic life.
II-5-6
-------
TABLE 11-5-1. PREFERRED TEMPERATURE OF SOME FISH SPECIES.
Preferred
Species
Common name Latin name
Life Acclimation
Stage Temperature,°C
Temperature, °C
Alewife
Threadfin shad
Sockeye salmon
Pink salmon
Chum salmon
Chinook salmon
Coho salmon
Cisco
Lake whitefish
Cutthroat trout
Rainbow trout
Atlantic salmon
Brown trout
Brook trout
Lake trout
Rainbow smelt
Alosa pseudoharengus
Dorosoma petenense
Oncorhynchus nerka
0. gorbuscha
0. keta
0. tshawytscha
0. Kisutch
Coregonus artedii
C. clupeaformis
Sal mo clarki
S. gairdneri
S. salar
S. trutta
Salvelinus fontinalis
Salvelinus namaycush
Osmerus mordax
J 18
J 21
A 24
A 31
A
J
A
J
J
J
J
A
A
A
A
J not given
J 18
J 24
A
A
A
J 6
J 24
A
J
A
20
22
23
23
>19
12-14
10-15
12-14
12-14
12-14
12-14
13
13
13
9-12
14
18
22
13
14-16
12-18
12
19
14-18
8-15
6-14
Grass pickerel
Esox americanus
vermiculatus
J,A
24-26
II-5-7
-------
TABLE II-5-1. PREFERRED TEMPERATURE OF SOME FISH SPECIES. (Continued)
Species L
Common name
Mustcel lunge
Common carp
Emerald shiner
White sucker
Buffalo
Brown bullhead
Channel catfish
White perch
White bass
Striped bass
Rock bass
Green sunfish
1fe
Acclimation
Latin name Stage Temperature,°C
Esox masquinongy
Cyprinus carpio
Notropis atherinoides
Catostomus commersoni
Ictiobus sp.
Ictalurus nebulosus
Ictalurus punctatus
Morone americana
M. chrysops
M. saxatilis
Ambloplites rupestris
Lepomis cyanellus
J
J
J
J
J
J
A
J
A
A
J
J
J
A
J
A
0
J
J
0
A
J
J
J
J
A
J
J
J
J
J
10
15
20
25
35
Summer
Summer
18
23
26
22-29
6
15
20
26-30
Summer
5
14
21
28
6
12
18
24
30
Preferred
Temperature,°C
26
17
25
27
31
32
33-35
25
19-21
31-34
21
27
31
29-31
35
30-32
10
20
25
31-32
28-30
12
22
26
28
26-30
16
21
25
30
31
II-5-8
-------
TABLE II-5-1. PREFERRED TEMPERATURE OF SOME FISH SPECIES. (Continued)
Species Life Acclimation Preferred
Common name Latin name Stage Temperature,°C Temperature,°C
Pumpkinseed
Bluegill
Small mouth bass
Spotted bass
Largemouth bass
White crappie
Black crappie
Yellow perch
Sauger
Walleye
Freshwater drum
L. gibbosus
L. machrochirus
Micropterus dolomieui
M. punctulatus
M. salmoides
Pomoxis annul aris
P. nigromaculatus
Perca flavescens
Stizostedion canadense
S. vitreum
Aplodinotus grunniens
J
J
J
J
A
J
J
J
J
J
J
J
J
J
J
J
J
J
J
J
J
J
J
A
J
A
J,A
A
J.A
A
8
19
24
26
6
12
18
24
30
15
18
24
30
6
12
18
24
30
5
24
27
10
21
31
33
31-31
19
24
29
31
32
20
23
30
31
17
20
27
30
32
26-32
10
26
28
28-29
27-29
24-31
19-24
18-28
20-25
29-31
II-5-9
-------
TABLE 11-5-2. SPAWNING TEMPERATURE OF SOME FISH SPECIES,
Species
Common name Latin name
Spawning temperature,°C
approximate
value or optimum
range or peak
Lamprey
Northern brook
Southern brook
Allegheny brook
Mountain brook
Silver
Least brook
Arctic
American brook
Western brook
Pacific
Sea
Sturgeon
Ichthyomyzon fosser
Ichthyomyzon gagei
Ichthyomyzon greeleyi
Ichthyomyzon hubbsi
Ichthyomyzon unlcuspis
Ichthyomyzon aepyptera
Lampetra japonlca
Lampetra lamottei
Lampetra richardsoni
Lampetra tridentata
Petromyzon marinus
Short nose
Lake
Atlantic
White
Acipenser brevi rostrum
Adpenser fulvenscens
Acipenser oxyrhynchus
Acipenser transmontanus
Paddlefish
Gar
Longnose
Short nose
Bowfin
Polydon spathula
Lepisosteus osseus
Lepisosteus platostomus
Ami a calva
Blueback herring Alosa aestivalis
Shad
Alabama Alosa alabamae
Hickory Alosa medlocris
Alewife Alosa pseudoharengus
American Alosa sapidissima
Gizzard Dorosoma cepedium
Threadfin Dorosoma petenense
13-77
15
19
10-12
10-16
12-15
8-20
>8
11-24
8-12
12-19
13-18
9-17
16
19-24
16-19
14-27
19-22
18-21
13-28
11-19
17-29
14-23
17
9-11
21
Spawning
season
month
May-Jun
Mar-May
May
Mar-Apr
Apr-Jun
Mar-May
May-Jul
Apr-Jun
Mar-Jun
Apr
Apr-Jul
Apr-Jun
Apr-Jun
Feb-Jul
May-Jul
May-Jun
Mar-Aug
May-Jul
Apr-Jul
Apr-Jul
Jan-Jul
May-Jun
Apr-Aug
Jan-Jul
Mar-Aug
Apr-Aug
II-5-10
-------
TABLE 11-5-2. SPAWNING TEMPERATURE OF SOME FISH SPECIES. (Continued)
Spawning temperature,°C
approximate Spawning
Species value or
Common name
Salmon
Pink
Sock eye
(Kokanee)
Coho
Whitefish
Cisco
Lake
Bloater
Alaska
Least Cisco
Kiyi
Shortnose cisco
Pygmy
Round
Mountain
Trout
Golden
Arizona
Cutthroat
Rainbow
Gila
Atlantic salmon
Brown
Arctic char
Brook trout
Latin name
Oncorhynchus gorbuscha
Oncorhynchus nerka
(anadromous)
Oncorhynchus nerka
(landlocked)
Oncorhynchus kisutch
Coregonus artedii
Coregonus clupeaformis
Coregonus hoyi
Coregonus nelsoni
Coregonus sardinella
Coregonus kiyi
Coregonus reighardi
Prospium coulteri
Prospium cylindraceum
Prospium spi lonotus
Salmo aguabonita
Sal mo apache
Salmo clarki
Salmo gairdneri
Salmo gilae
Salmo salar
Salmo trutta
Salvelinus alpinus
Salvelinus fontinalis
range
3-7
5-10
7-13
1-5
1-10
5
0-3
0-3
2-5
3-5
0-4
0-4
5-12
7-10
8
10
5-17
8
2-10
1-13
1-13
3-12
optimum season
or peak month
10 Jul-Oct
Jul-Dec
Aug-Feb
Oct-Jan
3 Nov-Dec
Sep-Dec
Nov-Mar
Sep-Oct
Sep-Oct
Oct-Jan
Apr-Jun
Oct-Jan
Oct-Dec
Sep-Dec
Jun-Jul
May
Jan-May
9-13 Apr-Jul/Nov-Feb
Apr-May
4-6 Oct-Dec
7-9 Oct-Feb
3-4 Sep-Dec
9 Aug-Dec
II-5-11
-------
TABLE II-5-2. SPAWNING TEMPERATURE OF SOME FISH SPECIES. (Continued)
Spawning temperature,°C
approximate Spawning
Species value or optimum season
Common name Latin name range or peak month
Dolly Varden
Lake
Inconnu
Arctic grayling
Rainbow smelt
Eulachon
Goldeye
Alaska blackfish
Salvelinus malma
Salvelinus namaycush
Stenodus leucichthys
Thymallus arcticus
Osmerus mordax
Thaleichthys pacificus
Hiodon alosoides
Oallia pectoral is
5-8
3-14
1-5
4-11
1-15
4-8
10-13
10-15
Sep-Nov
Aug-Oec
Sep-Oct
Mar-Jun
Feb-May
Mar-May
May-Jul
May-Aug
Central
mudminnow
Pickerel
Redfin
Grass
Chain
Northern pike
Muskellunge
Chiselmouth
Central
stoneroller
Goldfish
Redside dace
Lake chub
Common carp
Umbra limi
Esox americanus
americanus
Esox americanus
vermiculatus
Esox niger
Esox lucius
Esox masquinongy
Acrocheilus alutaceus
Campostoma anomalum
Carassius auratus
Clinostomus elongatus
Couesius plumbeus
Cyprinus carpio
13
10
Apr
Feb-Apr
7-12 10 Mar-May/Aug-Oct
6-16 8 Mar-May
3-19
9-15 13
17
13-27
16-30
>18
14-19
14-26 19-23
Feb-Jul
Apr -May
Jun-Jul
Apr-Jun
Feb-Nov
May
May-Jun
Mar-Aug
II-5-12
-------
TABLE II-5-2
. SPAWNING TEMPERATURE OF SOME FISH SPECIES.
Spawning temperature,
approximate
Species value or optimum
Common name Latfn name range or peak
Utah chub
Tui chub
Brassy minnow
Silvery minnow
Chub
River
Silver
Clear
Rosyface
Peamouth
Hornyhead chub
Shiner
Golden
Satinfin
Emerald
Bridle
Warpaint
Common
Fluvial
Wnitetail
Spottail
Rosyface
Saffron
Sacremento
blackflsh
Bluntnose minnow
Fathead minnow
Sacremento
squawfish
Northern
squawfish
G1la atrarla 12-16
Gila blcolor 16
Hybognathus hanklnsonl 10-13
Hybognathus nuchalls 13-21
Hybobsls mlcropogon 19-28
Hybobsis storeriana 18-21
Hybobsis wlnchelli 10-17
Hybobsis rubri formes 19-23
Mylocheilus caurfnus 11-22
Nocomis biguttatus 24
Notemigonus crysoleucas 16-21
Notropis analostanus 18-27
Notropis atherlnoides 20-28 24
Notropis blfrenatus 14-27
Notropis coccogenis 20-24
Notropis cornutus 15-28 19-21
Notropis edwardraneyi 28
Notropis galacturus 24-28
Notropis hudsonius 20
Notropis rubellus 20-29
Notropis rubri croceus 19-30
Orthodon microlepldotus 15
Pimephales notatus 21-26
Pimephales promelas 14-30 23-24
Ptychocheilus grandis 4
Ptychocheilus oregonensis 12-22 18
(Continued)
°C
Spawning
season
month
Apr-Aug
Apr-Jun
May-Jun
Apr -May
May-Aug
May-Jun
Feb-Mar
Apr-Jun
May-Jun
Spring
May-Aug
May-Aug
May-Aug
May-Jul
Jun-Jul
Apr-Jul
Jun
May-Jun
May-Jul
May-Jul
May-Jul
Apr-Jun
Apr-Sep
May-Aug
Apr-Jun
May-Jun
II-5-13
-------
TABLE II-5-2. SPAWNING TEMPERATURE OF SOME FISH SPECIES. (Continued)
Spawning temperature,°C
approximate
Species value or optimum
Common name Latin name range or peak
Blacknose dace
Longnose dace
Redside shiner
Creek chub
Fallfish
Pearl dace
Sucker
Longnose
White
Flannelmouth
Largescale
Mountain
Tahoe
Blue
Northern hog
Smal 1 mouth
buffalo
Bigmouth
buffalo
Spotted sucker
Blackfin sucker
Redhorse
Silver redhorse
River
Black
Golden
Shorthead
Greater
Rhinichthys atratulus
Rhinichthys cataractae
Richardsonius balteatus
Semotilus atromaculatus
Semotilus corporalis
Semotilus margarita
Catostomus catostomus
Catostomus commersoni
Catostomus latipinnis
Catostomus macrocheilus
Catostomus platyrhynchus
Catostomus tahoensis
Catostomus elongatus
Hypentelium nigricans
Ictiobus bubalus
Ictiobus cyprinellus
Minytrema melanops
Moxostoma atripinne
Moxostoma anisurum
Moxostoma breviceps
Moxostoma duquesnei
Moxostoma erythrurum
Moxostoma macrolepidotum
Moxostoma valenciennesi
16-22 21
12-16
10-18
>12
>16
17-18
>5
8-21
13
>7
10-19
11-14
10-15
>15
14-28 17-24
14-27 16-18
13-18
12-18
>13
22-25
13-23
15-22
11-22
16-19
Spawning
season
month
May-Jun
May-Aug
Apr-Jul
Apr-Jul
May-Jun
May-Jun
May-Jun
Mar-Jun
Apr-Jun
Apr-Jun
Jun-Jul
Apr-Jun
Apr-Jun
May
Mar-Sep
Apr-Jun
Apr-May
Apr
Apr -May
Apr
Apr-May
Apr-May
Apr-May
May-Jul
Humpback sucker Xyrauchen texanus
12-22
Mar-Apr
II-5-14
-------
TABLE II-5-2. SPAWNING TEMPERATURE OF SOME FISH SPECIES. (Continued)
Spawning temperature,°C
approximate
Species value or optimum
Common name Latin name range or peak
Catfish
White
Blue
Black bullhead
Brown bullhead
Channel
Flathead
Stonecat
Bridled madtom
White River
springfish
Desert pupflsh
Banded kill fish
Plains kill fish
Mosquitofish
Burbot
Brook stickleback
Threespine
stickleback
Trout-perch
White perch
White bass
Striped bass
Rock bass
Sacremento perch
Filer
Ictalurus catus
Ictalurus furcatus
Ictalurus melas
Ictalurus nebulosus
Ictalurus punctatus
Pylodlctis olivarls
Noturus flavus
Noturus miurus
Crenichthys balleyi
Cyprinodon macularius
Fundulus diaphanus
Fundulus kansae
Gambusia affinls
Lota lota
Eucalia inconstans
Gasterosteus aculeatus
Percopsis omlscomaycus
Morone americana
Morone chrysops
Morone saxatlHs
Ambloplites rupestris
Archoplites interruptus
Centrarchus macropterus
20-29
>22
>21
>21
21-29 27
22-28
27
25-26
32
>20 28-32
>21 23
28
23
0-2
4-21
5-20
6-21
11-20
12-21
12-22 16-19
16-26
22-28
17
Spawning
season
month
Jun-Jul
Apr-Jun
May-Jul
Mar-Sep
Mar-Jul
May-Jul
Jun-Aug
Jul-Aug
Apr-Oct
Apr-Sep
Jun-Aug
Mar-Oct
Jan-Feb
Apr-Jul
Apr-Sep
May-Aug
May-Jul
Apr-Jun
Apr-Jun
Apr-Jun
May-Aug
Mar-May
II-5-15
-------
TABLE II-5-2. SPAWNING TEMPERATURE OF SOME FISH SPECIES. (Continued)
Spawning temperature,°C
Common name
Banded pygmy
sunfish
Sunflsh
Redbreast
Green
Pumpkinseed
Warmouth
Orangespotted
Blueglll
Longear
Redear
Spotted
Bass
Redeye
Small mouth
Suwannee
Spotted
Largemouth
Species
Latin name
Elassoma zonatum
Lepomis auritus
Lepomis cyanellus
Lepomis gibbosus
Lepomis gulosus
Lepomis humilis
Lepomis machrochirus
Lepomis megalotis
Lepomis microlophus
Lepomis punctatus
Micropterus coosae
Mlcropterus dolomleui
Micropterus notius
Micropterus punctulatus
Micropterus salmoides
White crappie
Black crappie
Yellow perch
Sauger
Walleye
Pomoxis annularis
Pomoxis nigromaculatus
Perca flavescens
Stizostedion canadense
Stizostedion vitreum
Greenside darter Etheostoma blennioides
Johnny darter Etheostoma nigrum
Channel darter Percina copelandi
Blackside darter Percina maculata
Mottled sculpin Cottus bairdi
Freshwater drum Aplodinotus grunniens
approximate
value or
range
14-23
17-29
20-28
19-29
21-26
19-32
22-30
20-32
18-33
17-23
13-23
S 15-21
12-27
14-23
14-20
4-15
4-15
4-17
>10
20-21
16-17
10
18-24
optimum
or peak
25
17-18
21
16-20
12
9-15
6-9
23
Spawning
season
month
Mar -May
Apr-Aug
May-Aug
May-Aug
May-Aug
May-Aug
Feb-Aug
May-Aug
Mar-Sep
Mar-Nov
Apr-Jul
Apr-Jul
Feb-Jun
May-Jun
Apr-Jun/Nov-May
Mar-Jul
Mar-Jul
Mar-Jul
Mar-Jul
Mar-Jun
Apr-Jun
Jul
May-Jun
Apr -May
May-Aug
II-5-16
-------
CHAPTER 11-6
RIPARIAN EVALUATIONS
Riparian ecosystems can be variously identified but their common element is
that they are adjacent to aquatic systems. Brinson et al., (1981) defines
them as "riverine floodplain and streambank ecosystems. Cowardin et al.,
(1979) in their'Classification of Wetlands Habitats of the U.S.", do not
clearly delineate riparian and wetland zones. For this chapter emphasis
will be given to floodplain, riverine and lacustrine riparian habitats and
no distinction has been made between riparian and wetland land
environments.
The primary legislative justification for riparian protection is the Clean
Water Act, specifically that section dealing with water quality. Many
factors enter into the relationship between riparian ecosystems and water
quality; a simple correlation between any single measure of riparian
habitat and water quality does not exist. A well developed riparian zone
is frequently the juncture between terrestrial and aqautic environments and
its characteristics are governed to some extent by both. The riparian zone
is usually related to the adjacent terrestrial environment with respect to
climatic conditions, soil types, land topography etc. The aquatic system
is an integration of upstream drainage (Lotspeich 1980) and has the
riparian zone as an important component. The aquatic effects to the
riparian ecosystem will vary with factors such as stream size, climatic
vegetation and soil type. Although no ideal riparian habitat water quality
scenario is possible, general relationships can be derived.
A critical relationship exists between stream size and the extent of
riparian habitat. Small streams canopied by riparian vegetation will be
more influenced than large streams where riparian canopy represents only a
small fraction of the immediate channel. The small riparian zone in
relation to stream size of many large streams has frequently been cited in
order to diminish the importance of this habitat. The presumption is made
that riparian importance is minimal because the riparian/river size ratio
is small. It is also argued that alteration of smaller streams is
insignificant with respect to the total drainage basin and that such
activities have minimal implications for larger streams. An obvious impact
of large stream riparian modification is shore line destruction and
subsequent loss of near shore stream habitat. Although modification of a
single small tributary may have a minimal effect on the larger water body,
major drainage basin alterations could seriously damage water resources,
the larger stream being a product of its tributaries.
Riparian system have unique ecosystem qualities which should be considered
in addition to their water qualiy values. Riparian zones are cited as
classical ecotones which will usually support greater species and numerical
diversity than adjacent aquatic or terrestrial environments. Large numbers
of rare and endangered animal and plant species reside here. It is often
critical habitat for an entire life span or it may be used in a transitory
manner for reproduction, migration or as hunting territory for raptors and
carnivorous mammals. Even though organisms may not use the riparian zone
II-6
-------
as their primary living habitat, its loss may seriously disrupt foodchain
mechanisms and life history processes. Significant changes in species
numbers, diversity and types may occur in both the terrestrial and aquatic
environments following riparian destruction. It is estimated that less
than two percent of the land area in the U.S. is riparian habitat (Brinson
et al., 1981). Large portions have been converted to agricultural use,
e.g. the Mississippi bottomland hardwoods, and stream channelization
has destroyed adjacent riparian ecosystems. Timber removal has greatly
reduced riparian habitat in forested regions. Livestock grazing has had
extremely detrimental riparian effects on semi-arid rangelands. Land
values have favored agricultural and urban development immediately adjacent
to the aquatic environment with the exclusion of most natural vegetation.
PHYSICAL RELATIONSHIPS
Key physical stream characteristics are affected by the riparian ecosystem.
Water temperature responds to almost any riparian alteration in smaller
streams. Several studies (Karr and Schlosser 1978, Moring 1975, Campbell
1970) have demonstrated that shade afforded by adjacent vegetation
significantly moderates water temperature, reducing summer highs and
decreasing winter lows. This can have significant effects on many chemical
and biological processes. Chemical reaction rates are temperature
dependent and increased temperature generally increases reaction rates.
Adsorption, absorption, precipitation reactions, decomposition rates, and
nutrient recycling dynamics could all be altered. Many aquatic organisms
have relatively specific temperature requirements. Elevated temperatures
increase poikilotherm metabolic rates causing excessively low production
during food deprivation and the increased temperature may disrupt critical
life stages such as reproduction. Temperatures exceeding or substantially
below optimal requirements, even for relatively brief periods, can
completely alter the biota. Larger streams may not be physically affected
as readily as the smaller tributaries but large scale tributary
modifications could have dramatic downstream consequences.
Another direct physical consequence is alteration in the quality and
quantity of incident solar radiation. Optimal photosynthetic wave lengths,
especially for diatoms, may be altered by the canopy, but as will be
elaborated later, this may not have serious consequences to a diversified
biota. Turbidity will be reduced by riparian vegetation. This too will be
discussed in greater detail. A further loss with reduction in riparian
habitat is the fine particulate matter, especially the nutrient rich
organic material. This may be transferred to the adjacent terrestrial
environment during floods or carried directly to the large streams with
such a reduced residence time in the smaller stream that they become
nutrient limited.
FLUVIAL RELATIONSHIPS
Fluvial characteristics are governed by such processes as stream bank
stability, flow rates, rainfall seasonality and water volumes. Stream bank
stability is important in maintaining stream integrity. This stability is
a function of the local geology and riparian vegetation.
II-6-1
-------
Streams are not static but new channel formation rates are slowed with
increased bank stability. During high water, bank erosion is minimized and
excess flow energy dissipated over floodplains with minimal environmental
damage. Without riparian vegetation, flooding is more erosive and
extensive. Energies are not dissipated readily but remain excessive for
the duration of the high water. The geomorphological consequences can be
considerable; extreme erosion, formation of additional channels, upland
sediment deposition etc. The biological impact can be devastating, with
the aquatic habitat physically destroyed or silted to the extent it is no
longer a biologically viable unit. Under extreme conditions, silt levels
may be sufficient to cause embryo death and physiological damage to gill
breathing organisms. This scenario is best illustrated using the example
of stream channelization. High energy water movement leads to rapid land
drainage but also to extremely damaging floods when stream banks overflow.
Biological communities may become species depauperate, biomass greatly
reduced and those populations remaining may be undesirable compared to
previous inhabitants.
Riparian zone groundwater levels are controlled by adjacent surface water
levels. The vegetated riparian system retains more water and releases it
at slower rates than non-vegetated shore zones. This has important
implications for stream water quality. Flood surge may be diminished
downstream of precipitation events by water movement into non-saturated
riparian soils. This would reduce sediment transport capacity, flooding
and channel erosion. Water movement into the terrestrial water table is
especially important to stream stability in arid regions where rainfall may
occur rarely but may lead to devastating floods. Stream-side vegetation
moderates the potential impact of local rainfall events by retaining
surface runoff. Groundwater can moderate stream temperatures where
significant flow is derived from underground sources.
BIOLOGICAL RELATIONSHIPS
Primary production is controlled by the quality and quantity of incident
solar radiation, nutrients and plant community structure. In smaller
streams with extensive canopies the radiation quantity may be significantly
reduced and the wavelength distribution altered. This may reduce
production in that section but may at the same time make nutrients more
available to downstream organisms. Water temperature will also be
affected, and photosynthesis may be reduced by cooler water but also
temporarily extended by a reduction in seasonal temperature extremes. Many
stream primary producers, especially diatoms and mosses, have adapted to
reduced light intensity, and relatively high photosynthetic rates are
maintained under low light conditions.
Stream flow characteristics are also affected by debris. Flow rates are
moderated by the pool-riffle morphology common to streams with well
developed riparian systems. It has been demonstrated that the rate of
water movement can be significantly different for a given elevation loss
between well developed pool/riffle complexes and streams which allow free
water flow. The streams with the most complex morphology retain the water
II-6-2
-------
for the greatest period. This has important secondary implications for
groundwater, hydrologic regime, water temperature and biota.
Perhaps the most severe effect on water quality following riparian
destruction is increased channel sedimentation. Agricultural and forestry
practices frequently remove vegetation to the immediate streambank thus
allowing unhindered surface water movement directly into the stream.
Riparian vegetation will retard surface sheet flow, substantially reducing
stream sediment loads. Stream sedimentation results in extreme habitat
diversity loss, and the bottom morphology becomes a monotony of fine
grained sediments. The immediate biotic symptom may be acute suffocation
of the invertebrate fauna with the possibility of chronic physiological
stress. The long term effects are extensive. Table 11-6-1 prepared by
Karr and Schlosser (1978) illustrates the relationships between land use
practices and stream sediment loads.
Table 11-6-1: POTENTIAL EFFECTS OF VARYING MANAGEMENT PRACTICES ON
EQUILIBRIUMS OF EQUIVALENT WATERSHEDS. THESE ARE BEST ESTIMATES OF
RELATIVE EFFECTS FOR A VARIETY OF WATERSHED CONDITIONS, INCLUDING SOURCES
AND AMOUNTS OF SEDIMENTS.
Relative Amount of
Sediment From
Management
Practice
Land
Surface
Stream
Channel
Natural watershed
Clear land for
rowcrop agriculture;
maintain natural
stream channel
Channelize stream
in forested
watershed
Clear land and
channelize stream
Best land surface
management with
channelization
Best land surface
and natural channel
Very low Very low
High
Low
Suspended Source
Solids Load of
in Stream Sediment
Very low
Medium Land surface
Very low High
High
Low
Low
High
High
Low
High
Very high
Medium to
high
Low to
medium
Channel
banks
Land surface
and channel
banks
Channel
banks
Equilibrium
between land
and channel
II-6-3
-------
TABLE II-6-2: COMPARISON OF THE EFFECT OF WELL DEVELOPED AND REDUCED RIPARIAN ZONES ON WATER QUALITY OF SMALL STREAMS
Riparian system
well developed.
Reduced riparian
system
Flow
1. Extremes
moderated
2. Little reaction
to local events
1. Erratic flow
2. Reacts to local
rain events
Temperature
1. High and low
extremes
moderated
2. Reduced daily
fluctuations
Extreme
seasonal
variation
Extreme daily
fluctuation
Sedimentation
Moderated by
vegetation
Usually higher
loads, partic-
ularly
following
watershed
disruption
Primary Production
Reduced speciation related
to organisms able to
photosynthesis with
reduced light intensity
Increased production but
often of undesirable
species.
High nutrient loading
and temperatures favor
undesirable speciation
(filamentous blue-green
algae or macrophytes)
Nutrient Load
Moderated by
riparian uptake
Regulated release
through highly
organic soils.
Available supplies
because of riparian
primary production
Large seasonal
fluctuations
Availability to
stream biota related
to wash out rate,
flooding may remove
nutrients before
they are utilized by
aquatic biota
II-6-4
-------
TABLE 11-6-2 (Cont'd)
Diversity
I. Diverse speciatlon with
diverse habitat
selection
2. May have large speciation
in fish and invertebrates
or as common to western
streams, large in-
vertebrate population
diversity with little
fish diversity
Low species numbers
No. Individuals
May have large
number of species
with few organisms
for each taxa
Large number of
organisms for a
few taxa
Biomass
Diversity of
organism types
and able to
sustain large
biomass
Large biomass
with little
diversity
Groundwater
Slow change in
elevation
gaged to
changes in
stream level
1. Rapid change
fol lowing
changes in
stream flow
2. Rapid soil
drying
Riparian Vegetation
Self sustaining
with respect to
water, nutrients,
habitat etc.
Once system degrades
may no longer be
possible to sustain
riparian habitat
without extensive
reworking of the
stream bed and
adjacent upland
Surface Water
1. Little flooding
water general ly
retained in channel
2. If flood occur,
energy dissipated
by vegetation
1. Large scale flooding
may occur
2. High energy water
flow causing large
erosional losses
II-6-5
-------
Several studies have investigated the use of riparian wetlands for waste
water treatment. Generally, significant phosphorus and nitrogen reductions
occur following varying wetland exposure. EPA Regions IV and V have
prepared documentation for generic EIS statements which address the wetland
alternative to secondary and tertiary waste treatment technology. Riparian
vegetation has also been used to treat urban runoff where it has been found
to significantly reduce treatment costs and sediment loads, and to improve
water quality and greatly moderate flows.
Recent research has indicated that humic acids released from some riparian
ecosystems, particularly wetlands, can significantly affect water quality.
Humates are generally large organic molecules which may sequester
substances making them biologically unavailable or may, conversely, act as
chelating agents making them more available. These phenomena can also
occur with toxic materials. Humates may cause considerable oxygen demand
and significantly affect such chemical properties as COD. These substances
remain largely unclassified and their exact effects unknown.
RIPARIAN CASE HISTORY STUDIES
A long standing controversy has developed in western States where cattle
are permitted to graze adjacent to or in both permanent and intermittent
streams beds (Behnke 1979). The unprotected riparian vegetation is altered
in virtually all respects; species change, biomass is reduced, herbs and
shrubs become almost non-existent. A critical question is how this affects
water quality and ultimately the fishery. Platts (1982), following an
extensive literature review, concluded that studies conducted by fisheries
personnel generally found significant biomass and speciation changes
following "heavy grazing". Similar studies by range personnel frequently
repudiated these results but Platts suggests many were improperly designed
or alternative data interpretations are possible. Platts' overall
conclusion is "Regardless of the biases in the studies, when the findings
of all studies are considered together there is evidence indicating that
past livestock grazing has degraded riparian- stream habitats and in turn
decreased fish populations".
Studies are underway in the western U.S. testing stream exclosures as means
to improve riparian and stream habitat. These are usually qualitative
efforts and frequently do not emphasize water quality or stream biota
surveys. Hughes (personal communication) observed distinct physical and
biological differences between grazed and upgrazed small streams in a study
of a Montana watershed. Crouse and Kindschy (1982) have observed
consideration variation in riparian vegetation recovery following both long
and short term cattle exclosure.
Studies conducted in the Kissimmee-Okeechobee basin, Florida (Council of
Environmental Quality 1978), Indicate distinct physical and biological
differences that follow everglade stream channelization. Nutrients once
removed by riparian vegetation make their way to lakes and aid in
accelerating eutrophication. The Corps of Engineers (Council of
Environmental Quality 1978) is using the Charles River watershed in
Massachusetts to control downstream flooding. This project has preserved
large riparian watershed tracts to serve as "sponges" to control abnormally
high runoff. The preservation of southwestern playas and their vegetation
II-6-6
-------
has assumed added importance following realization of their function in
groundwater recharge and wildfowl preservation (Rolen 1982). Prarier
potholes have long been recognized as critical bird and mammal habitat and
recent studies have demonstrated that they too act as nutrient sinks.
groundwater recharge areas and as important mechanisms to retain excessive
precipitation and surface runoff (van de Valk et al., 1980). Southern
bottomland hardwood forests are essential for both indigenous fauna and
migratory birds but also are critical water management areas to retain
excessive runoff to prevent flooding.
The value of the freshwater tidal riparian zone to aquatic fauna is
considerable. Many commercially important anandromous fish require nearly
pristine environmental conditions to breed. Perhaps the best documented
example is the Pacific Coast Salmonid fishery which is extremely sensitive
to physical and chemical alterations. Increased sedimentation and
temperatures associated with riparian vegetation removal can destroy a
historical fishery. Large number of commercial and non-commercial
(sniffen, personal communication) east coast fish depend on extensive
freshwater floodplains during their life cycle. South eastern U.S. salt
marshes, perhaps an extended riparian definition, are critical for numerous
commercially important organisms. The panaeid shrimp totally depend on
this environment during the early stages of their life cycle (Vetter,
personal communication). It has been hypothesized that these marshes are
critical to many near shore organisms through organic carbon export (Odum
1973). Several midwestern fish species also are dependent on riparian
habitat, the muskelunge requiring it for completion of their life cycle.
Table 11-6-2 is an abbreviated summary of differences between small stream
with well developed riparian zones and streams with a reduced riparian
zone.
ASSESSMENT OF RELATIONSHIPS BETWEEN RIPARIAN AND AQUATIC SYSTEMS
A variety of methods exist to measure water quality in physical, chemical
and biological terms. These are treated in CHapter III-2 and will not be
discussed here. Riparian environmental measures are similar to those used
in terrestrial ecology (Mueller-Dumbois and Ellenberg 1974).
Ties between the aquatic and riparian or the aquatic, riparian and upland
environments can only be estimated. There is a paucity of such
information because of the extremely high research costs and the inability
to devise procedures to test experimental hypotheses.
The results are that most such evaluations are qualitative. Their quality
is based on the integrity and knowledge of the person making the
evaluation. The remainder of this section lists physical, chemical and
biological factors which might be considered when evaluating the riparian
aquatic interaction. It is not meant to be exhaustive but only an example
of factors affecting the interactions.
I. Riparian Measures and Their Effect on Water Quality
A. Pieomorphology (erosion, runoff rate, sediment loads)
1. Slope
2. Topography
3. Parent material
H-6-7
-------
8. Soils (sediment loads, nutrient inputs, runoff rates)
1. Particle size distribution
2. Porosity
3. Field saturation
4. Organic component
5. Profile (presence or absence of mottling)
6. Cation exchange capacity
7. Redox (Fh)
8. pH
C. Hydrology (water budget, flooding potential, nutrient loads)
1. Groundwater
a. Elevation
b. Chemical quality
c. Rate of movement
2. Climatic factors
a. Total annual rainfall and temporal distribution
1) Chemical quality
b. Temperature
c. Humidity
d. Light
II. Vegetative and Faunal Characteristics
A. Floristics ("community health", disturbance levels)
1. Presence/absence
2. Nativity
B. Vegetation (nutrient loads, "community health", disturbance levels)
1. Production
2. Biomass
3. Decomposition
4. Litter dynamics
a. Detritus
1) Size
2) Transportability
3) Quantity
5. Plant size classes
a. Grasses, herbs (forbs), shrubs, trees
6. Canopy density and cover
a. Light intensity
7. Cover values
C. Fauna (community disturbance, community health)
1. Production
2. Biomass
3. Mortality
D. Community structure
1. Diversity
2. Evenness
II-6-8
-------
III. Physiological Processes
A. Transpirational water loss (community health)
B. Photosynthetic rates (community health)
IV. Streambank characteristics
A. Stream sinvosity
B. Stream hank stability (sediment loads, habitat availability)
II-6-9
-------
°SECTION III : CHEMICAL EVALUATIONS
-------
CHAPTER III-l
WATER QUALITY INDICES
One of the most effective ways of communicating information on environ-
mental trends to policy makers and the general public is by use of
indices. Many water quality indices have been developed which seek to
summarize a number of water quality parameters into a single numerical
index. As with all indices the various components need to be evaluated
in addition to the single number. U.S. EPA (1978) published an
excellent review of water quality indices entitled "Water Quality
Indices: A Survey of Indices Used in the U.S." which provides the
reader with the types of indices used by various water pollution
control agencies. The purpose of this chapter is to identify and
explain the various indices that would be applicable to a use attain-
ability analysis. The choice of indices is at the discretion of the
States and will primarily be dictated by the water quality parameters
traditionally analyzed by the State.
NATIONAL SANITATION FOUNDATION INDEX (NSFI)/WATER QUALITY INDEX (WQI)
Brown et al (1970) presented a water quality index based upon a
national survey of water quality experts. In this survey respondents
were asked (1) which variables should be included in a water quality
index, (?.} the importance (weighting) of each variable and (3) the
rating scales (sub-index relationships) to be used for each variable.
Based on this survey, nine variables were identified: dissolved oxygen
pH, nitrates, phosphates, temperature, turbidity, total solids, fecal
coliform, and 5-day biochemical oxygen demand. Appropriate weights
were assigned to each parameter. The index is arithmetic and is based
on the equation:
WO IA = £ w;q.c
where: WOIAC= the water quality index, a number between 0 and 100.
V»= a quality rating using the rating transformation curve.
0)-.= relative weight of the th parameter such that =1.
Figures A-l-9 show the rating curves and relative weights for each of
the parameters. To determine the water quality index follow these
steps:
(1) determine the measured values for each parameter
(2) determine q for an individual parameter by finding the
appropriate value from curves (Figures A 1-9)
(3) multiply by the weight (w) listed on each figure
(4) add the wq for all parameters to determine the water
quality index (a number from 0-100)
The water quality index can then be compared to a "worst" or "best"
case stream. Examples of a best and worst quality stream cases follow:
in-i
-------
Best Quality Stream
Measured
values
Individual
quality
rating
(q-J
Weights
K)
Overall
quality
rating
DO, percent sat.
Fecal coliform
density, fi /100 ml
PH
BOO mg/l
Nitrate, mg/l
Phosphate, mg/l
Temperature °C
departure from equil
Turbidity, units
Total solids, mg/l
100
0
7.0
0.0
0.0
0.0
0.0
0
25
98
100
92
100
98
98
94
98
84
0.17
0.15
0.11
0.11
0.10
0.10
0.10
0.08
0.08
WQI=2w.qt= 96.3
Worst Quality Stream
DO. percent sat. 0
Fecal coliform
density, 0 /100 ml 5
pH 2
BOD , mg/l 30
Nitrate, mg/l 100
Phosphate, mg/l 10
Temperature °C
departure from equil +15
Turbidity, units 100
Total solids, mg/l 500
4
4
8
2
6
10
18
20
0.17
0.15
0.11
0.11
n.io
0.10
0.10
0.08
0.08
16.7
15.0
10.1
11.0
9.8
9.8
9.4
7.8
6.7
Parameters
Measured
values
Individual
qual ity
rating
(qL)
Overal 1
quality
Weights rating
(";) (q;xwL)
0
0.6
0.4
0.9
0.2
0.6
2.4
= 7.5
in-l-l
-------
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OUMLWB amu. X UTVUTIOH
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•Tl:
t.t.
in-i-2
-------
MTU QUALITY IWtl
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Hi. UNITS
A«t7Mf«TIC
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— KB
LIMITS
100
90
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III-1-3
-------
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T
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Mill
•IHUTU
AdlTtMTtC «AN — —
\
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1C 20 30 « SO 60 70
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'100
90 100
MTQ OMLITY Ittl
TOTAL ftOtfNATU
— — • AiiTwcTic «M — — KB cowtaua umn
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III-1-4
-------
*n* QUALITY i
A«CTM>«T1C KM
— — HI COVIOCIKt UNITS
A
T
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100
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WTC
TUWUTUK OCVtATtOa
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TOFUATUK. MGKKS COmCMOC OVAKTUM FROM UutUMlt* TOVUATUK (0)
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Witt QUALFY !«Q
--- IB
100
90
10
: TO
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III-1-5
-------
MTU QUALITY IOC1
TOTAL MLJM
AIITMVTIC i«AM KB caVIMHtt
103
JO
V
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HI-1-6
-------
DINIUS WATER QUALITY INDEX
In 197?, Pinius proposed a water quality index as part of a larger social
accounting system designed to evaluate water pollution control
expenditures. This index includes 11 variables and like the MSFI, it has a
scale which decreases with increased pollution, ranging from 0 to 100. The
index is computed as the weighted sum of its sub indices. The 11 variables
included in the index are: dissolved oxygen, biological oxygen demand,
Eschericia coli, alkalinity, hardness, specific conductivity, chlorides,
pH, temperature, coliform, and color. This index is unique in that the
calculated water quality index could be matched to specific water uses.
Oinius proposed different descriptor language for different index ranges
depending on the specific water use under consideration as illustrated in
Figure A-100. The index values can be derived from the following formula:
0 = 5(DO) + 214(BOD) + 400(5E.Coli) + 300(Coli)
5
+ 535
+
"t.lft
(SC)
2 + 4 +
,(• -6.lt>? /.97V-"-66/3
+ 62.9(C1) + 10
3
1
+ 54(ALK) _ + 10 __ +K(Ta-Ts) + 224 + 1?R(C)
+ .5 + 1 + 2 + 1
Note: If the pH is between 6.7 and 7.3, 100 should he substituted for
for the pH expression. If pH is greater than 7.3, the pH
expression should be 10
00 = dissolved oxygen in percent saturation
BOO = biological oxygen demand in mg/1
E.coli = Eschericia coli as E.coli per ml
Col i = coliform per ml
SC = specific conductivity expressed in microhms per cm at 25°C
Cl = chlorides in mg/1
HA = hardness as ppm CaCO
ALK = alkalinity as ppm CaCO
pH = pH units
Ta = actual temperature
Ts = standard temperature (average monthly temperature)
C = Color units
Once the quality unit is determined based on the above calculation, a
comparison to Figure A-10 should reveal the quality of the water for a
specific use.
HARK INS/KENDALL WATER QUALITY INDEX
A statistical index was developed by Harkins (1974) using a nonparametric
classification procedure developed by Kendall (1963). The procedure was
summarized by Harkins by the following four steps:
(1) For each water quality parameter used, choose a minimum or maximum
value as a starting point. This sector of values is the control
observation from which standardized distances will be computed.
ni-l-7
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III-1-8
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(2) Rank each column of water quality parameters including the control
value. Tied ranks are split in the usual manner.
(3) Compute the rank variance for each parameter using the equation:
Variance (Ri ) =|^x [(n3- n) - .|(t|J - U)]
where: i = l,2...p, *"
p = the number of parameter being used
n = the number of observations plus the number of control
points, and
k = the number of ties encountered.
These variances are used to standardize the indices computed.
(4) For each member of observation vector, compute the standardized
distances:
where R is the rank of the control value.
This index is meant as a method for summarizing a large amount of data to
present a concise picture of overall trends. This method provides a
simple, expedient method whereby one station can be compared with another
or previous time periods from a particular station may be compared with
another time period at the same station. A detailed example of this index
may be found in Harkins (1974).
OTHER INDICES
Many other water quality indices have been developed; some being variations
of the indices described previously. Several States (Georgia, Oregon,
Nevada, Illinois) have developed their own systems based on the
characteristics of the water bodies of the State. McOuffie and Haney
(1973) proposed an eight-variable water quality index which was applied to
streams in New York State.
III-1-9
-------
CHAPTER II1-2
pH, HARDNESS, ALKALINITY AND SALINITY
INTRODUCTION
The chemical composition and the chemical interactions of the aquatic environ-
ment exert an important influence on the aquatic life of a water body. Many
chemical constituents in a body of water have the ability to alter the toxic-
ity of specific pollutants, or to protect organisms from toxic materials by
removing them or by blocking their action. The importance to aquatic life of
four water quality parameters - pH, alkalinity, hardness and salinity - is
discussed in this section.
pH
The pH of water is a measure of its acid or alkaline nature. Specifically, it
is an expression of the hydrogen ion activity of the solution. Hydrogen ion
activity is mathematically related to the hydrogen ion concentration [H ], and
for most natural waters these may be considered equivalent. pH is expressed as
the negative logarithm of the hydrogen ion concentration:
pH = - log [H+]
The water molecule, H2o, ionizes to yield one hydrogen and one hydroxyl ion:
H20 * H+ + OH"
The equilibrium expression for this reaction is:
The concentration of water, [H^O], is considered to be a constant, and the
equation simplifies to:
Kw - [H + ][OH-] - 10'14
Because the product of the concentration of both ions is always 10 , when
they are equal to each other,
[H+] * [OH'] = 10"7, and
pH =« - log (10~7) = 7.
At pH 7 the solution is neutral. When there are more hydrogen ions than hydrox-
yl ions, the pH is less than 7 and the solution is acidic. When there are more
hydroxyl ions, the pH is greater than 7 and the solution is alkaline.
III-2-1
-------
The pH of most natural freshwaters in the U.S. is between 6 and 9. It is inter-
esting to note that the pH of most ocean waters falls in a much narrower
range, 8.1 to 8.3 (Warren 1971). This is due to the presence of several buffer-
ing systems in salt water which control pH changes. !n freshwater, pH is regu-
lated primarily by the carbonate buffer system. Biological activities such as
photosynthesis or respiration can cause significant die! variations i.i pH.
Extreme pH values or variations in pH can be caused by pollution such as acid
mine drainage.
Importance to Aquatic Life
The importance of pH to aquatic organisms resides primarily in its effect on
other environmental factors. In general, the change in pH itself is not direct-
ly harmful. Rather, the impact on aquatic life accompanies a change in an asso-
ciated variable such as the solubility or toxicity of a toxic pollutant. The
pH range 6.5-9.0 is considered to be generally protective for fish and the
range 5".0-9.0 is not considered directly'lethal "(EIFAC 1965).
Aquatic organisms have protective membranes and internal regulatory systems
which afford a degree of protection from the direct effects of hydrogen and
hydroxyl ions. The indirect effects of pH seem to intensify as the pH deviates
from the optimum (EIFAC 1969).
The degree of dissocation of weak acids is pH-dependent and thus the toxicity
of several common pollutants is affected. Ammonia (NH-j), hydrogen sulfide
(H^S), and hydrocyanic acid (HCN) are ^xamples. Under low pH conditions the
NH2 molecule ionizes and becomes the NH^ ion (Thurston, et al. 1974). The tox-
icfty of ammonia is attributed to the un-ionized form (NH^), so that increased
pH conditions result in increased levels of the toxic un-Tonized fraction.
The lower the pH, the smaller the degree of dissociation of hydrocyanic acid
to hydrogen and cyanide ions. The molecular form (HCN) is the toxic form, and
so the toxicity of cyanide is favored by low pH. The undissociated form of hy-
drogen sulfide (H^S) is the primary source of sulfide toxicity. Therefore,
under low pH conditions, very little H£ is dissociated, and toxicity is in-
creased.
The solubility of toxic metals is a function of pH. Metals in water tend to
form complexes with such anions as sulfate, carbonate or hydroxide. The solu-
bility of these complexes increases with decreasing pH, as illustrated for hy-
droxides in Figure III-2-1, so that low pH conditions may cause the release of
metals from sediment deposits into the water column. Metal toxicity is be-
lieved to be related to the total metal concentration (i.e., free ions plus
complexed ions) in solution (Calavari et al. 1980). Table III-2-1 illustrates
the effect of pH on metal concentrations in natural waters.
Due to the complexity of its interactions with elements of the environment,
there may be several mechanisms by which pH affects toxicity. The exact mecha-
III-2-2
-------
-log [M]
I I I \ I
8 10 12 14
PH
Figure III-2-1. Relationship Between pH and Solubility of Metallic Hydroxides
III-2-3
-------
TABLE III-2-1.
CONCENTRATION (ug/1) OF METALS IN LAKE WATERS OF VARIOUS
ACIDITIES (From Haines, 1981).
Localitv
Al
Cu
Ol
Metal
Mn
Nanacidijinl (pH
102 lakes. Ontario (average)
Blue Clulk 1 jke. Onurio
l-ikc I'jiudic. Stnlburv. Ontario
North Swctlcn (range)
Central Nor*av (range)
North Norway (range)
13
<50
<20-65
2
8
6
1-10
<0.l
0.05-0.23
0-0.5
3
40
<100
Inttrmtdiatt (pH
South-central Ontario. 14 lakes
(average)
Nelson Ljke. Ontario
IS
5.7
13
49
18
Acidifitd (pH 4.
Four lakes. Ontario (average)
Clearwater Lake. Sudhurv. Ontario
Four lakes. Su
-------
nlsm of direct toxlclty of pH In water Is not certain. It has been suggested
that at very low pH values, oxygen uptake may be affected and this may be the
toxic event. Acid-base regulation and 1onoregulat1on appear to be affected at
higher, but still acidic, pH values (Graham and Wood 1981). There 1s evidence
that the chronic effects of pH on fish Include effects on reproduction, such
as reduced egg production and hatchabllity (Peterson, et al. 1980), and on be-
havior (Mount 1973). Some mobile organisms may have the ability to avoid low
pH conditions if the detrimental conditions are localized. Evidence suggests
(U.S. EPA 1960, p. 180) that outside a range of 6.5 to 9.0, fish suffer ad-
verse physiological effects which Increase in severity as the degree of devi-
ation increases. Tables 111-2-2 and III-2-3 present pH values that have been
found to cause adverse effects on a number of fish species in the field and in
laboratory investigations, respectively. These values represent only the low
end of the tolerated range of pH. (The lower limit 1s most often exceeded due
to anthropogenic causes such as acid rainfall, acid mine drainage and
industrial discharges.)
Marine organisms, as a group, tend to be much less tolerant of extreme pH con-
ditions. As mentioned previously, the marine environment is buffered more ef-
fectively than freshwater. As a result, these organisms have not evolved an
ability to cope with pH variations outside their narrow optimum range.
ALKALINITY
Alkalinity 1s the property of water which resists or buffers against changes
in pH upon addition of add or base. The primary buffer in freshwater is the
carbonate-bicarbonate system. Phosphates, borates, and organic acids also im-
part buffer capacity to water. These additional buffer systems are more signi-
ficant 1n saltwater than 1n freshwater.
Bicarbonate (HC03~) is the major form of alkalinity. Carbon dioxide (CO-) dis-
solved 1n water is carbonic acid (H^CO.,).,Carbonic acid dissociates in two
steps to form bicarbonate and carbonate (tO^*) ions as follows:
C02 + H20 *» H2C03 ^ H* + HC03"
HC03" ^ H+ + C03
The ability of these chemical reactions to shift back and forth with changes
in hydrogen ion concentration (pH) to "absorb" these changes is what imparts
buffer capacity. This system tends to control pH best 1n the neutral range.
The form of alkalinity 1n solution 1s governed by pH. Figure III-2-2 illus-
trates this effect. Biological activities such as photosynthesis and respir-
ation cause shifts 1n pH and 1n the relative concentrations of the forms of
alkalinity, without significant effect on the total alkalinity. The production
of C02 during respiration shifts the equilibrium to the right, toward carbon-
ate formation. The removal of C02 from solution during algal photosynthesis
shifts the alkalinity equilibrium Co the left, toward the bicarbonate form.
III-2-5
-------
TABLE 111-2-2.
SPECIES OF FISH THAT CEASED REPRODUCING, DECLINED, OR DISAP-
PEARED FROM NATURAL POPULATIONS AS A RESULT OF ACIDIFICATION
FROM ACID PRECIPITATION, AND THE APPARENT pH AT WHICH THIS
OCCURRED (From Haines, 1981).
Family and species
Apparent pH at which population cea*ed
reproduction, declined, or disappeared
Salmontdae
I jke trout Satvrlinia immmtnak
Brook trout 5utlt bau Mtcnftma doJownrui
Ijrijeiniiiiih bau Mtenptrrut utlmouin
Rix.1 IMS* .ImUoflan
Pulllpkin^eeti Ltpoma
Bluet;ill Lfpomu marrockina
Perodae
Johnnv daner C/A/«5.5 : -5.8
; 4.2-5.0
: 4.4-5.0
: 5.2-5.H
. <4.7 ; 4.2-4.4
III-2-6
-------
TABLE III-2-3. VALUES OF pH FOUND IN LABORATORY EXPERIMENTS TO CAUSE VARIOUS
ADVERSE EFFECTS ON FISH SPECIES (From Haines, 1981).
Increased iitniuliiv
Familv and
ipeties
Salmonida«
Brook trout
Arctic char
Rainbow trout
Brown trout
Atlantic ulmon
Eioadae
Northern pike
Cyprinidae
Roach
Fathead minnow
Caiostomidae
White tucker
PerciHae
European perch
tmhrvo
65
5.6
4.3
5.5
4.0
4.1
3.4-4.4
36
1 9
40
4.0-55
4.1
5.0
5.6
5.9
4.5
56
5.5
Juveniles Krdmed
Frv or adults growth Oilier elicits
4.4 4.5 fi.5 Ri-duted e^ vialnliiv: 5.0
4.5 4.1 4.li lixiiM- d.un.iKc: 'i.'i
4.8
4.3 S.r»-l.| I.K
5.0
4.0 I'iuue dain^Kc: 5.0
4.3
4.1
5.0
5.9 2.1 4.5 Reduced egx viability: 0.6
5.3 1.3 Cr.ised Iceilinn: 4.5
4.0 Bone ilelnnnilv: 4. '2 : 5.0
III-2-7
-------
100
o
O
o
h-
"o
-------
water to form insoluble carbonate and hydroxide precipitates. Figure II1-2-3
illustrates that the concentration of heavy metals drops rapidly as the concen-
tration of carbonate increases. Metals which are precipitated from the water
column are effectively removed from the aquatic environment and no longer rep-
resent an immediate source of toxicity to aquatic life.
o
o
6
pCO3
10
12
Figure III-2-3. Relationships of metallic carbonate solubility and carbonate
concentrations
HARDNESS
Water hardness generally refers to the capacity of the water to precipitate
soap from solution. The constituents which impart hardness to water are poly-
valent cations, chiefly calcium (Ca) and magnesium (Mg). These form insoluble
complexes with a variety of anions, notably the salts of organic acids
(soaps). By convention, hardness is reported on the basis of equivalence as
mg/1 calcium carbonate (CaCCK).
Hardness cations are primarily associated with carbonate or sulfate anions.
Calcium and magnesium carbonate are referred to as carbonate hardness. When
the anlon 1s other than carbonate, such as sulfate or nitrate, this is refer-
red to as noncarbonate hardness. Because alkalinity and hardness are both ex-
III-2-9
-------
pressed as mg/1 CaCO^, it can be concluded that carbonate alkalinity will be
responsible for forming carbonate hardness and that hardness in excess of the
alkalinity is noncarbonate.
Importance to Aquatic Life
Hardness, the capacity of water to precipitate soap, is an aesthetic consider-
ation important to potable water supply. The importance of hardness to aquatic
life is related to the ions which impart hardness to water. There is some evi-
dence to suggest that hard water environments are more favorable for aquatic
life because they support more diverse and abundant biological communities
(Reid 1961).
There is a large body of evidence that hardness mediates the toxicity of heavy
metals to aquatic organisms. Mathematical correlations between the toxicity of
several heavy metals (Cr , Pb, Ag, Ni, Zn, Cd, and Cu) have been developed.
Table III-2-4 presents the equations (taken from the Water Quality Criteria
Documents) which enable the calculation of allowable metal concentrations as a
function of hardness. Although increased hardness can be correlated directly
with decreased toxicity, the mechanism of this effect is not certain. Two dif-
ferent mechanisms have been proposed, one chemical and one biological. Cala-
mari, et al. (1980) have reviewed the literature concerning these mechanisms,
and discussed both with regard to their own experimental data.
Hardness may operate through two chemical mechanisms to reduce heavy metal tox-
icity. Complexation of the toxic metal with carbonate might be the mechanism
if the free metal ion is the toxic species. Data may be found in the litera-
ture to support (Stiff 1971, Pagenkopf et al. 1974, Calamari and Marchetti
1975, Andrew et al. 1977), or contradict (Shaw and Brown 1974, Calamari et al.
1980) this suggestion. It is also possible that it is the calcium or magnesium
ion alone, rather than the associated carbonate, that is protective. Carroll
et al. (1979) present data which show that the calcium ion, much more than mag-
nesium, seems to reduce cadmium toxicity to brook trout.
Further, the question remains whether the hardness ions are antagonistic to
the action of the toxic metals and they may function biologically through
competitive inhibition of metal uptake or binding of sites of action. Kinkade
and Erdman (1975) published data to support the uptake inhibition mechanism.
Lloyd (1965) suggests that calcium has a protective effect on fish gill
tissue, an organ which is significantly involved in heavy metal uptake.
Calcium has been shown to decrease gill permeability to water, which would
influence metal uptake (Maetz and Bornancin 1975).
III-2-10
-------
TABLE III-2-4. DEPENDENCE OF HEAVY t€TAL TOXICITY ON WATER HARDNESS*
Metal Calculation of Maximum Allowable Concentration
Cadmium (Cd) e(1'05[ln 3.48)
Copper (Cu) e(0.94[ln (hardness)]-!.23)
Lead (Pb) e(1.22[ln (hardness)]-0.47)
N1ckel (N1) e(0.76[ln (hardness)]+4.02)
Si1ver (Ag) e(1.72[ln (hardness)]-6.52)
Zinc (Zn) e(0.83[ln (hardness)]+!.95)
EPA Ambient Water Quality Criteria Documents (1980).
There is evidence that calcium may be protective against the toxic action of
pollutants other than metals. Hillaby and Randal (1979) found that increased
calcium concentration decreased the acute toxicity of ammonia to rainbow
trout. Calcium concentration has also been associated with increased survival
of fish in acidic conditions (Haranath et al. 1978).
SALINITY
Salinity is a measure of the weight of dissolved salts per unit volume of
water. The chloride content of water, the chlorinity, is strongly correlated
with salinity. In freshwater, the total concentration of ionic components
constitutes salinity. The major anions are commonly carbonate, chloride, sul-
fate, and nitrate. The predominant associated cations are sodium, calcium,
potassium, and magnesium.
The source of these materials is the substrate upon which the water lies and
the earth through and over which water flows. The salinity of a given body of
water is a function of the quantity and quality of inflow, rainfall, and evap-
oration.
Importance to Aquatic Life
Salinity has an impact on a variety of parameters related to biological func-
III-2-11
-------
tions. It controls the ability of organisms to live in or pass through various
waters. It also has an effect on the presence of various food or habitat-
forming plants.
Salinity is important not only in an absolute sense, but the degree of vari-
ation in the salinity of a given water is biologically important. The invasion
of species to or from fresh or saltwater depends on their ability to tolerate
changes in salinity. Rapid changes in salinity cause disruption of osmoregula-
tion in aquatic organisms and can cause plasmolysis in plants. Organisms that
can tolerate a range of salinity can frequently use salinity gradients to
evade less tolerant predators.
Salinity is important to the heat capacity of aquatic systems. As salinity in-
creases, the specific heat of water decreases. This means that there is less
heat required to warm the water. Temperature is a significant factor in biolog-
ical activity and governs many physical processes in water as well.
Salinity also governs the dissolved oxygen concentration in water. For a given
temperature, the solubility of oxygen decreases with increasing salinity.
Table III-2-6 illustrates this effect. The dissolved oxygen concentration is
among the most critical of all water quality parameters to aquatic life.
The ions which make up the total salinity of water have individual effects as
well. The effects of calcium, magnesium, and carbonate have been discussed pre-
viously with respect to their effect on the toxicity of pollutants. Several of
the Ions (e.g., nitrate, and potassium) are plant nutrients.
Aquatic organisms have evolved a variety of physiological adaptations to the
salinity of their environments. These adaptations are largely related to their
osmoregulatory systems whose primary function 1s to solve the problem of the
difference between the salt concentration of the internal fluids of the organ-
ism and the salt concentration of the surrounding water. Freshwater organisms
must maintain an internal salt concentration against the tendency to gain
water from and lose salts to the environment. Osmoregulation in freshwater
fish results in the production of high volumes of liquid waste with a low salt
concentration. In contrast, marine organisms must maintain an internal salt
concentration that is lower than that of the environment, against a tendency
to lose water and gain salts. Osmoregulation in salt water fish results in the
production of small volumes of liquid waste carrying a relatively high salt
concentration.
The gills and kidneys of both types of fish are specially developed to accom-
plish these actions against the natural environmental gradient. Therefore, the
nature of these systems governs the ability of organisms to survive in regions
of varying salinity or to successfully migrate through them.
III-2-12
-------
TABLE III-2-5.
SOLUBILITY OF DISSOLVED OXYGEN IN WATER IN EQUILIBRIUM WITH
DRY AIR AT 760 mn Hg AND CONTAINING 20.9 PERCENT OXYGEN.
Tempera-
ture. *C
0
1
•>
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
0
14.6
14.2
13.8
13.5
13.1
12.8
12.5
12.2
11.9
11.6
11.3
11.1
10.8
10.6
10.4
10.2
10.0
9.7
9.5
9.4
9.2
9.0
8.8
8.7
8.5
8.4
8.2
8.1
7.9
7.8
7.6
Chloride
5000
13.8
13.4
13.1
12.7
12.4
12.1
11.8
11.5
11.2
11.0
10.7
10J
10.3
10.1
9.9
9.7
9.5
9.3
9.1
8.9
8.7
8.6
8.4
8.3
8.1
8.0
7.8
7.7
7.5
7.4
7.3
concentration.
10.000
13.0
12.6
12.3
12.0
11.7
11.4
11.1
10.9
10.6
10.4
10.1
9.9
9.7
9.5
9.3
9.1
9.0
8.8
8.6
8.5
8.3
8.1
8.0
7.9
7.7
7.6
7.4
7.3
7.1
7.0
6.9
mg/1
15.000
12.1
11.8
11.5
11.2
11.0
10.7
10.5
10.2
10.0
9.8
9.6
9.4
9.2
9.0
8.8
8.6
8.5
8.3
8.2
8.0
7.9
7.7
7.6
7.4
7.3
7.2
7.0
6.9
6.8
6.6
6.5
20.000
11.3
11.0
10.8
10.5
10.3
10.0
9.8
9.6
9.4
9.2
9.0
8.8
8.6
8J
8.3
8.1
8.0
7.8
7.7
7.6
7.4
7.3
7.1
7.0
6.9
6.7
6.6
6.5
6.4
6.3
6.1
III-2-13
-------
' SECTION IV: BIOLOGICAL EVALUATIONS
-------
CHAPTER IV-1
HABITAT SUITABILITY INDICES
Habitat Suitability Index (HSI) models developed by the U.S. Fish and
Wildlife Service are used to evaluate habitat quality for a fish species.
HSI models can be used Independently or in conjunction with the Habitat
Evaluation Procedures (HEP) applications described in Chapter II-l.
The HSI models provide a basic understanding of species habitat
requirements, and have utility and applicability to use attainability
analyses. There are several types of HSI models including pattern
recognition, word models, statistical, linear regression, and mechanistic
forms in the FWS model publication series. Use of models is predicated on
two assumptions: (1) an HSI value has a positive relationship to potential
animal numbers: and (?) there 1s a positive relationship between habitat
quality and some measure of carrying capacity. The mechanistic model
(Figure 1) sometimes referred to as a structural model is one type that
would he useful for use attainability assessments. Information from
literature reviews, expert opinion, and study results is integrated in
these models to define relationships between variables and habitat
suitability. Suitability Index (SI) graphs are developed for each model
variable (Figure ?.). The variables Included in a model represent key
habitat features known to affect the growth, survival, abundance, standing
crop, and distribution for specific species. The model provides a verbal
or mathematical comparison of the habitat being evaluated to the optimum
habitat for a particular evaluation species. For some mechanistic models
(Figure 3) a mathematical aggregation procedure is used to integrate
relationships of model components. In others (Figure 4) an HSI value is
defined as the lowest SI value for any variable in the model.
Nonmechanlstic models (e.g., statistical models for standing crop and
harvest) do not require use of SI graphs. Output from an HSI model,
regardless of the type, 1s used to determine the quantity of habitat for a
specific species at a site, and an HSI value ranges from 0 to 1, with 1
representing optimum conditions. The relationship:
Habitat area x Habitat quality (HSI) = Habitat Units (HU's)
provides the basis for obtaining habitat data to compare before and after
conditions for a site if pollution problems or other environmental
problems are solved.
As with all models, some potential sources of subjectivity exist in HSI
models. Potential subjectivity 1n mechanistic models may occur when: (1)
determining which variables should be Included in the model; (?.}
developing suitability Index graphs from contradictory or incomplete data:
(3) Incorporating information for similar species of different life stages
1n the suitability Index graphs: (4) determining whether or not highly
correlated variable really affect habitat suitability independently and
which variables, 1f any, should be eliminated from the model; (5)
determining when, where and how model variables should be measured; and
(fi) converting assumed relationships between variables Into mathematical
equations that aggregate suitability Indices for Individual variables into
a species HSI (Terrell et al., 1982). All models developed and published
IV-1-1
-------
by the U.S. Fish and Wildlife Service are subjected to reviews by species
experts to eliminate as much subjectivity as possible.
Appendix A-l of this manual is a reprint of the HSI developed for the
channel catfish. Readers are encouraged to read the appendix to gain
greater understanding of features of the model. HSI models for 19 aquatic
and estuarine fish species were published in FY 82, and an additional 20
are under development and planned for publication in FY 83. Models have
been published for striped bass, channel catfish, creek chub, cutthroat
trout, black crappie, white crappie, blue gill, slough darter, common
carp, smallmouth buffalo, black bullhead, green sunfish, largemouth bass,
northern pike, juvenile spot, juvenile Atlantic croaker, gulf menhaden,
brook trout, and the southern kingfish. Models for coastal species were
developed at the National Coastal Ecosystems Team (NCET) and those for
inland species were developed at the Western Energy and Land Use Team
(WELUT).
For more information concerning models for inland species, contact: Team
Leader, Western Energy and Land Use Team, 2627 Redwing Road, Fort Collins,
Colorado 805?6 (FTS 323-5100, or comm. 303-226-910(1). Individuals
interested in models for coastal species should contact Team Leader,
National Coastal Ecosystems Team, 1010 fiause Boulevard, Slide!!, Louisiana
70458 ( FTS 685-6511, or comm. 504-255-6511).
IV-1-2
-------
Habitat Variables
Life Requisites
% cover (V2)
Substrate type (V4)
X pools
* cover (V2)
Average current velocity (V1Q)
Temperature (adult) (V5),
Temperature (fry) (V12)
-^
Temperature (juvenile) (V14)
Dissolved oxygen (VQ)
Turbidity (Vy)
Salinity (adult) (Vg)' / /
Salinity (fry, juvenile) (V13)/ j
Length of agricultural j
growing season (Vg)
% pools
X cover (V2)
Dissolved oxygen (Vg)
Temperature (embryo) (V1Q)'
Salinity (embryo)
Food (CF)
Cover (Cc)
/I
.Water Quality
HSI
Reproduction (CR)
Figure 1. Tree diagram illustrating the relationship of habitat variables
and life requisites in the riverine model for the channel catfish HSI
model. The dashed line for the length of agricultural growing season
V6) is for optional use in the model (McMahon and Terrell 1982).
IV-l-3
-------
Variable
(V,)
Percent pools during
average summer flow.
25 50
75 100
(V,)
Percent cover (logs,
boulders, cavities,
brush, debris, or
standing timber) during
summer within pools,
backwater areas, and
littoral areas.
0.0
10 20 30 40 50
Figure 2. Suitability Index graphs for variables V, and V- in the
channel catfish riverine model. A SI value can rang"e from 0 to 1 with
representing an optimum condition (McMahon and Terrell 1982).
rv-l-4
-------
Food (CF)
C • V + V
F 2 4
I
Cover (CJ
r • f\i v V v V v'3
<-C ^Vl x V2 x V18;
Water Quality (C^
2(V5 * V12 * V + V7 x 2^8) + V9 + V13
CWQ 3
If Vg, V12, V14, V8, Vg, or V13 is <. 0.4, then CyQ equals the lowest
of the following: V5, V12, VH, VQ, Vg, V13, or the above equation.
Note: If temperature data are unavailable, 2(Vfi) (length of
agricultural growing season) may be substituted for the term
2(V 4-U 4-V \
^v5 •*• v12 * vu)
3 1n the above equation
Reproduction (CR)
If V8* V10' or vll is - 0>4> then CR e^11*15 tne lowest of the
following: Vg, V10, V^, or the above equation.
US I determination.
HSI - (CF x Cc x C^2 x CR2)1/6, or
If CWQ or CR is <_ 0.4, then the HSI equals the lowest of the
following: Cyg, CR, or the above equation.
Figure 3. Formulas for the channel catfish riverine HSI model (McMahon
and Terrell 1982).
rv-i-5
-------
Habitat Variables
Suitability Indices
Ratio of spawning habitat
to summer habitat [area that
Is less than 1 m deep and
vegetated (spring) divided
by total midsummer area] (V,)
Drop 1n water level during embryo
and fry stages (V2)
Percent of midsummer area with
emergent and/or submerged
aquatic vegetation or remains
of terrestrial plants (bottom
debris excluded) (V3)
IDS during midsummer
Least suitable pH in spawning
habitat during embryo and
fry stages (V5)
Average length of frost-free
season (V,)
Maximal weekly average
temperature (1 to 2 m
deep) (V7)
Area of backwaters, pools, or
other standing/sluggish
(less than 5 cm/sec) water
during summer, as a percent
of total area (VQ)
Stream gradient (Vg)
Figure 4. A tree diagram for the northern pike riverine HSI model. Note
that habitat variables are not aggregated for separate life requisite
components (Inskip 1982).
rv-i-6
-------
CHAPTER IV-2
DIVERSITY INDICES AND MEASURES OF COMMUNITY STRUCTURE
niversity is an attribute of biological community structure. The
concepts of richness and composition are commonly associated with
diversity. Species richness is simply the number of species, while
composition refers to the relative distribution of individuals among
the species, or evenness. Odum (1959) defined diversity indices as
mathematical expressions which describe the ratio between species and
individuals in a biotic community. A major advantage of diversity
indices is that they permit the summarization of large amounts of data
about the numbers and kinds of organisms into a single numerical
description of community structure which is comprehensible and useful
to people not immediately familiar with the specific biota. Some
diversity indices are expressions of the number of taxa, usually
species, in the community. Whittaker (1964) referred to these formulas
as indices of "species diversity", i.e. the more species - the greater
the diversity. "Dominance diversity indices" (Whittaker, 19M)
incorporate the concepts of both richness and evenness; thus, diversity
increases as the number of species increases or as the individuals
become more evenly distributed between the species.
The response of bottom fauna to four types of pollution is represented
in Figure IV-2-1 (Keup 1956). Figure IV-2-1A shows that organic
pollutants generally decrease the number of species present while
increasing the numbers of surviving taxa, whereas toxic pollutants tend
to reduce both numbers and kinds of organisms (Figure IV-2-13). In
general, the effect of all types of pollutant stress on community
structure is the loss of diversity. The value of diversity in natural
communities lies in the fact that the presence of many species insures
the likelihood of "redundancy of function" (Cairns et al. 1973). As
explained by Cairns and Dickson (1971), in a highly diverse community,
the constantly changing environment will probably affect only a small
portion of the complex bottom fauna community at any time. Because
there are many different kinds of organisms present, the role of those
eliminated as a result of natural environmental change will be filled
by other organisms. Thus the food cycle and the system 35 a whole
remain stable. On the other hand, natural environmental variation
might eliminate a significant portion of a community that has been
simplified hy pollutant stress. With no organism available to fill the
vacated niche, the functional capacity of the unstable community may be
jeopardized. Generally, maintenance of diversity is important because
it enhances the stability of a system.
Diversity indices are commonly computed as one tool among many in the
analysis of aquatic (as well as terrestrial) communities. Some
prevalent reasons for measuring community diversity are listed below
(these purposes are by no means independent of each other):
0 To investigate community structure or functions
0 To establish its relationship to other community properties
such as productivity and stability
0 To establish its relationship to environmental conditions
IV-2-1
-------
DIRECTION OF FLOW
A
OJ I
TJ
t i
1/1
2
UJ
cc.
"ME OR DISTANCE
Number of kinds
Number of organisms
Figure IV-2-1.
Response of bottom fauna to pollution: A=organic wastes;
B=toxic wastes; C=organic wastes showing temporary toxicity;
D=organic wastes mixed with toxic chemicals (from Keup,1966)
IV-2-2
-------
0 To compare communities
0 To evaluate the biotic health of the community
0 To assess the effects of pollutant discharges
0 To monitor water quality by biological rather than
physicochemical means
In analyses of freshwater aquatic communities, diversity studies generally
involve benthic macroinvertebrates or fish. Several advantages and
disadvantages have been given for the study of these groups (Cairns and
Dickson 1971, Karr 1081), and are listed in Table IV-2-1. These two groups
are generally considered to be the most suitable organisms for evaluation
of community integrity. Whereas it might be desirable to investigate the
diversity of both fish and macroinvertebrates, the two groups generally are
not used in combination to calculate a single diversity index because of
differences in sampling selectivity and error.
DIVERSITY INDICES
Many indices of diversity have been developed. Some indices selected from
the literature are presented in Table IV-2-2, and the more common ones are
discussed below.
Species Diversity Indices
Of the expressions described as species diversity indices (equations 1
through 4 in Table IV-2-2, plus others), the Margalef formula is probably
the most popular. Once the sampling and identification is completed, it is
an easy matter to calculate the diversity index using the Margalef formula
by substituting the number of species(s) and the total number of
individuals (n) into the equation below.
The use of this formula, and others of the type, has some important
limitations. First, it is not independent of sample size. Menhinick
(1964) found that for sample sizes from 64 to 300 individuals the Margalef
diversity index varied from 3.05 to 14.74, respectively. In that study,
four species diversity indices were evaluated for variation with sample
size and all were found unsatisfactory except for the equation referred to
as the Menhinick formula in Table IV-2-2. The second limitation of species
diversity indices is that, by definition, they do not consider the relative
abundance among species, and, therefore, rare species exert a high
contribution to the index value. To illustrate this limitation, Wi 1 hm
(1972) calculated diversity by the Margalef and Menhinick formulas for
three hypothetical communities each containing five species and mo
individuals (see Table IV-2-3). Communities A, B, and C exhibit a wide
range of relative distribution of individuals between the five species.
Intuitively, community A is more diverse than community C, but the two
species diversity indices fail to express any difference.
IV-2-3
-------
TABLE IV-2-1. ADVANTAGES AND DISADVANTAGES OF USING MACROINVERTEBRATES AND
F*SH
OF
BIOTICINTE(yiTY OF
COMMUNITIES (CAIRNS AND DICKSON. 1971; KARR , T5ETT)
MACROINVERTEBRATES
Advantages
0 Fish that are highly valued by humans
are dependent on bottom fauna as a
are extremely sensitive
and respond quickly to
food source.
0 Many species
to pollution
it.
0 Bottom fauna usually have a complex
life cycle of a year or more, and if
at any time during their life cycle
environmental conditions are outside
their tolerance limits, they die.
0 Many have an attached or sessile mode
of life and are not subject to rapid
migrations, therefore they serve as
natural monitors of water quality.
Disadvantages
al so
0 They require specialized
taxonomic expertise for
identification, which is
time-consuming.
0 Background life-history
information is lacking for
species and groups.
0 Results are difficult to
translate into values meaningful
to the general public.
many
FISH
Life history information is extensive
for most species.
Fish communities generally include a
range of species that represent a
variety of trophic levels (omnivores,
herbivores, insectivores,
planktivores, piscivores) and utilize
foods of both aquatic and terrestial
origin. Their position at the top of
the aquatic food web also helps
provide an integrated view of the
watershed environment.
Fish are relatively easy to identify.
Most samples can be sorted and
identified in the field, and then
released.
The general public can relate to
statements about conditions of the
fish community.
Poth acute toxicity (missing taxa)
and stress effects (depressed growth
and reproductive success) can be
evaluated. Careful examination of
recruitment and growth dynamics among
years can help pinpoint periods of
unusual stress.
Sampling fish communities is
selective in nature.
Fish are highly mobile. This
can cause sampling difficulties
and also creates situations of
preference and avoidance. Fish
also undergo movements on diel
and seasonal time scales.
There is a high requirement for
manpower and equipment for fiela
sampling.
IV-2-4
-------
TABLE IV-2-2. SUMMARY OF DIVERSITY INDICES
Descriptive Name
1. Simplest possible ratio of
species per individual
Formula
Reference
Wilhm, 1967
2. Sleason
log n
Menhinick, 1964,
Gleason, 1922
3. Margalef
s-1
In n
Margalef, 1951
1956
4. Menhinick
(n)
1/2
Menhinick, 1964
5. Mclntosh
- (In.2)
2,1/2
- n - (n)
I7T
Mclntosh, 1967
6. Simpson
Ini(nrl)
n (n-1)
Simpson, 1949
7. Brillouln
f 1
H » tA; !Jog n! - L log n.!, 3rillouin, 196C
n • — i i
8. Shannon-Wiener
H - -I (p,
Shannon and
Weaver, 1963;
Wiener, 1948
Approximate fonn of the
Shannon Index
- ,^ -
a - -1 i-l,log2iy-j
Shannon Index using
biomass (weight) units
Wilhm, 1968
IV-2-5
-------
TABLE IV-2-2. (Cont'd)
9. Hierarchical
Diversity Index
(HOI)
HOI • H'{F)+H',+H' (S'
r ur
Pielou, 1969,
1975
10. Hierarchical Trophic- HTOI » H1 (T. )+H' (T,)+H ' ,-(T.) Osborne et al .,
Based O.I. (HTDI) L l * i 1,1* -J 1980
11. Redundancy (r)
- d
3 - d .
max mm
Patten, 1962;
Wilhm, 1967
12. Equitability (e)
Lloyd and
Ghelardi, 1964
13. Evenness (J,J' , v)
max
Pielou 1969,
1975; Hurlbert,
1971
j-
max
max " min
14. Number of moves (NM)
*•n fvn - ; Vi
Fager, 1972
15. Sequential Comparison Index DI, «
number of runs
, num,er O species
DI
UT, j' number of taxa;
Cairns et al.
1968; Cairns S
Dickson, 1971;
Buikema et a"1 .
1980
IV-2-6
-------
TABLE IV-2-2. (Cont'd)
KEY
H * d s H' =3a diversity index.
n * total number of individuals.
n. » number of individuals in species i.
s * total number of species.
p. = probability of selecting an element of state i 2 __.
R. » rank of species i.
s1 « the species required to produce the calculated d.i. value if
the individuals were distributed among the species accord-
ing to MacArthur's (1957, 1960) "broken-stick" model.
IV-2-7
-------
TABLE IV-2-3.
Community
A
B
c
nl
20
40
1
DIVERSITY
"AR GAL
n2
20
30
1
« N
»• ' »
n3
20
15
1
OF THREE HYPOTHETICAL
MENH
n4
20
10
1
INICK,
n5
20
5
96
Aro
n
100
100
100
SHANNON
S
5
5
5
COMMUNI
-wIEMER
s-1
j A
In n
0.87
0.87
0.87
"1ES
IliDl
s
n1/2
n.so
0.50
0.50
EVAL
£"S
d
2.
1.
0.
DATED Bv THE
32
57
12
Another shortcoming of species per individual formulas is that they are not
aimensionless, thus substitution of alternate variables for numoers - SUCH
as biomass or energy 'low - would produce values dependent on tne arsitrar}
choice of units.
The major advantage of using species diversity indices 's the simplicity of
calculation; however, certain conditions for their prooer jse must be
c:>nsidered. Since these *ormulas are depenaent on sample size (except
possibly, the Menhinick equation), for intercommunity comparison the sample
sizes snould be as nearly identical as possible. It must be kept in mind
that tnese expressions represent only the numoer of species and not any
expression of relative abundance. Finally, for use of variables otner than
numbers, the units must be specified and kept consistent.
Dominance Diversity Indices
The most prominent dominance diversity index (equations 5 througn 8 in
Table IV-2-2, plus others) is the Shannon-Wiener formula. This index is
used extensively in research projects, as is the Simpson eauation. The
Shannon-Weiner diversity index evolved from information theory to the
functional equation shown below:
in wnich the ratio of the number of individuals colnected of species i
to the total number of individuals in tne sample (n^/") estimates the
total population value (N^/N), which is an approximation of tne
Drooaoility of collecting an individual of species i (P-J ). It snould be
noted tnat the units of d using Iog2 is the oinary unit, or bit. Natural
logarithms or login, are sometimes substituted into the eauation for
convenience, in which case different index values would be obtained, with
the units of nats or decits, respectively. The Shannon-Wiener aiversity
'naex is calculated using base 10 logarithms, for two simple, hypothetical
samples in Example IV-2-1 (see statistical analysis section). A formula
for conversion between differently-based logarithms is given below;
1og2Y « K443 in y * 3.323
The logarithm base and units should always be given when reporting data.
IV-2-8
-------
The dominance and species diversity indices discussed can be used to
measure the diversity of virtually any biological community (including
macroinvertebrates and fish), and their application is limited only by
sampling effectiveness. Wilhm and Dorris (1968) evaluated species
diversity of benthic macroinvertebrates using the Shannon-Wiener formula
and obtained values less than 1.0 in areas of heavy pollution, values from
l.n to 3.0 in areas of moderate pollution, and values exceeding 3.0 in
clean water areas (values given are in decits).
Disadvantages of using the Shannon index (or others of the type) include
the considerable time, expense, and expertise involved in sampling,
sorting, and identification of samples. Calculation of the index value can
be mathematically tedious if done manually, but is greatly simplified if a
computer is available. Computer programs for computing d and r are
provided in the literature (Wilhm, 1970; Cairns and Dickson, 1971).
The Shannon-Wiener formula has a number of features which enhance its
usefulness. This index of diversity is much more independent of sample
size than the species diversity indices (Wilhm 1972). Since it
incorporates the concept of dominance diversity, the relative importance of
each species collected is expressed and the contribution of rare species to
diversity is low. This is illustrated by the d values calculated using the
Shannon equation for the three communities in Table IV-2-3. Also, the
Shannon formula is dimensionless, facilitating the measurement of biomass
diversity. Odum (1959) recognized that the structure of the biomass
pyramid held more ecological (trophic) significance than the numbers
pyramid because it takes many small individuals to equal the mass of one
large individual. The Shannon-Wiener equation can easily be modified to
accomodate any units of weight as shown below:
a -
Wilhm (1968) pointed out that use of this diversity index with units of
energy flow might be even more valuable to the study of community structure
and function.
Hierarchical Diversity
Diversity indices, such as the Shannon-Wiener index, can be partitioned to
reflect the contribution made by different taxonomic and trophic levels.
Pielou (1975) suggested that a community showing more diversity at higher
taxonomic levels (e.g. genus and family) should be considered to be more
diverse than a community with the same number of species but congeneric or
cofamilial. Osborne et al (1980)questioned the ecological significance of
Pielou's suggestion, but investigated the use of the hierarchical diversity
index (HDI) shown below:
HDI = H'(F) + H'p(G) + H'FG(S)
in which H'(F) is the familial component of the total diversity, H'F(G)
is the generic component of the total diversity, and H'pr(S) is the
IV-2-9
-------
specific component of the total diversity. The equation used by Kaesler et
al. (1978) illustrates the calculation of the hierarchical components.
They used
o N. o fl Nf< o fl gij N1.
H ' « Ho * *,[} TT HF,i * \\} jl, "FT HG,ij * 6 ii, >! ki-,
where a ,3,Y, and 5 are weighting coefficients; subscripts 0, F, G, and S
reoresert order, family, genus, and species, respectively; o, f, and g
represent number of orders, families within orders, and genera within
families, respectively; N represents the number of individuals; and N^
represents the number of individuals in the ith group, Osborne et al.
(1980) concluded that identification to the family level was sufficient to
detect intersite differences in that study, while the order level (Hughes,
1978) and generic level (Kaesler et al., 1978) were sufficient in other
studies. Determination that identification to species or genus is
unnecessary for a particular study would reduce the time, expertise, and
expense required. A hierarchical diversity index would be of more
ecological value if it were based on trophic relationships rather than
taxonony. Osoorne, et al. (1980) presented the following hierarchical
trophic diversity index (HTDI):
HTDI = H'(TT) * H'T1(T2) + H'T1T2(T3)
in which H'(T]) is the general trophic level component of the total
trophic diversity, H'yi(T2) is the functional group component of the
total trophic diversity, and H'|H2(T3^ is the !owest taxonomic
unit component of the total trophic diversity. The classifications used in
the hierarchical trophic-based diversity index of Osborne et al. (1980) are
listed in Table IV-2-4A. Two classification systems were investigated by
Kaesler et al. (1978): the trophic classifications appear in Table IV-2-4B.
ana tne functional morphological classifications are shown in Table
IV-2-4C. All of these hierarchical diversity indices used benthic
macroinvertebrates as their group of study. Hierarchical diversity indices
based on trophic level and functional morphology are relatively new and
their utility will improve as more experience is gained. These indices are
of potentially great ecological value because of their functional (rather
tnan structural, e.g. taxonomic) approach to community analysis.
Evenness and Redundancy
When using dominance diversity indices, it is desirable to distinguish
between trie two concepts of diversity incorporated into them, since it is
theoretically possible for a community with a few, evenly-represented
soecies to have the same index value as a community with many,
unevenly-represented species. For this reasons, relative diversity
expressions (equations 11 through 14 in Table IV-2-2, plus others) such as
eveness and redundancy are often used in conjunction with dominance
diversity ind^cies. Redundancy is an expression of the dominance of one or
^ore soecies and is inversely proportional to the wealth of species (Wilhm
ana Dcrris, 19*3). To use the redundancy expression in conjunction with
the Shannon-Wiener index, the theoretical maximum diversity (dmax)
and -mniTiun diversity (dm-jn) are calculated by the equations:
~. (1} [I0g2n! - s Iog2 (n/s)!]
IV-2-10
-------
TABLE IV-2-4. FUNCTIONALLY-B^SED HIERARCHICAL CLASSIFICATION SVSTEHS
A. Hierarchical trophic classification used for HTDI calculations
HTI
(Trophic level )
Omni vore
Carni vore
Herbivore
Detriti vore
HT2
(Functional group)
Filter Feeders
Collector-Gatherer-
Shredder-Engulfer
Engulfer-Shredder
Collector-Filterer-
Engulfer
Engulfer-Grazer
Engulfer-Collector-
Grazer
Engulfer
Piercer
Scraper-Collector-Gatherer
Col lector.Gatherer-Shredder
Col lector-Filterer-Gatherer
Collector-Gatherer
Collector-Filterer
Shredder
Shredder
Col lector-Gatherer
HT3
(Number of individuals)
Number of individuals of each
taxon within each functional
group.
8. Trophic classification of macrobenthic invertebrates. For any specific
application, not all possible combinations are likely to be realized.
Level of
Hierarchy Name
Subdivi sions
I
II
III
IV
Functional group
Feeding mechanism
Dependence
Food habit
Species
shredders (vascular plant tissues)
collectors (detrital materials)
grazers (Aufwuchs)
predators
parasites
chewers and miners
filters (suspension feeders)
gatherers (sediment or deposit feeders)
scrapers
chewers and suckers
Swallov/ers and chewers
piercers
attachers
obiigate
facultati ve
herbi vory
detri ti vory
carni vory
omni vory
number of individuals
IV-2-11
-------
TABLE IV-2-4
FUNCTIONALLY-BASED HIERARCHICAL CLASSIFICATION SYSTEMS (Cont'd)
C. HBR (head, body, respiratory organ) classification of macrobenthic
invertebrates according to functional morphology: head position,
body shape, and respiratory organs.
Level of
Hierarchy
Name
Subdivisions
I
I!
Head position
category)
(feeding
Body shape (current
of stream)
III
Respiratory organs
(substratum)
IV
Species
hypognathous
prognathous
opisthorhynchous
vestigial or other
flattened irregular
flattened oval
flattened elongate
compressed laterally
cylindrical
elongate
short, compact
fusi form
irregular
hemicylindrical or
simple filamentous
compound filamentous gills
plate!ike gi11s
operculate gills
leaflike gills or organs
respiratory dish
respiratory tube
spiracular gills
caudal chamber
plastron
body integument
tracheal respiration
number of individuals
subtriangular
gills
IV-2-12
-------
1r-(l) Ilog2n! -lo,z[n-
Then the location of d between the theoretical extremes can be computed by
the redundancy formula: g
r
max
max* irn'n
Table IV-2-5 illustrates the expression of redundancy.
TABLE IV-2-5. THE SHANNON-WIENER INDEX AND CORRESPONDING
REDUNDANCY VALUES FOR 11 HYPOTHETICAL
COMMUNITIES, (after Patten, 1962).
Communities
Species A
Si 1
So 1
ST ...... 1
Sc 1
S* 1
B
2
1
1
1
1
_
C
2
2
1
1
_
D
3
1
1
1
•
E
2
2
2
-
_
(N =
F
3
2
1
-
_
6)
G
4
1
1
-
.
H
3
3
—
-
.
I J
4 5
2 1
— —
_
-
. v
K
6
-
—
_
-
_
"d(bits)2.58 2.25 1.93 1.79 1.61 1.47 1.25 1.00 0.92 0.65 0.00
R 0.00 0.13 0.25 0.30 0.38 0.43 0.52 0.61 0.64 0.75 1.00
Expressions have also been developed to describe the evenness of
apportionment of individuals among species in a community. Evenness
measures have historically taken two forms. One is the ratio of diversity
to the maximum possible diversity, where d,,,^ is defined as the
community in which all species are equally distributed:
max
cl/log s
Where the logarithm is to the same base as used in the corresponding
diversity index calculation. However, log s is only an approximation of
dmax because all species in the community generally will not be
sampled. A measure of evenness that does not depend on s is shown below:
d-d.
v * —
Jnnn
max " min
It was from this measure of evenness that the expression for redundancy
(shown above) was derived by the relationship r * 1-V; thus, redundancy may
also be thought of as a measure of the unevenness of apportionment of
individuals among species.
Sequential Comparison Index
The sequential comparison index (SCI) is probably the most widely used
index of diversity because of its extensive worldwide use in industrial
(non-academic) studies. The SCI is a simplified, rapid method for
estimating relative differences in biological diversity and has been used
IV-2-13
-------
mainly for assessing the biological consequences of pollution. Use of the
SCI requires no taxonomic expertise on the part of the investigator.
Although it has been used with microorganisms, the SCI is predominately
used to evaluate diversity in benthic macroinvertebrate communities. The
collected specimens are randomly poured into a white enamel pan with
parallel lines drawn on the bottom. Only two specimens are compared at a
time. Comparisons are based on differences in shape, color, and size of
the organisms. If the imminent specimen is apparently the same as the
previous one, it is part of the same "run"; if it is not, it is part of a
new run. An easy way of recording runs is to use a series of X's and O's.
For example, the specimens shown in line one of Figure IV-2-2 would be
recorded, from left to right as X Q_ X 0^ _X 0 X, or seven runs. The
specimens in line two would be tabuTated~by X X~X TJ X X X. Sample two only
contains three runs and is obviously less dfverse. Ultimately, it will be
necessary to know the total number of taxa in the collection. This can
either be counted after determining the number of runs or determined
simultaneously by underlining the symbol of each new taxon as shown above.
Cairns, et al. (1971) described the following stepwise procedure for
calculating the Sequential Comparison Diversity Index:
1. Gently randomize specimens in a jar by swirling.
2. Pour specimens out on a lined white enamel pan.
3. Disperse clumps of specimens by pouring preservative or water on
clumps.
4. If the sample has fewer than 250 specimens, determine the number of
runs for entire sample and go to Step 12.
5. If sample has more than 250 specimens, determine the number of runs for
the first 50 specimens.
fi. Calculate DIi where DIj = numbers of runs/50.
7. Plot DIi against the number of specimens examined as in Figure
IV-2-3.
8. Calculate the SCI for the next 50 specimens.
9. Determine the total number of runs for the 100 specimens examined.
10. Calculate a new DIj for 100 specimens as in Step 6 and plot the value
obtained on the graph made in Step 7, where DIi = number of runs/100.
11. Repeat this procedure in increments of 50 until the curve obtained
becomes asymptotic. At this point enough specimens have been examined
so that continued work will produce an insignificant change in the
final PIj value.
12. Calculate final DI^ where
DIi = number of runs
number of specimens
13. Record the number of different taxa observed in the entire sample. This
can be done after deriving the final 01^ or simultaneously by simply
noting each new taxon as it is examined in the determination of runs.
IV-2-14
-------
2.
tTO»
so x>oi»o)oot»e)ooMo«ao4«o«ao
NUMKR Of SPCCIMCM
Figure IV-2-2. Determination of runs in SCI
technique (from Cairns and Dickson, 1971).
Figure IV-2-3. DI, and sample
size (from Cairns and Dickson,
1971).
DI
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2 r
C.I
0
A = use line A to be 95°:
confident the mean DI-,
is within 20°. of true*value
B =
use 1 ine 3 to be 95:.-
confiaent the mean DI,
is within 10% of true^alue
!
ID I:
Number of times to repeat SCI
examination on same sample
Figure IV-2-4. Confidence limits for DIj values (from Cairns ana D^
1971)
IV-2-15
-------
14. Determine from Figure IV-2-4 the number of times the SCI examination
must be repeated on the same sample to be 95 percent confident that the
mean nij is within a chosen percentage of the true value for DIj.
In most pollution work involving gross differences between sampling
areas, Line A of Figure IV-2-4 should be used. For example, suppose
DIj were 0.60. Using Line A of Figure IV-2-4 the SCI should be
performed twice to he 95 percent confident that the mean DIj is
within 20 percent of the true value.
15. After determining N, rerandomize the sample and repeat the SCI
examination on the same number of specimens as determined in Step
11. Repeat this procedure N - 1 times.
Ifi. Calculate PI^ by the following equation:
DIj = DI] x (number of taxa)
17. Calculate PI-j- by the following equation:
DIj = (ni-)) x (number of taxa)
18. Repeat the above procedure for each bottom fauna collection.
19. After determining the DIj for each botto-n fauna collection at each
sampling station, there is a simple technique for determining if the
community structures of the bottom fauna as evaluated by the SCI
(ni-r^ value are significantly different within a station or between
stations. Calculate the 95 percent confidence intervals around each
OIj value. If the 95 percent confidence intervals do not overlap,
then the community structures of the bottom fauna as reflected by the
Olr values are significantly different. For example, suppose the
DIj value for Station 1 were 45 and for Station 2 were 28. In the
determination of DIj a decision was made to use Line A in Figure
IV-2-4, which means that the DIj is within 20 percent of the true
value 95 times out of 100. Therefore the 95 percent confidence
interval for the DIj value at Station 1 would be from 49.5 to 40.5,
or ID percent of the DIj value on either side of the determined
Dl-r. Station 2 would have a 95 percent confidence interval for the
DIj value of from 30.8 to 25.2. The bottom fauna communities at the
two stations as evaluatd by the DI-p index are significantly
di fferent.
The SCI permits rapid evaluation of the diversity of benthic
macroinvertehrates. Some insight into the integrity of the bottom
community can be gained fro**1 DIj values. Cairns and Dickson (1971)
reported that healthy streams with high diversity and a balanced density
see~i to nave Ply values above 12.0, while polluted communities with
skewed oop'j'atior structures have given values for OIj of R.O or less,
and -intermediate values have been found ir semipol luted situations.
IV-2-16
-------
SPECIAL INDICES
Several expressions that are not diversity indices per se but which
incorporate the concept of diversity have been formulated. These include
numerous biotic indices (Pantle and Buck, 1955; Beck, 1955; Beak, 1964;
Chutter 1971, Howmiller and Scott 1977, Hilsenhoff 1977, Winget and Mangum
1979), a composite index of "well-being" (Gammon 1976), and Karr's index
(Karr 1981). These indices are designed to evaluate the biotic integrity,
or health, of biological communities and ecosystems.
Biotic Indices
Beck (1955) developed a biotic index for evaluating the health of
streams using aquatic macroinvertebrates. In the equation
Biotic index « 2(n Class I) + (n Class II)
where n represents the number of macroinvertebrate species, more weight is
assigned to Class I organisms (those tolerant of little organic pollution)
than to Class II organisms (those tolerant of moderate organic pollution
but not of anaerobic conditions). A stream nearing septic conditions will
have a biotic index value of zero; whereas streams receiving moderate
amounts of organic wastes will have values from 1 to 6, and streams
receiving little or no waste will have values usually over 10 (Gaufin
1973).
The biotic index proposed by Hilsenhoff uses the arthropod community
(specifically insects, amphipods, and isopods) to evaluate the integrity of
aauatic ecosystems via the formula:
BI = 2 n.a./n
where n^ is the total number of individuals of the ith species (or
genus), ai is the tolerance value assigned to that species (or genus),
and n is the total number of individuals in the sample (Hilsenhoff, 1977;
Hilsenhoff, 1982). Pollution tolerance values of zero to five are assigned
to species (or genera when species cannot be identified) on the basis of
previous field studies. A zero value is assigned to species found only in
unaltered streams of very high water quality, a value of 5 is assigned to
species known to occur in severely polluted or disturbed streams, and
intermediate values are assigned to species occurring in intermediate
situations. Calculation of this and other biotic indices are methods of
biologically assessing water quality.
Index of Well-Being
Utilizing fish communities, Gammon developed a composite index of well-
being (IWB) as d t°°l f°r measuring the effect of various human
activities on aquatic communities (Gammon, 1976; Gammon and Reidy, 1981;
Gammon et al., 1981). This index was calculated by:
IUB = 0.51nn+0.51nw + dno •*• dwt
in which n is the number of individuals captured per kilometer, w is the
weic^t in kilocrams captured per km, d^g is the Shannon index based on
numbers, and dwt is tne Shannon index based on weights. (The Shannon
index was calculated using natural logarithms).
IV-2-17
-------
Karr's Index of Biotic Integrity (IBI)
Karr (1991) presented a procedure for classifying water resources by
evaluating their biotic integrity using fish communities. Use of the
system involves three assumptions: (1) the fish sample is a balanced
representation of the fish community at the sample site; (2) the sample
site is representative of the larger geographic area of interest; and (3)
the scientist charged with data analysis and the final classification is a
trained, competent biologist with considerable familiarity with the local
fish fauna. For each of the twelve criteria listed in Table IV-2-6, the
evaluator subjectively assigns a minus (-), zero (0), or plus (+) value to
the sample. The grades are assigned numerical values - (-)=!, (0)=3, (-0=5
- which are summed over all twelve criteria to produce an index of
community quality. The sampled community is then placed in one of the
biotic integrity classes described in Table IV-2-7 based on numerical
boundaries such as those tentatively suggested by Karr (1981) and shown in
Table IV-2-R.
TABLE IV-2-6. PARAMETERS USED IN ASSESSMENT OF FISH
COMMUNITIES. (SEE ARTICLE TEXT FDR DISCUSSION.)
Species Composition and Richness
Number of Species
Presence of Intolerant Species
Species Richness and Composition of Darters
Species Richness and Composition of Suckers
Species Richness and Composition of Sunfish (except
Green Sunfish)
Proportion of Green Sunfish
Proportion on Hybrid Individuals
Ecological Factors
Number of Individuals in Sample
Proportion of Omnivores (Individuals)
Proportion of Insectivorous Cyprinids
Proportion of Top Carnivores
Proportion with Disease, Tumors, Fin Damage, and
Other Anomalies
BIOLOGICAL POLLUTION SURVEY DESIGN
The first step in planning any survey of water quality is to identify
specific objectives and clearly define what information is sought. For
instance, the objective of a use attainability analysis might be to
evaluate the water quality or degree of degradation of a body of water, in
general, in order to ascertain the accuracy of the current use designation.
Alternately, the analysis objective might be to determine the extent of
damage caused by a discharge or series of discharges. From such
information, the potential attainable use can be identified; judgments must
then be made regarding the benefits/costs of improving the degree of waste
treatment.
IV-2-18
-------
TABLE IV-2-7: BIOTICINTEGRITY CLASSES USED IN ASSESSMENT OF FISH COMMUNITIES
ALONG UITH GENERAL DESCRIPTIONS OF THEIR ATTRIBUTES
Class Attributes
Excellent Comparable to the best situations without influence of
man; all regionally expected species for the habitat and
stream size, including the most intolerant forms, are
present with full array of age and sex classes; balanced
trophic structure.
Good Species richness somewhat below expectation especially
due to loss of most intolerant forms; some species with
less than optimal abundances or size distribution;
trophic structure shows some signs of stress.
Fair Signs of additional deterioration include fewer
intolerant forms, more skewed trophic structure (e.g.,
increasing frequency of omnivores); older age classes of
top predators may be rare.
Poor Dominated by omnivores, pollution-tolerant forms, and
habitat generalists; few top carnivores; growth rates
and condition factors commonly depressed; hybrids and
diseased fisn often present.
Very Poor Few fish present, mostly introduced or very tolerant
forms; hybrids common; disease, parasites, fin damage,
and other anomalies regular.
No Fish Repetitive sampling fails to turn up any fish.
TABLE IV-2-8: TENTATIVE RANGES FOR THE BIOTIC
INTEGRITY CLASSES.
Class Index Number
Excellent (E) 57-60
E-G 53-56
Good (G) 48-52
G-F 45-47
Fair (F) 39-44
F-P 36-38
Poor (P) 28-35
P-VP 24-27
Very Poor (VP) < 23
IV-2-19
-------
The next steps in planning the survey are to review all available reports
and records concerning the waste effluents and receiving waters, and to
make a field reconnaissance of the waterway, noting all sources of
pollution, tributaries, and uses made of the water.
Sampling Stations
There is no set number of sampling stations that will be sufficient to
monitor all types of waste discharges; however, some basic rules for a
sound survey design are listed below (Cairns and Oickson 1971). The
following describes an "upstream-downstream" study. The reader should also
consult Section IV-fi on the reference reach approach to see an alternative
method.
1. Always have a reference station or stations above all possible
discharge points. Because the usual purpose of a survey is to
determine the damage that pollution causes to aquatic life, there must
be some basis for comparison between areas above and below the point or
points of discharge. In practice, it is usually advisable to have at
least two reference stations. One should be well upstream from the
discharge and one directly above the effluent discharge, but out of any
possible influence from the discharge.
2. Have a station directly below each discharge.
3. If the discharge does not completely mix on entering the waterway but
channels on one side, stations must be subdivided into left-bank,
midchannel, and right-bank substations. All data collected
biological, chemical, and physical - should be kept separate by
substations.
4. Have stations at various distances downstream from the last discharge
to determine the linear extent of damage to the river.
5. All sampling stations must be ecologically similar before the bottom
fauna communities found at each station can be compared. For example,
the stations should be similar with respect to bottom substrate (sand,
gravel, rock, or mud), depth, presence of riffles and pools, stream
width, flow velocity, and bank cover.
6. Biological sampling stations should be located close to those sampling
stations selected for chemical and physical analyses to assure the
correlation of findings.
7. Sampling stations for bottom fauna organisms should be located in an
area of the stream that is not influenced by atypical habitats, such as
those created by road bridges.
8. In order to make comparisons among sampling stations, it is essential
that all stations be sampled approximately at the same time. Not more
than 2 weeks should elapse between sampling at the first and last
stations.
IV-2-20
-------
For a long-term biological monitoring program, bottom organisms should be
collected at each station at least once during each of the annual seasons.
More frequent sampling may be necessary if water quality of any discharge
changes or if spills occur. The most critical period for bottom fauna
organisms is usually during periods of high temperature and low flow of the
waterway. Therefore, if time and funds available limit the sampling
frequency, then at least one survey during this time will produce useful
information.
Sampling Equipment
Commonly used devices for sampling benthic macroinvertebrate communities
include the Peterson dredge, the surber square foot sampler, aquatic bottom
nets, and artificial substrate samplers. Proper use of the first three
pieces of equipment requires that the operator exert the same amount of
effort at each station before comparisons can be made. This subjectivity
can cause error, but can be minimized by an experienced operator.
Artificial substrates standardize sampling to some extent by providing the
same type of habitat for colonization when placed in ecologically similar
conditions. A simple type of artificial substrate sampler is a wire basket
containing rocks and debris. Others consist of masonite plates or plastic
webs which can be floated or submerged. Additional advantages of
artificial substrate samplers are quickness and ease of use.
electrofishing gear, encircling gear (haul
(otter trawl), gill nets, maze gear, and
As discussed above, the same
station when using this
reduce the selectivity of
Fish sampling equipment includes
seine, purse seine), towed nets
chemical toxicants (rotenone, antimycin).
sampling effort must be put forth at each
equipment. Also, measures should be taken to
fish sampling.
Number of Samples
If comparisons are to be made between stations in a pollution survey, each
station must be sampled equally. Either an equal number of samples must be
taken at each station or an equal amount of time and effort must be
expended.
Organisms are not randomly distributed in nature, but tend to occur in
clusters. Because of this, it is necessary to take replicate samples in
order to obtain a composite sample that is representative of that station.
There is no "cookbook recipe" which defines the number of samples to take
in a given situation. Cairns and Dickson (1971) have found practical
experience to show that not less
3 to 10 dredge hauls, and at
the minimum number of
a particular station.
samples increases the
represent
fauna of
replicate
replicate
sample.
than three artificial substrate samplers,
least three Surber square foot samples
samples required to describe the bottom
Naturally, increasing the number of
reliability of the data. The data of
samples taken at a given station are combined to form a pooled
It has been found that a plot of the pooled diversity index versus
IV-2-21
-------
cumulative sample units becomes asymptotic, and that once this asymptotic
diversity index value is found, little is gained by additional sampling.
Ideally, a base line study would be conducted to determine the optimum
number of samples for a pollution survey.
STATISTICAL ANALYSES
This section describes some of the statistical methods of comparing the
diversity indices calculated for different sampling stations.
Hutcheson's t-test
Hutcheson (1970) proposed a t-test for testing for difference between two
diversity indices:
. _ Hl ' H2
Hl ' H2
Where
and
is simply the difference between the two diversity indices,
- S2
1 H2
The variance of H may be approximated by:
.2
SH,
I f log2 f
1
log
'H
n
2'
Where f^ is the frequency of occurrence of species i and n is the total
number of individuals in the sample. The degrees of freedom (df)
associated with the preceding t are approximated by:
.22 ,.22
CSH
1
)2/
Convenient tables of f-jlog^ are provided by Lloyd, et al. (1968),
and t-distribution tables can be found in any statistics textbook (such as
Dixon and Massey, 1969; Zar, 1974; etc.). Example IV-2-1 demonstrates the
calculation of the Shannon-Wiener index (H) for two sets of hypothetical
sampling station data, and then tests for significant difference between
them using Hutcheson's t-test.
IV-2-22
-------
Example IV-2-1. Comparing Two Indices of Diversity (adapted from Zar
197d). ~~ ~"~ "
H0: The diversity index of station 1 is the same as the diversity
index of station 2.
HA: The diversity indices of stations 1 and 2 are not the same. The
level of significance (Q) « 0.05
Species
1
2
3
4
5
6
numoer of
individuals( i)
47
35
7
5
3
3
Station 1
percentaae( f)
47
35
7
5
3
3
1 1
78.5386
54.0424
5.9157
3.4949
1.4314
1.4314
f, log2 f,
131.4078
83.4452
4.9994
2.4429
0.6830
0.6830
n. n.
1 , 1
n-10* 1T
-0.1541
-0.1596
-0.0808
-0.0651
-0.0457
-0.0457
100
100
144.9044
223.6613 -0.5510
Species
1
2
3
4
5
6
number of
individuals^ f )
48
23
11
13
3
2
Station 2
percentagef f )
48
23
11
13
3
2
i i
80.6996
31.3197
11.4553
14.4813
1.4314
0.6021
f1 log2 f.
135.6755
42.6489
11.9294
16.1313
0.6830
0.1R13
n.
n *
-0.1530
-0.1468
-0.1054
-0.1152
-0.0457
-0.0340
!i
n
100
100
139.9894
207.2494 -0.6001
IV-2-23
-------
HI = 0.5510 H2 = 0.6001
sl = 0.00136884 Sf; » 0.00112791
Hl H2
S = 0.0499
V 2
t = -0.98
df = 198.2 = 200
From a t-distribution table: t« 0,5/2) 200 * ^
Therefore, since the t value is not as great as the critical value for the
95 percent level of significance (d= 0.05), the null hypothesis (H0) is
not rejected.
Analysi s of Variance
Analysis of variance (ANOVA) can be used to test the null hypothesis that
all means are equal, e.g. H0:u^=U2=...'U^, where k is the number of
experimental qroups. "Single factor or "one-way" ANOVA is used to test
the effect of one factor (sampling site) on the variable in question
(diversity) in Example IV-2-2. Two-way ANOVA can be used for comparison of
spacial and temporal data.
In Example IV-2-2, each datum (X,j) represents a diversity index that
has been calculated for j replicate samples at each of i stations.
Also, x. represents the mean of station i, ni represents the number of
replicales in sample i, and N(=£n.) represents the total number of indices
calculated in the survey.
After computing the mathematical summations, the ANOVA results are
typically summarized in a table as shown. The equality of means is
determined by the F test.
IV-2-24
-------
Ci, groups df, error df « group MS
error MS
The critical value for this test is obtained from an F-di stri bution table
based on the degrees of freedom of both the numerator and denominator.
Since the computed F is at least as large as the critical value, HQ is
rejected, e.g. the diversity index means at all stations are not equal.
Example IV-2-2. A Sinale Factor Analysis of Variance (adapted from Zar
H0: uj * U£ * U3 * U4 * U5
HA: The mean diversity indices of the five stations are not the same
Q = 0.05
Station 1
2. £2
3.32
3.6
-------
n.
i
groups sum of squares =
/n.
= 2.37
error sum of squares = total ss - groups ss
total degrees of freedom = N - 1 = 29
groups degrees of freedom = k - 1 = 4
error degrees of freedom = total df - groups df = 25
mean squared deviations from the mean (MS) = ss/df
groups MS = 21.92/4 = 5.48
error MS = 2.37/25 = 0.09
Summary of the Analysis of Variance
Source of Variation SS df
total
groups
error
F = groups MS
error MS
24.29
21.92
2.37
5.480
0.095
29
4
25
57.68
5.480
0.095
F 0.05(1),4,25 = 2'76
Therefore, Reject HQ : j^u^u =u4=Uc
Multiple Range Testing
The single factor analysis of variance tests whether or not all of tne -iean
diversity indices are the same, but gives no insight into the location of
the differences among stations. To determine between which stations the
equalities or inequalities lie, one must resort to multiple comparison
tests (also known as multiple range tests). The most commonly used nethods
are the Student-Newman-Keuls
Duncan's test (Duncan 1955).
Student-Newman-Keuls Test
test (Newman 1939, Keuls 1952) and the
Example IV-2-3 demonstrates the Student-Newman-Keuls (SNK) procedure for
the data presented in Example 2. Since the ANOVA in Example IV-2-2
rejected the null hypothesis that all means are equal, the StlK test may be
applied. First, the diversity index means are ranked in increasing order.
Then, pairwise differences ( xg-xA ) are tabulated
IV-2-2 . The value of p is determined by the number
of means being tested. Using the p value and the error
from the ANOVA, "studentized ranges," abbreviated QQ^d
from a table of q-distribution critical values. The
calculated by.
as shown in Example
of means in the range
degrees of freedom
.p are obtained
standard error is
SE = (S2/n)1/2 = (error MS/n)1/2
If
For
by:
the
k
each
group
sizes
comparison
are
invol
3E
not
ving
s
-
S
2
equal ,
unequal
? /
Mi
• v
a s
n, t
•
•
"3 •
a slight modification is necessary.
n, the standard error is approximated
IV-2-26
-------
Example IV-2-3. Student-Newman-Keuls Multiple Range Test witn Ecual
Sizes. This example uti i izes the raw aata ana analysis
variance presented in Example IV-2-2.
Sample
of
Ranks of sample means (i ) 1 2 3
Ranked sample means (x.) 3.21 4.02 4.11
.41
5.83
Comparison
{B vs. A)
5 vs.
5 vs.
=> vs.
5 vs.
4 vs.
4 vs.
4 vs.
3 vs.
3 vs.
2 vs.
I
2
3
A
1
2
3
1
2
1
SE = (error
Di fference
5.83-3.21=2.62
5.83-4.02=1.81
5.83-4.11-1.72
5.83-4.41=1.42
4.41-3.21=1.20
4.41-4.02=0.39
Do Not Test
4.11-3.21=0.90
Do Not Test
4.02-3.21=0.81
MS/n)'/Z
SE
0.
n.
0.
0.
0.
0.
0.
0.
« (0.
095/6)'^ »
q
126
126
126
126
126
126
126
126
20.
14.
13.
11.
9.
3.
7.
6.
79
37
65
27
52
10
14
43
P
5
A
3
2
4
3
3
2
-------
Difference (LSD) which is related to the t-test,
discussed previously. The LSD is calculated by:
a form of which was
te'/n)1/2
where s2 is the mean square for error, n is the number of
replications, and t is the tabulated t value for the error degrees of
freedom (MS and df for error are calculated in the analysis of
variance). After determining p as in the SNK procedure, R values are
obtained from a table dependent on the level of significance, error df, and
p. The shortest significant difference (SSD) is computed by the equation:
SSD = R(LSD)
Example IV-2-4 demonstrates Duncan's procedure for hypothetical data. As
before, the difference between means is calculated for every possible
pairwise comparison of means. This difference is then compared to the
corresponding SSD value and conclusions are drawn. If the difference is at
least as large as the SSD, then the null hypothesis - that the two means
are equal - is rejected;
accepted. The results are
test.
if the difference is less than SSD, H0 is
visually represented as described for the SNK
Example IV-2-4. Duncan's Multiple Range Test.
Hn: U!=u2=u3=U4
H^: The mean diversity indices of the four sampling stations are not
the same
d= 0.05
n = 4
error MS = 0.078
Ranks of sample means (i}
Ranked sample means (x^ }
LSD
0.05 = '0. 05
1
5.3
= 0.447
2
5.7
3
5.9
error df=9
4
6.3
Comparison
(B vs.
4 vs.
4 vs.
3 vs.
3 vs.
2 vs.
mean di
visual
A )
1
3
1
2
1
versi
Difference
(xB -
6.3-5.
6.3-5.
6.3-5.
5.9-5.
5.9-5.
5.7-5.
station
ty index
XA )
3=1.0
7=0.6
9 = 0.4
3=0.6
7 = 0.2
3=0.4
1
5.3
P
4
3
2
3
2
2
2
5.7
R
a
i
i
i
i
i
i
3
5.9
SSD
,df,p =R(LSD)
.07
.04
.00
.04
.00
.00
4
6.3
0.
0.
n.
48
46
45
0.46
0.
0.
45
45
Conclusion
reject
reject
accept
reject
accept
accept
HO
HO
HO
HO
HO
H0
: u4=U]
: u4=u2
:u4=u3
:U3=U1
:u3=u2
:u-=u.
representation
IV-2-28
-------
COMMUNITY COMPARISON INDICES
Introduction
Whereas the statistical analyses discussed above can discern significant
differences between diversity indices calculated at two or more sampling
stations, community comparison indices have been developed to measure the
degree of similarity or dissimilarity between communities. These indices can
detect spatial or temporal changes in community structure. Polluted
communities presumably will have different species occurrences and abundances
than relatively non-polluted communities, given that all other factors are
equal. Hence, community comparison indices can be used to assess the impact of
pollution on aquatic biological communities.
There are two basic types of community comparison indices: qualitative and
quantitative. Qualitative indices use binary data: in ecological studies, the
two possible attribute states are that a species is present or is not present
in the collection. This type of community similarity index is used when the
sampling data consists of species lists. Kaesler and Cairns (1972) considered
the use of presence-absence data to be the only justifiable (and defensible)
approach when comparing a variety of organism groups (e.g. algae and aquatic
insects). Also, qualitative similarity coefficients are simple to calculate.
When data on species abundance are available, quantitative similarity indices
can be used. Quantitative coefficients incorporate species abundance as well
as occurrence in their formulas, and thus, retain more information than
indices using binary data. An annotated list of community comparison indices
of both types appears in Table IV-2-9.
Qualitative Similarity Indices
Although the terminology used in the literature varies considerably, the
qualitative similarity indices in Table IV-2-9 (1 - 6) are represented using
the symbolism of the 2X2 contingency table shown in Figure IV-2-5. In the form
of the contingency table shown, collections A and B are entities and all of
the species represented in a collection are the attributes of that entity.
Indices 1 through 4 in Table IV-2-9 are constrained between values of 0 and 1,
while equation 6 has a potential range of -1 to 1. The minimum value
represents two collections with no species in common and the maximum value
indicates structurally identical communities.
According to Boesch (1977), the Jaccard, Dice, and Ochiai coefficients are the
most attractive qualitative similarity measures for biological assessment
studies. The Jaccard coefficient (1) is superior for discriminating between
highly similar collections. The Dice (2) and Ochiai (4) indices place more
emphasis on common attributes and are better at discriminating between highly
dissimilar collections (Clifford and Stehpenson, 1975; Boesch, 1977; Herricks
and Cairns, 1982). Thus, the nature of the data determines which index is most
suitable. The Jaccard coefficient has been widely used by some workers in
stream pollution investigations (Cairns and Kaesler, 1969; Cairns et al.,
1970; Cairns and Kaesler, 1971; Kaesler at al., 1971; Kaesler and Cairns,
1972; Johnson and Brinkhurst, 1971; Foerster et al., 1974). Peters (1968) has
written BASIC computer programs for calculating Jaccard, Dice, and Ochiai
indices.
IV-2-29
-------
FAPLE IV-2-9. SUMMARY OF COMMUNITY COMPARISON INDICES
Descriptive Name Formula
1. Jaccard Coefficient of Community S = — JV
2. Dice Index (Czekanowski, Sorenson) S = •* f
3. Sokal and Michener Simple Matching S =
Index
4. Och1a1 Index (Otsuka) S =
[(a*b)(a+c)]1/2
5. Fager Index S =
t(a+bMa+c)]1/Z 2(a+b)T7Z
6. Point Correlation Coefficient s ab-bc
(Kendall Coefficient of Association) ' [(a+b,(c»d,(a»c,(b»d,]i/z
2 I m1n(x. , x..)
7. Bray-Curtis Similarity Coefficient S . = —?—, 1? 15-
ao i ixia* xfb»
Bray-Curtis Dissimilarity D . = y . ia . V1P.
Coefficient ab l U1a X1b'
Percentage Similarity of Community S . = 1 - 0.5 £|p - p | = I min (p. , p.. 1
IV-2-30
-------
TABLE IV-2-9 (continued)
8. Pinkham and Pearson Index of
Similarity
•• in i ii \ X . , X ., J
s = 1 y ia 1b.
ab n L max (x. , x.. )
la ID
Pir
9. Morisita Index of Affinity
2 * x
ia
>ab
Vb
MOT
10. Morn Index of Overlap
H - H .
max ab
>ab " Hmax - Hmin
llor
11. Distance
ab
Boe
1 v
Sok
12. Product-Moment Correlation
Coefficient (Pearson)
" "xa)(xib "
- x ) Z (x T; ) I2
la a' l 1b b' J
Snt
IV-2-31
-------
TABLE IV-2-9 (continued)
Key: S a similarity between samples.
D = dissimilarity between samples.
a,b,c,d - (see Figure IV-2-5).
*,-*• *
-------
COLLECTION A
present
CD
O
e
4)
4)
O.
ft)
number of species
common to both
collections
number of species
present 1n A
but not 1n B
absent
number of species
present in B
but not 1n A
number of spdes
not represented 1n
either collection
Figure IV-2-5. 2x2 contingency table defining variables a, b, c, and d.
IV-2-33
-------
The Fager coefficient (5) is simply a modification of the Ochiai index.
Because a correction factor is subtracted from the Ochiai index, the Fager
coefficient may range from slightly less than zero to slightly less than one;
this makes it less desirable. The Fager index has been used a great deal in
marine ecology.
Both the Sokal and Michener index (3) and the Point Correlation Coefficient
(6) include the double-absent term d. A number of authors (Kaesler and Cairns,
1972; Clifford and Stephenson, 1975; Boesch, 1977) have criticized the
approach of considering two collections similar on the basis of species being
absent from both.
Pinkham and Pearson (1976) illustrated the weaknesses of qualitative
comparison indices. The basic shortcoming 1s that two communities having
completely different species abundances but the same species occurrence will
produce the maximum index value, indicating that the two collections are
identical.
Quantitative Comparison Indices
Quantitative indices (7 - 12) consider species abundance in addition to mere
presence-absence. Incorporating species abundance precludes the over-emphasis
of rare species, which has been a criticism of the Jaccard coefficient
(Whittaker and Fairbanks, 1958). Quantitative measures are not as sensitive to
rare species as qualitative Indices and emphasize dominant species to a
greater extent. Distance (11), Information (9, 10), and correlation (12)
coefficients weight dominance even more than other quantitative indices.
Quantitative indices also avoid the loss of information involved in
considering only presence-absence data when species abundance data are
available. However, data transformations (e.g., to logarithms, roots, or
percentages) may be desirable or necessary for the use of some quantitive
comparison indices. Calculation of quantitative indices is more complicated
than qualitative coefficients, but can be facilitated by computer application.
The Bray-Curtis index (7) is one of the most widely used quantitive comparison
measures. Forms of this index have been referred to as "index of associaton"
(Whittaker, 1952), as "dominance affinity" (Sanders, 1960), and as "percentage
similarity of community" (Johnson and Brinkhurst, 1971; Pinkham and Pearson,
1976; Brock, 1977). The simplest and probably most commonly used form of the
Bray-Curtis index is the Percent Similarity equation:
where the attributes have been standardized into a proportion or percent of
the total for that entity (collection). The shortcoming of the Percent
Similarity coefficient was illustrated by Pinkham and Pearson (1976) as shown
below.
IV-2-34
-------
TAXA
A B C D E
Station A
Station B
40 20 10 10 10
20 10 5 5 5
In this hypothetical comparison, all species are
A as at Station B but their relative abundance
maximum similarity value of 1.0 1s registered.
situation is germane to pollution assessment
difference between two sampling stations 1s the
eutrophication.
twice as abundant at Station
1s identical; therefore, the
The authors felt that this
surveys in which the only
relative degree of cultural
In Table IV-2-9, the Bray-Curtis Index is displayed as both a measure of
similarity and dissimilarity. Any community similarity Index can be converted
to a dissimilarity measure by the simple equality:
D « 1 - S
Of course, values obtained by a dissimilarity expression are inversely related
to similarity values; they Increase with decreasing similarity.
Pinkham and Pearson (1976) presented a community similarity Index (8) that
would overcome the shortcomings of other Indices (e.g. 1,3,7,12) that were
discussed in the article. Their similarity coefficient can be calculated
using either actual or relative (percent) species abundance, although they
suggested using actual abundance whenever possible. The authors also offered
a modified formula that Includes a weighting factor for assigning more
significance to dominant species:
'ab
Bl1n(xla'x1b)
xia.xib ,
v— i— /
xa *b
Two community comparison Indices that employ diversity Indices in their
formulas are the Morisita Index of Affinity (9) and the Horn Index of Overlap
(10). The Morisita comparison measure Incorporates the Simpson (1949)
diversity index, and the Horn coefficient uses the Shannon-Wiener (1948)
diversity index. Horn (1966) described the Morisita Index as the probability
that two individuals drawn randomly from communities A and B will both belong
to the same species, relative to the probability of randomly drawing two
individuals of the same species from A or B alone. Because the numerator of
the Morisita Index is a product rather than a difference ( or minimum value)
it tends to be affected by abundant species to a greater extent than the
Bray-Curtis or Pinkham and Pearson indices. Like those similarity measures,
IV-2-35
-------
the Morisita index ranges from zero for no resemblance to one for identical
collections. The Horn Index of Overlap is a manipulation of Shannon's
information theory equation that closely resembles the expression of community
redundancy developed by Margalef:
R - (H - H)/ (H - H . )
v max " v max min'
The observed value in Horn's index (Hab) is the Shannon index calculated for
the sum of the two collections being considered. The maximum diversity value
(Hmax) would occur if the two collections contained no species in common, and
the minimum diversity value (Hmin) would be attained if the two collections
contained the same species in the same proportions. It should be noted that
the equations given for Hab, Hmax, and Hmin in the key to Table IV-2-9 are
adapted from those given by Perkins (1983) since those appearing in the
original article (Horn, 1966) are apparently inconsistent with the Shannon
index. The Morisita and the Horn indices have been used in aquatic ecology
studies (Kohn, 1968; Bloom et al., 1972; Livingston, 1975; Heck, 1976).
If two entities (i.e. communities) are thought of as points in an
n-dimensional space whose dimensions are determined by their attributes (i.e.
species occurrence and abundance ), then the linear distance between the two
points in the hyperspace can be construed as a measure of dissimilarity
between the two entities. The two distance formulas shown in Table IV-2-9
(11) are simply forms of the familiar geometrical distance formula,
j _ i /,. ,, ^•- j. i,. ., \- i +it-
which has been expanded to accomodate n dimensions. Sokal (1961) divided the
distance by n to produce a mean squared difference, which he felt was an
appropriate measure of taxonomic distance. Values computed by the distance
formulas may range from zero for identical collections to infinity; the
greater the distance the less similar the two comunities are. Because the
difference in species abundance is squared in the numerator, the distance
formulas are heavily influenced by abundant species and may over-emphasize
dominance. The similarity of disparate communities with low species
abundances may be overstated, while the resemblance of generally similar
communities with a few disproportionately high species abundances may be
understated. To avoid indicating misleading resemblance, it may be necessary
to transform data (e.g. to squared or cubed roots) before computing taxonomic
distance.
The Product-Moment Correlation Coefficient (12) is a popular resemblance
measure that ranges from -1 (completely dissimilar) to +1 (entirely similar).
Several undersirable characteristics of this measure have been cited (Sneath
and Sokal, 1973; Clifford and Stephenson, 1975; Boesch, 1977). Deceptive
resemblance values can result from outstandingly high species abundances or
the presence of many species absences, and non-identical communities can
register perfect correlation scores. Pinkham and Pearson (1976) demonstrated
how the Product-Moment Correlation Coefficient, like the Percent Community
Similarity Index, indicates maximum similarity for two communities having the
same relative species composition but different actual species abundances.
IV-2-36
-------
Experimental Evaluation of Comparison Indices
Brock (1977) compared the Percent Community Similarity Index (7) and the
Pinkham and Pearson Similarity Index (8) for their ability to detect changes
in the zooplankton community of Lake Lyndon B. Johnson, Texas, due to a
thermal effluent. For this study, the Pinkham and Pearson index was
considered too sensitive to rare species and not sensitive enough to dominant
forms, whereas the Percent Similarity coefficient was more responsive to
variation in dominant species and relationships between dominant and
semi-dominant forms. Linking dominance to function, the author concluded that
the later index may better indicate structural-funcitonal similarity between
communities.
and
The
benthic
Perkins
Perkins
Pinkham
Perkins (1983) evalutaed the responsiveness of eight diversity indices
five community comparison indices to increasing copper concentrations.
indices were calculated for bioassays conducted using
macroinvertebrates and artificial streams. The indices evaluated by
correspond to equations presented in Tables IV-2-2 and IV-2-9 except:
tested the Bray-Curtis dissimilarity index; Perkins1 Biosim index is
and Pearson's index, and the distance formula tested by Perkins (not included
in this report) is shown below.
1/2
D =
The results of the study appear
are presented for comparison.
IS
n
x .
x .
i
a"xib
a+*ib
i
in Figure IV-2-6; the diversity index results
The diversity indices did not clearly demonstrate the perturbation caused by
increasing copper concentrations. The Shannon and Brillouin formulas
increased initially, in spite of a decreasing number of species, because of
increasing evenness of species distribution. Other than the increasing
diversity indicated at the lower copper concentrations, these two indices
reflected perturbation effectively by decreasing rapidly with increasing
pollutant concentration. The Mclntosh, Simpson, and Pielou (evenness) indices
(not shown for 28 days in Figure IV-2-6) resembled the trends demonstrated by
the Shannon and Brillouin formulas albeit less dramatically. Because the
results obtained for those three indices were less pronounced, they were more
difficult to interpret than the Shannon and Brillouin findings.
The community comparison indices were found to be good indicators of the
perturbation of macroinvertebrate communities caused by copper pollution.
Although the Bray-Curtis index was considered the most accurate after 14 days,
all of the comparison indices tested effectively reflected community response
after 28 days (see Figure IV-2-6). Note that by definition the Biosim,
Morisita, and Percent Community Similarity indices decrease as similarity
decreases, while the Distance and Bray-Curtis dissimilarity indices increase.
It has frequently been suggested that it may be desirable to apply several
indices in a pollution assessment study (Peters, 1968; Brock, 1977; Perkins,
1983).
IV-2-37
-------
l=Shannon
2=Brillouin
3=Pielou
4=Simpson
5=McIntosh
6=Menhinick
7=Species(xlO)
8=Equitability
,_og C~
(a)
(b)
l=Distance
2=Bray-Curtis
3=c Similarity
4=Morisita
5=Biosim
i.O
9-
8
05 iG
LogCV;
(d)
Figure IV-2-6. Evaluation of diversity indices and community comparison indices
using bioassay data: a,c=after 14 davs; b,d=after 28 davs (from
Perkins, 1983).
IV-2-38
-------
Numerical Classification or Cluster Analysis
A common use of similarity indices is in numerical clasification of biological
communities. Numerical classification, or cluster analysis, is a technique
for grouping similar entities on the basis of the rsemblance of their
attributes. In instances where subjective classification of communities is
not clear-cut, cluster analysis allows incorporation of large amounts of
attribute data into an objective classification procedure. Kaesler and Cairns
(1972) outlined five steps involved in normal cluster analysis. First, a
community similarity index is chosen based on pre-detertnined criteria and
objectives. Second, a matri-x of similarity coefficients is generated by
pairwise comparison of all possible combinations of stations. The third step
is the actual clustering based on the resemblance coefficients. A number of
clustering procedures are discussed in the literature (Williams, 1971; Sneath
and Sokal, 1973; Hartigan, 1975; Boesch, 1977). In the fourth step, the
clustered stations are graphically displayed in a dendogram. Because
multi-dimensional resemblance patterns are displayed in two dimensions and
because the similarity coefficients are averaged, a significant amount of
distortion can occur. For this reason, a distortion measure should be
evaluated and presented as the fifth step in the cluster analysis. The
Cophenetic Correlation Coefficient (Sokal and Rohlf, 1962) is a popular metric
of display accuracy. An additional step in any cluster analysis application
should be interpretation of the numerical classification results since the
technique is designed to simplify complex data and not to produce ecological
interpretation.
SUMMARY
The abili
of the bes't
ity of a water resource to sustain a balanced biotic community is one
„. -..,. jest indicators of its potential for beneficial use. This ability is
essential to the community's health. Although several papers have criticized
the use of diversity indices (Hurlbert,1971; Peet,1975; Godfrey,1978), Cairns
(1977) stated that "the diversity index is probably the best single means of
assessing biological integrity in freshwater streams and rivers". Cairns
concluded that no single method will adequately assess biological integrity,
but rather its quantification requires a mix of assessment methods suited for
a specific site and problem. The index of diversity is an integral part of
that mix. Community comparison indices are also useful in assessing the
biological health of aquatic systems. By measuring the simiarity (or
dissimilarity) between sampling stations, community comparison indices
indicate relative impairment of the aquatic resource.
IV-2-39
-------
CHAPTER IV-3
RECOVERY INDEX
It is important to examine the ability of an ecosystem to recover from
displacement due to pollutional stress in order to evaluate the potential
uses of a water body. Cairns (1975) developed an index which gives an
indication of the ability of the system to recover after displacement. The
factors and rating system for each factor are:
(a) Existence of nearby epicenters (e.g., for rivers these might be
tributaries) for providing organisms to reinvade a damaged system.
Rating System : l=poor, 2=moderate, 3=good
(b) Transportability or mobility of disseminules (the disseminules might be
spores, eggs, larvae, flying adults which might lay eggs, or other stages
in the life history of an organism which permit it to move to a new area).
Rating System : l=poor, 2-moderate, 3=good
(c) Condition of the habitat following pollutional stress (including
physical habitat and chemical quality).
Rating system : l=poor, 2=moderate, 3=good
(d) Presence of residual toxicants following pollutional stress.
Rating System : l=large amounts, 2=moderate amounts, 3=none
(e) Chemical-physical environmental quality after pollutional stress.
Rating System : l=in severe disequilibrium, 2=partially restored,
3=normal
of damaged area.
ble.
(f) Management or organizational capabilities for control of
Rating system : l=none, 2-some, 3=strong enforcement possibl
Using the characteristics listed above, and their respective rating
systems, a recovery index can be developed. The equation for the recovery
index follows:
Recovery Index =axbxcxdxexf
400+ = chances of rapid recovery excellent
55-399 = chances of rapid recovery fair to good
less than 55 = chances of rapid recovery poor
This index and the rating system was developed by Cairns based on his
experience with the Clinch River. For a full description of the rationale
for the rating factor, the reader should refer to Cairns (1975).
IV-3
-------
CHAPTER IV-4
INTOLERANT SPECIES ANALYSIS
NICHE CONCEPT
The ecological niche of a species is its position and role in the biological
community. Hutchinson (1957) described niche as a multidimensional space, or
hypervolume, that is delineated by the species' environmental requirements and
tolerances. Physical, chemical, and biological conditions and relationships
constitute the dimensions of the hypervolume, and the magnitude of each dimen-
sion is defined by the upper and lower limits of each environmental variable
within which a species can persist. If any one of the variables is outside of
this range the organism will die, regardless of other environmental conditions.
TOLERANCE
The "Law of Toleration" proposed by Shelford (1911) is illustrated in Figure
IV-4-1. For each species and environmental variable there is a range in the
variable intensity over which the organism functions at or near its optimum
level. Outside the maximum and minimum extremes of the optimum range there are
zones of physiological stress, and, beyond, there are zones of intolerance in
which the ."unctions of the organism are inhibited. The upper and lower toler-
ance limits (also called incipient lethal levels) are intensity levels of the
environmental variable that will eventually cause the death of a stated frac-
tion of test organisms, usually 50 percent.
VARIABILITY OF TOLERANCE
The tolerance of an organism for a lethal condition is dependent on its gene-
tic constitution - both its species and its individual genetic makeup - and
its early and recent environmental history (warren 1971). Acclimation has a
marked effect on the tolerance of environmental factors such as temperature,
dissolved oxygen, and some toxic substances (see Figure IV-4-2). Tolerance is
also a function of the developmental stage of the organism and it may change
with age throughout the life of the animal. Because of this variability, no
two organisms have exactly the same tolerance for a lethal condition and toler-
ance limits must be expressed in terms of an "average" organism.
INTERACTIONS INFLUENCING TOXICITY
An organism's tolerance for a particular lethal agent is dependent not only on
its own characteristics but also on the environmental conditions. The inter-
actions between lethal and nonlethal factors are well documented and are ad-
dressed elsewhere in this handbook (Chapters II-5 and III-2). Briefly, these
nonlethal effects include:
IV-4-1
-------
limit of to/treaeg
Upptr limit of toltrance •
Low-*
Figure IV-4-1,
Law of toleration in relation to distribution and
level—often a normal curve (modified by Kendeigh
Shelford (1911)).
oopulation
(1974) from
Figure IV-4-2.
~O 10 2O 3O
Acclimation r«mp«rorur« (C)
The zones of tolerance of brown bullheads (Ictalurus nebulosus)
and chum salmon (Oncorhynchus keta) as delimited by incipient
lethal temperature and influenced by acclimation temperature
(after Brett 1956).
IV-4-2
-------
CHAPTER IV-4
INTOLERANT SPECIES ANALYSIS
NICHE CONCEPT
The ecological niche of a species is its position and role in the biological
community. Hutchinson (1957) described niche as a multidimensional space, or
hypervolume, that is delineated by the species' environmental requirements and
tolerances. Physical, chemical, and biological conditions and relationships
constitute the dimensions of the hypervolume, and the magnitude of each dimen-
sion is defined by the upper and lower limits of each environmental variable
within which a species can persist. If any one of the variables is outside of
this range the organism will die, regardless of other environmental conditions.
TOLERANCE
The "Law of Toleration" proposed by Shelford (1911) is illustrated in Figure
IV-4-1. For each species and environmental variable there is a range in the
variable intensity over which the organism functions at or near its optimum
level. Outside the maximum and minimum extremes of the optimum range there are
zones of physiological stress, and, beyond, there are zones of intolerance in
which the ."unctions of the organism are inhibited. The upper and lower toler-
ance limits (also called incipient lethal levels) are intensity levels of the
environmental variable that will eventually cause the death of a stated frac-
tion of test organisms, usually 50 percent.
VARIABILITY OF TOLERANCE
The tolerance of an organism for a lethal condition is dependent on its gene-
tic constitution - both its species and its individual genetic makeup - and
its early and recent environmental history (Warren 1971). Acclimation has a
marked effect on the tolerance of environmental factors such as temperature,
dissolved oxygen, and some toxic substances (see Figure IV-4-2). Tolerance is
also a function of the developmental stage of the organism and it may change
with age throughout the life of the animal. Because of this variability, no
two organisms have exactly the same tolerance for a lethal condition and toler-
ance limits must be expressed in terms of an "average" organism.
INTERACTIONS INFLUENCING TOXICITY
An organism's tolerance for a particular lethal agent is dependent not only on
its own characteristics but also on the environmental conditions. The inter-
actions between lethal and nonlethal factors are well documented and are ad-
dressed elsewhere in this handbook (Chapters II-5 and III-2). Briefly, these
nonlethal effects include:
IV-4-1
-------
limit of tottronct
Upper limit of tolerance •
Low-*
Figure IV-4-1.
GRADIENT-
-High
Law of toleration in relation to distribution and oopulation
level—often a normal curve (modified by Kendeigh (1974) from
Shelford (1911)).
10 2O 3O
Acclimation famperorur* (C)
Figure IV-4-2.
The zones of tolerance of brown bullheads (Ictalurus nebulosus)
and chum salmon (Oncorhynchus keta) as delimited by incipient
lethal temperature and influenced by acclimation temperature
(after Brett 1956).
IV-4-2
-------
Hardness. Increasing hardness decreases the effect of toxic metals on aqua-
tic organisms by forming less-toxic complexes.
pH. The dissociation of weak acids and bases is controlled by pH and either
the molecular or ionic form may be more toxic.
Alkalinity and Acidity. These modify pH by constituting the buffering capa-
city of the system.
Temperature. Increasing temperature enhances the effect of toxicants by in-
creasing the rates of metabolic processes.
Dissolved Oxygen. Decreasing dissolved oxygen concentration augments the
exposure and absorption of toxicants by increasing the necessary irriga-
tion rate of respiratory organs.
When two or more lethal agents are present, several types of interactions are
possible: synergistic, additive, antagonistic, or no interaction.
INTOLERANT SPECIES ANALYSIS
The tolerance ranges for environmental variables differ widely between spe-
cies. Thus, the range of conditions under which an organism can survive (its
niche) is broader for some species than it is for others. Fish species with
narrow tolerance ranges are relatively sensitive to degradation of water qual-
ity and other habitat modifications, and their populations decline or disap-
pear under those circumstances before more tolerant organisms are affected. In
general, intolerant species can be identified and used in evaluating environ-
mental quality. The presence of typically intolerant species in a fish sam-
pling survey indicates that the site has relatively high quality; while the
absence of intolerant species that, it is judged, would be there if the envi-
ronment was unaltered indicates that the habitat is degraded.
LISTS OF INTOLERANT FISH SPECIES
While the tolerance limits of a fish species for a particular environmental
factor can be defined relatively precisely by toxicity bioassays, its degree
of tolerance may vary considerably over the range of physical, chemical, and
biological variables that may be encountered in the environment. The variables
that are the object of intolerant species analysis are intentionally left
vague in order to accommodate the variety of situations precipitated by man's
activities. A species may be intolerant of alterations in water quality or in
habitat structure, such as those listed below.
Water Quality Changes Habitat Alterations
increased turbidity substrate disruption
increased siltation cover removal
increased water temperature changes in velocity and discharge
increased dissolved solids removal of instream and streamside
organic enrichment vegetation
lowered dissolved oxygen water level fluctuation
impoundment and channelization
blockage or hinderance of migration
IV-4-3
-------
Many species can be Identified that are relatively intolerant of anthropogenic
alterations of the aquatic environment compared to other fish. Appendix C con-
tains a list of fish species, nationally, which are relatively intolerant to
one or more of the environmental changes shown above. The information in Appen-
dix C is based on literature sources (Hallen 1951; Trautman 1957; Carlander
1969, 1977; Scott and Grossman 1973; Pflieger 1975; Moyle 1976; Tlmbol and
Macioletc 1978; Smith 1979; Muncy et al. 1979; Lee et al. 1980; Morrow 1980;
Johnson and Finley 1980; U.S. EPA 1980; Karr 1981; Haines 1981; and Ball 1982)
and on the professional judgment of State and University biologists.
The darters and sculpins are listed only by genus in Appendix C. Identifica-
tion of those taxa to species would have been inconvenient (together, Ammo-
crypta, Etheostoma, Percina, and Cottus contain 150 species In the United
States) and largely unnecessary because, with a few possible exceptions, all
of the species of darters and sculpins can be considered intolerant. Karr
(1981) recognized the johnny darter (Etneostoma nlgrum) as the most tolerant
darter species in Illinois and Ball (198Z)
-------
CHAPTER IV-5
OMNIVORE-CARNIVORE (TROPHIC STRUCTURE) ANALYSIS
INTRODUCTION
Water pollution problems nearly always involve changes in the pathways by
which aquatic populations obtain energy and materials (Warren 1971). These
changes lead to differential success of constituent populations which affects
the composition of the aquatic community. Anthropogenic introduction of or-
ganic substances or mineral nutrients directly increases the energy and ma-
terial resources of the system, but other pollution problems - such as pH or
temperature changes, toxic materials, low dissolved oxygen, turbidity, silta-
tion, et cetera - also lead to changes in trophic pathways. Thus, the health
of a system can be evaluated through a study of its trophic structure. The
following material concentrates on stream and river systems. Lakes will have
different structural aspects.
TROPHIC STRUCTURE
The ecosystem has been described as the entire complex of interacting physi-
cochemical and biological activities operating 1n a relatively self-supporting
community (Reid and Wood 1976). The biological operations of an ecosystem can
be viewed as a series of compartments which are described by three general cat-
egories: producers, consumers, and decomposers. The producers include all auto-
trophic plants and bacteria (both photosynthetic and chemosynthetic) which, by
definition, are capable of synthesizing organic matter from inorganic sub-
strates. The consumers are heterotrophic organisms that feed on other organ-
isms, and are typically divided into herbivores and carnivores. Herbivores
(primary consumers) feed principally on living plants while carnivores (sec-
ondary, tertiary, and quarternary consumers) feed principally on animals that
they kill. Another type of consumer, the omnivore, feeds nearly equally on
plants and animals, and occupies two or more trophic levels. The decomposers
include all organisms that release enzymes which break down dead organisms.
Food chains are sometimes used to simply represent feeding relationships be-
tween trophic levels (e.g., plant > herbivore > carnivore). Ecosystems common-
ly contain three to five links 1n their food chains. Diagramming all of the
pathways of energy and material transfer in a community entails many inter-
connecting food chains, forming a complex food web.
The concept of trophic structure, first formally discussed by Lindeman (1942),
1s a method of dealing with the pathways of energy and material transfer which
focuses on functional compartments without considering the specific feeding
relationships. The pathways between functional compartments are illustrated in
Figure IV-5-1. Trophic structure is commonly represented by trophic or ecolog-
ical pyramids. An ecological pyramid is a diagramatic representation of the r-
elationships between trophic levels arranged with the producers making up the
base and the terminal or top carnivore at the apex. An ecological pyramid may
IV-5-1
-------
HERBIVORES,
PRODUCERS
CARNIVORES
, )- (C. )~
-------
represent the number of individuals that compose each trophic level, or, of
more ecological significance, the biomass or productivity of each level (Fig-
ure IV-5-2). Because energy transfer between trophic levels is less than 100 p-
ercent efficient the pyramid of productivity must always be regular in shape,
while pyramids of numbers and biomass may be partially inverted in some in-
stances (Richardson 1977).
TROPHIC STRUCTURE OF FISH COMMUNITIES
Fish communities generally include a range of species that represent a variety
of trophic levels. The trophic classification system shown below was used in
the assessment of fish fauna of the Illinois and Maumee River basins (Karr and
Dudley 1978, Karr et al. 1983).
(1) Invertivore - food predominantly (>75X) invertebrates.
(2) Invertivore/Piscivore - food a mixture of invertebrates and fish; rela-
tive proportions often a function of age.
(3) Planktivore - food dominated by microorganisms extracted from the water
column.
(4) Omnivore - two or more major (>25% each) food types consumed.
(5) Herbivore - feed mostly by scraping algae and diatoms from rocks, and
other stream substrates.
(6) Piscivore - feed on other fish.
Schlosser (1981, 1982a, 1982b) used the trophic structure of fish communities
to investigate differences in Illinois stream ecosystems. His categorization
scheme appears in Table 1.
In addition to representing a range of trophic levels, fish utilize foods of
both aquatic and terrestrial origin, and occupy a position at the top of the
aquatic food web in relation to plants and invertebrates. These facts enhance
the ability of fish communities to provide an integrative view of the water-
shed environment (Karr 1981).
BIOLOGICAL HEALTH
Degradation of water quality and habitat affects the availability of many food
resources, resulting in changes In the structure and functions, and, thus, the
health of the aquatic community. Structural characteristics include the num-
bers and kinds of species and the number of individuals per species. These
parameters can be evaluated relatively quickly via compilation of species
lists, calculation of diversity indices, and identification of indicator spe-
cies. The importance of evaluating the Impact of pollution on community func-
tions - such as production, respiration, energy flow, degradation, nutrient
cycling, and other rate processes - is becoming increasingly evident, and,
ideally, any study of community health should include both structural and
functional assessment. However, use of functional methods has been hindered
because they are often expensive, time-consuming, and not well understood.
IV-5-3
-------
TABLE IV-5-1.
TROPHIC GUILDS USED BY SCHLOSSER (1981, 1982A, 19828)
TO CATEGORIZE FISH SPECIES
Herbivore - detritivores (HD)
Omnlvores (OMN)
Generalized InsectIvores (GI)
Surface and Water Column
Insectlvores (SWI)
Benthlc Insectlvores (BI)
Insectlvore - Piscivores (IP)
HD species fed almost
toms or detritus.
entirely on d1a-
OMN species consumed plant and animal
material. They differed from GI species
in that, subjectively, greater than 25
percent of their diet was composed of
plant or detritus material.
GI species fed on a range of animal and
plant material including terrestrial
and aquatic insects, algae, and small
fish. Subjectively, less than 25 per-
cent of their diet was plant material.
SWI species fed
or terrestrial
surface.
on water column drift
insects at the water
BI species fed predominantly
ture forms of benthic insects.
on imma-
IP species fed on aquatic invertebrates
and small fish. Their diets ranged from
predominantly fish to predominantly in-
vertebrates.
IV-5-4
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Examining the trophic structure of a community can provide Insight into its
production and consumption dynamics. A trophic-structure approach to the study
of the functional processes of stream ecosystems has been proposed by Cummins
and his colleagues (Cummins 1974, 1975; Vannote et al. 1980). Their concept
assumes that a continuous gradient of physical conditions in a stream, from
Its headwaters to its mouth, will illicit a series of consistent and predict-
able responses within the constituent populations. The River Continuum Concept
Identifies structural and functional attributes that will occur at different
reaches of natural (unperturbed) stream ecosystems. These attributes (sum-
marized 1n Table IV-5-2) can serve as a reference for comparison to measured
stream data. Measured data which are commensurate with those predicted by the
river continuum model indicate that the studied system is unperturbed, while
disagreement between actual and expected data indicates that modification of
the ecosystem has occurred (Karr and Dudley 1978).
EVALUATION OF BIOLOGICAL HEALTH USING FISH TROPHIC STRUCTURE
Karr (1981) developed a system for assessing blotic Integrity using fish com-
munities, which is discussed 1n Chapter IV-2: Diversity Indices. Three em-
pirical trophic metrics are incorporated into Karr's index of biotic integrity
(IBI). They are:
(1) the proportion of individuals that are omnivores,
(2) the proportion of insectivorous individuals of the Cyprinidae family,
and
(3) the presence of top carnivore populations.
Karr (1981) observed that the proportion of omnivores In a community increases
as the quality of the aquatic environment declines. Nearly all major consumer
species are omnivorous to a degree (Darnell 1961), so populations are con-
sidered to be truly omnivorous only 1f they feed on plants and animals in
nearly equal amounts or indiscriminately (Kendeigh 1974). Recall that Karr and
Schlosser used 25 percent of plant material ingested as the level for distin-
guishing between omnivores and other trophic guilds. Presumably, changes 1n
the food base due to pollutlonal stress allow the euryphagic omnivores to be-
come dominant because their opportunistic foraging ecology makes them more suc-
cessful than more specific feeders. Omnivores are often virtually absent from
unmodified streams. Even in moderately - altered streams omnivorous species
usually constitute a minor portion of the community. For this reason, the bi-
ologist responsible for assessment must be familiar with the local fish fauna
and aquatic habitats in order to be able to interpret subtle disproportions in
trophic structure. In general, Karr (1981) has found samples with fewer than
20 percent of Individuals as omnivores to be representative of good environ-
mental quality, while those with greater than 45 percent omnivores represent
badly degraded sites.
Karr (1981) reported that a strong Inverse correlation exists between the abun-
dance of insectivorous cyprinlds and omnivores. Thus, communities containing a
large proportion of Insectivorous members of the minnow family (>45%) tends to
Indicate relatively high environmental quality.
IV-5-5
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TABLE IY-5-2.
GENERAL CHARACTERISTICS OF RUNNING WATER ECOSYSTEMS ACCORDING TO SIZE OF STREAM.
(From Karr and Dudley 1978, modified from Cummins 1975)
Stream
size
*Smal 1
headwater
streams
( stream
order
1-3)
'Medium
sized
streams
(4-6)
*Large
rivers
(7-12)
Primary
energy
source
Coarse partlculate
organic matter
(CPOM) from the
terrestrial
environment
Little primary
production
Fine partlculate
organic matter
(FROM), mostly
Considerable
primary
production
FPOM from
upstream
Production
(trophic)
state
Heterotrophlc
P/R <1
Autotrophlc
P/R >1
Heterotrophlc
P/R
-------
Faucsh et al. (unpublished manuscript) investigated the regional applicability
of the IBI. Results from the two least disturbed watersheds 1n the study --
the Embaras River, Illinois and the Red River, Kentucky — confirmed the fixed
scoring criteria proposed by Karr (1981) for omnlvores and Insectivorous cypri-
nids. At most of the undisturbed sites 1n each stream, omnivores constituted
20 percent or less of all Individuals and at least 45 percent of individuals
were insectivorous cyprinids.
The presence of viable, vigorous populations of top carnivores is another in-
dicator of a relatively healthy, trophlcally diverse community used in Karr's
index. As described earlier, top carnivores constitute the peak of the eco-
logical pyramid, and, therefore, occupy the highest trophic level in that par-
ticular community. Degradation of environmental quality causes top carnivore
populations to decline and disappear. Theoretically, since top carnivore pop-
ulations are supported (directly or indirectly) by all of the other (lower)
trophic levels, they serve as a natural monitor of the overall health of the
community. Because of their position atop the food chain, terminal carnivores
are most vulnerable to detrimental effects of biomagnified toxicants. Also,
predatlon by top carnivores keeps the populations of forage and rough fish in
check, thereby functioning to maintain biotic integrity. As always, it is as-
sumed that the project biologist will use considerable personal knowledge of
local ichthyology and ecology in adjusting expectations of top carnivore spe-
cies to stream size. The top carnivore populations must be evaluated in rela-
tion to what would be there if the habitat were not modified. Defining the
baseline is a major problem in any study of pollutional stress. In determining
the baseline community, the biologist may rely on the faunas of similar, unal-
tered habitats in the area, literature information, and personal experience --
remembering the concepts of the river continuum model.
The results of research conducted throughout the midwest tend to support the
theoretical basis of the omnivore and top carnivore metric approaches to as-
sessing biotic integrity (Larimore and Smith 1963, Cross and Collins 1975,
Menzel and F1erst1ne 1976, Karr and Dudley 1978, Schlosser 1982a, Karr et al.
1983). Fausch et al. (unpublished manuscript) evaluated five watersheds in
Illinois, Michigan, Kentucky, Nebraska, and North and South Dakota using the
IBI, and found that scores accurately reflected watershed and stream condi-
tions.
However, experts in the field recognize that the omnivore - top carnivore anal-
ysis may not be applicable 1n every situation on a nationwide basis. Reser-
vations over use of this approach seem to be based on three variables.
(1) Type of pollutional stress - e.g., the trophic metrics proposed by Karr
(1981) were largely derived from agricultural watersheds in which sedi-
mentation and nutrient enrichment are the predominant forms of anthro-
pogenic stress; other pollution problems such as toxic waste discharge
could conceivably have a different Impact on fish trophic structure.
IV-5-7
-------
(2) Type of aquatic habitat - e.g., headwater streams, large rivers, and
flowing swamps represent very different environments which are charac-
terized by a variety of trophic pathways and food sources.
(3) Type of ambient fish fauna - e.g., no or very tolerant top carnivores
might be present naturally, or no or very intolerant omnivores.
LIST OF OMNIVOkES AND TOP CARNIVORES
Examples of resident omnivore and top carnivore fish species are listed nation-
ally in Appendices B-l and B-2, respectively. These tables were compiled based
on information found in the literature (Morita, 1963; Carlander, 1969, 1977;
Pflieger, 1975; Moyle, 1976; Timbol and Maciolek, 1978; Smith, 1979; Morrow,
1980; Lee et al.,1980; Karr et al., 1983). The purpose of the lists is to
provide a framework for assessing omnivore and top carnivore populations.
However, because of the geographic variability in feeding habits, the gaps in
available foraging data, and the dynamic nature of range boundaries, some
members of the 11st may not occupy the specified trophic compartment in a
particular area, while other species that belong on the list may have been
overlooked. The list is intended to be used by knowledgeable biologists who
are capable of adding and deleting species where necessary to produce a list
which is appropriate for the particular area of study.
IV-5-8
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CHAPTER IV-6
REFERENCE SITES
Introduction
The goal of this section is to suggest an objective, ecological
approach that should aid States in determining the ecological potential of
priority aquatic ecosystems, evaluating and refining standards,
prioritizing ecosystems for improvements, and comprehensively evaluating
the ecological quality of aquatic ecosystems. The objectives of this
section are to demonstrate the need for regional reference sites and to
demonstrate how they can be determined. To do this the need for some type
of control or reference sites will be discussed and alternate types will be
outlined, the concept of ecological regions and methods for determining
them will be described, aspects that should be considered when selecting
reference sites will be listed, and the limitations of the regionalization
method will be discussed.
Although correlation between a disturbance and the resulting
functional or structural disorder can stimulate considerable insight, the
disorder that results from disturbing a water body can be demonstrated
scientifically only by comparing it with control or reference sites. To
scientifically test for functional or structural disorder, data must be
collected when the disturbances are present and when the disturbances are
absent but everything else is the same. Disorders that are unique to the
disturbed areas must be related to the disturbances but separated from
natural variability. This requires carefully selected reference sites, but
it is difficult or impossible to find pristine control or reference sites
in most of the conterminous United States. Also, it is unlikely that
pristine reference sites would be appropriate for most disturbed sites
because they would differ in ways besides the distrubance, as will be
discussed later.
The most commonly used reference sites are upstream and downstream of
the recovery zone of a point source. However, these sites provide little
value where diffuse pollution is a problem, where channel modifications are
extensive, where point sources occur all along the stream, where the
stream's morphology or flow changes considerably among sites, or where
various combinations of these disturbances occur. Hughes et al. (1983)
suggest a different approach, which reduces the problems of upstream-
downstream reference sites. Their approach is based on first determining
large, relatively-homogeneous, ecological regions (areas with similar
land-surface form, climate, vegetation, etc.) followed by selection of a
series of reference sites within each region. These sites could possibly
serve as references for a number of polluted sites on a number of streams
thereby economizing on and simplifying concurrent or future studies. A
modification of Hughes et al.'s approach has been tested on two polluted
streams in Montana (Hughes MS) and the approach is being rigorously tested
on 110 sites in Ohio (Omernik and Hughes 1983).
IV-6-1
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The logical basis for Omernik and Hughes' approach was developed from
alley (1976), Green (1979), Hall et al. (1978), and arren (1979). Their
logic fits well with the proposed water quality standards regulation
(Federal Register 1982} that suggests grouping of streams wherever
possible. Bailey stressed that heterogeneous lands, such as those managed
by the U.S. Forest Service, must be hierarchically classified by their
capabilities. He added that classification should be objective,
synthesized from present mapped knowledge, and based on the spatial
relationships of several environmental characteristics rather than on one
characteristic or on the similarity of the characteristics alone.
One of Green's ten principles for optimizing environmental assessments
is that wherever there are broad environmental patterns, the area should be
broken into relatively homogeneous subareas. Clearly, this principle
applies to most States. Hall et al. found that studies that incorporate
several variously-impacted sites were more useful than separate intensive
studies of one or two sites and more practical than long-term pre- and
post- impact studies.
Warren proposed that a watershed/stream classification should
integrate climate, topography, substrate, biota, and culture at all levels,
as opposed to considering them separately. He also stated that the
integration and classification should be hierarchical and be determined
from the potentials of the lands and waters of interest, rather than from
their present conditions. Streams within Warren's proposed classification
would have increasingly similar ecological potentials as one moved down
through the hierarchy to ever smaller watersheds or ecological regions.
The Concept of Ecological Regions
The ecological potential of a reference or disturbed site is
considered to be the range of ecological conditions present in a number of
typical, but relatively-undisturbed sites within an ecological region.
Suchrelatively-undisturbed sites, can be found even in the channelized
streams of the Midwest Corn Belt (Marsh and Luey 1982). One should not
suppose that such sites represent pristine or undisturbed controls, only
that they are the best that exist given the prevalent land use patterns in
an ecological region. Because of the major economic and political strains
required, we do not believe that resource managers or even knowledgeable
and concerned citizens will change those general land use patterns much.
But such persons will need to know the best conditions they can expect in a
water body in order to decide whether the economic and noneconomic benefits
of a particular water body standard are worth their economic and
noneconomic costs. To make such determinations rationally, the reference
sites must also be typical of a region. That is, their watersheds must
wholly reflect the predominant climate, land-surface form, soil, potential
natural vegetation, land use, and other environmental characteristics
defining that region, and the site itself must contain no anomalous
feature. For example, a cobble-bottomed stream in an entirely forested,
highly dissected watershed would not be typical of the sand and
gravel-bottomed streams in the agricultural prairies of the Midwest, nor
could it be a useful predictor of such an agricultural stream's ecological
potential, even though such a watershed and stream might be found in such a
region.
IV-6-2
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Although all aquatic ecosystems differ to some degree, the basis of
ecological regions is that there also is considerable similarity among
aquatic ecosystem characteristics and that these similarities occur in
definable geographic patterns. Also, the variabilities in the present and
potential conditions of the chemical and physical environment and the biota
are believed to be less within an area than among different areas. For
example, streams in the Appalachian Mountains, are more similar to each
other than to those in the Corn Belt or those on the Atlantic Coastal
Plain. It is assumed that streams acquire their similarities from
similarities in their watersheds and that streams draining watersheds with
similar characteristics will be more similar to each other than to those
draining watersheds with dissimilar characteristics. Thus, an ecological
region is defined as a large area where the homogeneity in climate,
land-surface form, soil, vegetation, land use, and other environmental
characteristics is sufficient to produce relative homogeneity in stream
ecosystems.
The concept of an ecological region is an out-growth of the work of
vegetation ecologists, climatologists, physiographers, and soil
taxonomists, all of whom have sought to display national patterns by
mapping classes of individual environmental characteristics (USDI
Geological Survey 1970). James (1952) discusses the value of integrating
or regionalizing such environmental characteristics and Warren (1979)
provides an excellent rationale for classifying ecological regions, but
Bailey's ecoregion map (1976) comes the closest to actually doing so.
However, Bailey's map incorporates a hierarchical approach, concentrating
on an individual environmental characteristic at each level, and does not
yet incorporate land-surface form or land use. Hughes and Omernik (1981b)
agree with Warren that it is most useful to integrate these features at
every level in the hierarchy of ecological regions. Such an approach
facilitates the mapping of ecological regions at a national, state, or
county level with increasing resolution (but decreasing generality) at each
lower level.
Ecological regions should improve States' abilities to manage aquatic
ecosystems in at least four ways (Hughes and Omernik 1981b): (1) They
should provide ecologically-meaningful management units. Such units allow
objective and logical synthesis of existing data from ecologically-similar
aquatic ecosystems and, using that synthesis, extrapolation to other
unstudied ecosystems in the same ecological region. (2) They should
provide an objective, ecological basis to refine use classifications and to
evaluate the attainment of uses for aquatic ecosystems. This is because
they provide an ecological basis for determining typical and potential
states of aquatic ecosystems located in similar watersheds. (3) They
should provide an objective ecological basis to prioritize aquatic
ecosystems for improvements or for attainability analyses. Given knowledge
of the typical and potential conditions of aquatic ecosystems in the
separate ecological regions of a State, that State can rationally determine
what to expect from improvements and thereby know where it will get the
greatest ecological returns for its investments. (4) They should simplify
setf'ng site-specific criteria on site-specific biota, as allowed by the
proposed water quality regulation. Rather than set separate criteria for a
large number of sites at enormous expense, a State could use criteria
obtained from a series of sites that typify potential conditions in each
ecological region of that state or neighboring states.
IV-6-3
-------
The process of selecting reference sites can be broken into two major
phases with most of the work done in an office. First, the ecological
regions, and most-typical area(s) of interest are determined. Second,
various sizes of candidate watersheds and reaches are evaluated for
typlcalness and level of disturbance in order to select reference sites.
Determining Ecological Regions
There are several methods for determining ecological regions.
Trautman (1981) suggested that one factor, physiography, could be used to
determine patterns of stream types and fish assemblages in Ohio. Lotspeich
and Platts (1982) believed regions should be determined from two factors,
climate and geology. Bailey (1976) used three factors, climate, soil, and
potential natural vegetation, in his ecoregion map of the United States but
suggested adding land-surface form and lithology if smaller ecoregions are
mapped. Warren (1979) proposed that five factors, climate, topography,
substrate, biota and culture, should all be incorporated in watershed
classification. Hughes and Omernik (1981b), Omernik et al. (1982), and
Omernik and Hughes (1983) overlaid maps of land-surface form, soil
suborders, land use, and potential natural vegetation in studies of the
Corn Belt and Ohio, but suggest using precipitation, temperature, and
lithology if major differences in these factors are suspected. Lotspeich
and Platts, Bailey, and Uarren all emphasized the use of hierarchical
ecoregions, moving from broad national regions thousands of square
kilometers in size to small watersheds a few square kilometers in area. A
much different approach to determining ecological regions is the stream
habitat classification of Pflieger et al. (1981). They used cluster
analysis of fish collections from throughout Missouri to group localities
having similar fish faunas. Where States have computerized fish collection
data from a thousand or more sites, cluster analysis is a useful approach,
however only a handful of States have such data.
Because of the diversity of methods for determining ecological
regions, the limited testing of their applicability to aquatic ecosystems,
and the limited number of large computerized data files, States are
encouraged to select a method that allows the greatest potential for later
modification. The method of Hughes and Omernik requires no prior
collection data and appears to allow more modification than the others.
The greater number of characteristics used to determine regions increases
the opportunity that those regions will have a variety of uses by several
agencies and greater value in predicting impacts of managment actions.
Therefore, their method is outlined by the following steps:
1. Select the area and aquatic characteristics of interest. In many cases
the area of interest will be a State, but wherever major environmental
characteristics or watersheds do not coincide with state borders, States
may find it useful and economical to work cooperatively and incorporate
portions of neighboring States. Aquatic characteristics of interest may
include fish and macro-invertebrate assemblages and various aspects of
the chemical and physical environment affecting those assemblages.
IV-fi-4
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2. Select broad environmental characteristics most likely to control the
aquatic characteristics of Interest. Environmental characteristics to
consider are climate (especially mean annual precipitation and summer
and winter temperature extremes), land-surface form (types of plains,
hills, or mountains), surficial geology (types of soil parent material),
soils (whether wet or dry, hot or cold, shallow or deep, or low or high
in nutrients), potential natural vegetation (grassland, shrubland, or
forestland, and dominant species), major river basins (especially
Important in unglaciated areas for limiting fish and mollusk
distribution), and land use (especially cropland, grazing land, forest,
or various mixes of these). National maps of most of these
characteristics are available 1n USDI-Geological Survey (1970), but,
often, larger-scale State map-s can be obtained from State agencies or
university departments.
3. Examine maps of the selected environmental characteristics for classes
of characteristics that occur in regional patterns. When original maps
differ in scale or when finer resolution is required, a mechanical
enlarger/reducer, photocopy machine, photo-enlarger, or slide projector
can be used to produce maps of the desired scale. Select those classes
of characteristics that best represent tentative ecological regions.
For example, 1s the predominant class of land-surface form flat plains
or high hills; 1s the predominant potential natural vegetation oak
forest or ash forest? List the predominant class of all the
characteristics considered for each tentative ecological region.
4. Overlay the selected environmental characteristics mapped at the same
scale and outline the most-typical areas in each tentative ecological
region. The maps are examined 1n combination on a light table and lines
are drawn on a sheet of clear plastic or transparent paper (e.g.
albanene). Most-typical areas are those areas in each tentative
ecological region where all the predominant classes of environmental
characteristics In that region are present. These can be considered as
most-typical areas because they contain all the classes of
characteristics that will be used to determine that ecological region.
For example, if the predominant classes of land use, potential natural
vegetation, and land-surface form in an ecological region are cropland,
grassland, and plains, respectively, only the portion of that region
where cropland, grassland, and plains all occur together would be
most-typical. This overlay approach and some of the environmental
characteristics are similar to those used by McHarg (1969) in his
examination of the values of various land uses in the Potomac River
Basin.
5. Determine which environmental characteristics best distinguish between
regions. Where the major characteristics abruptly differ at the same
place (e.g. hilly forestlands vs. prairie croplands) this 1s easily
done, but where there are gradual transitions (e.g. from flat to smooth
and irregular plains with decreasing amounts of croplands and Increasing
forestlands) 1t 1s more difficult and the boundrles are less precise.
At one boundary the dlstlngulslng characteristic may be land-surface
form and surfidal geology, at another 1t may be land use or a river
IV-6-5
-------
basin divide. Thus, this boundary determination is a subjective - not a
mechanical or McHargian - process and it requires considerable judgment
and knowledge of the key environmental characteristics along the
tentative boundary. See Figure IV-7-1 for an example of a final
product. Fianlly, the regional lines are transferred to a base map of
the area of interest. On a State level, most of this work should be
done using map scales of 1:500,00.0 to 1:7,500,000. The base map should
then be circulated among knowledgeable professionals to evaluate the
significance of the ecological regions as drawn.
For cases where top-priority aquatic ecosystems are anomalies, or where
the State is interested in only a few sites, it may be more appropriate to
use a slightly different approach based only on the watershed
characteristics of the sites in question. For such cases, rather than
analyze the entire State, researchers can determine the climate,
land-surface form, soils, potential natural vegetation, land use, river
basin, etc. of the watershed upstream of the site of interest. The same
classes of characteristics elsewhere in the State or neighboring States can
then be determined from maps. The rest of the regional1zat1on process is
the same as described above. The major difference in this approach is
that, because of the spatially-narrower objective, fewer ecological regions
will be determined, consequently, the product would have only local
application.
Petermining Candidate References Reaches
The most-typical areas are considered the most-logical places to
locate reference reaches for several reasons: (1) Such areas should
contain a narrower range of land use or disturbance potentials compared to
the entire region or other regions. Hence, there should be a narrower
range of aquatic ecosystem conditions in these most-typical areas compared
to the entire region or other regions. (2) Such areas are more likely to
be free of major anomalies that might produce undisturbed sites that are
also atypical, such as an entirely forested, mountainous watershed in a
region typified by shruhlands and plains. (3) Such areas can potentially
represent the greatest number of streams 1n the ecological region because
they drain watersheds having all the predominant classes of environmental
characteristics that were used to identify the region. (4) Such areas best
represent the prevailing land use of the ecological region and the best
background conditions likely. For example, there is little likelihood of
transforming an area dominated by rangeland into forestland, therefore, the
predominant land use in the watershed of a reference reach in such an area
should be grazing.
For the above reasons, if watersheds of reference or benchmark reaches
are to have the broadest possible applicability, they should fall entirely
within the most-typical areas of ecological regions. Thus, the size of the
most-typical area will determine the maximum size of such watersheds. The
smallest watersheds should Include the smallest Intermittent or permanent
streams and ponds that support spawning or rearing or valued populations.
Valued populations may Include sport, commercial, rare, threatened,
endangered, forage, or intolerant species of any phylum.
IV-6-6
-------
Refining the Number of Candidate Reference Reaches
Regardless of how candidates for reference watersheds are determined
there are several important aspects to consider when selecting reference
reaches:
1. Human Disturbances. Obviously, watersheds that contain dense human
populations, concentrations of mines or industry, several or important
point sources, or major and atypical problems with diffuse pollution
(e.g. acidification, soil erosion, overgrazing, mine wastes, landslides)
should be eliminated from consideration as reference watersheds.
Intentional stocking of sport fishes and incidental releases of aquarium
and bait organisms have extended the ranges of many aquatic species. If
these introductions are only local, knowledge of such populations should
he considered when selecting least-disturbed watersheds because
introduced stocks of species are one of the most detrimental changes
that humans initiate in aquatic ecosystems. Where human disturbances
are mapped this step should be done for the entire State.
2. Size: Because of the gradual change in many stream characteristics from
headwaters to rivers (Vannote et al. 1980), plus application of
MacArthur and Wilson's (1967) theory of island biogeography to lakes
(Rarbour and Brown 1974), it is important to consider the size of the
reference reaches when they are to be compared with a priority water
body. Although stream order (Strahler 1957) has often been used by
biologists to approximate stream size, Hughes and Omernik (1981a, 1983)
give several reasons why watershed area and mean annual discharge are
preferable measures. Limnologists typically use surface area and volume
to estimate lake size. Although regional differences make any
generalizations difficult, the stream order of priority and reference
reaches should not differ by more than one order in most cases and the
watershed areas usually should differ by less than one order of
magnitude.
3. Surface water hydrology. While determining size, the researcher should
also briefly examine the types of the watersheds, streams, or lakes for
anomalies. Large scale topographic maps will usually reveal whether the
streams are effluent or influent, I.e., whether the net movement of
water if from the streams to the ground water or the reverse. The same
maps reveal drainage lakes, lake type (kettle, solution, oxbow, etc.),
amount of ditching or canalization, and drainage pattern (dendritic,
trellis, aimless, etc.).
4. Refugia. Parks, monuments, wildlife refuges, natural areas, preserves,
state and federal forests, and woodlots are often indicated on large
scale topographic maps and locations of others can be obtained from
state agencies charged with their administration. Such refugia are
often excellent places to locate reference sites and reference
watersheds.
IV-6-7
-------
5. Groundwater hydrology. Reports from the State water resource agency and
the State office of the U.S. Geological Survey reveal whether lakes are
Influent or effluent. The direction of water movement in lakes is
extremely Important in determining their nutrient balance, causes of
eutrophlcation, and possible results of lake restoration efforts. For
example, 1n shallow effluent lakes with small watersheds the major
source of nutrients is the atmosphere and hence uncontrollable.
6. Runoff per unit area. \Th1s 1s extremely important in estimating stream
size. The summari zed runoff data are published in U.S. Geological
Survey reports for each State. These data can be used to estimate
1sol1nes of runoff per unit area or existing runoff maps produced by
State water resource agencies can be used. For a national example, see
USDI - Geological Survey (1970).
7. Water chemistry. These data can be used to estimate background or
typical conditions. Most are not summarized, but they can be located
using NAHDEX and are available from computerized data bases such as
HATSTORE and STORET and from State water reports of the U.S. Geological
Survey and State water resource agencies.
8. Geoclimatlc history. The historical geomorphology and climate determine
the basin divides and historical connections among water bodies and
basins. The absence of such connections and the locations of basin
divides and major gradient changes determine centers of origin or
endemlsm. Regionally, continental glaciation, ocean subsidence, and
pluvial flooding, and locally, stream capture, canals, and headwater
flooding all provided passages across apparent barriers that allowed
range extension, and, In large part, determine the present ranges of
primary freshwater fish and mollusks. This information is usually
available from university geology departments and often from the state
geologist.
9. Known zoogeographic patterns. These are best revealed by maps in books
and articles on the biota of the state, e.g. Smith (1983), Trautman
(1981), or Pflieger (1975). Such patterns may also be predicted by
present river basins where the basin divides are substantial and the
river mouths distant.
After considering the broad watershed and regional aspects of the
candidate watersheds, the highly-degraded or unusual watersheds should be
easily rejected. Candidate reaches can then be selected and ranked or
clustered by expected level of disturbance. At this level of resolution,
the researcher should study air photo mosaics and large-scale (1:24,000-
1:250,000) maps of the candidate reaches. Stream gradient, distance from
other refugia, barriers (falls, dams) between reference reaches and other
refugia, distance from the major receiving water, number of mines, and
buildings, amount of channelization, and presence of established monitoring
or gaging sites should all be considered. The 11st of candidate reaches
should be distributed to other professionals to query them about their
knowledge of disturbance levels, previous or concurrent studies, fish
stocking schedules, fish catch per unit effort, spawning or hatching
pulses, valued species, etc.
IV-6-8
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Selecting Actual Reference Sites
All the preceding research can, and should, be done in an office. It
is then useful to view and photograph the reduced number of candidate
reaches from the air. A small wing-over airplane flying 300-1500 meters
above the ground is ideal for this or recent stereo pairs of air photos can
suffice. The candidate reach should be examined at several access points
to assess typical and least-disturbed conditions, i.e., the absence of farm
yards, feed lots, livestock grazing, irrigation diversions, row crops,
channelization, mines, housing developments, clearcuts, or other small
scale disturbances should be rejected, though the candidate reaches may be
moved upstream of them. The main reasons for this aerial view are to
determine what the candidate watersheds and reaches typically look like, to
characterize relatively undisturbed conditions, and to help select actual
reference sites. The photographs are also useful as visual aids in
briefings and public meetings. This phase is not essential if the chief
state ecologist has developed this knowledge of present conditions through
years of experience statewide.
Finally, the remaining candidate reaches can be assessed and ranked
for disturbance from the ground. Three to four candidate reference sites
in each reach should be examined for typical natural features, least-
disturbed channel and riparian characteristics, and ease of access. The
concept of typicalness of natural features is similar to that of
typicalness of watershed features; for example, riffle-pool morphology and
swift current would not be typical of coastal plain or swamp streams and
such anomolous sites should not be included as reference sites.
One of the best indicators of least-disturbed sites is extensive,
old, riparian forest (see Section II-6). Another is relatively-high
heterogeneity in channel width and depth (shallow riffles, deep pools,
runs, secondary channels, flooded backwaters, sand bars, etc.). Abundant
large woody debris (snags, root wads, log jams, brush piles}, coarse bottom
substrate (gravel, cobble, boulders), overhanging vegetation, undercut
banks, and aquatic vascular macrophytes and additional substrate
heterogeneity and concealment for biota. Relatively high discharges;
clear, colorless, and odorless waters; visually-abundant diatom, insect,
and fish assemblages; and the presence of beavers and piscivorous birds
also indicate relatively-undisturbed sites.
In order to confidently ascertain whether a designated biotic use of
a priority aquatic ecosystem is attainable it is necessary to (1) clearly
define that use in objective, measurable, biotic conditions and (2) examine
those conditions in at least three least-disturbed reference sites. We
have described a process to locate and rank a number of least-disturbed
reference sites. However, there are several limitations to that approach.
To date this process has only been tested on streams with watersheds less
than 1600 km2. Major lakes and rivers can be examined in the same
manner, but a multistate or national analysis will be needed and greater
allowances for variability in the level of disturbance and the degree of
typicalness may be necessary because large ecosystems encompass more
variability, they are more likely to receive major point sources, and they
are rarer to begin with.
IV-6-9
-------
Where priority aquatic ecosystems are unique it will be more
difficult to find reference sites. For example, if the priority system is
a forested watershed with a high-gradient stream in Iowa, where such a
system is rare, it would be necessary to seek reference sites in
neighboring States. Where a stream passes through extremely dissimilar
ecological regions, reference streams should do likewise. For example, the
Yampa River of Northwestern Colorado passes from spruce-forested mountains
through sagebrush tablelands and should not be compared with a river that
flows through only one of those regions.
Stream reaches above barriers, such as the falls on the Cumberland
River or the relatively steep gradients of the Watauga River at the North
Carolina-Tennessee border, should not be compared with those below because
few purely aquatic species have passed those historical barriers. Streams
that had glacial or pluvial connections (such as the Susquehanna and James
Rivers) may have more species in common than neighboring rivers of either,
the neighboring rivers have similar environmental conditions. Gilbert
(19RP.) provides a clear discussion of these possible zoogeographic
anomalies using examples from the eastern United States. Decisions about
reference sites must also take such knowledge into consideration.
Finally, ecological regions and reference sites as described herein
are believed most useful for making comparisons between broad assemblage-
level patterns or patterns between widely-ranging and common species of
importance, not between the presence or absence of specific uncommon or
localized species viewed separately. That is, multivariate approaches such
as ordination and classification or hiotic indices such as Karr's (1981)
are most applicable and researchers should not expect to discriminate among
sites that vary only slightly.
Summary
The final product of this approach is a map like that of Figure
IV-7-1. Data from the reference sites in each ecological region can be
compared with those from disturbed sites in that region. For aquatic
ecosystems that cross boundaries between ecological regions, state
ecologists ought to examine data from the reference sites in those
respective regions. Comparisons should he limited to ecosystems of similar
size.
Rather than an ad hoc, best - biological judgment approach, a
regionalization approach as described provides a rational, objective means
to compare similarities and differences over large areas. The regions
provide ecologically-meaningful management units and they would help in the
organization and interpretation of State water quality and NPS reports.
Plata from the reference sites provide an objective, ecological basis to
refine use classifications and, when compared with more disturbed sites, to
evaluate the attainment of uses. Knowledge of potential conditions in a
region provides an objective, ecological basis to predict effects of land
use changes and pollution controls, to prioritize aquatic ecosystems for
improvements, and to set site-specific criteria. Regular monitoring of the
reference sites and comparisons with historical information will provide a
useful assessment of temporal changes, not only in those aquatic
ecosystems, but in the ecological regions that they model.
IV-fi-10
-------
I NORTHWEST FLAT PLAINS
O WESTERN ROLLING PLAINS
ID NE and SW IRREGULAR
H DISSECTED SOUTHEAST
Most Typical Areas
Generally Typical Area*
• Study Watershed*
IV-6-H
-------
0 SECTION V: INTERPRETATION
-------
CHAPTER V
INTERPRETATION
INTRODUCTION
There are many use classifications which might be assigned to a water body,
such as navigation, recreation, water supply or the protection of aquatic
life. These need not be mutually exclusive. The water body survey as discussed
in this manual is concerned only with aquatic life uses and the protection of
aquatic life in a water body.
The water body survey may also be referred to as a use attainability analysis.
The objectives in conducting a water body survey are to identify:
1. What aquatic protection uses are currently being achieved in the water
body,
2. What the causes are of any impairment to attaining the designated aqua-
tic protection uses, and
3. What the aquatic protection uses are that could be attained, based on
the physical, chemical and biological characteristics of the water body.
The types of analyses that might be employed to address these three points are
summarized in Table V-l. Most of these are discussed in detail elsewhere in
this manual.
CURRENT AQUATIC PROTECTION USES
The actual aquatic protection use of a water body is defined by the resident
biota. The prevailing chemical and physical attributes will determine what
biota may be present, but little need be known of these attributes to describe
current uses. The raw findings of a biological survey may be subjected to
various measurments and assessments, as discussed in Chapters IV-2, IV-4, and
IV-5. After performing a biological Inventory, omnivore-carnivore analysis,
and intolerant species analysis, and calculating a diversity index and other
indices of biological health, one should be able adequately to describe the
condition of the aquatic life in the water body.
It will be helpful to digress at this juncture briefly to discuss water body
use classification systems and their relationship to the water body survey.
Classification systems vary widely from state to state. Some consist of as few
as three broad categories, while others include a number of more sharply-
defined categories. Also, the use classes may be based on geography, salinity,
recreation, navigation, water supply (municipal, agricultural, or industrial),
or aquatic life. Often an aquatic protection use must be categorized as either
V-l
-------
TABLE V-l. SUMMARY OF TYPICAL WATER BODY EVALUATIONS (from EPA.1983, Water Quality Standards Handbook).
PHYSICAL EVALUATIONS CHEHICAL EVALUATIONS BIOLOC.1CAL EVALUATION
• Instrea* Characteristics
- size (mean width/depth)
- flow/velocity
- total volume
- reaeratton rates
- gradient/pools/riffles
- temperature
- suspended solids
- sedimentation
- channel modifications
- channel stability
* Substrate composition and
characteristics
* Channel debris
• Sludge deposits
• Riparian characteristics
• Downstream characteristics
• dissolved oxygen
• toxicants
* nutrients
• nitrogen
- phosphorus
• sediment oxygen demand
• salinity
• hardness
• alkalinity
• PH
• dissolved solids
Biological Inventory (Existing Use
Analysis)
- fish
- macrolnvertebrates
- mlcrolnvertebrates
- phytoplankton
- macrophytes
Biological Condition/Health Analysis
- Diversity Indices
- HSI Models
- Tissue Analyses
- Recovery Index
- Intolerant Species Analysis
- Omnivore-Carnlvore Analysis
Biological Potential Analysis
- Reference Reach Comparison
V-2
-------
a warmwater or coldwater fishery. Clearly, little information is required
to place a water body into one of these two categories. Far more
information may be gathered in a water body survey than is needed to
assign a classification, based on existing classes, but the additional
data may be necessary to evaluate management alternatives and refine use
classification systems for the protection of aquatic life in the water
body.
Since there may not be a spectrum of aquatic protection use categories
available against which to compare the findings of the biological survey;
and since the objective of the survey is to compare existing uses with
designated uses, and existing uses with potential uses, as seen in the
three points listed above, the investigators may need to develop their own
system of ranking the biological health of a water body (whether
qualitative or quantitative) in order to satisfy the intent of the water
body survey. Implicit to the water body survey is the development of
management strategies or alternatives which might result in enhancement of
the biological health of the water body. To do this it would be necessary
to distinguish the predicted results of one strategy from another, where
the strategies are defined in terms of aquatic life. The existing state
use classifications will probably not be helpful at this stage, for one
may very well be seeking to define use levels within an existing use
category, rather than describing a shift from one use classification to
another. To conclude, it may he helpful to develop an internal use
classification system to serve as a yardstick during the course of the
water body survey, which may later be referenced to the legally
constituted use categories of the state. Sample scales of aquatic life
classes are presented in Table V-? and v-3.
CAUSES OF IMPAIRMENT OF AOUATIC PROTECTION USES
If the biological evaluations indicate that the biological health of the
system is impaired relative to a "healthy" or least disturbed control
station or reference aquatic ecosystem (e.g., as determined by reference
reach comparisons), then the physical and chemical evaluations can be used
to pinpoint the causes of that impairment. Figure V-l shows some of the
physical and chemical parameters that may be affected by various causes of
change in a water body. The analysis of such parameters will help clarify
the magnitude of impairments to attaining other uses, and will also be
important to the third step in which potential uses are examined.
ATTAINABLE AQUATIC PROTECTION USES
The third element to be considered is the assessment of potential uses of
the water body. This assessment would be based on the findings of the
physical, chemical and biological information which has been gathered, but
additional study may also be necessary. Procedures which might be
particularly helpful in this stage include the Habitat Suitability Index
Models of the Fish and Wildlife Service, that may indicate which fish
species could potentially occupy a given habitat; and the Recovery Index
of Cairns et al. (1977) which estimates the ability of a system to
recover following stress. A reference reach comparison will be
particularly important. In addition to establishing a comparative
V-3
-------
Class
TABLE V-2. BIOLOGICAL HEALTH CLASSES WHICH COULD BE USED
IN WATER BODY ASSESSMENT (Modified from Karr, 1981)
Attributes
Excel lent
Good
Fair
Poor
Very Poor
Extremely Poor
Comparable to the best situations unaltered by man; all re-
gionally expected species for the habitat and stream size,
including the most intolerant forms, are present with full
array of age and sex clases; balanced trophic structure.
Fish and macroinvertebrate species richness somewhat less
than the best expected situation, especially due to loss of
most intolerant forms; some species with less than optimal
abundances or size distribution (fish); trophic structure
shows some signs of stress.
Fewer intolerant forms of fish and macroinvertebrates are
present. Trophic structure of the fish community is more
skewed toward an increasing frequency of omnivores; older
age classes of top carnivores may be rare.
Fish community is dominated by omnivores; pollution-toler-
ant forms and habitat generalists; few top carnivores;
growth rates and condition factors commonly depressed; hy-
brids and diseased fish may be present. Tolerant macroinver-
tebrates are often abundant.
Few fish present, mostly introduced or very tolerant forms;
hybrids common; disease, parasites, fin damage, and other
anomalies regular. Only tolerant forms of macroinverte-
brates are present.
No fish,
life.
very tolerant macroinvertebrates, or no aquatic
V-4
-------
Table V-3; Aquatic Life Survey Rating System (EPA, 1963 Draft)
A reach that is rated a five has;
-A fish community that is well balanced among the different levels
of the food chain.
-An age structure for the most species that is stable, neither
progressive (leading to an increase in population) or regressive
(leading to a decrease in population).
-A sensitive sport fish species or species of special concern always
present.
-Habitat which will support all fish species at every stage of their
life cycle.
-Individuals that are reaching their potential for growth.
-Fewer individuals of each species.
-All available niches filled.
A reach that is rated a four has:
-Many of the above characteristics but some of them are not
exhibited to the full potential. For example, the reach has a well
balanced fish community; the age structure is good, sensitive
species are present; but the fish are not up to their full growth
potential and may be present in higher numbers; an aspect of the
habitat is less than perfect (i.e. occasional high temperatures
that do not have an acute effect on the fish); and not all food
organisms are available or they are available in fewer numbers.
A reach that is a three has:
-A community is not well balanced, one or two tropic levels
dominate.
-The age structure for many species is not stable, exhibiting
regressive or progressive charisteristics.
-Total number of fish is high, but individuals are small.
-A sensitive species may be present, but is not flourishing.
-Other less sensitive species make up the majority of the biomass.
-Anadromous sport fish infrequently use these water as a migration
route.
A reach that is rated a two has;
-Few sensitive sport fish are present, nonsport fish species are
more common than sport fish species.
-Species are more common than abundant.
-Age structures may be very unstable for any species.
-The composition of the fish population and dominate species is very
changeble.
-Anadromous fish rarely use these waters as a migration route.
-A small percent of the reach provides sport fish habitat.
A reach that is a one has:
-The ability to support only nonsport fish. A occasional sport fish
may be found as a transient.
A reach that is rated a zero has:
-No ability to support a fish of any sort, an occasional fish may be
found as a transient.
V-5
-------
SOURCE OF MODIFICATION
DH
Alkalinity
Hardness
Chlorides
Sul fates
TDS
UN
MH,-N
Total -P
Ortho-P
BOO,
COO3
TOC
COO/BOO,
0.0. *
Aromatic Compounds
Fluoride
Cr
Cu
Pb
In
Cd
Fe
Cyanide
011 and Grease
Col 1 forms
Chlorophyll
Diversity
Slomass
Riparian Characteristics
Temperature
TSS
vss
Color
Conducti vity
Channel Characteristics
Drainage
reclpiUtlor
J-O.
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Figure V-l. Potential Effects of Some Sources of Alteration on Stream Parameters;
0 • decrease, 1 • increase. C • change.
V-6
-------
baseline community, defining a reference reach can also provide insight to the
aquatic life that could potentially occur if the sources of impairment were
mitigated.
The analysis of all information that has been assembled may lead to the defini-
tion of alternative strategies for the management of the water body at hand.
Each such strategy corresponds to a unique level of protection of aquatic
life, or aquatic life protection use. If it is determined that an array of
uses are attainable, further analysis which is beyond the scope of the water
body survey would be required to select a management program for the water
body.
A number of factors which contribute to the health of the aquatic life will
have been evaluated during the course of the water body survey. These may be
divided into two groups: those which can be controlled or manipulated, and
those which cannot. The factors which cannot be regulated may be attributable
to natural phenemona or may be attributable to irrevocable anthropogenic
(cultural) activities. The potential for enhancing the aquatic life of a
water body essentially lies in those factors over which some control may be
exerted.
Whether or not a factor can be controlled may itself be a subject of contro-
versy for there may be a number of economic judgments or institutional consid-
erations which are implicit to a definition of control. For example, there are
many cases in the West where a wastewater discharge may be the only flow to
what would otherwise be an Intermittent stream. If water rights have been es-
tablished for that discharge then the discharge cannot be diverted elsewhere,
applied to the land for example, in order to reduce the pollutant load to the
stream. If a stream does not support an anadromous fishery because of dams and
diversions which have been built for water supply and recreational purposes,
it 1s unlikely that a concensus could be reached to restore the fishery by re-
moving the physical barriers - the dams - which impede the migration of fish.
However, 1t may be practical to build fish ladders and by-passes to allow
upstream and downstream migration. In a practical sense these dams represent
anthropogenic activity which cannot be reversed. A third example might be a
situation 1n which dredging to remove toxic sediments in a river may pose a
much greater threat to aquatic life than to do nothing. In doing nothing the
toxics may remain in the sediment in a biologically-unavailable form, whereas
dredging might resuspend the toxic fraction, making it biologically available
and also facilitating wider distribution in the water body.
The points touched upon above are presented to suggest some of the phenomena
which may be of importance In a water body survey, and to suggest the need to
recognize whether or not they may realistically be manipulated. Those which
cannot be manipulated essentially define the limits of the highest potential
use that might be realized in the water body. Those that can be manipulated
define the levels of Improvement that are attainable, ranging from the current
aquatic life uses to those that are possible within the limitations imposed by
factors that cannot be manipulated.
V-7
-------
SECTION VI: REFERENCES
-------
CHAPTER VI
REFERENCES
CHAPTER II-l: FLOW ASSESSMENTS
Bovee, K., 1982. A Guide to Stream Habitat Analysis Using the Instream Flow
Incremental Methodology, FWS/OBS-82/26. U.S. Fish and Wildlife Service, Fort
Collins, CO.
Hilgert, P., 1982. Evaluation of Instream Flow Methodologies for Fisheries in
Nebraska. Nebraska Game & Park Commission Technical Bulletin No. 10, Lincoln,
NB.
Tennant, D.L., 1976. Instream Flow Regimens for Fish, Wildlife, Recreation and
Related Environmental Resources, pp. 359-373. In J.F. Osborn, and C.H. Allman,
eds. Proceedings of the Symposium and Specialty Conference in Instream Flow
Needs. Vol. II, American Fisheries Society, Bethesda, MD.
CHAPTER 11-2: SUSPENDED SOLIDS AND SEDIMENTATION
Atchinson, G.J., and B.W. Menzel, 1979. Sensitivity of Warmwater Fish
Populations to Suspended Solids and Sediments. In Muncey, R.J. et al. "Effects
of Suspended Solids and Sediment on Reproduction and Early Life of Warmwater
Fishes." U.S. EPA, Corvallis, OR, EPA/600/3-79-049.
Benson, N.G., and B.C. Cowell, 1967. The Environmental and Plankton Diversity
in Missouri River Reservoirs, pp. 358-373. In Reservoir Fishery Resources
Symposium. Reservoir Comm., Southern Div., Am. Fish. Soc., Bethesda, MD.
Butler, J.L., 1963. Temperature Relations in Shallow Turbid Ponds. Proc. Okla.
Acad. Sci. 43:90.
Cairns, J. Jr., 1968. Suspended Solids Standards for the Protection of Aquatic
Organisms. Eng. Bull. Purdue University 129:16.
Chew, R.L., 1969. Investigation of Early Life History of Largemouth Bass in
Florida. Florida Game and Fish Comm. Proj. Rept. F-024-R-02. Tallahassee, FL.
Ellis, M.M., 1969. Erosion Salt as a Factor in Aquatic Environments. Ecology
17:29.
European Inland Fisheries Advisory Committee, 1964. Water Quality Critria for
European Freshwater Fish: Report on Finely Divided Solids and Inland
Fisheries. EIFAC Tech. Paper(l) 21 pp.
Iwamoto, R.N., E.O. Salo, M.A. Madeq, R.L. Comas and R. Rulifson, 1978.
Sediment and Water Quality: A Review of the Literature Including a Suggested
Approach for Water Quality Criteria With Summary of Workshop and Conclusions.
EPA 910/9-78-048.
-------
Swingle, H.S., 1956. Appraisal of Methods of Fish Population Study Part IV:
Determination of Balance in Farm Fish Ponds. Trans. N. Am. Wild. Conf. 21:298.
Trautman, M.6., 1957. The Fishes of Ohio. Ohio State Univ. Press, Columbus.
683 pp.
U.S. EPA. 1976. Quality Criteria for Water. U.S. EPA, Washington, O.C. U.S.
Government Printing Office, 055-001-01099.
CHAPTER 11-3: POOLS, RIFFLES AND SUBSTRATE COMPOSITION
Edwards, E.A., et al., 1982. Habitat Suitability Index Models: Black Crappie.
U.S. Fish and Wildlife Service, Ft. Collins, CO. FWS/OBS-82/10.6.
Edwards, E.A., et al., 1982. Habitat Suitability Index Models: White Crappie.
U.S. Fish and Wildlife Service, Ft. Collins, CO. FWS/OBS-82/10.7.
Hickman, T. and R.F. Raleigh, 1982. Habitat Suitability Index Models:
Cutthroat Trout. U.S. Fish and Wildlife Service, Ft. Collins, CO.
FWS/OBS-82/10.5.
Hynes, H.B.N., 1970. The Ecology of Running Waters. University of Toronto
Press, Toronto.
Lagler, Karl F., et al., 1977. Ichthyology. John Wiley & Sons, NY. 506 pp.
La Gorce, J. (editor), 1939. The Book of Fishes. National Geographic Society,
Washington, D.C. 367 pp.
McMahon, T.E., 1982. Habitat Suitability Index Models: Creek Chub. U.S. Fish
and Wildlife Service, Ft. Collins, CO. FWS/OBS-82/10.4.
McMahon, T,E. and J.W. Terrell, 1982. Habitat Suitability Index Models:
Channel Catfish. U.S. Fish and Wildlife Service, Ft. Collins, CO.
FWS/OBS-82/10.2.
Migdalski, Edward C. and G.S. Fichter, 1976. The Fresh and Salt Water Fishes
of the World. Alfred A. Knopf, NY. 316 pp.
Odum, E.P., 1971. Fundamentals of Ecology. W.B. Saunders Co. 574 pp.
Stalnaker, C.B. and J.L. Arnette (editor), 1976. Methodologies for the
Determination of Stream Resource Flow Requirements: An Assessment. U.S.
Fish and Wildlife Service, FWS/OBS-76/03.
Stuber, Robert J., et al., 1982. Habitat Suitability Index Models: Bluegill.
U.S. Fish and Wildlife Service, Ft. Collins, CO. FWS/ OBS-82/10.8.
Whitton, 8.A., (editor), 1975. River Ecology. University of California Press.
724 pp.
VI-2
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CHAPTER 11-4: CHANNEL CHARACTERISTICS AND EFFECTS OF CHANNELIZATION
Arner, D.H., et al. 1976. Effects of Channelization on the Luxapalila River on
Fish, Aquatic Invertebrates, Water Quality, and Furbearers. U.S. Fish and
Wildlife Service, Washington, D.C. FWS/DBS-76/08.
Barclay, J.S., 1980. Impact of Stream Alterations on Riparian Communities in
Southcentral Oklahoma. U.S. Fish and Wildlife Service, Albuquerque, NM.
FWS/OBS-80/17.
Brown, S., et al., 1979. Structure and Function of Riparian Wetlands. In
Strategies for Protection and Management of Floodplaln Wetlands and Other
Riparian Ecosystems, Johnson, R.R., and McCormick, J.F. (editors), U.S. Dept.
of Agriculture, Washington, D.C., Tech. Rept. WO-12, pp. 17-32.
Bulkley, R.V., 1975. A Study of the Effects of Stream Channelization and Bank
Stabilization on Warm Water Sport Fish in Iowa: Subproject No. 1. Inventory of
Major Stream Alterations in Iowa. U.S. Fish and Wildlife Service, Washington,
D.C. FWS/OBS-76/11.
Bulkley, R.V., et al. 1976. Warmwater Stream Alteration in Iowa: Extent,
Effects on Habitat, Fish, and Fish Food, and Evaluation of Stream Improvement
Structures (Summary Report). U.S. Fish and Wildlife Service, Washington, D.C.,
FWS/OBS-76/16.
Cairns, J., Jr., et al., 1976. The Recovery of Damaged Streams. Assoc. SE
Biol. Bull., 13:79.
Chow, V.T., 1959. Open Channel Hydraulics. McGraw-Hill Book Co., NY. 680 pp.
Chutter, F.M., 1969. The Effects of Silt and Sand on the Invertebrate Fauna of
Streams and Rivers. Hydrobiologla, 34:57.
Cummins, K.W., 1973. Trophic Relations of Aquatic Insects. Ann. Rev. Entomol.,
18:183.
Cummins, K.W., 1974. Structure and Function of Stream Ecosystems. Bioscience,
24:631.
Cummins, K.W., 1975. Ecology of Running Waters: Theory and Practice. In Proc.
Sandusky River Basin Symposium, in Baker, D.B., et al., (editors) Heidelburg
College, Tiffin, OH.
Cummins, K.W., and G.H. Lauff, 1969. The Influence of Substrate Particle Size
on the M1crodistr1bution of Stream Macrobenthos. Hydroblologia, 34:145.
Etnier, D.A., 1972. Effect of Annual Rechanneling on Stream Population. Trans.
Amer. Fish. Soc., 101:372.
Frederickson, L.H., 1979. Floral and Faunal Changes in Lowland Hardwood
Forests in Missouri Resulting from Channelization, Drainage, and Impoundment.
U.S. Fish and Wildlife Service, Washington, D.C. FWS/OBS-78/91.
VI-3
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Gammon, J.R., 1979. The Effects of Inorganic Sediment on Stream Biota. Water
Poll. Con. Res. Series, 108050 DWC 12/70, U.S. EPA, Washington, D.C.
Gorman, O.T., and Karr, J.R., 1978. Habitat Structure and Stream Fish
Communities. Ecology, 59:507.
Grlswold, B.L., et al., 1978. Some Effects of Stream Channelization on Fish
Populations, Macroinvertebrates, and Fishing in Ohio and Indiana. U.S. Fish
and Wildlife Service, Columbia, MO, FWS/OBS-77/46.
Muggins, O.G., and R.E. Moss, 1975. Fish Population Structure in Altered and
Unaltered Areas of a Small Kansas USA Stream. Trans. Kansas Acad. Sci., 77:18.
Huish, M.T., and G.B. Pardue, 1978. Ecological Studies of One Channelized and
Two Unchannelized Swamp Streams in North Carolina. U.S. Fish and Wildlife
Service, Washington, D.C. FWS/OBS-78/85.
Hynes, H.B.N., 1970. The Ecology of Running Waters. Univ. of Toronto Press,
Toronto, 555 pp.
Karr, J.R., and I.J. Schlosser, 1977. Impact of Nearstream Vegetation and
Stream Morphology in Water Quality and Stream Biota. U.S. EPA, Athens, GA,
Ecol. Res. Series, EPA-600/3-77-097.
King, D.L., and R.C. Ball, 1967. Comparative Energetics of a Polluted Stream.
Limnol. Oceanog., 12:27.
King, L.R., 1973. Comparison of the Distribution of Minnows and Darters
Collected in 1947 and 1972 in Boone County, Iowa. Proc. Iowa Acad. Sci., 80:
133.
King, L.R., and K.D. Carlander, 1976. A Study of the Effects of Stream
Channelization and Bank Stabilization on Warmwater Sport Fish in Iowa:
Subproject No. 3. Some Effects of Short-Reach Channelization on Fishes and
Fish Food Organisms in Central Iowa Warmwater Streams. U.S. Fish and Wildlife
Service, Washington, D.C. FWS/06S-76/13.
Lavandler, R., and Caplancef, J., 1975. Effects of Variations in Dissolved
Oxygen on the Benthic Invertebrates of a Stream in the Pyreenees. Ann. Limnol.
11.
Leopold, L.B., et al., 1964. Fluvial Processes in Geomorphology. W.H. Freeman
and Co., San Francisco, CA.
Leopold, L.B., and W.B. Langbein, 1966. River Meanders. Scientific American
214:60.
Lund, J., 1976. Evaluation of Stream Channelization and Mitigation of the
Fishery Resources of the St. Regis River, Montana. U.S. Fish and Wildlife
Service, Washington, D.C. FWS/OBS-76-07.
Maki, T.E., et al., 1980. Effects of Stream Channelization on Bottomland and
Swamp Forest Ecosystems. Univ. of North Carolina, Chapel Hill, NC,
UNC-WRRI-80-147.
VI-4
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Marzolf, G.R., 1978. The Potential Effects of Clearing and Snagging on Stream
Ecosystems. U.S. Fish and Wildlife Service, Washington, D.C. FWS/OBS-78-14.
Meehan, W.R., 1971. Effects of Gravel Cleaning on Bottom Organisms in the
Southern Alaska Streams. Prog. Fish-Cult., 33:107.
Mlnshall, G.W., and P.V. Winger, 1968. The Effect of Reduction in Stream Flow
on Invertebrate Drift. Ecology, 49:580.
Minshall, J.W. and J.N. Minshall, 1977. Microdistribution of Benthic
Invertebrates 1n a Rocky Mountain Stream. Hydroblologia, 53:231.
Montalbano, F., et al., 1979. The Kissimmee River Channelization: A
Preliminary Evaluation of Fish and Wildlife Mitigation Measures. In Proc. of
the Mitigation Symp., Colorado State Univ., Ft. Collins, CO, pp. 508-515.
Morris, L.A., et al., 1968. Effects of Main Stream Impoundments and
Channelization Upon the Limnology of the Missouri River, Nebraska. Trans.
Amer. F1sh. Soc., 97:380.
Nebeker, A.V., 1971. Effect of Temperature at Different Altitudes on the
Emergence of Aquatic Insects from a Single Stream. Jour. Kansas. Entomol.
Soc., 44:26.
O'Rear, C.W., Jr., 1975. The Effects of Stream Channelization on the
Distribution of Nutrients and Metals. East Carolina Univ., Greenville, NC,
UNC-WRRI-75-108.
Parrlsh, J.D., et al., 1978. Stream Channel Modification in Hawaii. Part D:
Summary Report. U.S. F1sh and Wildlife Service, Columbia, MO FWS/OBS-78/19.
Pfleiger, W.L., 1975. The Fishes of Missouri. Missouri Dept. Conserv.,
Jefferson City, MO.
Possardt, E.E., et al., 1976. Channelization Assessment, White River, Vermont:
Remote Sensing, Benthos, and Wildlife. U.S. Fish and Wildlife Service,
Washington, D.C. FWS/OBS-76/07.
Schmal, R.N., and D.F. Sanders, 1978. Effects of Stream Channelization on
Aquatic Macrolnvertebrates, Buena Vista Marsh, Portage County, WI. U.S. Fish
and Wildlife Service, Washington, D.C. FWS/DBS-78/92.
Simpson, P.W., et al., 1982. Manual of Stream Channelization Impacts on Fish
and Wildlife. U.S. Fish and Wildlife Service, Kearneysvilie, WV FWS/OBS-82/24.
Swenson, W.A., et al., 1976. Effects of Red Clay Turbidity on the Aquatic
Environment. In Best Management Practices for Non-Point Source Pollution
Control Seminar, U.S. EPA, Chicago, IL, EPA 905/9-76-005.
Tebo, L.B., 1955. Effects of Slltatlon, Resulting from Improper Logging, on
the Bottom Fauna of a Small Trout Stream in the Southern Appalachians. Prog.
Fish-Cult. 17:64.
VI-5
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Vannote, et al., 1980. The River Continuum Concept. Can. Jour. Fish. Aquat.
Sci., 37:130.
Wallen, E.I., 1951. The Direct Effect of Turbidity on Fishes. Oklahoma ASM,
Stillwater, OK, Biol. Series No. 2, 48:1.
Walton, O.E., Jr., 1977. The Effects of Density, Sediment Size, and Velocity
on Drift of Acroneuria abnormis (Plecoptera). OIKOS, 28:291.
Wharton, C.H., and M.M. Brinson, 1977. Characteristics of Southeastern River
Systems. In Stategies for Protection and Management of Floodplain Wetlands and
Other Riparian Ecosystems, Johnson, R.R. and J.F. McCormick (editors),
U.S.D.A., Washington, D.C., Tech. Report WO-12, pp. 32-40.
Whitaker, G.A., et al., 1979. Channel Modification and Macrolnvertebrate
Diversity in Small Streams. Wat Res. Bull., 15:874.
Williams, D.C., and J.H. Muncie, 1978. Substrate Size Selection by Stream
Invertebrates and the Influence of Sand, Limnol. Oceanog. 73:1030.
Winger, P.V., et al., 1976. Evaluation Study of Channelization and Mitigation
Structures in Crow Creek, Franklin County, Tennessee and Jackson County,
Alabama. U.S. Soil Conservation Service, Nashville, TN.
Wolf, J., et al., 1972. Comparison of Benthlc Organisms in Semi-Natural and
Channelized Portions of the Missouri River. Proc. S.D. Acad. Sci., 51:160.
Yang, C.T., 1972. Unit Stream Power and Sediment Transport. A.S.C.E., Jour.
Hydraulics Oiv., 98:1805.
Zimmer, D.W., 1977. Observations of Invertebrate Drift in the Skunk River,
Iowa. Proc. Iowa Acad. Sci., 82:175.
Zimmer, D.W., and R.W. Bachman, 1976. A Study of the Effects of Stream
Channelization and Bank Stabilization on Warmwater Sport F1sn 1n Iowa:
Subproject No. 4. The Effects of Long Reach Channelization on Habitat and
Invertebrate Drift in Some Iowa Streams. U.S. Fish and Wildlife Service,
Washington, D.C. FWS/OBS-76/14.
Zimmer, D.W., and R.W. Bachman, 1978. Channelization and Invertebrate Drift in
Some Iowa Streams. Water Res. Bull. 14:868.
CHAPTER 11-5: TEMPERATURE
Brungs, W.A. and Jones, B.R., 1977. Temperature Criteria for Freshwater F1sh:
Protocol and Procedures, U.S. EPA, Duluth, EPA-600/ 3-77-061.
Butler, J.N., 1964. Ionic Equilibrium, A Mathematical Approach, Addison-
Wesley, Reading, MA.
Carlander, K.D., Handbook of Freshwater Fishery Biology, Vols. I (1969) and 11
(1977). Iowa State University Press, Ames, Iowa.
VI-6
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Cherry, D. and Cairns, C., 1982. Biological Monitoring, Part V - Preference
and Avoidance Studies, Water Research, 16:263.
Hokanson, K., 1977. Temperature Requirements of Some Perdds and Adaptations
to the Seasonal Temperature Cycle, J. Fish. Res. Board Can., 34:1524-1550.
Karr, J.R. and Schlosser, 1978. I.J., Water Resources and the Land Water Inter-
face, Science 201: 229-234.
Klein, L., 1962. River Pollution, II. Causes and Effects, Butterworths, London.
Machenthun, K.M., 1969. The Practice of Water Pollution Biology, U.S. DOI,
Federal Water Pollution Control Agency, U.S.G.P.O., Washington, DC.
Metcalf and Eddy, Inc., 1972. Wastewater Engineering, McGraw-Hill.
Morrow, J.E., 1980. The Freshwater Fishes of Alaska, Alaska Northwest
Publishing Company, Anchorage.
Scott, W., and Crossman, E., 1973. Freshwater Fishes of Canada, Fish. Res.
Board Can., Bulletin 184.
Stumm, W. and Morgan, 1970. J. Aquatic Chemistry, WiIey-Intersc1ence, New York.
Warren, C.E., 1971. Biology and Water Pollution Control, W.B. Saunders
Company, Philadelphia.
CHAPTER 11-6: RIPARIAN EVALUATIONS
Behnke, A.C., et al., 1979. Biological Basis for Assessing Impacts of Channel
Modification: Invertebrate Production, Drift and Fish Feeding 1n Southeastern
Blackwater River. Environmental Resources Center, Rep. 06-79. Georgia Inst.
Techn., Atlanta.
Behnke, R.J., 1979. Values and Protection of Riparian Ecosystems. In The
Mitigation Symposium: A National Workshop on Mitigating Losses of Fish and
Wildlife Habitats. Gustav A. Sandon, Tech. Coordinator, U.S.D.A., Rocky Mt.
For. and Rng. Exp. Stn., Ogden, UT, Gen. Tech. Rept., RM-65 p. 164-167.
Bolen, E.G., 1982. Playas, Irrigation and Wildlife 1n West Texas.
Transactions, North American Wildlife Conference.
Brinson, M.M., B.L. Swift, R.C. Plantico and J.S. Barclay, 1981. Riparian
Ecosystems: Their Ecology and Status. U.S. F1sh and Wildlife Service
FWS/OBS-81/17.
Campbell, C.J., 1970. Ecological Implication of Riparian Vegetation
Management. J. Soil Water Conserv. 25:49.
Crouse, M.R. and R.R. Klndschy, 1981. A Method for Predicting Riparian
Vegetation Potential. Presented at Symposium on Acquisition and Utilization of
Aquatic Habitat Inventory Information. Portland, OR.
VI-7
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Cowardln, L.M., et al., 1979. Classification of Wetlands and Deepwater
Habitats of the United States. U.S. Fish and Wildlife Service, Washington,
D.C. FWS/OBS-79/31.
Council of Environmental Quality, 1978. Our Nation's Wetlands. An Interagency
Task Force Report. U.S. Government Printing Office, Washington, D.C.
(041-011-000045-9).
Greeson, P.E., et al., editors, 1979. Wetland Function and Values: The State
of Our Understanding. American Water Resources Association, Minneapolis, MN.
Hawkins, C.P., M.L. Murphy and N.H. Anderson, 1982. Effects of Canopy,
Substrate Composition and Gradient on the Structure of Macrolnvertebrate
Communities 1n Cascade Range Streams of Oregon. Ecology 63:1840.
Johnson, R.R. and D.A. Jones, 1977. Importance, Preservation and Management of
Riparian Habitat: A Symposium. U.S.D.A. For. Serv., Gen. Tech. Rep. RM-43. Ft.
Collins, Co.
Johnson, R.R. and J.F. McCormlk, 1978. Strategies for Protection and
Management of Floodplaln Wetlands and Other Riparian Ecosystems. U.S.D.A. For.
Serv., Gen. Tech. Rep. WO-12, Washington, D.C.
Karr, J.R. and I.J. Schlosser, 1977. Impact of Vegetation and Stream
Morphology on Water Quality and Stream Biota. U.S. EPA Cincinnati, Ohio EPA/
3-77-097.
Karr, J.R. and I.J. Schlosser, 1978. Water Resources and the Land-Water
Interface. Science 201:229.
Lotspelch, F.B., 1980. Watershed as the Basic Ecosystem: This Conceptual
Framework Provides a Basis for a Natural Classification System. Water
Resources Bulletin, American Water Resources Association, 16(4):581.
Morlng, J.R., 1975. Fisheries Research Report No. 9, Oregon Dept. of Fish and
Wildlife, CorvalHs.
Mueller-Dombols, D. and H. Ellenberg, 1974. Alms and Methods of Vegetation
Ecology. John Wiley and Sons, NY.
Peterson, R.C. and K.W. Cummins, 1974. Leaf Processing in a Woodland Stream.
Freshwater Biology 4:343.
Platts, W.S., 1982. Livestock and Riparian-Fishery Interactions: What are the
Facts? Trans. No. Amer. Wildlife Conf. (47), Portland, OR.
Ross, S.T. and J.A. Baker, 1983. The Response of Fishes to Periodic Spring
Floods in a Southeastern Stream. The American Midland Naturalist 109:1.
Schlosser, I.J., 1982. F1sh Community Structure and Function Along Two Habitat
Gradients in a Headwater Stream. Ecological Monographs 52:395.
VI-8
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Sedell, 0., et al., 1975. The Processing of Conifer and Hardwood Leaves 1n Two
Coniferous Forest Streams. I. Weight Loss and Associated Invertebrates. Verh.
des. Inter. Verelns. Limn. 19:1617.
Sharpe, W.E., 1975. Timber Management Influences on Aquatic Ecosystems and
Recommendations for Future Research. Water Res. Bui. 11:546.
U.S. EPA, 1976. Forest Harvest, Residue Treatment, Reforestation and
Protection of Water Quality. U.S. EPA, Washington, D.C. EPA 910/9-76-020.
Van der Valk, A.G., C.B. Davis, J.L. Baker and C.F. Beer, 1980. Natural
Freshwater Wetlands as Nitrogen and Phosphorus Traps for Land Runoff p.
457-467. In Wetland Functions and Values: The State of Our Understanding, P.E.
Greeson, et al. (editors) Amer. Water Res. Asso. Minneapolis, MN.
CHAPTER III-l: WATER QUALITY INDICES
Brown, R.M., et al., 1970. "A Water Quality Index - Do We Dare?" Water and
Sewage Works, p. 339.
Dinius, S.H., 1972. "Social Accounting System for Evaluating Water Resources"
Water Resources Res. 8(5):1159.
Harkins, R.D., 1974. "An Objective Water Quality Index" Jour. Water Poll.
Cont. Fed. 46(3):588.
Kendall, M.t 1975. Rank Correlation Methods, Charles Griffen and Co., London.
U.S. EPA, 1978. "Water Quality Indices: A Survey of Indices Used in the United
States," U.S. EPA, Washington, D.C., 600/4-78-005.
CHAPTER III-2: HARDNESS, ALKALINITY, pH AND SALINITY
Andrew, R.W., et al., 1977. Effects of Inorganic Complexing on the Toxidty of
Copper to Daphnia magna. Water Research, 11: 309.
CalamaM, D. and Marchettl, R., 1975. Predicted and Observed Acute Toxlcity of
Copper and Ammonia to Rainbow Trout (Salmo gairdneri Rich.). Progress in Water
Technology, 7: 569.
Calamarl, D., et al., 1980. Influence of Water Hardness on Cadmium Toxicity to
Salmo gairdneri Rich. Water Research. 14: 1421.
Carroll, J.J., et al., 1979. Influences of Hardness Constituents on the Acute
Toxlcity of Cadmium to Brook Trout (Salvelnus fontinails). Bulletin of Environ-
mental Contamination and Toxicology, 22: 575.
European Inland Fisheries Advisory Commission. 1969. Water Quality Criteria
for European Freshwater Fish - Extreme pH Values and Inland Fisheries. Water
Research, 3: 593.
VI-9
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Graham, M.S. and Wood, C.M., 1981. Toxlcity of Environmental Acids to the
Rainbow Trout: Interactions of Water Hardness, Acid Type, and Exercise.
Canadian Journal of Zoology, 59: 1518.
Haines, T.A., 1981. Acid Precipitation and its Consequences for Aquatic
Ecosystems: A Review. Transactions of the American Fisheries Society, 110:669.
Haranath, V.B., et al., 1978. Effect of Exposure to Altered pH Media on Tissue
Proteolysis and Nitrogenous End Products in a Freshwater Fish Tilapia
mossambica (Peters). Indian Journal of Experimental Biology, 16: 1088.
Hillaby, B.A., and Randall, D.J., 1979. Acute Ammonia Toxicity and Ammonia
Excretion in Rainbow Trout (Salmo gairdneri). Journal of the Fisheries
Research Board of Canada 36:621.
Kintade M.L.,_ and Erdman, H.E., 1975. The Influence of Hardness Components
(Ca and Mg ) in Water on the Uptake and Concentration of Cadmium in a
Simulated Freshwater Ecosystem. Environmental Research, 10: 308.
Lloyd, R., 1965. Factors that Affect the Tolerance of Fish to Heavy Metal
Poisoning, In: Biological Problems in Water Pollution, 3rd Seminar, U.S.
Department of Health Education and Welfare, pp. 181-187.
Maetz, J. and Bornancin M., 1975, referenced in Calamari, et al., 1980.
Mount, D.I.,1973. Chronic Effect of Low pH on Fathead Minnow Survival, Growth,
and Reproduction. Water Research, 7: 987.
Pagenkopf, G.K., et al., 1974. Effect of Complexation on Toxicity of Copper to
Fish. Journal of the Fisheries Research Board of Canada, 31: 462-465.
Peterson, R.H., et al.,1980. Inhibition of Atlantic Salmon Hatching at Low pH.
Canadian Journal of Fisheries and Aquatic Sciences, 37:370.
Reid, G.K., 1961. Ecology of Inland Waters and Estuaries, 0. Van Nostrand
Company, New York.
Sawyer, C.N. and McCarty, P.L., 1978. Chemistry for Environmental Engineering,
McGraw-Hill Book Company, New York.
Shaw, T.L. and Brown, V.M., 1974. The Toxicity of Some Forms of Copper to
Rainbow Trout. Water Research, 8: 377-392.
Stiff, M.J., 1971. Copper/Bicarbonate Equilibria in Solutions of Bicarbonate
Ions at Concentrations Similar to those Found in Natural Waters. Water
Research, 5: 171-176.
Thurston, R.V., et al., 1974, referenced in U.S. EPA, 1976.
U.S. EPA, 1976. Quality Criteria for Water, U.S. EPA, Washington, O.C.
Warren, C.E. 1971. Biology and Water Pollution Control, W.B. Saunders Company,
Philadelphia, Pennsylvania.
VI-10
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CHAPTER IV-1: HABITAT SUITABILITY INDICES
Inskip, P.O., 1982. Habitat Suitability Index Models: Northern pike, U.S. Fish
and Wildlife Service, Ft. Collins, CO, FWS/OBS-82/10.17.
McMahon, T.E. and J.W. Terrell, 1982. Habitat Suitability Index Models:
Channel Catfish. U.S. F1sh and Wildlife Service, Ft. Collins, CO,
FWS/OBS-82/10.2.
Terrell, J.W., et al., 1982. Habitat Suitability Index Models: Appendix A.
Guidelines for Riverine and Lacustrine Applications of Fish HSI Models With
the Habitat Evaluation Procedures, U.S. Fish and Wildlife Service, Ft.
Collins, CO, FWS/OBS-82/10.A.
CHAPTER IV-2: DIVERSITY INDICES AND MEASURES OF COMMUNITY STRUCTURE
Beak, T.W., 1964. Biotic Index of Polluted Streams and Its Relationship to
Fisheries. Second International Conference on Water Pollution Research, Tokyo,
Japan.
Beck, W.M. Jr., 1955. Suggested Method for Reporting Biotic Data. Sewage Ind.
Wastes, 27:1193.
Bloom, S.A., et al., 1972. Animal-Sediment Relations and Community Analysis of
a Florida Estuary. Marine Biology, 13:43.
Boesch, D.F., 1957. Application of Numerical Classification in Ecological
Investigations of Water Pollution. EPA-600/3-77-033, U.S. EPA, Corvallis.
Bray, J.R. and Curtis, J.T., 1957. An Ordination of the Upland Forest
Communities of Southern Wisconsin. Ecological Monographs, 27:325.
Brillouin, L., 1960. Science and Information Theory. 2nd ed. Academic Press
Inc. NY.
Brock, D.A., 1977. Comparison of Community Similarity Indexes. Journal Water
Pollution Control Federation, 49:2488.
Buikema, A.L. Jr., 1980. Pollution Assessment: A Training Manual. UNESCO, U.S.
MAB Handbook No. 1. Washington, D.C.
Cairns, J. Jr., et al., 1968. The Sequential Comparison Index - A Simplified
Method for Non-Biologists to Estimate Relative Differences in Biological
Diversity in Stream Pollution Studies. Jour. Water Poll. Control Fed., 40:1607.
Cairns, J.R., Jr. and K.L. Dickson, 1969. Cluster Analysis of Potomac River
Survey Stations Based on Protozoan Presence-Absence Data. Hydrobiologia,
34:3-4, 414-432.
Cairns, J. Jr., et al., 1970. Occurrence and Distribution of Diatoms and Other
Algae in the Upper Potomac River. Notulae Naturae Acad. Nat. Sci.
Philadelphia, 436:1.
VI-11
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Cairns, J. Jr. and K.L. Dickson, 1971. A Simple Method for the Biological
Assessment of the Effects of Waste Discharges on Aquatic Bottom-Dwelling
Organisms. Jour. Water Poll. Control Fed., 43:755.
Cairns, J., Jr. and R.L. Kaesler, 1971. Cluster Analysis of Fish In a Portion
of the Upper Potomac River. Trans. American Fishery Society, 100:750.
Cairns, J. Jr., et al., 1973. Rapid Biological Monitoring Systems for
Determining Aquatic Community Structure in Receiving Systems. In Biological
Methods for the Assessment of Water Quality, (J. Cairns, Jr. and K.L. Dickson,
editors) American Society for Testing and Materials, STP 528, p. 148.
Cairns, J.R., Jr., 1977. Quantification of Biological Integrity. In The
Integrity of Water (R.K. Ballerrtine and L.J. Guarraia, editors) U.S.
Government Printing Office, Washington, D.C.
Chutter, F.M., 1972. An Empirical Biotic Index of the Quality of Water in
South African Streams and Rivers. Water Resources, 6:19.
Clifford, H.T. and W. Stephenson, 1975. An Introduction to Numerical
Classification. Academic Press, New York.
Czekanowski, J., 1913. Zarys Metod Statystycznych. Die Grundzuge der
Statischen Metoden, Warsaw.
Dixon, W.J. and F.J. Massey, Jr., 1969. Introduction to Statistical Analysis,
3rd ed. McGraw-Hill, NY.
Duncan, D.B., 1955. Multiple Range and Multiple F Tests, Biometrics, 11:1.
Fager, E.W., 1972. Diversity: A Sampling Study. Amer. Natur., 106:293.
Foerster, J.W., et al., 1974. Thermal Effects on the Connecticut River:
Phycology and Chemistry. Journal Water Pollution Control Federation, 46:2138.
Gammon, J.R., 1976. The Fish Populations of the Middle 340 km of the Wabash
River. Technical Report No. 86, Purdue University Water Resources Research
Center, West Lafayette, IN, pp. 1-48.
Gammon, J.R. and J.M. Reidy, 1981. The Role of Tributaries During an Episode
of Low Dissolved Oxygen in the Wabash River, IN. In AFS Warmwater Streams
Symposium. American Fish Society, Bethesda, MD.
Gammon, J.R., et al., 1981. Role of Electrofishing in Assessing Environmental
Quality of the Wabash River. In Ecological Assessments of Effluent Impacts on
Communities of Indigenous Aquatic Organisms (J.M. Bates and C.I Weber,
editors) Am. Soc. Testing and Materials, STP 730, Philadelphia, PA.
Gaufin, A.R., 1973. Use of Aquatic Invertebrates in the Assessment of Water
Quality. In Biological Methods for the Assessment of Water Quality, {J.
Cairns, Jr. and K.L. Dickson, editors) Am. Soc. for Testing and Materials, STP
528, Philadelphia, PA.
VI-12
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Gleason, H.A., 1922. On the Relation Between Species and Area. Ecology, 3:158.
Godfrey, P.J., 1928. Diversity as a Measure of Benthic Macrolnvertebrate
Community Response to Uater Pollution. Hydrob1olog1a, 57:111.
Hartlgan, J.A., 1975. Clustering Algorithms. W1ley-Intersc1ence, NY.
Heck, K.L. Jr., 1976. Community Structure and the Effects of Pollution in
Sea-Grass Meadows and Adjacent Habitats. Marine Biology, 35:345.
Herrlcks, E.E. and J. Cairns Jr., 1982. Biological Monitoring. Part III:
Receiving System Methodology Based on Community Structure. Water Research,
16:141.
Hllsenhoff, W.L., 1977. Use of Arthropods to Evaluate Water Quality of
Streams. WI Dept. Nat. Resour. Tech. Bull. No. 100.
, 1982. Using a Blotic Index to Evaluate Water Quality in
Streams. HI Dept. Nat. Resour. Tech. Bull No. 132.
Horn, H.S., 1966. Measurement of "Overlap" in Compaative Ecological Studies.
American Naturalist, 100:419.
Howmlller, R.P. and M.A. Scott, 1977. An Environmental Index Based on Relative
Abundance of OUgochaete Species. Jour. Water Poll. Control Fed. 49:809.
Hughes, B.D., 1978. The Influence of Factors Other than Pollution on the Value
of Shannon's Diversity Index, for Benthic Macrolnvertebrates in Streams, Water
Res., 92:359.
Hurlbert, S.H., 1971. The Nonconcept of Species Diversity: A Critique and
Alternative Parameters. Ecology, 52:577.
Hutcheson, K., 1970. A Test for Comparing Diversities Based on the Shannon
Formula. Jour. Theoret. B1ol. 29:151.
Jaccard, P., 1912. The Distribution of Flora in an Alpine Zone. New Phytol.,
11:37.
Johnson, M.G. and R.O. Brlnkhurst, 1971. Associations and Species Diversity in
Benthic Macrolnvrtebrates of Bay of Qunlnte and Lake Ontario. Jour. Fish. Res.
Bd. Canada, 28:1683.
Kaesler, R.L., et al., 1971. Cluster Analysis of Non-Insect
Macro-Invertebrates of the Upper Potomac River. Hydrobiologia, 37:173.
, 1978. Use of Indices of Diversity and Hierarchical
Diversity In Stream Surveys. In Biological Data 1n Water Pollution Assessment;
Quantitative and Statistical Analyses (K.L. Dickson, et al., editors). Am.
Soc. Testing and Materials, STP 652, Philadelphia, PA.
Kaesler, R.L. and J. Cairns, Jr., 1972. Cluster Analysis of Data from
Umnologlcal Surveys of the Upper Potomac River. Am. Midland Naturalist, 88:56.
VI-13
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Keuls, M., 1952. The Use of the "Studentized Range" in Connection with an
Analysis of Variance. Euphytica, 1:112.
Keup, L.E., 1966. Stream Biology for Assessing Sewage Treatment Plant
Efficiency. Water and Sewage Works, 113:411.
Kohn, A.J., 1968. Microhabitats, Abundance and Food of Conus on Atoll Reefs in
the Maldive and Chagos Islands. Ecology, 49:1046.
Livingston, R.J., 1975. Impact of Kraft Pulp-Mill Effluents on EstuaMne
Coastal Fishes in Apalachee Bay, FL. Marine Biology, 32:19.
Lloyd, M.J., et al., 1968. On the Calculation of Information-Theoretical
Measures of Diversity. Amer. Midland Natur., 79:257.
Lloyd, M., and R.J. Ghelardf, 1964. A Table for Calculating the "EquitabfHty"
Component of Species Diversity. Jour. Anim. Ecol., 33:217.
MacAuthur, R.H., 1957. On the Relative Abundance of Bird Species. Proc. Nat.
Acad. Sci. Washington, D.C. 43:293.
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VI-16
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Karr, J.R., 1981. Assessment of Biotic Integrity Using Fish Communities.
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DDT, Endosulfan, Endrln, Heptachlor, Lindane, PCBs, Toxaphene, Cyanide,
Arsenic, Cadmium, Chromium, Copper, Lead, Mercury, Nickel, Selenium, Silver,
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VI-17
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CHAPTER IV-5: OMNIVORE-CARNIVORE ANALYSIS
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Evidence of Degradation, Prospects for Recovery. In Environmental Impact of
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VI-18
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Menzel, B.W., and H.L. F1erst1ne, 1976. A Study of the Effects of Stream
Channelization and Bank Stabilization on Warmwater Sport Fish in Iowa. No. 5:
Effects of Long-Reach Stream Channelization on Distribution and Abundance of
Fishes. U.S. F1sh and Wildlife Service, Columbia, MO, FWS/OBS-76-15.
Morita, C.M., 1953. Freshwater Fishing in Hawaii. Div. of Fish and Game, Dept.
Land Nat. Res., Honolulu, HI.
Morrow, J.E., 1980. The Freshwater Fishes of Alaska. Alaska Northwest
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Moyle, P.B., 1976. Inland Fishes of California. University of California
Press, Berkeley.
Odum, H.T., 1957. Trophic Structure and Productivity of Silver Springs, FL,
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Pflieger, W.L., 1975. The Fishes of Missouri. Missouri Dept. Conserv.,
Jefferson City, MO.
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Ed., D. Van Nostrand Co., NY.
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from the United States and Canada, 4th ed., Special Publ. No. 12, American
Fisheries Soc., Bethesda, MD.
Schlosser, I.J, 1981. Effects of Perturbations by Agricultural Land Use on
Structure and Function of Stream Ecosystems. Ph.D. dissertation, University of
Illinois, Champaign - Urbana, IL.
, 1982a. Trophic Structure, Reproductive Success, and Growth
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, 1982b. Fish Community Structure and Function Along Two Habitat
Gradients in a Headwater Stream. Ecol. Monog. 52: 395.
Scott, W.B., and E.J. Crossman, 1973. Freshwater Fishes of Canada. Fisheries
Research Board of Canada, Bull. 184.
Shelford, V.E., 1911. Ecological Succession. Biol. Bull. 21:127, 22:1.
Smith, P.W., 1979. The Fishes of Illinois. University of Illinois Press,
Urbana, IL.
Timbol, A.S. and J.A. Maciolek, 1978. Stream Channel Modification in Hawaii.
Part A: Statewide Inventory of Streams, Habitat Factors, and Asociated Biota.
U.S. Fish and Wildlife Service, Columbia, MO, FWS/08S-78/16.
VI-19
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Trautman, M.B., 1957. The Fishes of Ohio. Ohio State University Press,
Columbus, OH.
U.S. EPA, 1980. Ambient Water Quality Criteria (several volumes) for
Aldrin/Dieldrin, Chlordane, DDT, Encosulfan, Endrin, Heptachlor, Lindane,
PCBs, Toxaphene, Cyanide, Arsenic, Cadmium, Chromium, Copper, Lead, Mercury,
Nickel, Selenium, Silver, and Zinc. U.S. EPA, Washington, D.C., EPA 440/5-80.
Wallen, E.I., 1951. The Direct Effect of Turbidity on Fishes. Oklahoma A&M
College, Stillwater, OK, Biol. Series No. 2% 48:1.
Warren, C.E., 1971. Biology and Water Pollution Control. W.B. Saunders,
Philadelphia, PA.
CHAPTER IV-6: REFERENCE REACH COMPARISON
Bailey, R.G., 1976. Ecoregions of the United States. U.S.D.A.-Forest Service.
Intermtn. Reg. Ogden, UT.
Barbour, C.D. and J.H. Brown, 1974. Fish Species Diversity in Lakes. Am. Nat.
108:473.
Federal Register, 1982. Proposed Water Quality Standards and Public Meetings.
47(210):49234.
Gilbert, C.R., 1980. Zoogeographic Factors in Relation to Biological
Monitoring of Fish. In Biological Monitoring of Fish (C.H. Hocutt and J.R.
Stauffer, Jr., editors). D.C. Hath Co., Lexington, MA, p. 309-355.
Green, R.H., 1979. Sampling Design and Sampling Methods for Environmental
Biologists. John Wiley and Sons, NY.
Hall, J.D., et al., 1978. An Improved Design for Assessing Impacts of
Watershed Practices on Small Streams. Verh. Interna. Verein. Limnol. 20:1359.
Hughes, R.M., Effects of Mining Wastes on Two Stream Ecosystems: Demonstration
of an Approach for Estimating Ecological Integrity and Attainable Uses.
Hughes, R.M., et al., 1982. An Approach for Determining Biological Integrity
in Flowing Waters. In Place Resource Inventories: Principles and Practices
(T.B. Brann, L.O. House IV, and H.G. Lund, editors). Soc. Am. Foresters,
Bethesda, MD.
Hughes, R.M. and J.M. Omernik, 1981a. Use and Misuse of the Terms Watershed
and Stream Order. In The Warmwater Streams (L.A. Krumholz, editor). Symposium
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, 1981b. A Proposed Approach to Determine
RegionalPatternsHiAquaticETosystems. In Acquisition and Utilization of
Aquatic Habitat Inventory Information (N.B. Armantrout, editor). Am. Fish.
Soc., Bethesda, MD.
VI-20
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» 1983. An Alternative for Characterizing Stream
S1 ze.Tn Dynamics o? Lotlc Ecosystems (T.D. Fontaln III and S.M. Bartell,
editors). Ann Arbor Science, Ann Arbor, MI.
Karr, J.R., 1981. Assesment of B1ot1c Integrity Using F1sh Communties.
Fisheries 6:21.
Lotspelch, F.B. and W.S. Platts, 1982. An Integrated Land-Aquatic
Classification System. N. Amer. J. F1sh. Mgmt. 2:138.
MacArthur, R.H. and E.O. Wilson, 1967. The Theory of Island Biogeography,
Princeton Univ. Press., Princeton, NJ.
Marsh, P.C. and J.E. Luey, 1982. Oases for Aquatic Life fn Agricultural
Watersheds. Fisheries 7:16.
Omernlk, J.M. and R.M. Hughes, 1983. An Approach for Defining Regional
Patterns of Aquatic Ecosystems and Attainable Stream Quality in Ohio. Progress
Report. U.S. EPA, Corvallls, OR.
Pflelger, W.L., M.A. Schene, Jr., and P.S. Haverland. 1981. Techniques for the
Classification of Stream Habitats With Examples of Their Application in
Defining the Stream Habitats of Missouri. In Acquisition and Utilization of
Aquatic Habitat Inventory Information (N.B. Armantrout, editor). Am. Fish.
Soc., Bethesda, MD.
Strahler, A.N., 1957. Quantitative Analysis of Watershed Geomorphology. Trans.
Am. Geophys. Union 38:913.
Trautman, M.G., 1981. The Fishes of Ohio. Ohio State Univ. Press.
U.S.D.I.-Geological Survey, 1970. The National Atlas of the United States of
America. U.S. Government Printing Office, Washington, D.C.
Vannote, R.L., et al., 1980. The River Continuum Concept. Can. J. Fish. Aquat.
Sci. 37:130.
Warren, C.E., 1979. Toward Classification and Rationale for Watershed
Management and Stream Protection. EPA-600/3-79-059. NT IS Springfield, VA.
VI-21
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APPENDIX A-l:
SAMPLF HABITAT SUITABILITY INDEX
(Channel Catfish)
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Biological Services Program
FWS/OBS42/10.2
FEBRUARY 1982
HABITAT SUITABILITY INDEX MODELS:
CHANNEL CATFISH
Fish and Wildlife Service
U.S. Department of the Interior
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FWS/OBS-82/10.2
February 1982
HABITAT SUITABILITY INDEX MODELS: CHANNEL CATFISH
by
Thomas E. McMahor
and
James W. Terrell
Habitat Evaluation Procedures Group
Western Energy and Land Use Team
U.S. Fish and Wildlife Service
Drake Creekside Building One
2625 Redwing Road
Fort Collins, Colorado 80526
Western Energy and Land Use Team
Office of Biological Services
Fish and Wildlife Service
U.S. Department of the Interior
Washington, D.C. 20240
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PREFACE
The habitat use Information and Habitat Suitability Index (HSI) models
presented in this document are an aid for Impact assessment and habitat man-
agement activities. Literature concerning a species' habitat requirements and
preferences is reviewed and then synthesized into HSI models, which are scaled
to produce an index between 0 (unsuitable habitat) and 1 (optimal habitat).
Assumptions used to transform habitat use Information into these mathematical
models are noted, and guidelines for model application are described. Any
models found in the literature which may also be used to calculate an HSI are
cited, and simplified HSI models, based on what the authors believe to be the
most Important habitat characteristics for this species, are presented.
Use of the models presented 1n this publication for Impact assessment
requires the setting of clear study objectives and may require modification of
the models to meet those objectives. Methods for reducing model complexity
and recommended measurement techniques for model variables are presented 1n
Appendix A.
The HSI models presented herein are complex hypotheses of species-habitat
relationships, not statements of proven cause and effect relationships.
Results of model performance tests, when available, are referenced; however,
models v.at have demonstrated reliability in specific situations may prove
unreliable In others. For this reason, the FWS encourages model users to
convey comments and suggestions that may help us increase the utility and
effectiveness of this habitat-based approach to fish and wildlife planning.
Please send comments to:
Habitat Evaluation Procedures Group
Western Energy and Land Use Team
U.S. Fish and Wildlife Service
2625 Redwing Road
Ft. Collins, CO 80526
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CONTENTS
Page
PREFACE iii
ACKNOWLEDGEMENTS Vl
HABITAT USE INFORMATION I
General 1
Age, Growth, and Food 1
Reproduction 1
Specific Habitat Requirements 1
HABITAT SUITABILITY INDEX (HS1) MODELS 4
Model Applicability 4
Model Description - Riverine B
Model Description - Lacustrine 8
Suitability Index (SI) Graphs for
Model Variables 9
Riverine Model 15
Lacustrine Model 17
Interpreting Model Outputs 22
ADDITIONAL HABITAT MODELS 24
Model 1 24
Model 2 25
Mode) 3 25
REFERENCES CITED 25
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CHANNEL CATFISH (Ictalurus punctatus)
HABITAT USE INFORMATION
General
The native range of channel catfish (J_ctaly_rus punctatus) extends from
the southern portions of the Canadian prairie provinces south to the Gulf
states, west to the Rocky Mountains, and east to the Appalachian Mountains
(Trautman 3957; Miller 1966; Scott and Grossman 1973). They have been widely
introduced outside this range and occur in essentially all of the Pacific and
Atlantic drainages in the 48 contiguous states (Moore 1968; Scott and Crossman
1973). The greatest abundance of channel catfish generally occurs in the open
(unleveed) floodplains of the Mississippi and Missouri River drainages (Waiden
1964).
AgeJ Growth, and Food
Age at maturity in channel catfish 1s variable. Catfish from southern
areas with longer growing seasons mature earlier and at smaller sizes than
those from northern areas (Davis and Posey 1958; Scott and Crossman 1973).
Southern catfish mature at age V or less (Scott and Crossman 1973; Pflieger
1975) while northern catfish mature at age VI or greater for males and at age
VIII or greater for females (Starostka and Nelson 1974).
Young-of-the-year (age 0) catfish feed predominantly on plankton and
aquatic insects (Bailey and Harrison 1948; Walburg 1975). Adults are oppor-
tunistic feeders with an extremely varied diet, including terrestrial and
aquatic insects, detrital and plant material, crayfish, and molluscs (Bailey
and Harrison 1948; Miller 1966; Starostka and Nelson 1974). Fish may form a
major part of the diet of catfish > 50 cm 1n length (Starostka and Nelson
1974). Channel catfish diets 1n rivers and reservoirs do not appear to be
significantly different (see Bailey and Harrison 1948; Starostka and Nelson
1974). Feeding is done by both vision and chemosenses (Davis 1959) and occurs
primarily at night (Pflieger 1975). Bottom feeding 1s more characteristic but
food is also taken throughout the water column (Scott and Crossman 1973).
Additional Information on the composition of adult and juvenile diets 1s
provided 1n Leldy and Jenkins (1977).
Reproduction
Channel catfish spawn in late spring and early summer (generally late May
through mid-July) when temperatures reach about 21° C (Clemens and Sneed 1957;
Marzolf 1957; Pflieger 1975). Spawning requirements appear to be a major
factor 1n determining habitat suitability for channel catfish (Clemens and
Sneed 1957). Spawning is greatly inhibited 1f suitable nesting cover 1s
unavailable (Marzolf 1957).
Specific Habitat Requirements
Channel catfish populations occur over a broad range of environmental
conditions (Sigler and Miller 1963; Scott and Crossman 1973). Optimum riverine
-------
habitat is characterized by warm temperature* (Clemens and Snttd 1957; Andrews
et at. 1972; Biesinger et al. 1979). and a diversity of velocities, depths, and
structural features that provide cover and food (Bailey and Harrison 1948).
Optimum lacustrine habitat is characterized by large surface area, warm temper-
atures, high productivity, low to moderate turbidity, and abundant cover
(Davis 1959; Pflieger 1975).
Fry, juvenile, and adult channel catfish concentrate in the warmest
sections of rivers and reservoirs (Ziebe.ll 1973; Stauffer et al. 1975; McCall
1977). They strongly seek, cover, but quantitative data on cover requirements
of channel catfish in rivers and reservoirs are not available. Debris, logs,
cavities, boulders, and cutbanks in lakes and in low velocity (< 15 cm/sec)
areas of deep pools and backwaters of rivers will provide cover for channel
catfish (Bailey and Harrison 1948). Cover consisting of boulders and debris
in deep water 1s important as overwintering habitat (Miller 1966; Jester 1971;
Cross and Collins 1975). Deep pools and littoral areas (£ 5-m deep) with
£ 40% suitable cover are assumed to be optimum. Turbidities > 25 ppm but
< 100 ppm may somewhat moderate the need for fixed cover (Bryan et al. 1975).
Riffle and run areas with rubble substrate and pools (< 15 cm/sec) and
areas with debris and aquatic vegetation ate conditions associated with high
production of aquatic insects (Hynes 1970) consumed by channel catfish in
rivers (Bailey and Harrison 1948). Channel catfish are most abundant in river
sections with a diversity of velocities and structural features. Therefore, it
is assumed that a riverine habitat with 40-602 pools would be optimum for
providing riffle habitat for food production and feeding and pool habitat for
spawning and resting cover (Bailey and Harrison 1948). It also is assumed
that at least 20* of lake or reservoir surface area should consist of littoral
areas (S 5 m deep) to provide adequate area for spawning, fry and juvenile
rearing, and feeding habitat for channel catfish.
High standing crops of warmwater fishes are associated with total
dissolved solids (TDS) levels of 100 to 350 ppm for reservoirs in which the
concentrations of carbonate-bicarbonate exceed those of sulfate-chloride
(Jenkins 1976). It is assumed that high standing crops of channel catfish in
lakes or reservoirs will, on the average, correspond to this TDS level.
Turbidity in rivers and -reservoirs and reservoir size are other factors
that may influence habitat suitability for channel catfish populations.
Channe1 catfish are abundant 1n rivers and reservoirs with varying levels of
turbidity and siltation (Cross and Collins 1975). However, low to moderate
turbidities (< 100 ppm) are probably optimal for both survival and growth
(Finneil and Jenkins 1954; Buck 1956; Marzolf 1957). Larger reservoirs
(> 200 ha) are probably more suitable reservoir habitat for channel catfish
populations because survival and growth are better than in smaller reservoirs
(Finnell and Jenkins 1954; Marzolf 1957). Other factors that may affect
reservoir habitat suitability for channel catfish are mean depth, storage
ratio (SR), and length of agricultural growing season. Jenkins (1974) found
that high mean depths were negatively correlated with standing crop of channel
catfish. Mean depths are an inverse correlate of shoreline development (Ryder
et al. 1974), thus higher mean depths may mean less littoral area would be
available. Jenkins (1976) also reported that standing crops of catfishes
(Ictaluridae) peaked at an SR of 0.75. Standing crops of channel catfish were
-------
postively correlated to growing season length (Jenkins 1970). However, harvest
of channel catfish reported in reservoirs was not correlated with growing
season length (Jenkins and Morals 1971.).
Dissolved oxygen (DO) levels of 5 mg/1 are adequate for growth and
survival of channel catfish, but 0.0. levels of 2 7 mg/1 are optimum (Andrews
et al. 1973; Carlson et al. 1974). Dissolved oxygen levels < 3 mg/1 retard
growth (Simco and Cross 1966), and feeding is reduced at D.O. levels < 5 mg/1
(Randolph and Clemens 1976).
Adult. Adults in rivers are found in large, deep pools with cover. They
move To"iTffles and runs at night to feed (McCammon 1956; Davis 1959, Pflieger
1971; 1975). Adults in reservoirs and lakes favor reefs and deep, protected
areas with rocky substrates or other cover. They often move to the shoreline
or tributaries at night to feed (Davis 1959; Jester 1971; Scott and Crossman
1973).
The optimal temperature range for growth of adult channel catfish 1s
26-29° C (Shrable et al. 1969; Chen 1976). Growth is poor at temperatures
< 21° C (McCammon a.nd LaFaunce 1961; Macklin and Soule 1964; Andrews and
Stickney 1972) and ceases at < 18° C (Starostka and Nelson 1974). An upper
lethal temperature of 33.5° C has been reported for catfish acclimated at
25° C (Carlander 1969).
Adult channel catfish were most abundant in habitats with salinities
< 1.7 ppt in Louisiana, although they occurred in areas with salinities up to
11.4 ppt (Perry 1973). Salinities S 8 ppt are tolerated with little or no
effect, but growth slows above this level and does not occur at salinities
> 11 ppt (Perry and Avault 1968).
Embryo. Dark and secluded areas are required for nesting (Marzolf 1957).
Males build and guard nests in cavities, burrows, under rocks, and in other
protected sites (Davis 1959; Pflieger 1975). Nests 1n large Impoundments
generally occur among rubble and boulders along protected shorelines at depths
of about 2-4 m (Jester 1971). Catfish in large rivers are likely to move into
shallow, flooded areas to spawn (Bryan et al. 1975). Lawler (1960) reported
that spawning in Utah Lake, Utah, was concentrated in sections of the lake
with abundant spawning sites of rocky outcrops, trees, and crevices. The male
catfish fans embryos for water exchange and guards the nest from predators
(Miller 1966; Minckley 1973). Embryos can develop In the temperature range of
15.5 to 29.5° C, with the optimum about 27° C (Brown 1942; Clemens and Sneed
1957). They do not develop at temperatures < 15.5° C (Brown 1942). Embryos
hatch in 6-7 days at 27° C (Clemens and Sneed 1957).
Laboratory studies indicate that embryos three days old and older can
tolerate salinities up to 16 ppt until hatching, when tolerance drops to 8 ppt
(Allen and Avault 1970). However, 2 ppt salinity is the highest level in
which successful spawning in ponds has been observed (Perry 1973). Embryo
survival and production in reservoirs will probably be high In areas that are
not subject to disturbance by heavy wave action or rapid water drawdown.
Fry. The optimal temperature range for growth of channel catfish fry 1$
29-30° C (West 1966). Some growth does occur down to temperatures of 18° C
(Starostka and Nelson 1974), but growth generally is poor in cool waters with
average summer temperatures < 21° C (McCammon and LaFaunce 1961; Macklin and
3
-------
Soule 1964; Andrews et al. 1972) and in areas with short agricultural growing
seasons (Starostka and Nelson 1974). Upper incipient lethal levels for fry
are about 35-38° C, depending on acclimation temperature (Moss and Scott 1961;
Allen and Strawn 1968). Optimum salinities for fry range from 0-5 ppt;
salinities it 10 ppt are marginal as growth is greatly reduced (Allen and
Avault 1970).
Fry habitat suitability in reservoirs is related to flushing rate of
reservoirs in midsummer. Walburg (1971) found abundance and survival of fry
greatly decreased at flushing rates < 6 days in July and August.
Channel catfish fry have strong shelter-seeking tendencies (Brown et al.
197C), and cover availability will be important in determining habitat suit-
ability. Newly hatched fry remain in the nest for 7-8 days (Marzolf 1957) and
then disperse to shallow water areas with cover (Cross and Collins 1975). Fry
are commonly found aggregated near cover in protected, slow-flowing (velocity
< 15 cm/sec) areas of rocky riffles, debris-covered gravel, or sand bars in
clear streams (Davis 1959; Cross and Collins 1975), and in very shallow
(< 0.5 m) mud or sand substrate edges of flowing channels along turbid rivers
and bayous (Bryan et al. 1975). Dense aquatic vegetation generally does not
provide optimum cover because predation on fry by centrarchids is high under
these conditions, especially in clear water (Marzolf 1957; Cross and Collins
1975). Fry overwinter under boulders in riffles (Miller 1966) or move to
cover in deeper water (Cross and Collins 1975).
Juvenile. Optimal habitat for juveniles is assumed to be similar to that
for fry. The temperature range most suitable for juvenile growth 1s reported
to be 28-30° C (Andrews et al. 1972; Andrews and Stlckney 1972). Upper lethal
temperatures are assumed to be similar to those for fry.
HABITAT SUITABILITY INDEX (HS1) MODELS
Model Applicability
Geographic area. The model 1s applicable throughout the 48 conterminous
States. The standard of comparison for each Individual variable suitability
index is the optimum value of the variable that occurs anywhere within the 48
conterminous States. Therefore, the model will never provide an HSI of 1.0
when applied to water bodies in the Northern States where temperature-related
variables do not reach the optimum values for channel catfish found 1n the
Southern States.
Season. The model provides a rating for a water body based on Its ability
to support a self-sustaining population of channel catfish through all seasons
of the year.
Cover types. The model is applicable in riverine, lacustrine, palustrlne,
and estuarine habitats, as described by Cowardin et al. (1979).
Minimum habitat area. Minimum habitat area Is defined as the minimum
area of contiguous suitable habitat that is required for a species to succes-
fully live and reproduce. No attempt has been made to establish a minimum
-------
habitat size for channel catfish, although this species 1s most abundant 1n
larger water bodies.
. The acceptable output of these models is an index
between 0 and 1 which the authors believe has a positive relationship to
carrying capacity. In order to verify that the model output was acceptable,
sample data sets were developed for calculating HSl's from the models..
The sample data sets and their relationship to model verification are
discussed in greater detail following the presentation of the models.
Model Description
It is assumed that channel catfish habitat quality is based primarily on
their food, cover, water quality, and reproduction requirements. Variables
that have been shown to have an impact on the growth, survival, distribution.
abundance, or other measure of well-being of channel catfish are placed in the
appropriate component and a component rating derived from the Individual
variable sJubiHty <--d;:*s (c<:s. 1 a-i 2). .a'-^es -."a-, s--'*:-. *»r •-.£-.
quaV. ty for cnannel catfisn. Dot wnicn oo r.oi eis-. ",y fit * nio tnese "four major
components, are combined under the "other component" heading. Levels of a
variable that are near lethal or result in no growth cannot be offset by other
variables.
Model Description - Riverine
Food component. Percent cover (V2) is assumed t-» he important for rating
the food component because if cover
-------
Habitat Variables
* cover (V,)
Substrate type (VJ
% pools (V»)
'» cover (V,)
Average current velocity (V,t)
Temperature (adult) (Vf)
Temperature (fry) (V^
Temperature (juvenile)
Dissolved oxygen (Vt) -
Turbidity (VT)
Salinity (adult) (V,)
Salinity (fry, juvenile) (V,,)
Length of agricultural growing season (V«)
S pools (V,)
% cover (V,)
Dissolved oxygen (V,)-
Temperature (embryo)
Llfe Requlsim
Food (Cp)
Cover (Cc)
Water quality
Salinity (embryo) (V,i)
Reproduction
Figure 1. Tree diagram illustrating relationship of habHot variables
and life requisites in the riverine model for the channel catfish.
Dashed lines indicate optional variables in the model.
-------
Habitat Variables
Life Requisites
% cover (V,)
% littoral area (V,)
Total dissolved solids (V,t)
Food (Cp),
% cover (V,)
% littoral area (V»)
Cover (Cc),
Temperature (adult) (Vt)
Temperature (fry) (V,,)
Temperature (juvenile)
Dissolved oxygen (V,)
Turbidity (V,)
Salinity (adult) (V,)
Salinity (fry, juvenile) (V,,)
Length of agricultural growing season (V»)
Water quality
cover (V,)
% HU'jr-dl df,, (V.)
Dissolved oxygen (V,)
Temperature (embryo) (V,,)
Salinity (embryo) (V,,)
Reproduction (CR)'
Storage ratio (Vi
Flushing rate (V,T)
Other (CQT)
Figure 2. Tree diagram Illustrating relationship of habitat variables
and life requisites in the lacustrine model for the channel catfish.
Dashed lines Indicate optional variables in the model.
-------
Reproduction component. Percent pools (Vj) is in the reproductive compo-
nent bt-cause channel catfish spawn in low velocity areas In river*. Percent
cover (V,) is in this component since channel catfish require cover for
spawning. If minimum dissolved oxygen (00) levels within pools and backwaters
during midsummer (V,) are adequate, they should be adequate during spawning,
which occurs earlier in the year. DO levels measured during spawning and
embryo development could be substituted for V,. Two additional variables,
average water temperatures within pools and backwaters during spawning and
embryo development (V1() and maximum salinity during spawning and embryo
development (VM) are included' because these water quality conditions affect
embryo survival and development.
Model Description - lacustrine
Food component. Percent cover (V,) is included since 1t Is assumed that
if cover Is available, channel catfish would be more likely to utilize an area
for feeding. Percent littoral area (V,) is included because littoral areas
generally produce the greatest amount of food and feeding habitat for catfish.
Total dissolved solids (TOS) (VIt) 1s included because adult channel catfish
eat fish, and fish production in lakes and reservoirs is correlated with TDS.
Cover component. Percent cover (V,) is included since channel catfish
strongly seek structural features of logs, debris, brush, and other objects
for shelter. Percent littoral area (V,) 1s Included because all life stage
predominantly utilize cover found in littoral areas of a lake.
Water quality component. Refer to riverine model description.
Reproduction component. Percent cover (V2) is included since catfish
build nests in dark and secluded areas; spawning 1s not observed 1f suitable
cover 1s unavailable. Percent littoral area (V,) 1s Included since catfish
spawning 1s concentrated along the shoreline. DO (V,). temperature (Vlt) and
salinity (V,,) are included because these water quality parameters affect
embryo survival and development.
Other component. For reservoirs, storage ratio (V4») and maximum flushing
rate when fry are present (V,T) are included in this component because storage
ratio may affect standing crop and the flushing of fry from a reservoir outlet
can reduce the abundance of fry.
-------
Suitability Index (SI) Graphs for Model Variables
This section contains suitability index graphs for the 18 variables
described above, and equations for combining selected variables into a species
HSI using trie component approach. Variables pertain to a riverine (R) habitat,
lacustrine (L) habitat, or both (R, L).
Habitat Variable
Percent pools during
average summer flow.
1
.0
0.8 J
.? °-6-
1 0.4:
• ^
" 0.2-
0.0
Suitability Graph
25
50
75 IOC
R,l
Percent cover (logs,
boulders, cavities,
brush, debris, or
standing timber) during
summer wi thin pool s,
backwater areas, and
littoral areas.
X
OJ
•o
3
t/1
1.0
0.8-
•- 0.6-
0.4-
0.2-
0.0
10 20 30 40 50
-------
(V,) Percent littoral area
during summer.
1.0
25 50 75 TOO
4/1
0.0
(Vfc) Food production potential
in river by substrate type
present during average
summer flow.
A) Rubble dominant in
riffle-runs with some
gravel and/or boulders
present; fines (silt
and sand) not common;
aquatic vegetation
abundant (> 30fo) in
pool areas.
B) Rubble, gravel ,
boulders, and fines
occur in nearly equal
amounts in riffle-run
areas;
tion is
pool areas.
C) Some rubble and gravel
present, but fines or
boulders are dominant;
aquatic vegetation is
scarce (< 10%) in pool
areas.
0) Fines or bedrock are
the dominant bottom
material. Little or
no aquatic vegetation
or rubble present.
1.0
X
QJ
•o
C
13
aquatic vegeta-a
10-30% in "
0.8 -
0.6 .
0.4 -
0.2
0.0
B C
Class
10
-------
R,L (V,) Average midsummer water
temperature within
pools, backwaters, or
littoral areas (Adult).
1.0
O.B -
0.6 -
0.4 J
0.2 '
0.0
10 20 30 40
°C
R,L (V,) Length of agricultural
growing season (frost-
free days).
Note: This variable
Is optional.
1.0
X
•g 0.8
*—*
£ 0.6
| 0.4
5 0.2
0.0
125
Days
250
R,L (Vv) Maximum monthly average
turbidity during summer.
0.0
100
11
-------
(V,) Average minimum dissolved
oxygen levels within
pools, backwaters, or
littoral areas during
midsummer.
1.0
•S 0.3 -
c
£ 0.6 -
•r"
£j * J • *•
*i
4-*
5 0.2
0.0
R,L (V,) Maximum salinity
during summer
(Adult).
1.0
x
•o 0.8
c
S 0.6
5 0.4
4->
S 0.2
0.0
10
Ppt
R,L (V,,) Average water
temperatures within
pools, backwaters,
and littoral areas
during spawning and
embryo development
(Embryo).
•o
c
1.0
£ 0.8 J
>> 0.6
2 0.4 -
fO
0.2
0.0
10
20
°C
12
-------
Maximum salinity
ouring spawning
and embvyo development
(Embryo).
10
ppt
20
(Vn) Average midsummer water
temperature within pools,x
backwaters, or littoral ^ Q.8 •
areas (Fry).
40
(V,,) Maximum salinity
during summer
(Fry, Juvenile).
x 1.0
a*
0.8 -
I °'6
0.4 -
0.2
0.0
S 6 78 9 10
PPt
13
-------
tcmpurjture within
pools, backwaters, or
littoral areas
(Juvenile).
10
(V,,)
Storage ratio.
•o
1.0 4
0.8 -
£ 0.6 -
(Vlt) Monthly average IDS
(total dissolved
solids) during
summer.
1000
-------
(V,,)
(V,,)
Riverine Model
Maximum reservoir
flushing rate while
fry present (Fry).
Average current velocity
1n cover areas during
average summer flow.
•o
0.0
1.0
0.8
0.6
0.4
0.2
0.0
5
Days
10 20
30 40
cm/ sec
50
These equations utilize the life requisite approach and consist of four
components: food, cover, water quality, and reproduction.
Food (CF).
V, * V.
IS
-------
Cover (Cc).
Cc * (V, x V, x V,,)1/3
Water Quality (C^).
* Via * V, J
.. 3 + VT + 2(V.) + V, * V.,
CWQ ' 7
If V», V,,, Vj.. V,. V,, or V», 1s s 0.4, then Cyg equals the lowest
of the following: V», V,,, Vlk, V,, V,. V,,, or the above equation.
Note: If temperature data are unavailable, 2(V«) (length of agricul-
tural growing season) nay be substituted for the tem
2(V, * V», * Vlfc)
c in the above equation
Reproduction (C«).
CR* (V, x V,» x V,1 x V,.1 x V»)1/8
If V,, V,,, or.Vn Is S 0.4, then CR equals the lowest of the
following: Vt, Vlt, Vllt or the above equation.
HS1 determination.
HSI - (Cp x Cc x C^' x CR»)1/6 , or
If C,^ or CD 1s $ 0.4, then the HSI equals the lowest of the
wQ R
following: C^Q, CR, or the above equation.
16
-------
Sources of data and assumptions made In developing the suitability Indices
are presented In Table 1.
Sample data sets using riverine HSI model are listed 1n Table Z.
Lacustrine Model
This model utilizes the life requisite approach and consists of five
components: food, cover, water quality, reproduction, and other.
Food (Cp).
V, * V, + V,,
Cover (C»).
cc - (v, x v,;
Water Quality (C.^
Cyg = same as 1n Riverine HSI Model
Reproduction (CR).
CR = (V,1 x V, x V,1 x ¥»,» x V,,)1''8
If V,. V,,, or V,, 1s S 0.4, then CR equals the lowest of th«
following: V,, V](, V,,, or the above equation.
Other (CQT).
C"
V,, * V,,
OT 2
17
-------
Table 1. Data sources and assumptions for channel catfish suitability Indices.
Variable and source
Assumption
V, Bailey and Harrison 1948
V, Bailey and Harrison 1948
Marzolf 1957
Cross and Collins 1975
V, Bailey and Harrison 1948
Marzolf 1957
Cross and Collins 1975
V» Bailey and Harrison 1948
V» Clemens and Sneed 1957
West 1966
Shrable et al. 1969
Starostka and Nelson 1974
Biesinger et al. 1979
V, Jenkins 1970
VT Finnell and Jenkins 1954
Buck 1956
Marzolf 1957
V, Moss and Scott 1961
Andrews et al. 1973
Carlson et al. 1974
Randolph and Clemens 1976
V, Perry and Avault 1968
Perry 1973
Optimum conditions for a diversity of
velocities, depths, and structural
features for channel catfish will be
found when there are approximately equal
amounts of pools and riffles.
The strong preference of all life stages
of channel catfish for cover Indicates
that some cover must be present for
optimum conditions to occur.
Lakes with small littoral area will pro-
vide less area for cover and food pro-
duction for channel catfish and are there-
fore less suitable.
The amount and type of substrate or the
amount of aquatic vegetation associated
with high production of aquatic Insects
(used as food by channel catfish and
channel catfish prey species) 1s optimum.
Temperatures at the warmest time of year
must reach levels that permit growth in
order for habitat to be suitable. Optimum
temperatures are those when maximum growth
occurs.
Growing seasons that are correlated with
high standing crops are optimum.
High turbidity levels are associated with
reduced standing crops and therefore are
less suitable.
Lethal levels of dissolved oxygen are
unsuitable. DO levels that reduce feeding
are suboptimal.
Salinity levels where adults are most
abundant are optimum. Any salinity
level at which adults have been
reported has some sultabilty.
18
-------
Table 1. (concluded)
Variable and source
Assumption
V,,
'1*
v,,
Brown 1942
Clemens and Sneed 1957
Perry and Avault 1968
Perry 1973
MeGammon and LaFaunce 1961
Moss and Scott 1961
MackTin and Soule 1964
West 1966
Allen and Strawn 1968
Andrews 1972
Starostka and Nelson 1974
Allen and Avault 1970
Andrews et al. 1972
Andrews and Stlckney 1972
Jenkins 1976
V14 Jenkins 1976
Walburg 1971
Miller 1966
Scott and Crossman 1973
Cross and Collins 1975
Optimum temperatures are those which
result in optimum growth. Temperatures
that result in death or no growth are
unsuitable.
Salinity levels at which spawning has
been observed are suitable.
Optimum temperatures for fry are those
when growth 1s best. Temperatures that
result in no growth or death are unsuit-
able.
Salinities that do not reduce growth
of fry and juveniles are optimum.
Salinities that greatly reduce growth
are unsuitable.
Temperatures at which growth of juveniles
1s best are optimum. Temperatures that
result 1n no growth or death are unsuit-
able.
Storage ratios correlated with maximum
standing crops are optimum; those cor-
related with lower standing crops are
suboptlmum.
Total dissolved solids (TOS) levels cor-
related with high standing crops of warm-
water fish are optimum; those correlated
with lower standing crops are suboptimum.
The data used to develop this graph are
primarily from southeastern reservoirs.
Flushing rates correlated with reduced
levels of fry abundance are suboptimal.
High velocities near cover objects will
decrease the amount of usable habitat
around the objects and are thus
considered suboptlmutn.
19
-------
Table 2. Sample data sets using riverine HSI mocel.
Variable
* pools Vi
% cover V,
Substrate for V,.
food production
Temperature-Adul t
(° C) V,
Growing season \/t
Turbidity (ppm) V,
Oi ssol ved oxygen
(mg/1) V,
Sal ini ty-adult
(Ppt) V,
Temperature-Embryos
(°C) V»,
Sal ini ty-Embryo
(Ppt) VV1
Temperature-Fry
C° c) vl7
Sal inity-Fry/
Juvenile (ppt) Vj,
Temperature-
Juvenile (° C) V,,.
Velocity Vt,
Data set 1
Data SI
60 1.0
50 1.0
silt- 0.7
gravel
28 1.0
180 0.8
50 1.0
4.5 0.6
< 1 1.0
25 0.8
< 1 1.0
26.5 0.8
< 1 1.0
29 1.0
15 1.0
Data set 2
Data SI
90 0.6
10 0.4
silt- 0.5
sand
32 0.4
-
210 0.5
4.0 0.5
< 1 1.0
21.5 0.5
< 1 1.0
32 0.7
< 1 1.0
32 0.7
5 1.0
Data
Data
15
5
sand
22
-
160
4.0
< 1
23.5
< 1
23
< 1
22
30
set 3
SI
0.5
0.2
0.2
O.b
-
0.8
0.5
l.C
O.S
1.0
0.5
1.0
0.5
0.3
20
-------
Table 2. (concluded)
Variable
Component SI
CF •
CC *
CWQ *
CR *
HSI -
Data set 1
Data SI
0.85
1.00
0.87
0.86
0.88
Data set 2
Data SI
0.45
0.62
0.40"
0.58
0.40"
Data set 3
Data SI
0.20
0.31
0.69
0.47
0.43
•Note: C..Q S 0.4; therefore, HSI = Cyg 1n Data Set 2.
21
-------
HSI determination.
HSI = (CF x Cc x C^' x CRS x CQT)1/7 , or
If C-jn or CD is i 0.4, then the HSI equals the lowest of the
wy K
following: CWQ, CR, or the above equation.
Sample data sets using lacustrine HSI model are listed in Table 3.
Interpreting Model Outputs
The proper interpretation of the HSI produced by the models is one of
comparison. If two water bodies have large differences in HSI's, then the one
with the higher HSI should be able to support more catfish than the water body
with the lower HSI, given that the model assumptions have not been violated.
The actual differences in HSI that indicate a true difference in carrying
capacity are unknown and likely to be high. We have aggregated a large number
of variables into a single index with little or no quantitative information on
how the variables interact to effect carrying capacity. The probability that
we have made an error in our assumptions on variable interactions is high.
However, we believe the model is a reasonable hypothesis of how the selected
variables interact to determine carrying capacity.
Before using the model, any available statistical models, such as those
described under model 3 in the next section, should be examined to determine
if they better meet the goals of model application. Statistical models are
likely to be more accurate in predicting the value of a dependent variable,
such as standing crop, from habitat related variables than the HSI models
described above. A statistical model is especially useful when the habitat
variables in the data set used to derive the model have values similar to the
proposed model application site. The HSI models described above may be most
useful when habitat conditions are dissimilar to the statistical model data
set or it is important to evaluate changes in variables not included in the
statistical model.
The sample data sets consist of different variable values (and their
corresponding SI score), which although not actual field measurements, are
thought to represent realistic conditions that could occur in various channel
catfish riverine or lacustrine habitats. We believe the HSI's calculated from
the data reflect what carrying capacity trends would be in riverine or lacus-
trine habitats with the characteristics listed in the respective data sets.
22
-------
Tablt 3. Sample data sets using lacustrine HSI model.
Variable
£ cover V,
% littoral area V,
Temperature-Adul t
(° C) V,
Growing season V,
Turbidity VT
Dissolved oxygen V,
Salinity-Adult
(ppt) V,
Temperature-Embryo
(° C) V,.
Salinity-Embryo
(ppt) V,»
Temperature-Fry
(° C) V,,
Salinity-Fry/
Juvenile (ppt) V,,
Temperature-
Juvefiile (° C) V,»
Storage ratio Vlt
TDS (ppm) V,.
Data
Data
50
40
26
180
175
4.5
< 1
25
< 1
26.5
< 1
29
1.5
200
set 1
SI
1.0
1.0
1.0
0.8
0.7
0.6
1.0
0.8
1.0
0.8
1.0
1.0
0.9
1.0
Data
Data
10
20
20
-
210
4.5
< 1
21.5
< 1
32
< 1
32
.3
300
set 2
SI
0.4
0.7
0.3
-
0.5
0.6
1.0
0.5
1.0
0.7
1.0
0.7
0.7
1.0
Data
Data
5
70
33
-
250
2.5
< 1
28
< 1
23
< 1
22
0.8
600
set 3
SI
0.2
0.6
0.2
-
0.3
0.2
1.0
0.5
1.0
0.5
1.0
0.5
1.0
0.6
Flushing rate
while fry
present (days) VJT 15 1.0 4 0.4 11 1.0
23
-------
Table 3. (concluded)
Variable
Component SI
c =
cc =
CWQ-
CR =
COT =
HS1 =
Data set 1
Data SI
1.00
1.00
0.82
0.83
0.95
0.89
Data set 2
Data SI
0.70
0.52
0.30"
0.56
0.55
0.30-
Data set 3
Data SI
0.47
0.33
0.20"
0.20
1.00
0.20"
•Note: CWQ S 0.4; therefore, HS1 = C^ 1n Data Sets 2 and 3.
ADDITIONAL HABITAT MODELS
Model 1
Optimal riverine habitat for channel catfish is characterized by the
following conditions, assuming water quality is adequate: warm, stable water
temperatures (summer temperatures of 25-31° C); an approximate 40-602 area of
deep poo's; and abundant cover in the form of logs, boulders, cavities, and
debris (> 40% of pool area).
uf. _ number of above criteria present
Mil -
3
24
-------
Model 2
Optimal lacustrine habitat for channel catfish is characterized by the
following conditions, assuming water quality is adequate: warm, stable water
temperatures (summer temperatures of 25-30° C); large surface area (> 500 ha);
moderate to high fertility (TDS 100-350 ppm); clear to moderate turbidities
(< 100 JTU); and abundant cover (> 40% in areas < 5 m deep).
CT _ number of above criteria present
nil — r
Model_J
Use the reservoir standing crop regression equations for catflshes pre-
sented by Aggus and Morais (1979) to predict standing crop, then divide the
predicted standing crop by the highest standing crop value used to develop the
regression equation, in order to obtain an HSI.
REFERENCES CITED
Aggus, L. R., and D. I. Morals. 1979. Habitat suitability index equations
for reservoirs based on standing crop of fish. Natl. Reservoir Res.
Program. Rept. to U.S. FlshWildl. Serv., Hab. Eva!. Proj., Ft. Collins,
CO. 120 pp.
Allen, K. 0., and J. W. Avault. 1970. The effect of salinity on growth of
channel catfish. Proc. Southeastern Assoc. Game and Fish Commissioners
23:319-331.
Allen, K. 0., and K. Strawn. 1968. Heat tolerance of channel catfish,
Ictalurus punctatus. Proc. Southeastern Assoc. Game and Fish
Commissioners 21:399-411.
Andrews, J. W. , and R. R. Stickney. 1972. Interactions of feeding rates and
environmental temperature on growth, food conversion and body composition
of channel catfish. Trans. Am. Fish. Soc. 101(1):94-99.
Andrews, J. W., L. H. Knight, and T. Murai. 1972. Temperature requirements
for high density rearing of channel catfish from fingerlings to market
size. Prog. Fish-Cult. 34:240-242.
Andrews, J. W. , T. Murai, and G. Gibbons. 1973. The influence of dissolved
oxygen on the growth of channel catfish. Trans. Am. Fish. Soc.
102(4):835-838.
25
-------
Bailey. R. M., and H. M. Harrison, Jr. 1948. Food habits of the southern
channel catfish (Ic_taJ_ynjs lacusiris Rupctatuj) in the Des Moines River,
Iowa. Trans. Am. ~F~ish. Soc."75:110-138".
Biesinger, K. E., R. B. Brown, C. R. Bernick, G. A. Flittner, and K. E. F.
Hokanson. 1979. A national compendium of freshwater fish and water
temperature data. Vol. I. U.S. Environ. Protection Agency Rep. , Environ.
Res. Lab., Ouluth, Minn. 207 pp.
Brown, B. E., I. Inman, and A. Jearld, Jr. 1970. Schooling and shelter
seeking tendencies in fingerling catfish behavior. Trans. Am. Fish. Soc.
99(3):540-545.
Brown, L. 1942. Propagation of the spotted channel catfish (Ictalurus
lacustris punctatus). Trans. Kansas Acad. Sci . 45:311-314.
Bryan, C. F., F. M. Truesdale, and 0. S. Sabins. 1975. A limnological Survey
of the Atchafalaya Basin, annual report. Louisiana Coop. Fish. Res.
Unit, Baton Rouge. 203 pp.
Buck., H. D. 1956. Effects of turbidity on fish and fishing. Trans. N. Am.
Wildl. Conf. 21:249-261.
Carlander, K. C. 1969. Channel catfish. Pages 538-554 jn Handbook of fresh-
water fishes of the United States and Canada, exclusive of the
Perciformes. Iowa State Univ. Press, Ames. 752 pp.
Carlson, A. R. , R. E. Siefert, and L. J. Herman. 1974. Effects of lowered
dissolved oxygen concentrations on channel catfish (Ictalurus punctatus)
embryos and larvae. Trans. Am. Fish. Soc. 103(3):623-626.
Chen, T. H. 1976. Cage culture of channel catfish in a heated effluent from
a power plant, Thomas Hill reservoir. Ph.D. Dissertation, Univ. Missouri,
Columbia. 98 pp.
Clemens, H. P., and K. E. Sneed. 1957. Spawning behavior of channel catfish,
Ictalurus punctatus. U.S. Fish Wildl. Serv. Spec. Sc1. Rep.-Fish. 219.
11 PP.
Cowardin, L. M., V. Carter, F. C. Golet, and E. T. LaRoe. 1979. Classifica-
tion of wetlands and deepwater habitats of the United States. U.S.D.I.
Fish and Wildlife Service. FWS/OBS-79/31. 103pp.
Cross, F. B., and J. T. Collins. 1975. Fishes in Kansas. Univ. Kansas Mus.
Nat. Hist. Publ. Educ. Ser. 3. 180 pp.
Davis, J. 1959. Management of channel catfish in Kansas. Univ. Kansas Mus.
Nat. Hist. M1sc. Publ.21. 56 pp.
Davis, J. T.. and L. E. Posey, Jr. 1958. Length at maturity of channel
catfish (Ictalurus lacustrls) in Louisiana. Proc. Southeastern Assoc.
Game and Fish. Commissioners 21:72-74.
26
-------
Flnnell, J. C., and R. M. Jenkins. 1954. Growth of channel catfish in
Oklahoma waters: 1954 revision. Oklahoma Fish. Res. Lab., Kept. 41.
37 pp. (Cited in Miller 1966.)
Hynes. H. B. N. 1970. The ecology of running waters. Univ. Toronto Press,
Canada. 555 pp.
Jenkins, R. M. 1970. The influence of engineering debiijn and operation and
other environmental factors on reservoir fivher> resources. Water
Resources Bull. 6(1):110-119.
Jenkins, R. M. 1974. Reservoir management prognosis: migraines or miracles.
Proc. Southeastern Assoc. Game and Fish Commissioners 27:374-385.
Jenkins, R. M. 1976. Prediction of fish production in Oklahoma reservoirs on
the basis of environmental variables. Ann. Oklahoma Acad. Sci. 5:11-20.
Jenkins, R. M., and D. I. Morais. 1971. Reservoir sport fishing effort and
harvest in relation to environmental variables. Pages 371-384 j_n G. E.
Hall, ed. Reservoir fisheries and limnology. Am. Fish. Soc. Spec.
Publ. 8.
Jester, D. B. 1971. Effects of commercial fishing, species introductions,
and drawdown control on fish populations in Elephant Butte Reservoir, New
Mexico. Pages 265-285 jj) G. E. Hall, ed. Reservoir fisheries and
limnology. Am. Fish. Soc. Spec. Publ. 8.
Lawler, R. E. 1960. Investiqations of the channel catfish of Utah Lake. Utah
State Dept. Fish Game. Inform. Bull. 60-8. 69 pp.
Leidy, G. R., and R. M. Jenkins. 1977. The development of fishery compart-
ments and population rate coefficients for use in reservoir ecosystem
modeling. Contract Report Y-77-1, prepared for Office, Chief of
Engineers, U.S. Army, Washington, D.C. 72 pp.
Macklin, R., and S. Soule. 1964. Feasibility of establishing a warmwatcr
fish hatchery. Calif. Fish .Game, Inland Fish. Admin. Kept. 64-14.
13 pp. (Cited 1n Miller 1966.)
Marzolf, R. C. 1957. The reproduction of channel catfish in Missouri ponds.
J. Wildl. Manage. 21(l):22-28.
McCall, T. C. 1977. Movement of channel catfish, Ictalurus punctatus. in
Cholla Lake, Arizona, as determined by ultrasonic tracking. Western
Assoc. Game Fish. Comrn. 57:359-366.
McCammon, G. W. 1956. A tagging experiment with channel catfish (Ictalurus
punctatus) 1n the lower Colorado River. Calif. Fish Game 42(4):323-335.
McCammon, G. W., and D. A. LaFaunce. 1961. Mortality rates and movement in
the channel catfish population of the Sacramento Valley. Calif. Fish
Game 47(l):5-26.
27
-------
Killer, E. E. 1966. Channel catfish. Pages 440-463 j_n A. Calhoun, ed.
Inland fisheries management. Calif. Fish Game Res. Agency, Sacramento
546 pp.
Minckley, W. L. 1973. Fishes of Arizona. Arizona Fish Game Publ., Phoenix
293 pp.
Moore, G. A. 1968. Vertebrates of the United States. McGraw-Hill, New York.
Moss, D. 0., and 0. C. Scott. 1961. Dissolved oxygen requirements of three
species of fish. Trans. Am. Fish. Soc. 90(4):377-393.
Perry, W. G. 1973. Notes on the spawning of blue and channel catfish 1n
brackish water ponds. Prog. Fish-Cult. 35(3):164-166.
Perry, W. G., and J. W. Avault. 1968. Preliminary experiments on the culture
of b'ue, channel, and white catfish in brackish water ponds. Proc.
Southeastern Assoc. Game and Fish Commissioners 22:396-406.
Pfliege*-, W. L. 1971. A distributional study of Missouri fishes. Univ.
Kansas Mus. Nat. Hist. Publ. 20(3).225-570.
Pflieger, W. L. 197S. Fishes of Missouri. Missouri Dept. Conserv. Publ.,
Columbia. 343 pp.
Randolph, K. N., and H. P. Clemens. 1976. Some factors influencing the
feeding behavior of channel catfish in culture ponds. Trans Am Fish
Soc. 105(6):718-724.
Ryder, R. A. 1965. A method for estimating the potential fish production of
north-temperate lakes. Trans. Am. Fish. Soc. 94(3):214-218.
Ryder, R. A., S. R. Kerr. K. H. Loftus, and H. A. Regier. 1974. The morpho-
edaphic index, a fish yield estimator - review and evaluation. J. Fish.
Res. Board Can. 31(5)-.663-688.
Scott, W. B., and E. J. Crossman. 1973. Freshwater fishes of Canada. Fish.
Res. Board Can". Bull. 184. 966 pp.
Shrable, J. B., 0. W. Tiemeier, and C. W. Deyoe. 1969. Effects of temperature
on rate of digestion by channel catfish. Prog. Fish-Cult. 31(3):131-138.
Sigler, W. F., and R. R. Miller. 1963. Fishes of Utah. Utah Fish Game, Salt
Lake City. 203 pp.
Simco, 0. A., and F. B. Cross. 1966. Factors affecting growth and production
of channel catfish, I etalurus punctatus. Univ. Kansas Mus. Nat. Hist
Publ. 17(4):191-256.
Starostka, V. J., and W. R. Nelson. 1974. Channel catfish in Lake Oahe. U.S.
Fish Wild!. Setv. Tech. Pap. 81. 13 pp.
28
-------
Stauffer, J. R., Jr., K. L. Dickson, J. Cairns, Jr.. W. F. Calhoun, M. T.
Kasnik, and R. H. Myers. 197S. Summer distribution of fish species in
the vicinity of a thermal discharge, New River, Virginia. Arch.
Hydrobiol. 76(3) -.2&7-301.
Trautman, M. B. 1957. fishes of Ohio. Ohio State Univ. Press. 683 pp.
Walburg, C. H. 1971. Loss of young fish in reservoir discharge and year-class
survival, lewis and Clark. Lake, Missouri River. Pages 441-448 u) G. E.
Hall, ed. Reservoir fisheries and limnology. Am. Fish. Soc. Spec.
Publ. 8.
Walburg, C. H. 1975. Food of young-of-year channel catfish In Lewis and
Clark Lake, a Missouri River reservoir. Am. Midi. Nat. 93(1):218-221.
Walden, H. T. 1964. Familiar freshwater fishes of America. Harper and Row,
New York. 324 pp.
West, B. W. 1966. Growth, food conversion, food consumption and survival at
various temperatures of the channel catfish, Ictalurus punctatus
(Rafinesqje). M.S. Thesis. Univ. Arkansas, Fayettevil le. (C~Ued in
Shrable et al. 1969.)
Ziebell, C. 1973. Ultrasonic transmitters for tracking channel catfish.
Prog. Fish-Cult. 35(l):28-32.
29
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APPENDIX 8-1. NATIONAL LIST OF OMNIVORE FISH SPECIES.
Common name
Gizzard shad
Threadfin shad
Central mudminnow
Eastern mudminnow
Mexican tetra
Longfin dace
Goldfish
Grass carp
Common carp
Silverjaw minnow
Alvord chub
Utah chub
Tui chub
Blue chub
Sonora chub
Yaqui chub
Speckled chub
Blotched chub
California roach
Virgin spinedace
Hardhead
Bluehead chub
Golden shiner
White shiner
Common shiner
Bigmouth shiner
Blacknose shiner
Spottail shiner
Swallowtail shiner
Sand shiner
Skygazer shiner
Mimic shiner
Blackside dace
Northern redbelly dace
Southern redbelly dace
Bluntnose minnow
Fathead minnow
Blacknose dace
Speckled dace
Redside shiner
Creek chub
River carpsucker
Quill back
Highfin carpsucker
Utah sucker
Longnose sucker
Bluehead sucker
Owens sucker
Flannelmouth sucker
Largescale sucker
Sacramento sucker
Latin name
Dorosoma cepedianum
Dorosoma petenense
Umbra limi
Umbra pygmaea
Astyanax tetra
Agosia chrysogaster
Carassius auratus
Ctenopharyngodon idella
Cyprinus carpio
Ericymba buccata
Gil a alvordensis
Gi la atravia
Gila bicolor
Gila coerulea
Gila ditaenia
Gila purpurea
Hybopsis aestivalis
Hybopsis insignis
Lavinia symmetricus
Lepidomeda mollispinis
Mylopharodon conocephalus
Nocomis leptocephalus
Notemigonus crysoleucas
Notropis albeolus
Notropis cornutus
Notropis dorsalis
Notropis heterolepis
Notropis hudsonius
Notropis procne
Notropis stramineus
Notropis uranoscopus
Notropis volucellus
Phoxinus cumberlandensis
Phoxinus eos
Phoxinus erythrogaster
Pimephales notatus
Pimephales promelas
Rhi.nichthys atratulus
Rhinichthys osculus
Richardsonius balteatus
Semotilus atromaculatus
Carpiodes carpio
Carpiodes cyprinus
Carpiodes velifer
Catostomus ardens
Catostomus catostomus
Catostomus discobolus
Catostomus fumeiventris
Catostomus latipinnis
Catostomus macrocheilus
Catostomus occidentalis
-------
Mountain sucker Catostomus platyrhyncus
R1o grande sucker Catostomus plebelus
Tahoe sucker Catostomus tahoensls
Blue sucker Cycleptus elongatus
Smallmouth buffalo Ictiobus bubalus
Black buffalo Ictiobus nlger
Oriental weatherfish Misgurnus anguillicaudatus
Snail bullhead Ictalurus brunneus
Black bullhead Ictalurus melas
Yellow bullhead Ictalurus natalis
Flat bullhead Icalurus platycephalus
Channel catfish Ictalurus punctatus
Walking catfish Clarias batrachus
Chinese catfish Clarias fuscus
Desert pupfish Cyprinodon macularius
Sheepshead minnow Cyprinodon variegatus
Plains killifish Fundulus zebrinus
Porthole livebearer Poeciliopsis gracilis
Gila topminnow Poeciliopsis ocddentalis
Hnfish Lagodon rhomboides
Black acara Cichlasoma bimaculatum
Rio grande perch Cichlasoma cyanoguttatum
Firemouth Cichlasoma meeki
Jewelfish Hemichromis bimaculatus
Mozambique tilapia Tilapia mossambica
Redbelly tilapia Tilapia z1H1
Shiner perch Cymatogaster aggregata
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APPENDIX B-2. NATIONAL LIST OF TOP CARNIVORE FISH SPECIES.
Common name
Bull shark
Alligator gar
Spotted gar
Longnose gar
Florida gar
Shortness gar
Bowfin
Machete
Ladyfish
Tarpon
Skipjack herring
Hickory shad
Pink salmon
Chum salmon
Coho salmon
Sock eye salmon
Chinook salmon
Golden trout
Arizona trout
Cutthroat trout
Rainbow trout
Atlantic salmon
Brown trout
Arctic char
Bull trout
Brook trout
Dolly varden
Lake trout
Inconnu
Redfin pickerel
Grass pickerel
Northern pike
Muskellunge
Chain pickerel
Sacramento squawfish
Colorado squawfish
Northern squawfish
Umpqua squawfish
Flathead catfish
Burbot
Fat snook
Tarpon snook
Snook
White bass
Striped bass
Yellow bass
Rock bass
Roanoke bass
Redeye bass
Small mouth bass
Suwanee bass
Latin name
Carcharhinus leucas
Atractosteus spatula
Lepisosteus oculatus
Lepisosteus osseus
Lepisosteus platyrhincus
Lepisosteus platostomus
Ami a calva
Elops affinis
Elops saurus
Megalops atlanticus
Alosa chrysochloris
Alosa mediocris
Oncorhynchus gorbuscha
Oncorhynchus keta
Oncorhynchus kisutch
Oncorhynchus nerka
Oncorhynchus tshawytscha
Sal mo aguabonita
Salmo apache
Sal mo clarki
Salmo gairdneri
Salmo salar
Salmo trutta
Salvelinus alpinus
Salvelinus confluentus
Salvelinus fontinalis
Salvelinus malma
Salvelinus namaycush
Stenodus leucichthys
Esox americanus americanus
Esox americanus vermiculatus
Esox lucius
Esox masquinongy
Esox niger
Ptychocheilus grandis
Ptychocheilus lucius
Ptychocheilus oregonensis
Ptychocheilus umpquae
Pylodictis olivaris
Lota lota
Centropomus parallelus
Centropomus pectinatus
Centropomus undecimalis
Morone chrysops
Morone saxatilis
Morone mississippiensis
Ambloplites rupestris
Ambloplites cavifrons
Micropterus coosae
Micropterus dolomieui
Micropterus notius
-------
Spotted bass Mlcropterus punctulatus
Largemouth bass Mlcropterus salmoides
Guadalupe bass Mlcropterus trecull
White crapple Pomoxis annularis
Black crapple Pomoxis nigromaculatus
Yellow perch Perca flavescens
Sauger Stizostedion canadense
Walleye Stizostedion vitreum
Gray snapper Lutjanus griseus
Freshwater drum Aplodinotus grunniens
Spotted seatrout Cynoscion nebulosus
Red drum Sciaenops ocellatus
Goldeye Hiodon alosoides
White catfish Ictalurus catus
Blue catfish Ictalurus furcatus
Tucunare Cichla ocellaris
Snakehead Channa striata
-------
APPENDIX C. NATIONAL LIST OF INTOLERANT FISH SPECIES.
Common name
Cisco
Arctic Cisco
Lake whitefish
Bloater
Kiyi
Bering cisco
Broad whitefish
Humpback whitefish
Shortnose cisco
Least cisco
Shortjaw cisco
Pink salmon
Chum salmon
Coho salmon
Sockeye salmon
Chinook salmon
Pygmy whitefish
Round whitefish
Mountain whitefish
Golden trout
Arizona trout
Cutthroat trout
Rainbow trout
Atlantic salmon
Brown trout
Arctic char
Bull trout
Brook trout
Dolly varden
Lake trout
Inconnu
Arctic grayling
Largescale stoneroller
Redside dace
Cut lips minnow
Bigeye chub
River chub
Pallid shiner
Pugnose shiner
Rosefin shiner
Bigeye shiner
Pugnose minnow
Whitetail shiner
Blackchin shiner
Blacknose shiner
Spottail shiner
Sailfin shiner
Tennessee shiner
Yellowfin shiner
Ozark minnow
Ozark shiner
Latin name
Coregonus artedii
Coregonus autumnal is
Coregonus clupeaformis
Coregonus hoyi
Coregonus kiyi
Coregonus laurettae
Coregonus nasus
Coregonus pidschian
Coregonus reighardi
Coregonus sardinella
Coregonus zenithicus
Oncorhynchus gorbuscha
Oncorhynchus keta
Oncorhynchus kisutch
Oncorhynchus nerka
Oncorhnchus tshawytscha
Prosopium coulteri
Prosopium cylindraceum
Prosopium williamsoni
Salmo aguabonita
Salmo apache
Salmo clarki
Salmo gairdneri
Salmo salar
Salmo trutta
Salvelinus alpinus
Salvelinus confluentus
Salvelinus fontinalis
Salvelinus malma
Salvelinus namaycush
Stenodus leucichthys
Thymallus arcticus
Campostoma oligolepis
Clinostomus elongatus
Exoglossum maxillingua
Hybobsis amblops
Nocomis micropogon
Notropis amnis
Notropis anogenus
Notropis ardens
Notropis boops
Noropis emiliae
Notropis galacturus
Notropis heterodon
Notropis heterolepis
Noropis hudsonius
Notropis hypselopterus
Notropis leuciodus
Notropis lutipinnis
Notropis nubilus
Notropis ozarcamis
-------
Silver shiner
Duskystripe shiner
Rosyface shiner
Safron shiner
Flagfin shiner
Telescope shiner
Topeka shiner
Mimic shiner
Steelcolor shiner
Coosa shiner
Bleeding shiner
Bandfin shiner
Blackside dace
Northern redbelly dace
Southern redbelly dace
Blacknose dace
Pearl dace
Alabama hog sucker
Northern hog sucker
Roanoke hog sucker
Spotted sucker
Silver redhorse
River redhorse
Black jumprock
Gray redhorse
Black redhorse
Rustyside sucker
Greater jumprock
Blacktail redhorse
Torrent sucker
Striped jumprock
Greater redhorse
Ozark mad torn
Elegant madtom
Mountain madtom
Slender madtom
Stonecat
Black madtom
Least madtom
Margined madtom
Speckled madtom
Brindled madtom
Frecklebelly madtom
Brown madtom
Roanoke bass
Ozark rock bass
Rock bass
Longear sunfish
Darters
Darters
Darters
Sculpins
O'opu alamoo (goby)
O'opu nopili (goby)
O'opu nakea (goby)
Notropis photogenls
Notropis pilsbryi
Notropis rubellus
Notropis rubricroceus
Notropis signipinnis
Notropis telescopus
Notropis topeka
Notropis volucellus
Notropis whipplei
Notropis xaenocephalus
Notropis zonatus
Notropis zonlstius
Phoxinus cumberlandens1s
Phoxinus eos
Phoxinus erythrogaster
Rhinichthys atratulus
Semotilus margarlta
Hypentelium etowanum
Hypentelium nigricans
Hypentelium roanokense
Minytrema melanops
Moxostoma anisurum
Moxostoma carinatum
Moxostoma cervinum
Moxostoma congestum
Moxoatoma duquesnei
Moxostoma hamiltoni
Moxostoma lachneri
Moxostoma poecilurum
Moxostoma rhothoecum
Moxostoma rupiscartes
Moxostoma valenciennesi
Noturus albater
Noturus elegans
Noturus eleutherus
Noturus exilis
Noturus flavus
Noturus funebHs
Noturus hildebrandi
Noturus insignis
Noturus leptacanthus
Noturus miurus
Noturus munitus
Noturus phaeus
Ambloplites cavifrons
Ambloplites constellatus
Ambloplites rupestris
Lepomis mega lot is
Ammocrypta sp.
Etheostoma sp.
Percina sp.
Cottus sp.
Lentipes concolor
Sicydium stimpsoni
Awaous stamineus
-------
United State*
Environmental Protection
Agency
Office of Water
Regulations end Standard]
Washington, DC 20480
Water
Technical Support Manual:
Waterbody Surveys and
Assessments for Conducting
Use Attainability Analyses
Volume II: Estuarine Systems
-------
FOREWORD
The Technical Support Manual: Water Body Surveys and Assessments for
Conducting Use Attainability Analyses In Estuarlne Systemscontains
guidance prepared by EPA to assist States in Implementing the revised Water
Quality Standards Regulation (48 FR 51400, November 8, 1983). This
document addresses the unique characteristics of estuarlne systems and
supplements the Technical Support Manual: Water Body Surveys and
Assessments for Conducting Use Attainability Analyses (EPA,November,
1983).The centralpurpose of these documents Is to provide guidance to
assist States 1n answering three central questions:
(1) What are the aquatic protection uses currently being achieved 1n the
water body?
(2) What are the potential uses that can be attained based on the
physical, chemical and biological characteristics of the waterbody?
and
(3) What are the causes of any Impairment of the uses?
Consideration of the suitability of a water body for attaining a given use
1s an Integral part of the water quality standards review and revision
process. EPA will continue to provide guidance and technical assistance to
the States 1n order to Improve the scientific and technical bases of water
quality standards decisions. States are encouraged to consult with EPA at
the beginning of any standards revision project to agree on appropriate
methods before the analyses are Initiated, and to consult frequently as
they are conducted.
Any questions on this guidance may be directed to the water quality
standards coordinators located In each of the EPA Regional Offices or to:
El Hot Lomnltz
Criteria and Standards Uivlslon (WH-585)
401 M Street S.W.
Washington, D.C. 20460
Steven Schatzow, Director
Office of Water Regulations and
Standards
-------
TABLE OF CONTENTS
FOREWORD
CHAPTER I. INTRODUCTION 1-1
CHAPTER II. PHYSICAL AND CHEMICAL CHARACTERISTICS II-l
INTRODUCTION II-l
PHYSICAL PROCESSES II-l
ESTUARINE CLASSIFICATION 11-9
INFLUENCE OF PHYSICAL CHARACTERISTICS ON USE ATTAINABILITY 11-15
CHEMICAL PARAMETERS 11-20
TECHNIQUES FOR USE ATTAINABILITY EVALUATIONS 11-23
ESTUARY SUBSTRATE COMPOSITION 11-54
ADJACENT WETLANDS 11-55
HYDROLOGY AND HYDRAULICS 11-56
CHAPTER III. CHARACTERISTICS OF PLANT AND ANIMAL COMMUNITIES III-l
INTRODUCTION III-l
COLONIZATION AND PHYSIOLOGICAL ADAPTATIONS III-l
MEASURES OF BIOLOGICAL HEALTH AND DIVERSITY 111-3
ESTUARINE PLANKTON 111-7
ESTUARINE BENTHOS 111-10
SUBMERGED AQUATIC VEGETATION 111-17
ESTUARINE FISH 111-23
SUMMARY 111-32
CHAPTER IV. SYNTHESIS AND INTERPRETATION IV-1
INTRODUCTION IY-1
USE CLASSIFICATIONS IV-1
ESTUARINE AQUATIC LIFE PROTECTION USES IV-6
SELECTION OF REFERENCE SITES IV-7
CURRENT AQUATIC LIFE PROTECTION USES IV-8
CAUSES OF IMPAIRMENT OF AQUATIC LIFE PROTECTION USES IV-9
ATTAINABLE AQUATIC LIFE PROTECTION USES IV-9
RESTORATION OF USES IV-11
CHAPTER V. REFERENCES V-l
APPENDICES
A. DEFINITION OF THE CONTAMINATION INDEX (CT) AND THE
TOXICITY INDEX (Tj) *
B. LIFE CYCLES OF MAJOR SPECIES OF ATLANTIC COAST ESTUARIES
C. SUBMERGED AQUATIC VEGETATION
0. ENVIRONMENTAL REQUIREMENTS OF CERTAIN GULF COAST SPECIES
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CHAPTER I
INTRODUCTION
EPA's Office of Water Regulations and Standards has prepared guidance to
accompany changes to the Water Quality Standards Regulation (48 FR 51400).
Programmatic guidance has been compiled and published 1n the Water Quality
Standards Handbook (EPA, December 1983). This document discusses the water
qualityreviewand revision process; general programmatic guidance on
mixing zones, flow, and economic considerations; use attainability
analyses; and site specific criteria.
One of the major pieces of guidance 1n the Handbook 1s "Water Body Surveys
and Assessments for Conducting Use Attainability Analyses." This guidance
lays out the general framework for designing and conducting a use
attainability analysis, whose objective 1s to answer the questions:
1. What are the aquatic life uses currently being achieved 1n the
water body?
2. What are the potential uses that can be attained, based on the
physical, chemical and biological characteristics of the water
body?
3. What are the causes of Impairment of the uses?
Technical guidance on conducting water body surveys and assessments was
provided 1n the Technical Support Manual: Water Body Surveys and
Assessments for Conducting Use Attainability Analyses (EPA, November 1983)
In response to requests by several States for additional Information. The
Technical Support Manual essentially provides methods and tools for
freshwater evaluations, but does not cover estuarlne water bodies. The
chapters presented 1n this volume address those considerations which are
unique to the estuary. Those factors which are common to the freshwater
and the estuarlne system — chemical evaluations 1n particular, are not
discussed 1n this volume. Thus It 1s Important that those who will be
Involved 1n the water body survey should also consult the 1983 Technical
Support Manual. The methods and procedures offered In these guidance
documents are optional and the States may apply them selectively, or they
may use their own techniques or methods for conducting use attainability
analyses.
The technical material presented In this volume deals with the major
physical, chemical and biological attributes of the estuary: tides and
currents, stratification, substrate characteristics; the Importance of
salinity, dissolved oxygen and nutrient enrichment; species diversity,
plant and animal populations, and physiological adaptations which permit
freshwater or marine organisms to survive 1n the estuary.
Given that estuaries are very complex receiving waters which are highly
variable In description and are not absolutes 1n definition, size, shape,
aquatic life or other attributes, those who will be performing use
1-1
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attainability analyses on estuarlne systems should consider this volume as
a frame of reference from which to Initiate study design and execution, but
not as an absolute guide.
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CHAPTER II
PHYSICAL AND CHEMICAL CHARACTERISTICS
INTRODUCTION
The term estuary is generally used to denote the lower reaches of a river
where tide and river flows interact. The generally accepted definition for
an estuary was provided by Pritchard in 1952: "An estuary is a semi-
enclosed coastal body of water having a free connection with the open sea
and containing a measureable quantity of seawater." This description has
remained remarkably consistent with time and has undergone only minor
revisions (Emery and Stevenson, 1957; Cameron and Pritchard, 1963). To
this day, such qualitative definitions are the most typical basis for
determining what does and what does not constitute an estuary.
Estuaries are perhaps the most important social, economic, and ecologic
regions in the United States. For example, according to the Department of
Commerce (DeFalco, 1967), 43 of the 110 Standard Metropolitan Statistical
Areas are on estuaries. Furthermore, recent studies indicate that many
estuaries, including Delaware Bay and Chesapeake Bay, are on the decline.
Thus, the need has arisen to better understand their ecological functions
to define what constitutes a "healthy" system, to define actual and
potential uses, to determine whether designated uses are impaired, and to
determine how these uses can be preserved or maintained. This is the basis
for the Use Attainability Analysis.
As part of such a program, there is a need to define impact assessment pro-
cedures that are simple, in light of the wide variability among estuaries,
yet adequately represent the major features of each system studied.
Estuaries are three-dimensional waterbodies which exhibit variations in
physical and chemical processes in all three directions (longitudinal,
vertical, and lateral) and also over time. However, following a careful
consideration of the major physical and chemical processes and the time
scales involved in use assessment, one can often define a simplified
version of the prototype system for study.
In this chapter, a discussion is presented of important estuarine features
and of major physical processes. A description of chemical evaluations 1s
also presented, although the discussion herein is very limited since an
extensive presentation was included in the earlier U.S. EPA Technical
Support Manual (U.S. EPA November 1983). From this background, guidance
for use attainability evaluations is given which considers the various
assumptions that may be made to simplify the complexity of the analysis,
while retaining an adequate description of the system. Finally, a frame-
work for selecting appropriate desk-top and computer models for use
attainability evaluations is outlined.
PHYSICAL PROCESSES
Introduction
Estuarine flows are the result of a complex interaction of:
II-l
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o tides,
o wind shear,
o freshwater inflow (momentum and buoyancy),
o topographic fractional resistance,
o Cor1o11s effect,
o vertical mixing, and
o horizontal mixing.
In performing a use attainability study, one must simplify the complex
prototype system by determining which of these effects or combination of
effects Is most Important at the time scale of the evaluation. To do this,
1t 1s necessary to understand each of these processes and their Impacts on
the evaluation. A complete description of all of the above 1s beyond the
scope of this report. Rather, illustrated are some of the features of each
process, particularly in terms of magnitude and time scale.
Tides
Tides are highly variable throughout the United States, both 1n amplitude
and phase. Figure II-l (NOAA 1983) shows some typical tide curves along
the Atlantic, Gulf of Mexico, and Pacific Coasts. Tidal amplitude can vary
from 1 foot or less along the Gulf of Mexico (e.g., Pensacola, Florida) to
over 30 feet in parts of Alaska (e.g., Anchorage) and the Maritime
Provinces of Canada (e.g., the Bay of Fundy). Tidal phasing Is a
combination of many factors with differing periods. However, 1n the United
States, most tides are predominantly based on 12.5-hour (semidiurnal), 25-
hour (diurnal) and 4-day (semi-lunar) combinations. In some areas, such as
Boston (Figure II-l), the tide is predominantly semidiurnal with 2 high
tides and 2 low tides each day. In others, such as along the Gulf of
Mexico, the tides are more typically mixed.
Tidal power is directly related to amplitude. This potential energy source
can promote Increased mixing through increased velocities and Interactions
with topographic features.
Wind
In many exposed bays or estuaries, particularly those 1n which tidal
forcing 1s smaller, wind shear can have a tremendous Impact on circulation
patterns at time scales of a few hours to several days. An example is
Tampa Bay on the West Coast of Florida, where tidal ranges are
approximately 3 feet, and the terrain Is generally quite flat. Wind can be
produced from localized thunderstorms of a few hours duration, or from
frontal movements with durations on the order of days. Unlike tides, wind
1s unpredictable 1n a real time sense. The usual approach to studying wind
driven circulations 1s to develop a wind rose (Figure II-2) from local
meteorological data, and base the study of Impacts on statistically
significant magnitudes and directions, or on winds that might produce the
most severe impact.
II-2
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• it 10
A d,
' toon ii. 'pof
- l« it qu«r t rr
- Moor, nn t lu«l
- ,„.»•„,.,
A 11 in, > i. on '.t '
l .... » -
Figure II-l. Typical Tide Curves for United States Ports.
II-3
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*ett
WUL' • '•0*O*f
C"«ei»«»ri
MO *I»M'0*UI
•0%
• I
Figure II-2. 'ypical Wind Rose. (H.C. Perkins, 1974!
Freshwater Inflows
Freshwater Inflows from a major riverine source can be highly variable from
day to day and season to season. At the shorter time scale, the river may
be responding to a localized thunderstorm, or the passage of a front. In
many areas, however, the frequency of these events tends to group Into a
season (denoted the wet season) which 1s distinct from the remainder of the
year (the dry season). The average monthly streamflow distributions In
Figure II-3 Illustrate that 1n Virginia the wet season 1s typically from
December to May and comes mainly from portal systems. In Florida, however,
the trend 1s reversed, with the wet season coinciding with the summer
months when localized thunderstorms predominate.
It 1s Important to consider the effect of freshwater flows on estuarine
circulation, because streamflow 1s the only major mechanism which produces
a net cross sectional flow over long averaging times. A common approach 1s
to represent the estuary as a system drive by net freshwater flows in the
downstream directory with other effects averaged out and lumped Into a
dispersion-type parameter. When using this assumption to evaluate the
estuary system, one must weigh the consequences very carefully.
Freshwater 1s less dense and tends to "float" over seawater. In some
cases, freshwater may produce a residual 2-layer flow pattern (such as 1n
II-4
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the James Estuary (Virginia) or Potomac Rivers) or even a 3-layer flow
pattern (as 1n Baltimore Harbor). The danger 1s to treat such a distinctly
2-layer system as a cross-sectlonally averaged, river driven system, and
then try to explain why pollutants are observed upstream of a discharge
point when no mechanism exists to produce this effect using a one-
dimensional approach.
Friction
The estuary's topographic boundaries (bed and sides) produce frlctlonal
resistance to local currents. In some estuaries with highly variable
geometries, this can produce a number of net nontidal (or tldally-averaged)
effects such as residual eddies near headlands or tidal rectification.
Pollutants trapped 1n residual eddies, perhaps from a wastewater treatment
plant outfall, may have very large residence times that are not predictable
from cross-sectlonally averaged flows before such pollutants are flushed
from the system.
Cor1o11s Effect
In wide estuaries, the CoMolls effect can cause freshwater to adhere to
the right-hand bank (facing the open sea) so that the surface slopes upward
to the right of the flow. The Interface has an opposite slope to maintain
geostrophlc balance. For specific configurations and corresponding flow
regimes, the boundary between outflow and Inflow may actually cut the
surface (Figure II-4a). This 1s the case 1n the lower reaches of the St.
Lawrence estuary, for example, where the well-defined Gaspe current holds
against the southern shore and counter flow 1s observed along the northern
side. This effect 1s augmented by tidal circulation which forces ocean
waters entering the estuary with the flood tide to adhere to the left side
of the estuary (facing the open sea), and the ebb flow to the right side.
Thus, as 1s often apparent from the surface salinity pattern 1n an estuary,
the outflow Is stronger on the right-hand side (Figure II-4b). The exact
location and configuration of the saltwater/freshwater Interface depends on
the relative magnitude of the forces at play. Quantitative estimates of
various mixing modes 1n estuaries are discussed below.
Vertical Mixing
All mixing processes are caused by local differences 1n velocities and by
the fact that liquids are viscous (I.e., possess Internal friction). In
the vertical direction, the most common mixing occurs between riverine
fresh waters and the underlying saline ocean waters.
If there were no friction, freshwater would flow seaward as a shallow layer
on top of the seawater. The layer would become shallower and the velocity
would decrease as the estuary widened toward Its mouth. Friction between
the two types of water requires a balancing pressure gradient down-estuary,
explaining the salt wedge formation which deepens toward the mouth of the
estuary, as seen 1n Figure II-5. Friction also causes mixing along the
Interface. A particularly well-defined salt wedge Is observed 1n the
estuary of the Mississippi River.
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0 1867500-Raoidan River near Cuipeoer. Va Drainage area. 472 ig
Z
o
02030500-Siate River near Arvoma. Va
Drainage area. 226 sq mi
0 2045 500-Not!o * a y
ar Stcny Creek. Va. Drainage area. 57^
3198000-NF Holston River near Sj'<'He J \
222
OCT NO1.
Figure II-3. Monthly Average Streamflows for location in
Virginia, (from U. S. Geological Survey 1982)
II-6
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MQUTH
a. Cross-section A-A looking
Down-estuary.
HEAD
b. Surface Salinity Distribu-
tion (ppt).
Figure II-4. Net Inflow and Outflow in a Tidal Estuary, Northern
Hemisphere.
If significant mixing does not occur along the freshwater/saltwater Inter-
face, the layers of differing density tend to remain distinct and the
system 1s said to be highly stratified In the vertical direction. If the
vertical mixing 1s relatively high, the mixing process can almost
completely break down the density difference, and the system 1s called
well-mixed or homogeneous.
In sections of the estuary where there 1s a significant difference between
surface and bottom salinity levels over some specified depth (e.g., differ-
ences of about 5 ppt or greater over about a 10 foot depth), the water
column Is regarded as highly stratified. An Important Impact of vertical
stratification on use attainability Is that the vertical density differ-
ences significantly reduce the exchange of dissolved oxygen and other
constituents between surface and bottom waters. Consequently, persistent
stratification can result 1n a depression of dissolved oxygen (DO) In the
high salinity bottom waters that are cut off from the low salinity surface
waters. This 1s because bottom waters depend upon vertical mixing with
surface waters, which can take advantage of reaeratlon at the air-water
Interface, to replenish DO that 1s consumed as a result of organic
materials within the water column and bottom sediments. In sections of the
estuary exhibiting significant vertical stratification, vertical mixing of
DO contributed by reaeratlon is limited to the low salinity surface waters.
II-7
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As a result, persistent stratified conditions can cause the DO concentra-
tion 1n botto» water to fall to levels that cause stress on or mortality to
the resident communities of benthlc organisms.
Another potential Impact of vertical stratification 1s that anaerobic con-
ditions 1n bottom Maters can result In increased release of nutrients such
as phosphorus and ammonia-nitrogen from bottom sediments. During later
periods or 1n sections of the estuary exhibiting reduced levels of
stratification, these Increased bottom sediment contributions of nutrierlts
can eventually be transported to the surface water layer. These Increased
HEAD
MOUTH
SALINITY
DISTRIBUTION (S)
Figure II-5. Layered Flow in a Salt-wedge Estuary (Longitudinal Profile).
11-8
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nutrient loadings on surface waters can result in higher phytoplankton con-
centrations that can exert diurnal DO stresses and reduced light penetra-
tion for rooted aquatic plants. In summary, the persistence and areal
extent of vertical stratification 1s an Important determinant of use at-
tainability within an estuary.
s often neglected
horizontal mixing
friction, or vis-
the interactions
ting 1n eddies of
tend to be broken
average advection
Horizontal Mixing
Mixing also occurs In the horizontal plane, although it i
in favor of vertical processes. As with vertical mixing,
Is caused by localized velocity variations and internal
coslty. The velocity variations are usually produced by
of topographic and bed or side frlctlonal effects, resul
varying sizes. Thus, horizontal constituent distributions
down by differential advection, which when viewed as an
(laterally, or cross-sectionally) 1s called dispersion.
ESTUARINE CLASSIFICATION
Introduction
It is often useful to consider some broad classifications of estuaries,
particularly in terms of features and processes which enable us to analyze
them in terms of simplified approaches. The most commonly used groupings
are based on geomorphology, stratification, circulation patterns, and time
scales.
Geomorphologlcal Classification
Over the years, a systematic structure of geomorphological classification
has evolved. Dyer (1973) and Fischer et al. (1979) identify four groups:
o Drowned river valleys (coastal plain estuaries),
o Fjords
o Bar-built estuaries, and
o Other estuaries that do not fit the first three classifications.
Typical examples of North American estuaries are presented 1n Table II-l.
Coastal plain estuaries are generally shallow with gently sloping bottoms,
with depths increasing uniformly towards the mouth. Such estuaries have
usually been cut by erosion and are drowned river valleys, often displaying
a dendritic pattern fed by several streams. A well-known example is
Chesapeake Bay. Coastal plain estuaries are usually moderately stratified
(particularly in the old river valley section) and can be highly influenced
by wind over short time scales.
Bar built estuaries are bodies of water enclosed by the deposition of a
sand bar off the coast through which a channel provides exchange with the
open sea, usually servicing rivers with relatively small discharges. These
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TABLE II-l. TOPOGRAPHIC ESTUARINE CLASSIFICATION
Type
Dominant
Long-Term Process
Degree of
Stratification
Examples
Coastal
Plain
Bar Bu1H
Fjords
River Flow
Moderate
Wind
Low or None
Tide
Other Estuaries Various
High
Various
Chesapeake Bay, MD/VA
James River, VA
Potomac River, MD/VA
Delaware Estuary, DE/NJ
New York Bight, NY
Little Sarasota Bay, FL
Apalachlcola Bay, FL
Galveston Bay, TX
Roanoke River, VA
Albemarle Sound, NC
Pamllco Sound, NC
Albernl Inlet, B.C.
Silver Bay, AL
San Francisco Bay, CA
Columbia River, WA/OR
11-10
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are usually unstable estuaries, subject to gradual seasonal and cata-
strophic variations In configuration. Many estuaries in the Gulf Coast and
Lower Atlantic Regions fall Into this category. They are generally a few
meters deep, vertically well mixed and highly influenced by wind.
Fjords are characterized by relatively deep water and steep sides, and are
generally long and narrow. They are usually formed by gladation, and are
more typical 1n Scandinavia and Alaska than the contiguous United States.
There are examples along the Northwest Pacific Ocean, such as Alberni Inlet
in British Columbia. The freshwater streams that feed a fjord generally
pass through rocky terrain. Little sediment is carried to the estuary by
the streams, and thus the bottom is likely to be a clean rocky surface.
The deep water of a fjord is distinctly cooler and more saline than the
surface layer, and the fjord tends to be highly stratified.
The remaining estuaries not covered by the above classification are usually
produced by tectonic activity, faulting, landslides, or volcanic eruptions.
An example is San Francisco Bay which was formed by movement of the San
Andreas Fault System (Dyer, 1973).
Stratification
A second classification of estuaries 1s by the degree of observed strati-
fication, and was developed originally by Pritchard (1955) and Cameron and
Pritchard (1963). They considered three groupings (Figure 11-6):
o The highly stratified (salt wedge) type
o Partially mixed estuary
o Vertically homogeneous estuary
Such a classification is intended for the general case of the estuary
influenced by tides and freshwater inflows. Shorter term events, such as
strong winds, tend to break down highly stratified systems by Inducing
greater vertical mixing. Examples of different types of stratification are
presented in Table II-2.
In the stratified estuary (Figure II-6a), large freshwater inflows ride
over saltier ocean waters, with little mixing between layers. Averaged
over a tidal cycle, the system usually exhibits net seaward movement in the
freshwater layer, and net landward movement in the salt layer, as salt
water is entrained into the upper layer. The Mississippi River Delta is an
example of this type of estuary.
As the interfaclal forces become great enough to partially break down the
density differences, the system becomes partially stratified, or partially
well-mixed (Figure II-6b). Tidal flows are now usually much greater than
river flows, and flow reversals in the lower layer may still be observed,
although they are generally not as large as for the highly stratified
system. Chesapeake Bay and the James River estuary are examples of this
type.
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y
SUftFACC
SALINITY
(a) Stratified
SURFACE
BOTTOM
BOTTOM
| VELOCITY |s
SALINITY
SURTACC
SALINITY
1HQIBV3HNFW
(b) Partially mixed
Figure 11-6. Classification of Estuarine Stratification.
(c) Well-mixed
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TABLE II-2. STRATIFICATION CLASSIFICATION
Type
Highly Stratified
River Discharge
Large
Examples
Mississippi River, LA
Mobile River, AL
Partially Mixed
Medium
Chesapeake Bay, MD/VA
James Estuary, VA
Potomac River, MO/VA
Vertically Homogeneous
Small
Delaware Bay, DE/NJ
Raritan River, NJ
Biscayne Bay, FL
Tampa Bay.FL
San Francisco Bay, CA
San Diego Bay, CA
11-13
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In a well mixed system (Figure II-6c), the river Inflow 1s usually very
small, and the tidal flow Is sufficient to completely break down the
stratification and thoroughly mix the system vertically. Such systems are
generally shallow so that the tidal amplitude to depth ratio 1s large and
mixing can easily penetrate throughout the water column. The Delaware and
Rarltan River estuar1es/are examples of well-mixed systems.
Circulation Patterns
Circulation 1n an estuary (I.e., the velocity patterns as they change over
time) 1s primarily affected by the freshwater outflow, the tidal Inflow,
and the effect of wind. In turn, the difference 1n density between outflow
and inflow sets up secondary currents that ultimately affect the salinity
distribution across the estuary. The salinity distribution 1s important in
that 1t affects the distribution of fauna and flora within the estuary. It
1s also Important because 1t 1s Indicative of the mixing properties of the
estuary as they may affect the dispersion of pollutants, flushing proper-
ties, and additional factors such as friction forces and the size and
geometry of the estuary contribute to the circulation patterns.
The complex geometry of estuaries, in combination with the presence of
wind, the effect of the earth's rotation (Corlolls effect), and other
effects, often results 1n residual currents (I.e., of longer period than
the tidal cycle) that strongly Influence the mixing processes 1n estuaries.
For example, uniform wind over the surface of an estuary produces a net
wind drag force which may cause the center of mass of the water 1n the
estuary to be displaced toward the deeper side since there 1s more water
there. Hence a torque Is Induced causing the water mass to rotate.
In the absence of wind, the pure Interaction of tides and estuary geometry
may also cause residual currents. For example, flood flows through narrow
Inlets set up so-called tidal jets, which are long and narrow as compared
to the ebb flows which draw from a larger area of the estuary, thus forcing
a residual circulation from the central part of the estuary to the sides
(Stommel and Farmer, 1952). The energy available 1n the tide is 1n part
extracted to drive regular circulation patterns whose net result is similar
to what would happen if pumps and pipes were installed to move water about
1n circuits. This is why this type of circulation is referred to as "tidal
pumping" to differentiate from wind and other circulation (Fisher, et al.,
1979).
Tidal "trapping" 1s a mechanism -- present in long estuaries with side
embayments and small branching channels -- that strongly enhances
longitudinal dispersion. It Is explained as follows. The propagation of
the tide in an estuary -- which represents a balance between the water mass
inertia, the hydraulic pressure force due to the slope of the water
surface, and the retarding bottom friction force -- results 1n main channel
tidal elevations and velocities that are not in phase. For example, high
water occurs before high slack tide and low water before low slack tide
because the momentum of flow in the main channel causes the current to
continue to flow against an opposing pressure gradient. In contrast, side
channels which have less momentum can reverse the current direction faster,
11-14
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thus "trapping" portions of the main channel water which are then available
for further longitudinal dispersion during the next flood tide.
Time Scales
The consideration of the time scales of the physical processes being
evaluated is very Important for any water quality study. Short-term
conditions are much more influenced by a variety of short-term events which
perhaps have to be analyzed to evaluate a "worst case" scenario. Longer
term (seasonal) conditions are influenced predominantly by events which are
averaged over the duration of that time scale.
The key to any study is to Identify the time scale of the impact being
evaluated and then analyze the forcing functions over the same time scale.
As an example, circulation and mass transport in the upper part of
Chesapeake Bay can be wind driven over a period of days, but 1s river
driven over a period of one month or more. Table 11-3 lists the major
types of forcing functions on most estuarlne systems and gives some Idea of
their time scales.
INFLUENCE OF PHYSICAL CHARACTERISTICS ON USE ATTAINABILITY
"Segmentation" of an estuary can provide a useful framework for evaluating
the Influence of estuarlne physical characteristics such as circulation,
mixing, salinity, and geomorphology on use attainability. Segmentation is
the compartmentalizing of an estuary into subunits with homogeneous
physical characteristics. In the absence of water pollution, physical
characteristics of different regions of the estuary tend to govern the
suitability for major water uses. Therefore, one major objective of
segmentation is to subdivide the estuary into segments with relatively
homogeneous physical characteristics so that differences 1n the biological
communities among similar segments may be related to man-made alterations.
Once the segment network 1s established, each segment can be subjected to a
use attainability analysis. In addition, the segmentation process offers a
useful management structure for monitoring conformance with water quality
goals 1n future years.
The segmentation process is an evaluation tool which recognizes that an
estuary 1s an Interrelated ecosystem composed of chemically, physically,
and biologically diverse areas. It assumes that an ecosystem as diverse as
an estuary cannot be effectively managed as only one unit, since different
uses and associated water quality goals will be appropriate and feasible
for different regions of the estuary. The segmentation approach to use
attainability assessment and water quality management has been successfully
applied to several major receiving water systems, most notably Chesapeake
Bay, the Great Lakes, and San Francisco Bay.
A potential source of concern about the construction and utility of the
segmentation scheme for use attainability evaluations 1s that the estuary
is a fluid system with only a few obvious boundaries, such as the sea
surface and the sediment-water Interface. Boundaries fixed 1n space are to
be imposed on an estuarlne system where all components are in communication
with each other following a pattern that 1s highly variable 1n time. Fixed
boundaries may seem unnatural to scientists, managers, and users, who are
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TABLE 11-3. TIME SCALES OF MAJOR PROCESSES
Forcing Function
Time Scale
TIDE
One cycle
Neap/Spring
0.5-1 day
14 days
WIND
Thunderstorm
Frontal Passage
1-4 hours
1-3 days
RIVER FLOW
Thunderstorm
Frontal Passage
Wet/Dry Seasons
0.5-1 day
3-7 days
4-6 months
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more likely to view the estuary as a continuum than as a system composed of
separable parts. The best approach to dealing with such concerns is a
segmentation scheme that stresses the dynamic nature of the estuary. The
scheme should emphasize that the segment boundaries are operationally
defined constructs to assist in understanding a changeable, intercommuni-
cating system of channels, embayments, and tributaries.
In order to account for the dynamic nature of the estuary, it is recommend-
ed that estuarine circulation patterns be a prominent factor in delineating
the segment network. Circulation patterns control the transport of and
residence times for heat, salinity, phytoplankton, nutrients, sediment, and
other pollutants throughout the estuary. Salinity should be another impor-
tant factor in delineating the segment network. The variations in salinity
concentrations from head of tide to the mouth typically produce a separa-
tion of biological communities based on salinity tolerances or preferences.
A segmentation scheme based upon physical processes such as circulation and
salinity should track very well with the major chemical and biological
processes. However, after developing a network based upon physical
characteristics, segment boundaries can be refined with available chemical
and biological data to maximize the homogeneity of each segment.
To illustrate the segmentation approach to evaluating relationships between
physical characteristics and use attainability, the segmentation scheme
applied to Chesapeake Bay is described below. While most of the estuaries
subjected to use attainability evaluations will be considerably smaller and
less diverse than Chesapeake Bay, the principles illustrated in the
following example can serve as useful guidance for most estuary evaluations
regardless of the spatial scale. Figure II-7 shows the main stem and
tributary segments defined for Chesapeake Bay by the U.S. Environmental
Protection Agency's Chesapeake Bay Program (U.S. EPA Chesapeake Bay
Program 1982). As may be seen, the segment network consists of eight main
stem segments designated by the prefix "CB" and approximately forty
segments covering major embayments and tributaries. The methodology for
delineating the main stem segments will be described first, followed by a
discussion of the major embayments and tributaries.
Starting at the uppermost segment and working down the main stem, the
boundary between CB-1 and CB-2 separates the mouth of the Susquehanna River
from the upper Bay and lies 1n the region of maximum penetration of salt-
water at the head of the Bay. South of this region most freshwater
plankton would not be expected to grow and flourish, although some may be
continually brought into the area by the Susquehanna River.
The boundary between CB-2 and CB-3 1s the southern limit of the turbidity
maximum, a region where suspended sediment causes light limitation of
phytoplankton production most of the year. This boundary also coincides
with the long-term summer average for the 5 parts per thousand (ppt)
salinity contour which is an important physiological parameter for oysters.
The boundary between CB-3 and CB-4 1s located at the Chesapeake Bay Bridge.
It marks the northern limit of the 10 ppt salinity contour and of deep
water anaerobic conditions in Chesapeake Bay stratification. In segment
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CHESAPEAKE BAY
SECnCNTATtOK HAP
Figure II-7.
Chesapeake Bay Program segments used in data
analysis.(from U.S.EPA Chesapeake Bay Program 1982)
11-18
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CB-4, water deeper than about 30 ft usually experiences oxygen depletion in
summer which may result 1n oxygenless conditions and hydrogen sulflde
production. When anaerobic conditions occur, these deep waters are toxic
to fish, crabs, shellfish, and other benthlc animals. Due to the Increased
release of nutrients from bottom sediments under oxygenless conditions, the
anaerobic layer 1s also rich in phosphorus and ammon1a-N which may reach
surface waters by diffusion, mixing, and vertical advection either later In
the year or in less stratified sections of the Bay. In spring, the region
near the bridge 1s the site where phytopiankton and fish larvae that travel
in the deep layer from the Bay mouth are brought to the surface by a
combination of physical processes.
The boundary between CB-4 and CB-5 was established at a narrows. Below
this point, the Patuxent and Potomac Rivers Intersect the main stem of the
Bay. It 1s characterized by average summer salinities of 12 to 13 ppt and
1s located at the approximate midpoint of the area subject to bottom water
anaerobic conditions during the summer.
The boundary between CB-5 and CB-6/7 approximates the 18 ppt salinity
contour and the southern limit of significant vertical stratification and
anaerobic conditions in the bottom waters. Most, of the deeper areas of the
Bay are found in segment CB-5. As mentioned earlier, the bottom waters of
segments CB-4 and CB-5 experience considerable nutrient enrichment during
the summer when phosphorus and ammon1a-N are released from bottom
sediments. This region also exhibits high nitrate-N concentrations in the
fall when the ammonia-N accumulated in summer is oxidized. The southern
boundary of CB-5 also approximates the region where the elevated n1trate-N
concentrations from the relatively high streamflows during the spring
season becomes a critical factor In phytoplankton growth.
The boundary between CB-6 and CB-7 horizontally divides the lower Bay into
two regions with different circulation patterns. North of this boundary,
the Bay's density stratification results in two distinct vertical layers,
with bottom waters moving in a net upstream flow and the surface layer
flows moving downstream. Between this boundary and the Bay mouth the
density distribution tends toward a cross-stream {I.e., horizontal)
gradient rather than a vertical gradient. Net advectlve flows throughout a
vertically well-mixed water column tend to flow northward In segment CB-7
and southward 1n CB-6 and CB-8. This pronounced horizontal gradient also
exists across the Bay mouth. Thus, plankton and f 1 sh larvae are brought
Into the Bay with the higher salinity ocean waters along the eastern side
of the lower Bay until they become entrained into the lower layer at
segment CB-5 and are transported up the Bay to grow and mature.
Eastern shore embayments such as Eastern Bay (EE-1), the subestuary of the
Choptank River (EE-2) and the Pocomoke and Tangier Sounds (EE-3) have
salinities similar to adjacent Bay waters, and they are shallow enough to
permit light penetration necessary for the growth of submerged aquatic
vegetation (SAVs). These areas provide shelter for many benthlc Inver-
tebrates and small fish which make an important contribution to the Bay's
rich environment.
11-19
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Boundaries have been delineated at the mouths of the Bay's major tributar-
ies. These boundaries define the sources of freshwater, sediment, nutri-
ents, and other constituents delivered to the main stem of the Bay. Along
these boundaries, frontal zones between the tributary and main stem waters
tend to concentrate detHtal matter and nutrients, with circulation
patterns governing the transport of many organisms to this food source.
The major tributaries are further subdivided Into three segment classifica-
tions: tidal fresh (TF), river estuarlne transition zone (RET), and lower
subestuary (LE). The tidal fresh segments are biologically Important as
spawning areas for anadromous and semlanadromous fish such as the alewlfe,
herrings, shad, striped bass, white perch and yellow perch. There are also
freshwater species which are resident In these areas such as catfish,
minnows and carps. Algal blooms tend to be most prolific within the tidal
fresh zone. The extent of these blooms is dependent upon nutrient supply, a
range of factors such as retention time, and light availability. Most of
the algal species that can flourish within tidal fresh segments are
Inhibited as they encounter the more saline waters associated with the
transition zone.
The highest concentration of suspended solids 1s found at the Interface of
fresh and saline waters and it approximates the terminus of density
dependent estuarlne circulation. The area where this phenomenon occurs is
typically referred to as the "turbidity maximum" zone. The significance of
this area lies in its value as a sediment trap entraining not only material
introduced upstream but, additionally, material transported in bottom
waters from downstream. This mechanism also tends to concentrate any
material associated with the entrained sediment. For example, Kepone
accumulations within the James River estuary are highest in the turbidity
maximum zone.
The final segment type found within the major tributaries is identified as
the lower subestuary segment. This area extends from the turbidity maximum
to the point where the tributary Intersects the main stem of the Bay.
Highly productive oyster bars are found in these segments. There is a
heavy concentration of oyster bars in the lower subestuaries because of the
favorable depth, salinities, and substrate. In general, the oyster bars
are located in depths of less than 35 feet in salinities greater than 7-8
ppt and on substrates which are firm. Seasonal depressions of dissolved
oxygen in bottom waters prevent the establishment of oyster bars in most
waters over 35 feet deep.
CHEMICAL PARAMETERS
This section provides a brief discussion of chemical indicators of aquatic
use attainment for estuaries. Three clarifications are necessary before
beginning this discussion. First, while 1t 1s useful to refer to these
parameters as "chemical" characteristics to distinguish them from the
physical and biological parameters in a use attainability evaluation, these
characteristics are traditionally referred to as water quality criteria and
are referred to as such in other sections of this report. Second,
chlorophyll-a is introduced in this section rather than in Chapter III
because it is the primary Impact indicator for chemicals such as nitrogen
11-20
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and phosphorus. Third, because an extensive discussion of chemical ;er
quality Indicators 1s presented 1n the earlier U.S. EPA Technical Support
Manual (U.S. EPA November 1983), the discussion herein Is very 11m1te-.
Manual users who are Interested 1n a more extensive discussion are referred
to the previous volume.
The most critical water quality Indicators for aquatic use attainment 1n an
estuary are dissolved oxygen, nutrients and chlorophyll-a, and toxicants.
Dissolved oxygen (DO) 1s an Important water quality Indicator for all
fisheries uses. The DO concentration In bottom waters 1s the most critical
Indicator of survival and/or density and diversity for most shellfish and
an Important Indicator for flnflsh. 00 concentrations at mid-depth and
surface locations are also Important Indicators for flnflsh. In evaluating
use attainability, assessments of DO Impacts should consider the relative
contributions of three different sources of oxygen demand: (a)
photosynthesis/respiration demand from phytoplankton; (b) water column
demand; and (c) benthlc oxygen demand. If use Impairment 1s occurring,
assessments of the significance of each oxygen sink can be used to evaluate
the feasibility of achieving sufficient pollution control to attain the
designated use.
Chlorophyll-a Is the most popular Indicator of algal concentrations and
nutrient overenrlchment which In turn can be related to diurnal DO
depressions due to algal respiration. Typically, the control of phosphorus
levels can Hm1t algal growth In the upper end of the estuary, while the
control of nitrogen levels can limit algal growth near the mouth of the
estuary; however, these relationships are dependent upon factors such as
N:P ratios and light penetration potential which can vary from one estuary
to the next, thereby producing different limiting conditions within a given
estuary. Excessive phytoplankton concentrations, as 1nd1ca*^d by
chlorophyll-a levels, can cause adverse DO Impacts such as: la) wide
diurnal variations 1n surface DO's due to daytime photosynthetic oxygen
production and nighttime oxygen depletion by respiration, and (b) depletion
of bottom DO's through the decomposition of dead algae. Thus, excessive
chlorophyll-a levels can deplete the oxygen resources required for bottom
water fisheries, exert stress on the oxygen resources of surface water
fisheries, and upset the balance of the detrltal foodweb 1n the seagrass
community through the production of excessive organic matter.
Excessive chlorophyll-a levels also result In shading which reduces light
penetration for submerged aquatic vegetation. Consequently, the prevention
of nutrient overenrlchment Is probably the most Important water quality
requirement for a healthy SAV community.
Blooms of certain phytoplankton can also be toxic to fish. For example,
blooms of the toxic "red tide" organism during the early 1970's resulted 1n
extensive fish kills 1n several Florida estuaries.
The nutrients of concern In the estuary are nitrogen and phosphorus. Their
sources typically are discharges from sewage treatment plants and Indus-
tries, and runoff from urban and agricultural areas. Increased nutrient
levels lead to phytoplankton blooms and a subsequent reduction in DO
levels, as discussed above. In addition, algal blooms decrease the depth
11-21
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to which light Is able to penetrate, thereby affecting SAV populations 1n
the estuary.
Sewage treatment plants are typically the major source of nutrients to
estuaries In urbanized areas. Agricultural land uses and urban land uses
represent significant nonpolnt sources of nutrients. Often wastewater
treatment plants are the major source of phosphorus loadings while nonpolnt
sources tend to be major contributors of nitrogen. In estuaries located
near highly urbanized areas, municipal discharges probably will dominate
the point source nutrient contributions. Thus, It Is Important to base
control strategies on an understanding of the sources of each type of
nutrient, both 1n the estuary and 1n Its feeder streams.
In the Chesapeake Bay, an assessment of total nitrogen, total phosphorus,
and N:P ratios Indicates that regions where resource quality 1s currently
moderate to good have lower concentrations of ambient nutrients, and N:P
ratios between 10:1 and 20:1, Indicating phosphorus-limited algal growth.
Regions characterized by little or no SAV's (I.e., phytopiankton-dominated
systems) or massive algal blooms had high nutrient concentrations and
significant variations In the N:P ratios. Moving a system from one class
to another could Involve either a reduction of the limiting nutrient (N or
P) or a reduction of the non-limiting nutrient to a level such that It
becomes limiting. For example, removal of P from a system characterized by
massive algal blooms could force It to become a more desirable
phytopiankton-domlnated system with a higher N:P ratio.
Clearly the levels of both nitrogen and phosphorus are Important deter-
minants of the uses that can be attained In an estuary. Because point
sources of nutrients are typically much more amenable to control than
nonpolnt sources, and because nutrient (phosphorus) removal for municipal
wastewater discharges 1s typically less expensive than nitrogen removal
operations, the control of phosphorus discharges 1s often the method of
choice for the prevention or reversal of use Impairment In the upper
estuary (I.e., tidal fresh zone). However, the nutrient control programs
for the upper estuary can have an adverse effect on phy topiankton growth 1n
the lower estuary (I.e., near the mouth) where nitrogen 1s typically the
critical nutrient for eutrophlcatlon control. This Is because the
reduction of phytoplankton concentrations In the upper estuary will reduce
the uptake and settling of the non-limiting nutrient which Is typically
nitrogen, thereby resulting In Increased transport of nitrogen through the
upper estuary to the lower estuary where 1t 1s the limiting nutrient for
algal growth. The result 1s that reductions In algal blooms within the
upper estuary due to the control of one nutrient (phosphorus) can result 1n
Increased phytoplankton concentrations 1n the lower estuary due to higher
levels of the uncontrolled nutrient (nitrogen). Thus, tradeoffs between
nutrient controls for the upper and lower estuary should be considered 1n
evaluating measures for preventing or reversing use Impairment. The
Potomac Estuary 1s a good example of a system where tradeoffs between
nutrient controls for the upper and lower estuary are being evaluated.
The Impacts of toxicants such as pesticides, herbicides, heavy metals and
chlorinated effluents are beyond the scope of this volume. However, the
presence of certain toxicants 1n excessive concentrations within bottom
sediments or the water column may prevent the attainment of water uses
11-22
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(particularly fisheries propagation/harvesting and seagrass habitat uses)
1n estuary segments which satisfy water quality criteria for DO,
chlorophyll-a/nutrient enrichment, and fecal conforms. Therefore, poten-
tial Interferences from toxic substances need also to be considered 1n a
use attainability study.
TECHNIQUES FOR USE ATTAINABILITY EVALUATIONS
Introduction
Use attainability evaluations generally follow the conceptual outline:
o Determine the present use of the estuary,
o Determine whether the present use corresponds to the designated
use,
o If the present use does not correspond to the designated use,
determine why, and
o Determine the optimal use for the system.
In assessing use levels for aquatic life protection, the first two Items
are evaluated In terms of biological measurements and Indices. However, If
the present use does not correspond to the designated use, one turns to
physical and chemical factors to explain the lack of attainment, and the
highest level the system can achieve.
The physical and chemical evaluations may proceed on several levels depend-
ing on the level of detail required, amount of knowledge available about
the system (and similar systems), and budget for the use- attainability
study. As a first step, the estuary Is classified In terms of physical
processes (e.g., stratification, flushing time) so that It can be compared
with reference estuaries that exhibit similar physical characteristics.
Once a similar estuary 1s Identified, 1t can be compared with the estuary
of Interest In terms of water quality differences and differences 1n
biological communities which can be related to man-made alteration (I.e.,
pollution discharges). It Is Important to consider a number of simplifying
assumptions that can be made to reduce the conceptual complexity of the
prototype system for easier classification and more detailed analyses.
The second step 1s to perform desk-top or simple computer model calcula-
tions to Improve the understanding of spatial and temporal water quality
conditions 1n the present system. These calculations Include continuous
point source and simple box model type calculations, among others.
The third step 1s to perform more detailed analyses to Investigate system
Impact from known anthropogenic sources through the use of more sophisti-
cated computer models. These tools can be used to evaluate the system
response to removing Individual point and nonpolnt source discharges, so as
to assist with assessments of the cause(s) of any use Impairment.
11-23
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Desktop Evaluations of System Characteristics
This section discusses desktop analyses for evaluating relationships
between physical/chemical characteristics and use attainability. Desktop
evaluations that can provide guidance for the selection of appropriate
mathematical models for use attainability studies are also discussed.
Such evaluations can be used to characterize the complexity of an estuary,
Important physical characteristics such as the level of vertical stratifi-
cation and flushing times, and violations of water quality criteria.
Depending upon the complexity of the estuary, these evaluations can
quantify the temporal and spatial dimensions of Important physical/
chemical characteristics and relationships to use attainability needs as
summarized below:
1. Vertical Stratification
a. Temporal Scale: During which seasons does 1t occur? What 1s
the approximate duration of stratification 1n each season?
b. Spatial Scale: How much area 1s subject to significant
stratification in each season?
2. Flushing Times
a. Temporal Scale: What are the flushing times for each major
estuary segment and the estuary as a whole?
b. Spatial Scale: Which segments exhibit relatively high flushing
times? Relatively low flushing times?
3. Violations of Water Quality Criteria (based upon statistical
analysis of measured data)
a. Temporal Scale: Which seasons exhibit violations? How fre-
quently and for what durations do violations occur 1n each
season? Are the violations caused by short-term or long-term
phenomena? Short-term phenomena include: DO sags due to
combined sewer overflows or short-term nonpoint source
loadings, and diurnal DO variations due to significant
chlorophyll-a levels. Long-term phenomena Include: seasonal
eutrophlcation impacts due to nutrient loadings, seasonal DO
sag due to point source discharges, and seasonal occurrence of
anaerobic conditions 1n bottom waters due to persistent
vertical stratification.
b. Spatial Scale: What 1s the spatial extent of the violations
(considering longitudinal, horizontal, and vertical direc-
tions)?
4. Relationship of Physical/Chemical Characteristics to Use Attain-
ability Needs
11-24
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a. Temporal Scale: Are use designations more stringent during
certain seasons (e.g., spawning season)? Are acceptable
physical/chemical characteristics required 100 percent of the
time 1n each season In order to ensure use attainability?
b. Spatial Scale: Are there segments In the estuary which cannot
support designated uses due to physical limitations? Are
acceptable physical/chemical characteristics required In 100
percent of the estuary segment or estuary 1n order to ensure
attainability of the use?
Simplifying Assumptions. Zison et al. (1977) and Mills et al. (1982) list
a number of simplifying assumptions that can be made to reduce the com-
plexity of estuary evaluations. However, care must be taken to ensure that
such assumptions are applicable to the estuary under study and that they do
not reduce the problem to one which 1s physically or chemically unreason-
able. The following assumptions may be considered (Z1son et al., 1977;
Mills et al., 1982):
a. The present salinity distribution can be used as a direct measure
of the distribution of all conservative continuous flow pollutants
entering the estuary, and can be used as-the basis for calculating
dispersion coefficients for a defined freshwater discharge con-
dition,
b. The vertical water column is assumed to be well mixed from top to
bottom,
c. Flow and transport through the estuary 1s essentially one-
dimensional ,
d. The Cor1ol1s effect may be neglected, which means that the estuary
1s assumed to be laterally homogeneous,
e. Only steady-state conditions will be considered, by using cal-
culations averaged over one or more tidal cycles to estimate a
freshwater driven flow within the estuary,
f. Regular geometry may be assumed, at least over the length of each
segment, which means that topographically Induced circulations are
neglected,
g. Only one river inflow can be used in the evaluation,
h. No variations in tidal amplitude are permitted, and
i. All water leaving the estuary on each tidal cycle is replaced by a
given percentage of "fresh" seawater.
The above 11st of assumptions are directed towards the specific objective
of reducing the estuary to a one-dimensional, quasi-steady-state system
amenable to desktop calculations. In reality these assumptions need to be
carefully weighed so that Important processes are not omitted from the
analysis.
11-25
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One approach is to start with a completely three-dimensional system, deter-
mine which assumptions can reasonably be made, and see what the answer
means in terms of a simplified analysis. Procedures for making such
determinations are discussed 1n the next section, but several examples are
presented here for illustration.
The fact is that many narrow estuaHne systems 1n which lateral homogeneity
can be assumed, also exhibit 2 or more layers of residual flow, making the
assumption of a one-dimensional system Invalid. Conversely, given a
vertically well-mixed system like Biscayne Bay, one cannot assume lateral
homogeneity because the system is usually very wide wind mixing is too
significant to permit such a simple analysis.
Degree of Stratification.
Freshwater 1s lighter than saltwater. Therefore, the river may be thought
of as a source of buoyancy, of amount:
Buoyancy = ApgQ, (1)
T
where ^P = the^dlfference 1n density between sea and river water,
M/LJ
g = acceleration of gravity,,L/T
Or - freshwater river flow, L /T
M = units of mass
L = units of length
T = units of time
The tide on the other hand 1s a source of kinetic energy, equal to:
kinetic energy = "wut3 (2)
where P - the seawater density,
W s the estuary width
Ut * the square root of the averaged squared velocities.
The ratio of the above two quantities, called the "Estuarlne Richardson
Number" (Fischer 1972), 1s an estuary characterization parameter which is
indicative of the vertical mixing potential of the estuary:
(3)
11-26
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If R is very large (above 0.8), the estuary 1s typically considered to be
strongly stratified and the flow to be typically dominated by density
currents. If R 1s very small, the estuary 1s typically considered to be
well-mixed and the density effects to be negligible.
Another desktop approach to characterizing the degree of stratification 1n
the estuary 1s to use a stratification-circulation diagram (Hansen and
Rattray 1966). The diagram (shown 1n Figure 1 1 -8) requires the calculation
of two parameters:
\ C
Stratification Parameter = ^ — (4)
and Circulation Parameter = rr=-
uf
where AS = time averaged difference between salinity levels at
the surface and bottom of the estuary,
S s cross-sectional mean salinity,
U = net non-tidal surface velocity, and
in = mean freshwater velocity through the section.
To apply the stratification-circulation diagram 1n Figure II-8, which Is
based on measurements from a number of estuaries with known degrees of
stratification, calculate the parameters of Equation (4) and plot the
resulting point on the diagram. Type la represents slight stratification
as In a laterally homogeneous, well-mixed estuary. In Type Ib, there 1s
strong stratification. Type 2 1s partially well-mixed and shows flow
reversals with depth. In Type 3a the transfer 1s primarily advectlve, and
1n Type 3b the lower layer 1s so deep, as In a fjord, that circulation does
not extend to the bottom. Finally, Type 4 represents the salt-wedge type
with Intense stratification (Dyer 1973).
The purpose of the analysis 1s to examine the degree of vertical resolution
needed for the analysis. If the estuary 1s well-mixed, the vertical dimen-
sion may be neglected, and all constituents 1n the water column assumed to
be dispersed evenly throughout. If the estuary 1s highly stratified, at
least a 2-layer analysis must follow. For the case of a partially-mixed
system, a judgment call must be made. The James River may be considered as
an example which 1s partially stratified but was treated as a 2-layer
system for a recent toxics study (O'Connor, et al., 1983).
A final desktop method for characterizing the degree of stratification
1s the calculation of the estuary number proposed by Thatcher and Harleman
(1972):
11-27
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10
Uf
(Station code: M, Mississippi River mouth; C, Columbia
River estuary; J, James River estuary; NM, Narrows of
the Mersey estuary; JF, Strait of Juan de Fuca; S,
Silver Bay. Subscripts h and 1 refer to high and low
river discharge; numbers indicate distance (in miles)
from mouth of the James River estuary.
Firure II-8. Stratification Circulation Diagram and Examples.
11-28
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Ed-
(5)
where
E . -
estuary number,
tidal prism volume (volume between low and high tides),
freshwater inflow,
tidal period, and
densimetric Froude number =
'1
where
layer velocity,
acceleration due to gravity,
density difference across Interface,
density in layer, and
layer thickness.
Again, by comparing the calculated value with the values from known
systems, one can Infer the degree of stratification present. The reader
should consult Thatcher and Harleman (1972) for further details.
Horizontal variations in density may still exist in a vertically well-mixed
estuary, resulting in circulation that is density driven in the horizontal
direction. It is helpful to understand density-driven circulation In an
estuary (baroclinic circulation) in order to assess its effect in relation
to turbulent diffusion on the landward transport of salinity. While
numerous studies have been performed over the years (e.g., Hansen and
Rattray 1965, 1966; Rigter, 1973), no unifying theory has emerged clearly
delineating longitudinal, transverse and vertical dispersion mechanisms.
This means that we still have to rely to a large extent on actual in-situ
data.
Decisions about whether 1t is reasonable to
Coriolis effects and wind is often judgmental.
offer the following criterion for neglecting
criterion is based on the Rossby number:
neglect processes such as
However, Cheng (1977) did
the Coriolis effect. The
ttu
(6)
11-29
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where R^ = Rossby number,
IT = characteristic wind velocity = 1/2 peak surface
velocity,
n « earth's rotation rate, and
L * length of estuary,
Cheng suggested that for R < 0.1, the Cor1ol1s effect 1s small. Wind 1s
so highly variable and unpredictable that 1t 1s almost always neglected.
In general, 1t has little effect on steady-state conditions, except 1n
large open estuaries.
Finally, the use of simplified geometries, such as uniform depth and width
1s highly judgmental. One may choose to neglect side embayments, minor
tributaries, narrows and Inlets as a sympHfylng approach to achieve
uniform geometry. However, it 1s always Important to consider the
consequences of this assumption.
Flushing Time. The time that 1s required to remove pollutant mass from a
particular point 1n an estuary (usually some upstream location) 1s called
the flushing time. Long flushing times are often Indicative of poor water
quality conditions due to long residence times for pollutants. Flushing
time, particularly 1n a segmented estuary, can also be used 1n an Initial
screening of alternate locations for facilities which discharge constitu-
ents detrimental to estuarlne health If they persist 1n the water column
for lengthy periods.
Factors Influencing flushing times are tidal ranges, freshwater inflows,
and wind. All of these forcing functions vary over time, and may be
somewhat unpredictable (e.g., wind). Thus, flushing time calculations are
usually based on average conditions of tidal range and freshwater inflows,
with wind effects neglected.
The Fraction of Fresh Water Method for flushing time calculation 1s based
upon observations of estuarlne salinities:
Srt - S0
F - -2 * (7)
where F » flushing time 1n tidal cycles,
S = salinity of ocean water, and
S° = mean estuarlne salinity.
The tidal prism method for flushing time calculation considers the system
as one unit with tidal exchange being the dominant process:
11-30
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(8)
where F » flushing time 1n tidal cycles,
V, » low tide volume of the estuary, and
P * tidal prism volume (volume between low and high tides).
The Tidal Prism technique was further modified by Ketchum (1951) to segment
the estuary Into lengths defined by the maximum excursion of a particle of
water during a tidal cycle. This technique can now Include a freshwater
Inflow:
v + P
n VL1 P1
F =< £ (9)
where F a flushing time 1n tidal cycles,
1 a segment number,
n = number of segments
V. . = low tide volume 1n segment 1, and
P. * tidal prism volume 1n segment.
Riverine Inflow 1s accounted for by setting the upstream length equal to
the river velocity multiplied by the tidal period, and setting:
PQ - QfT (10)
where P = tidal prism volume In upstream segment,
qf a freshwater flow, and
TT - tidal period.
Finally, the replacement time technique 1s based upon estuarlne geometry
and longitudinal dispersion:
tR = 0.4 L2/EL (11)
where t. 3 replacement time,
L = length of estuary, and
EL 3 longitudinal dispersion coefficient.
11-31
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This technique requires knowledge of a longitudinal dispersion coefficient,
E., which may not be known from direct estuarlne measurements. A coeffici-
ent based upon measured data from a similar estuary may be
Table II-4 for typical values 1n a number of U.S. estuaries)
estimated from empirical relationships, such as the one
Harleman (1964):
assumed (see
or 1t may be
reported by
EL = 77 n u R
5/6
or Harleman (1971):
,5/6
max
(13)
where
max
longitudinal dispersion coefficient (ft /sec),
Manning's roughness coefficient (0.028-0.035, typically),
velocity (ft/sec),
maximum tidal velocity, and
hydraulic radius = A/P
where A = cross sectional area,
P = wetted perimeter.
Desktop Calculations of Pollutant Concentrations
Classification and characterization are means of Identifying estuarlne
types and their major processes as a basis for comparison with reference
estuaries. There are some desktop methods for calculating ambient water
quality for defined pollutant loading conditions wh
-------
TABLE 11-4
OBSERVED LONGITUDINAL DISPERSION COEFFICIENTS
Estuary
Delaware River (DE/NJ)
Hudson River (NY)
East River (NY)
Cooper River (SO
Savannah River (GA, SO
Lower Rarltan River (NO)
South River (NJ)
Houston Ship Channel (TX)
Cape Fear River (NC)
Potomac River (MD/YA)
Compton Creek (NJ)
Wapplnger and F1shk11l Creek (NY)
San Francisco Bay (CA):
Southern Arm
Northern Arm
SOURCE: From Mills et al. (1982).
River Flow Dispersion Coefflcents
(cfs)
2500
5000
0
10000
7000
150
23
900
1000
550
10
2
-
(m2/sec)
150
600
300
900
300-600
150
150
800
60-300
30-300
30
15-30
18-180
46-1800
(ft2/sec)
1600
6500
3250
9700
3250-6500
1600
1600
8700
650-3250
325-3250
325
160-325
200-2000
500-20000
11-33
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where C . = pollutant concentration in segment 1,
TJ: = flushing time for segment 1,
Q! = freshwater flow, and
V* = water volume at segment 1.
For a direct discharge along the estuary, the concentration of a
conservative pollutant at any section downstream 1s given by (Dyer 1973):
(15)
and at a section upstream:
(16)
where
subscript x
subscript o
subscript s
concentration,
Inflow concentration,
Inflow rate,
fraction of freshwater 1n segment,
river flow,
salinity,
denotes distance downstream,
denotes point of Injection, and
denotes ocean salinity.
A refinement to the above desktop methods Involve calculations for noncon-
servatlve pollutants. The usual approach 1s to rely upon a first order
decay relationship:
Ct = Co
-kyt
(17)
where Ct = concentration at time t,
CQ - Initial concentration, and
kT * decay or reaction rate at temperature T.
The decay rate, k, 1s often expressed as a function of water temperature,
based upon the departure from a standard temperature (usually 20°C):
11-34
-------
*T . *20 e1-20 .18)
where k5n = decay or reaction rate at 20°C, and
™ = constant (1.03-1.04).
The final pollutant concentration 1s then calculated by applying a first-
order decay to the dilution concentration given from Equations (14)-(16),
based on an estimate of travel time to the cross-section of Interest.
The second approach 1s to greatly simplify the governing mass transport
equation, and derive a closed-form solution which can be evaluated using a
hand-held calculator, for continuous, discrete discharges of either con-
servative or non-conservative pollutants (Mills et al., 1982). From the
basic simplified equation for a continuous discharge of a nonconservatlve
pollutant:
(19)
the following solution can be readily derived:
cx s co exp
(20)
where c = concentration at distance x (x 1s positive downstream, and
negative upstream)
c = Initial concentration,
u = mean velocity,
E, = longitudinal dispersion coefficient, and
k = decay rate.
1n the upstream and downstream directions, respectively. Again, dispersion
coefficients, If not directly known, can be estimated from similar
estuaries, or from empirical formulas, such as those given In Equations
(12) and (13).
For multiple pollutant discharges, the resulting concentration curves for
each source may be superimposed to give a final composite profile along the
estuary (Figure II-9).
Finally, Equation (20) can be used to estimate the length of salinity
Intrusion by using salt as the constituent and assuming cross-sectional
homogeneity and an ocean salinity of 35 ppt (Stommel 1953):
11-35
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LOWER
MIDDLE
UPPER
Figure 11-9 Pattern of Recent Changes in the Distribution of Submerged Aquatic Vegetation (SAV)
in the Chesapeake Bay: 1950-1980. Arrows Indicate Former to Present Limits. Solid
Arrows Indicate Areas Where Eelgrass (Zostera Marina) Dominated. Open Arrows Indicate
Other SAV Species.
(from U.S. EPA Chesapeake Bay Program, 1982)
11-36
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3.5554 A E.
x - -—
where x = length of intrusion from ocean to 1 ppt isohallne,
A = cross-sectional area of estuary,
E. = longitudinal dispersion coefficient, and
Or - freshwater inflow rate.
Such a desktop evaluation of salinity Intrusion can be used to relate
changes in freshwater Inflow to use attainability within the upper estuary.
Other Desktop Evaluations for Use Attainability Assessments
The most common desktop evaluations of use attainability within estuaries
are statistical analyses of water quality monitoring data to determine the
frequency of violation of criteria for the designated aquatic use. Statis-
tical evaluations of contraventions of water quality criteria should
consider the confidence intervals for the number of violations that are
attributable to random variations (rather than actual water quality
deterioration). For example, consider an estuary monitoring station with
12 dissolved oxygen (DO) observations per year (I.e., a single slackwater
sample each month) with a standard of 5 mg/1 DO. If statistical analyses
of the DO observations indicate that the upper and lower confidence limits
for the frequency of random violations of the 5 mg/1 DO standard cover a
range of 1 to 4 violations per year, a regulatory agency should be cautious
in deciding whether actual use impairment has occurred unless more than 4
violations are observed annually.
In addition to the State water quality standard values, both quantitative
and qualitative measures should be considered for relationships between
water quality criteria and use attainment. Quantitative measures include
parametric statistical tests (i.e., assume normal frequency distribution)
such as correlation analyses and simple and multiple regression analyses,
as well as nonparametric statistical tests (I.e., distribution-free) such
as the Spearman and Kendall correlation analysis. These quantitative tests
might involve relating water quality indicators (e.g., DO, chlorophyl1-a)
to use attainability Indicators such as Juvenile index data (numbers per
haul) for different flnflsh or commercial landings data (tons) for selected
fisheries. Qualitative measures Include graphical displays of historical
trends in water quality and use attainment. For example, a map showing the
areas which have experienced a decline 1n bottom DO conditions during the
past 25 years could be overlaid on a map showing areas which experienced a
decline In oyster beds over the same period. Another example, which proved
to be very persuasive in the recent development of the U.S. EPA Chesapeake
Bay management program (U.S. EPA Chesapeake Bay Program, 1982), is
described in Figures II-9 through 11-12. Figures II-9 and 11-10 Illustrate
the decline in submerged aquatic vegetation (SAV) in Chesapeake Bay during
the past three decades. Figures 11-11 and 11-12 illustrate changes in
nutrient enrichment within Chesapeake Bay over the same period. The water
quality index plotted in Figure 11-12 Is based on changes in the concen-
trations of both nitrogen and phosphorus. As may be seen, the areas of
11-37
-------
LOWER
MIDDLE
UPPER
Figure 11-10 Sections of Chesapeake Bay Where Submerged Aquatic Vegetation (SAV) has
Experienced the Greatest Decline: 1950-1980
(from U.S. EPA Chesapeake Bay Program, 1982)
11-38
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!•!•«»
j
g
I
|-i!«QC<> IMBOi »
-------
MC.HOS
CMCSAPfMC IAT
Oagrcotng qualify
Improving quality
Figure 11-12.
Water Quality Trends in Chesapeake Bay. If either N or P trends
(from Figure 11-11) are increasing, then the overall water quality
is said to be degrading.
11-40
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"degrading quality" in Figure 11-12 typically correspond to areas where
submerged aquatic vegetation has experienced the greatest decline. Based
on these types of qualitative comparisons and quantitative evaluations, the
U.S. EPA Chesapeake Bay Program has secured considerable State, Federal,
and Regional support for more aggressive water quality management efforts
to protect Chesapeake Bay. Key to making decisions is the presentation of
quantitative data as well as qualitative Information.
In developing quantitative and qualitative measures for relationships
between water quality and use attainability, care should be taken to
distinguish the impacts of pollution discharges from the impacts of
non-water quality factors such as physical alterations of the system. For
example, in some estuaries, dredging/spoil disposal activities associated
with the construction and maintenance of ship navigation channels and
harbors may have contributed to use impairment over the years. Among the
potential impacts of channel dredging is the reduction 1n the coverage of
SAV's. Therefore, in order to minimize Interferences from dredging/spoil
disposal, analyses of water quality and use impairment for certain
fisheries (e.g., shellfish) and SAV habitats should be based upon periods
which do not Include major dredging/spoil disposal operations. Another
example of physical alterations which should be accounted for In any trend
analyses is poor tidal flushing resulting from the construction of bridges
and causeways. Potential contributions of extreme meteorologic conditions
(e.g., hurricanes, air temperature) to use Impairment should also be
considered.
If it is determined that some estuary segments exhibit use attainment
although violations of water quality criteria occur, the development of
site-specific water quality criteria should be considered. Development of
site-specific criteria 1s a method for taking unique local conditions Into
account. In the case of the water quality indicators (i.e., non-toxicants)
being considered in this guidance manual, a potential application of site-
specific criteria could be the establishment of temporal dimensions for
water quality criteria to restrict use attainment requirements to certain
seasons (I.e., in the event that year-round conformance with the water
quality criteria is not required to protect the viability of the designated
water use).
Computer Modeling Techniques for Use Attainability Evaluations
For many estuaries, field data on circulation, salinity, and chemical
parameters may be inadequate for desktop evaluations of use attainability.
In these cases, computer-based mathematical models can be used to expand
the data base and define causal relationships for use attainability
assessments. Specifically, there are three major areas In which computer
models of estuaries can contribute to use attainability evaluations:
1. Applications of hydrodynamic and mass transport models can expand
physical parameter data bases (I.e., circulation, salinity) in
order to identify aquatic use segments and to determine whether
physical characteristics are adequate for use attainment.
11-41
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2. Applications of water quality models can expand chemical parameter
(I.e., water quality) data bases In order to determine whether
ambient water quality conditions are adequate for use attainment.
3. In cases where use -Impairment 1s noted despite acceptable physical
characteristics, applications of water quality models can identify
the causes of use Impairment and alternative control measures that
promise use attainment.
The major problem facing the engineer or scientist performing the evalua-
tion is to select the most appropriate numerical model for a given study.
Such a selection process must be based on a consideration of system
geometry, physical and chemical processes of Importance, and the temporal
and spatial scales at which the evaluation 1s being conducted.
Previously discussed were some of the simplifications that can be made to
reduce the conceptual complexity of an estuary from its inherently three-
dimensional nature. Unfortunately, few quantitative measures exist to
define precisely how such determinations should be made. Most criteria for
selecting the most appropriate mathematical modeling approach are based on
"intuitive judgment" or "experience" with few comparative indices, such as
stratification diagrams and numbers, to make the selection less arbitrary.
One particular problem that needs to be addressed is the selection of
steady-state versus dynamic approaches to estuarine modeling. Again,
intuition leads one to accept that steady-state approaches are fine for
rivers or river-flow dominated systems, such as the upper 50-miles of the
Potomac River estuary near Washington, D.C. However, for areas further
downstream in the estuary where the river flow is less dominant particu-
larly 1n the dry season, one would intuitively consider using a dynamic
approach. The question then 1s how to formulate a criterion for choosing
between steady-state and dynamic modeling approaches. The governing
parameters in the selection criteria might be expected to be some com-
bination of freshwater inflow, tidal prism volume, density variations, and
tidal period, perhaps 1n the form of the estuary number, En, given by
Equation (7) or some other "number." A comparative study of various
approaches at differing estuary numbers, E-, might lead to an empirical
formulation of a useful criterion for moael selection, similar to the
stratification diagram.
Once the appropriate simplifying assumptions have been made, the type of
model needed can be determined. There are several model classifications
that could be utilized for selection purposes. A four level scheme was
used by Ambrose et al. (1981) to classify and compare a number of estuarine
receiving water models. The recommended model classification scheme 1s as
follows:
Level 1 - desktop methodologies,
Level 2 - steady-state or tldally averaged models
Level 3 - one-dimensional or quasi-two-dimensional real time models,
and
Level 4 - two-dimensional or three-dimensional real time models.
11-42
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Within each of the four levels, a number of numerical models are listed
(Ambrose et al. 1981) and their utility for problem solving 1s discussed.
In actuality, however, there are many more categories, which are sub-
divisions of the levels suggested by Ambrose et al. (1981). These are
summarized 1n Table 11-5 and discussed below, except Level 1 which was
previously discussed.
Within Level 2, there are two subdivisions: one-dimensional steady-state
models, and two-layer steady-state models. One-dimensional steady-state
models assume that the hydraulics are driven entirely by a constant river
Inflow to the estuary or by net non-tidal (t1dally averaged) flow. Con-
ditions are assumed to be uniform over the cross-section, and the effects
of Corlolls, wind, tidal, and stratification are neglected. Examples in
this category are QUAL II (Roesner et al., 1981) and the WASP models
(OIToro et al. 1981).
Two-layer (hydraulic) steady-state models are a simple, but fairly
significant extension beyond the one-layer models, 1n that the advectlve
transport can be resolved to allow for layered residual flow as In the
James River. O'Connor et al. (1983) developed such a model to study the
fate of Kepone 1n the James River, 1n which the net river flow could be
specified 1n the top layer, and the net upstream density-driven flow
specified 1n the lower hydraulic layer. In addition, this model has two
sediment layers, one fluid and one fixed, with exchanges between all
layers.
In Level 3, models can be subdivided Into two categories: one-dimensional
real time, and quasi-two-dimensional real time. The category of one-
dimensional real-time models has an advantage over steady-state models 1n
that the velocity field simulation can be completely dynamic, allowing
tides, wind, friction, variable freshwater Inflows, and longitudinal
density variations to be Included. Again, the estuary 1s assumed to be
cross-sectlonally homogeneous.
Quasi-two-dimensional real-time models are an Improvement on the
one-dimensional real-time representation In that they allow branching
systems to be simulated. In addition, the link-node models (such as OEM
and RECEIV) can be configured to approximate a two-dimensional horizontal
geometry, thus allowing lateral variations to be Included In the system
evaluation. A very popular model 1n both these Level 3 categories 1s the
Dynamic Estuary Model (OEM) which represents the geometry with a branching
link-node network (Genet et al., 1974). This model 1s probably the most
versatile of Its kind and has been applied to numerous estuarlne systems,
bays, and harbors throughout the world. It contains a hydrodynamic
program, DYNHYD, or DYNTRAN (Walton et al., 1983) 1n Us density driven
form, and a compatible water quality program, DYNQUAL, which can simulate
up to 25 water quality constituents, Including four trophic levels.
There are a variety of categories that might be considered 1n Level 4.
Many two-dimensional, vertically-Integrated, finite-difference hydrodynamic
programs exist. There are, however, relatively few that contain a water
quality program that simulates constituents other than salinity and/or
temperature (Blumberg, 1975; Hamilton, 1975; Elliot, 1976). These are real
time models, assuming only vertical homogeneity (Corlolis effects are now
11-43
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TABLE 11-5. CATEGORIES Of RECEIVING WATER MODELS
LEVEL
CATEGORY
INCLUDES
NEGLECTS
EXAMPLE MODELS
Desktop
1-0, steady-state
2-layer,
steady-state
1-0 real tli
Quasi 2-D
real tlM
2-0. finite-difference
verticil Integrated
Uniform flows
River flows
Longitudinal
variability
River flows
Residual upstrean
flows
Longitudinal and
vertical variability
Tides, wind, river
flows, friction
Longitudinal
variability
Tides, wind, river
flows, friction
Longitudinal and
lateral variability
Tides, wind, river
flows, friction
Cor1o11s
Longitudinal and
lateral variability
Wind, CorloKs.
friction, tide
Lateral and vertical
variations
Wind. Corlolls.
friction, tide
Lateral and vertical
variations
W
-------
Included). An example of a water quality model in this category is the
hydrodynamic and water quality model developed by Ross and Jerkins (1983)
which has been extensively applied to Tampa Bay.
Similar to the above category are the two-dimensional, vertically-
integrated, finite-element models. The physical process and simplifica-
tions are Identical. The difference is that the geometry is represented as
a series of elements (usually triangles) which can better represent complex
coastlines. Examples of models in this category are the CAFE1/OISPER1
hydrodynamic models (Wang and Connor 1975; Leimkuhler 1974), the Chesapeake
Bay Circulation Model, CBCM (Walton et al., 1983), and a water quality
model developed by Chen (1978). The first two models can simulate only
mass transport of a non-conservative constituent, whereas Chen's model is
capable of representing most major water quality processes. CBCM has the
additional advantages of a three-dimensional form and the capability to
link 1-2 or 2-3-dimensional models to treat tributaries from a main bay or
subgrid scale cuts in a main bay which cannot be resolved adequately at the
horizontal spatial scale.
There are a number of two-dimensional, laterally-averaged models (longi-
tudinal and vertical transport simulations) that treat mass transport of
salt and temperature, but very few that Include nonconservatlve constit-
uents or water quality routines. While models in this category assume
lateral homogeneity and neglect Corlolis effects, they can represent
vertical stratification although for numerical reasons, care should be
taken in defining vertical layers to represent the saltwater/freshwater
interface of high stratified systems. The tributary submodels of CBCM
(Walton et al., 1983) are included in this category.
Last is the category of three-dimensional, finite-difference and finite-
element models. These models allow all physical processes to be included,
although many were developed for systems of constant salinity (lakes or
oceans) which cannot simulate stratification processes. Models in this
category include CBCM (Walton et al. 1983) and the models of Leendertse et
al. (1973) which simulate hydrodynamics and the transport of salt, tem-
perature, and other conservative constituents.
Sample Applications of Estuary Models
Delineation of Aquatic Use Segments. Figure 11-7 illustrates the use of
measured data on physical parameters to delineate homogeneous aquatic use
segments 1n Chesapeake Bay. For many estuaries, the measured data on
circulation and salinity will not have sufficient spatial and temporal
coverage to permit a comprehensive analysis of use attainability zones. In
cases where the measured data base is inadequate, computer models can be
used to expand the physical parameter data bases for segmentation of the
estuary.
Figure 11-13 illustrates the use of model projections for Tampa Bay,
located on the Gulf Coast of central Florida, to delineate relatively
homogeneous segments for use attainability evaluations (Camp Dresser A
McKee, Inc. 1983). Tampa Bay is considerably smaller and shallower than
Chesapeake Bay, with a surface area (approx. 350 sq. ml.) that is less than
10 percent of the Maryland/Virginia estuary's (approx. 5,000 sq. mi.
11-45
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INTERBAY
PENINSULA
Figure 11-13.
Map of Tampa Bay lowing Sample Estuary Segments
(A through N) and Net Current Velocities for a
Single Tidal Cycle (from Camp Dresser and McKee 1983)
11-46
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including tributaries). The Tampa Bay estuary exhibits extremely diverse
and abundant marine life which has been attributed to the geographic
position of the estuary between temperate and subtropical waters. As a
result of Tampa Bay's location, winter water temperatures rarely fall to
levels which could kill tropical organisms and summer water temperatures
are moderate enough to be tolerated by many of the temperate species.
Another contributing factor to the diversity and abundance of Tampa Bay
marine life is that salinity is typically in the range 25-35 ppt over most
of the estuary, without the wide fluctuations and significant vertical
stratification that characterize many other estuaries. As a result of the
stability of the salinity regime, many ocean species can coexist with
typical estuarine species.
Tampa Bay's salinity regime is also much different from Chesapeake Bay's.
Whereas extensive areas in Chesapeake Bay exhibit vertical stratification,
Tampa Bay is very well-mixed vertically due in large part to its relatively
shallow mean depth (I.e., relationship of storage volume to surface area).
Unlike Chesapeake Bay where circulation and mass transport must be evalu-
ated in the vertical as well as horizontal and longitudinal directions,
only the horizontal and longitudinal directions need to be considered for
Tampa Bay evaluations. Therefore, the sample analysis of Tampa Bay is a
good example of a segmentation approach to an estuary where the use is not
significantly influenced by vertical stratification. It is also a good
example of how an estuary circulation model can be used to segment an
estuary for use attainability analyses.
The estuary segment boundaries shown in Figure 11-13 have been delineated
on a map of Tampa Bay showing circulation model projections of net current
velocities (i.e., magnitude and direction) for a single tidal cycle. The
model projections are based upon a two-dimensional circulation model
(horizontal and longitudinal directions) which had previously been
calibrated to measured current velocity and tidal elevation data for Tampa
Bay (Ross and Jerkins, 1978). The use of the model expanded the available
circulation data base from a limited number of gaging stations to
comprehensive coverage of the entire Bay. One of the most important
factors in subdividing the Tampa Bay estuary system into relatively
homogeneous subunits 1s the ship navigation channel extending from the
mouth of the Bay to the vicinity of Interbay Peninsula with branches
extending into Hillsborough Bay (segment 0) and into the lower end of Old
Tampa Bay (segment C). As may be seen from the convergence of velocity
vectors in the vicinity of the navigation channel, there tends to be
relatively little mixing between waters on either side of the Main Bay
channel. Therefore in Figure 11-13, the navigation channel and the
adjoining dredge spoil areas serve as the approximate boundary between seg-
ments H and I and between segments F and G. Each of these segments appears
to be relatively isolated from its counterpart on the opposite side of the
navigation trench before mixing occurs 1n the vicinity of the navigation
channel, thereby justifying the designation of each as a separate segment.
Water movement 1s also somewhat isolated on approximately either side of
the navigation channel branches extending Into Hillsborough Bay and the
lower end of Old Tampa Bay. However, since net current velocities tend to
converge a short distance south of the two ship channel branches, the
11-47
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boundaries between segments E and F and E and G in Figure 11-13 depart
somewhat from the navigation trench.
Another circulation factor considered In the delineation of estuary
segments 1s the Impact of causeways and bridges on tidal flushing. Based
upon the circulation patterns shown 1n Figure 11-13, 1t seems appropriate
to assign separate segment designations (A, B, and C) to the areas above
the three bridge crossings 1n Old Tampa Bay: Courtney Campbell Causeway
(boundary between segments A and B), Howard Franklin Bridge (boundary
between segments B and C) and Gandy Bridge (boundary between segments C and
F). Likewise, McKay Bay (segment K), which 1s separated from Hlllsborough
Bay by the 22nd Street Causeway, also merits a separate segment desig-
nation.
A final circulation factor In the open bay 1s the location of net rotary
currents (Indicated by circles 1n Figure 11-13) which are called "gyres."
The gyres result from water moving back and forth with the tides, while
following a net circular path. Gyres can have a significant effect on
flushing times, since waters caught 1n the gyres typically exhibit much
higher residence times than waters which are not affected by these areas of
net rotary currents. The use of the main ship channel and causeway/bridge
crossings as segment boundaries 1n Figure 11-13 has generally Isolated the
major gyres or groups of gyres. Further subdivision of the Hlllsborough
Bay segment (D) to Isolate the waters on the eastern and western sides of
the ship channel (which bisects segment D) does not appear to be warranted
because of the two gyres 1n the middle section of the Bay and the gyre in
lower Bay. In other words, the gyres in Hlllsborough Bay are Indicative of
an Irregular circulation pattern that seems to mix waters on both sides of
the ship channel. Likewise, the gyres within segment B are Indicative of a
circular mixing pattern throughout the segment which suggests that further
subdivision Into eastern and western sections Is not justified.
The segment network In Figure 11-13 also maintains relatively homogeneous
salinity levels within each segment. The greatest longitudinal variations
1n salinity occur In segments F and G which exhibit 3-5 ppt Increases in
average annual values between the upper and lower ends of the segment. If
these longitudinal variations 1n salinity will result in significant
differences in the biological community, further subdivision of segments F
and G should be considered.
Figure 11-13 also shows five separate segments for significant embayments:
Safety Harbor (J), McKay Bay (K), Alafia River (L), Hillsborough River (M),
and Little Manatee River (N). The latter three represent the tidal sec-
tions of the Indicated river. In addition to these five embayments there
may be other inlets which should be separated from Tampa Bay segments for
separate use attainability studies.
In summary, the network shown in Figure 11-13 illustrates how hydrodynamic
and salinity data produced by an estuary model can be used to segment the
Tampa Bay system. In addition to the type of hydrodynamic data shown in
Figure 11-13, the estuary model can be used for "particle tracer" studies
that can further address issues such as mixing of waters on either side of
the ship channel and the impacts of gyres.
11-48
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Evaluation of Use Attainment Based Upon Ambient Mater Quality Data. It is
often the case that the measured ambient water quality data case 1s inade-
quate from temporal and/or spatial standpoints for a definitive assessment
of use attainment.
An example of temporal limitations 1s an ambient water quality data base
that suffers from a small sample size (e.g., 6-12 slackwater observations
at each station per year), thereby resulting 1n extremely wide confidence
Intervals for the number of violations of standards and criteria that are
attributable to random variations (rather than actual water quality
deterioration).
Another example of temporal limitations 1s an observed water quality
data base that 1s restricted to a single daytime observation on each
sampling day. This type of data base may not provide any insights into
diurnal variations in 00 which can result in use impairment, since
nighttime DO's can be significantly lower than daytime values due to
diurnal variations in algal production/respiration.
An example of spatial limitations in the measured water quality data base
1s Inadequate coverage of longitudinal and/or horizontal variations 1n
water quality. Adequate longitudinal coverage 1s required in all estuaries
to assess the significance and spatial extent of maximum and minimum con-
centrations 1n the estuary. Adequate horizontal coverage is required in
relatively wide estuaries where horizontal transport processes are
significant.
Another example of spatial limitations would be the collection of surface
water samples only within an estuary which exhibits extensive areas of
vertical stratification. The lack of bottom water samples may prevent an
adequate assessment of use attainment, since potential depressions of
bottom water 00 levels cannot be evaluated.
In cases where the measured water quality data base is inadequate from
either temporal or spatial standpoints, an estuary model should be used to
expand the data base for use attainability evaluations. The model must
first be calibrated with the available measured data base to demonstrate
that its representation of the prototype produces water quality statistics
that are not significantly different from the measured statistics. The
reliability of the estuary model projections depends upon the amount and
type of measured data available for model calibration. If the measured
data base provides reasonably good coverage of spatial and temporal (e.g.,
both short-term and long-term) variations in water quality, projections by
a model calibrated to this data base should be quite reliable in a statis-
tical sense. If the measured data base used for calibration is quite
limited, estuary model projections will be less reliable; however, the
application of an appropriate model to an estuary with limited measured
data can still provide significant Insights for use attainability eval-
uations and considerable guidance for future estuary monitoring programs.
To illustrate the use of an estuary model for use attainment evaluations, a
sample application of a one-dimensional (1-0) model to Naples Bay, Florida
is described below (Camp Dresser & McKee, Inc. 1983). Naples Bay (see
Figure 11-14) is a rather small estuary (less than 1.5 sq. mi. surface
11-49
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c:
T-
"»1
X
o
o
GO*OO* HS5
Figure 11-14. Node and Channel Network for the Naples Bay DEM
model.
11-50
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area) located on the Gulf Coast of southeastern Florida. The City of
Naples' municipal wastewater treatment plant (secondary treatment) which
discharges to the Gordon River portion of the Naples Bay estuary, 1s the
only major point source of pollution. This sample application Illustrates
the Impacts of an 8.0 million gallons per day (mgd) discharge from the
Naples wastewater treatment plant. Nonpolnt pollution loadings are con-
tributed by rainfall runoff and groundwater recharge from a 155 sq. ml.
drainage area, the majority of which discharges to the estuary at the
uppermost point 1n the system (node no. 1 1n Figure 11-14). The Gulf of
Mexico boundary condition (Introduced at node no. 29 1n Figure 11-14) also
contributes nutrients and other constituents to the lower Bay. Since the
Naples Bay system 1s a relatively narrow and shallow estuary, 1t was
assumed that a 1-D model which only represents longitudinal transport would
be adequate for this water quality evaluation (I.e., horizontal and
vertical gradients are neglected). A schematic of the 1-0 representation
of the Naples Bay system with the Dynamic Estuary Model (DEM) 1s shown 1n
Figure 11-14.
As Indicated 1n the earlier section on modeling techniques, the DEM model
(Genet et al., 1974) applied to Naples Bay is one of the most widely used
estuary models 1n the U.S. DEM provides a representation of 1ntert1dal
hydrodynamics and mass transport with computation Intervals which are
typically less than one hour. The model simulates 1-D flow, mass trans-
port, and water quality processes 1n a network of channels connected by
junctions called "nodes." As shown 1n Figure 11-14, the DEM model network
applied to Naples Bay consists of 29 nodes and 28 channels. This network
Includes all the appropriate conveyance and storage features of the proto-
type system, including bifurcation around an Island (between nodes 7 and
10), and the canal system adjacent to the main water body. Streamflows,
wastewater discharges, and associated pollutant loadings are added to the
system at the nodes. Based upon a set of motion equations solved for the
channels and a set of continuity equations solved for the nodes, the hydro-
dynamic portion of the model calculates flows and velocities 1n the chan-
nels and water surface elevations at the nodes. An accurate representation
of hydrodynamic processes within the system 1s developed to adequately
model mass transport and water quality processes.
The output from the hydrodynamic model becomes Input to the water quality
model which calculates mass transport between nodes and calculates changes
in concentration due to physical, chemical and biological processes. Water
quality processes represented by this portion of the model include: mass
transport based upon advectlon and dispersion, BOD decay, nitrification,
algal productivity, benthic sources of pollutants, dissolved oxygen sources
and sinks, and fecal coliform die-off.
Following calibration and verification of the Naples Bay model with mea-
sured hydrodynamic and water quality data, the model was used to assess
estuary-wide water quality. Figure 11-15 shows the model projections of
wet season chlorophyll-a (i.e., phytoplankton concentrations) for secondary
treatment operations which were in effect at the Naples wastewater treat-
ment plant. As indicated in an earlier section, chlorophyll-a 1s an
Important indicator of estuary health for use attainability evaluations.
11-51
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o>
2
<
I
Q.
O
-------
The chlorophyll-a simulations shown In Figure 11-15 represent "worst case"
water quality conditions at the start of the wet season (I.e., 4-month
period of significant rainfall and high streamflow). As may be seen from
the plot of "Secondary STP" conditions along the main stem of the Bay, the
combination of point and nonpolnt source loadings of nitrogen and phosphor-
us under wet season conditions results In chlorophyll-a levels exceeding 50
ug/1 for almost 3.0 miles and maximum values on the order of 80 ug/1 for
about 1.0 mile. The volume-weighted mean chlorophyll-a (I.e., weighted by
the storage volume 1n each estuary segment) for the upper two mi'.^s (I.e.,
Gordon River) of the estuary 1s about 60 ug/1, while the volume-weighted
mean for the entire estuary Is about 45 ug/1. These maximum and mean con-
centrations can be compared with state or regional water quality criteria
for local use attainability evaluations. Additional model projections can
be developed for other wet season and dry season conditions to evaluate the
frequency of use Impairment expressed in terms of ambient water quality.
Since chlorophyll-a Impacts are primarily of Interest in terms of associ-
ated impacts on DO, the estuary model can also be used to evaluate diurnal
DO impacts for use attainability assessments. Once chlorophyll-a and DO
relationships have been evaluated, the estuary model can be used to evalu-
ate nitrogen and phosphorus goals that maintain chlorophyll-a at levels
ensuring use attainment.
Evaluations of Use Impairment Causes and Alternative Control'-. Estuary
models are probably most useful for management evaluations -following a
determination of use impairment in certain sections of the estu*. ~y. Models
can be used to define the causes of impairment and to define the effect of
alternate controls on attaining the use. Such analyses require the
development of causal relationships between pollution loadings, physical
modifications and the resulting changes In uses. It 1s very difficult to
develop such causal relationships from statistical analyses of measured
data. For example, regression equations can merely Indicate that pollution
loadings and Impairment of the uses appear to be correlated based upon ti.e
measured data base. Such regression equations should not be interpreted as
definitive indications of cause-effect relationships. Evaluations of
cause-effect relationships require the use of a deterministic estuary
model.
Evaluations of use Impairment causes will typically focus on comparisons of
point and nonpolnt source pollution impacts. The estuary model is well-
equipped to perform such evaluations because both point and nonpoint source
loadings can be "shut off (i.e., deleted from the system) for evaluations
of relative contributions to use impairment. Applications of the Naples
Bay model will be used to Illustrate how evaluations of cause-effect rela-
tionships can be performed. After analyses of the impacts of existing
secondary treatment operations at the 8.0 mgd wastewater treatment plant,
the Naples Bay model was rerun with no wastewater discharges. For this
model run, the only sources of nutrients and other constituents were
norpoint source flows from the Bay's 155 sq. mi. drainage area and ocean
boundary conditions at the mouth of the Bay. The resulting chlorophyll-a
projection for "worst case" wet season conditions are shown in Figure 11-15
as the "Zero STP Discharge" plot. As may be seen, the maximum chlorophyll-
a concentration Is about 25 ug/1, with concentrations on the order of 15-25
ug/1 for about 5.0 miles. The chlorophyll-a concentrations for the "Zero
STP Discharge" condition are typically only 25-50 percent of the existing
11-53
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"Secondary STP" levels for about 5.0 miles. Also, the location of the
maximum chlorophyll-a concentration 1s shifted about 1.0 mile further
downstream for the "Zero STP Discharge" condition. The mean volume-
weighted chlorophyll-a for the entire Bay Is approximately 20 ug/1 which Is
less than half of the "Secondary STP" mean. These evaluations suggest that
secondary effluent discharges from the wastewater treatment plant are the
major cause of relatively high chlorophyll-a levels under wet season
conditions. Approximately 50-55 ug/1 or about 70 percent of the peak
chlorophyll-a concentration (80 ug/1) and about 25 ug/1 or 55 percent of
systemwlde volume-weighted mean concentration can be attributed to the
wastewater treatment plant.
Chlorophyll-a 1s a specific Index of phytoplankton blomass. Thus, assuming
that the chlorophyll-a levels associated with the "Secondary STP" condition
Indicate use Impairment, the estuary model provides a mechanism for eval-
uating the use attainability benefits of alternate controls. The Naples
Bay model was rerun with the 8.0 mgd discharge upgraded to advanced waste-
water treatment (AWT) levels. The simulated AWT upgrading Involved
reducing total phosphorus effluent levels from 7.0 mg/1 to 0.5 mg/1 as P,
the achievement of almost total nitrification 1n comparison with less than
50 percent nitrification for secondary treatment conditions, and reducing
5-day biochemical oxygen demand (BOD) from 20 mg/1 to 5 mg/1. Nonpolnt
source loadings and ocean boundary conditions were set at the same levels
as the "Secondary STP" model runs. As shown 1n Figure 11-15, the projected
chlorophyll-a concentrations for the "AWT" conditions are 20-30 percent
lower than the "Secondary STP" levels for approximately a two mile section
that Includes the maximum concentrations for both scenarios. The AWT
scenario's maximum concentrations of chlorophyll-a are on the order of
50-60 ug/1 for about 2.5 miles, while the volume-weighted mean concentra-
tion for the entire Bay system 1s about 40 ug/1. Even under AWT condi-
tions, the maximum chlorophyll-a levels for AWT conditions are still about
35 ug/1 greater than the maximum values for "Zero STP Discharge" condi-
tions.
The maximum and mean concentrations for AWT conditions can be compared with
water quality criteria to determine 1f this control measure can achieve use
attainment. If the projected chlorophyll-a reductions are not sufficient
to prevent use Impairment, the model can be rerun to assess the use
attainability benefits of nonpolnt source controls 1n addition to AWT
Implementation.
ESTUARY SUBSTRATE COMPOSITION
The bottom of most estuaries 1s a mix of sand, silt and mud that has been
transported and deposited by ocean currents or by freshwater sources.
Rocky areas may also be seen, particularly In the fjord-type estuary. None
of these substrate types are particularly hospitable to aquatic plants and
animals, which accounts 1n part for the paucity of species seen 1n an
estuary.
Much of the estuarlne substrate 1s 1n flux. The steady addition of new
bottom material, transported by currents, may smother existing communities
and hinder the establishment of new plants and animals. Currents may cause
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a constant shifting of bottom sediment, further hindering the colonization
of species. Severe storms or flooding may also disrupt the bottom.
The sediment load Introduced at the head of the estuary will be determined
by the types of terrain through which the river passes, and upon land use
practices which may encourage runoff and erosion. It Is Important to take
land use practices Into consideration when examining the attainable uses of
the estuary. The heavier particles carried by a river will settle out
first when water velocity decreases at the head of the estuary. Smaller
particles do not readily settle and may be carried a considerable distance
Into the estuary before they settle to the bottom. The fines may never
settle and will contribute to the overall turbidity which 1s characteristic
of estuaries.
It 1s often difficult for plants to colonize estuaries because they may be
hindered by a lack of suitable anchorage points, and by the turbidity of
the water which restricts light penetration (McLusky, 1971). Attached
plant communities (macrophytes) develop 1n sheltered areas where silt and
mud accumulate. Plants which become established 1n these areas help to
slow prevailing currents, leading to further deposition of silt (Mann).
The growth of plants often keeps pace with rising sediment levels so that
over a long period of time substantial deposits of sediment and plant
material may be seen.
Attached plant communities, also known as submerged aquatic vegetation
(SAV), serve very Important roles as habitat and as food source for much of
the biota of the estuary. Major estuary studies, Including an Intensive
years-long study of the Chesapeake Bay, have shown that the health of SAV
communities serves as an Important Indicator of estuary health. Although
excess slltatlon may have some adverse effects on SAV, as discussed above,
this problem is minor compared to the effects of nutrient and toxics
loadings to the estuary. When SAV communities are adversely affected by
nutrients and/or toxics, the aquatic Hfe uses of the estuary also will be
affected. The ecological role of SAV 1n the estuary will be discussed
further 1n Chapter III, and its importance to the study of attainable uses
in Chapter IV.
Sediment/substrate properties are important because such properties: d)
determine the extent to which toxic compounds in sediments are available to
the biota; and (2) determine what types of plants and animals may become
established. The presence of a suitable substrate may not be sufficient,
however, since nutrient, 00, and/or toxics problems may cause the demise
and prevent the reestabllshment of desirable plants and animals. There-
fore, characterization of the substrate is important to a use attainability
study in order to understand what types of aquatic life should be expected
1n a given area.
ADJACENT WETLANDS
Tidal and freshwater wetlands adjacent to the estuary can serve as a buffer
to protect the estuary from external phenomena. This function may be
particularly Important during wet weather periods when relatively high
streamflows discharge high loads of sediment and pollutants to the estuary.
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The volume of sediment carried by streamflow during wet weather periods 1s
substantially greater than the amount transported Into the estuary by
rivers and streams during dry weather periods. Such shock loads could
quickly smother plant and animal communities and jeopardize their survival.
Wetlands can serve an Important function by protecting the estuary from
such shock loads. Because of the sinuous pattern of streams that flow
through the wetlands, and the high density of plants, water velocities will
be reduced enough to allow settlement of a substantial proportion of the
sediment load before 1t reaches the estuary. This simultaneously protects
the estuary and contributes to the maintenance of the wetlands.
The sediment load discharged by streamflow may be accompanied by nutrients
and other pollutants. Excessive loadings of nutrients such as nitrogen and
phosphorus may promote eutrophlcatlon and the growth of algal mats in the
estuary, which Is undesirable from both aquatic use and aesthetic stand-
points. On the other hand, these nutrients are beneficial to the main-
tenance of plant life 1n the wetland.
Another Important function of a wetland 1s to reduce peak streamflow dis-
charges Into the estuary during wet weather periods. To the extent that
this peak flow attenuation prevents abrupt changes 1n salinity, the flora
and fauna of the estuary are protected. It has been common practice to
straighten existing channels and cut new channels In wetlands to speed
drainage and enable the use of wetlands for agriculture or other develop-
ment. Such channelization may diminish the protective functions of the
wetland and have an adverse Impact on the health of the estuary.
While the wetland may help to withhold nutrients In the form of nitrogen
and phosphorus from the estuary, 1t serves as a major source of nutrients
1n the form of detritus. A substantial portion of dead plant material In
the wetland 1s transported to the estuary as detritus. Detritus fs a basic
fuel of the estuary, serving as the main source of nutrient for filter
feeders and many fish at the bottom of the food chain. The estuary is
highly productive, more so than the freshwater or marine environment,
because of this source of nutrients.
Since the alteration or destruction of wetlands may hold important impli-
cations for the health of the estuary, it is important during the course of
a water body survey to examine historical trends in the wetland acreage,
locations, and characteristics for clues which explain changes 1n the
estuary and its uses. The extent to which wetlands have been irreversibly
altered may establish bounds on the uses that might be expected. Converse-
ly, restoration of wetlands may provide some means of restoring uses pro-
vided that other conditions such as toxic or nutrient loadings are not a
problem, or some other irreversible change has not been made to the
estuary.
HYDROLOGY AND HYDRAULICS
There are two Important sources of freshwater to the estuary-streamflow and
direct precipitation. In general, streamflow represents the greatest con-
tribution to the estuary and direct precipitation the smallest.
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The location of the salinity gradient In the river controlled estuary 1s to
a large extent an artifact of streamflow. The location of salinity 1so-
concentratlon lines may change considerably, depending upon whether stream-
flow 1s high or low. This 1n turn may affect the biology of the estuary,
resulting 1n population shifts as biological species adjust to changes 1n
salinity.
Most species are able to survive within a range of salinity levels, and
therefore most aquatic uses may not be adversely affected by minor shifts
1n the salinity gradient. Most of the biota can also sustain temporary
extreme changes 1n salinity, either by flight or through some other mechan-
ism. For example, molluscs may be able to withstand temporary excursions
beyond their preferred salinity range by simply closing themselves off from
their environment. This 1s Important to their survival since the adult 1s
unable to relocate 1n response to salinity changes. However, molluscs can-
not survive this way Indefinitely.
Generally speaking, the response of a stream or estuary to rainfall events
depends upon the Intensity of rainfall, the drainage area affected by the
rainfall and the size of the estuary. Movement of the salt front 1s depen-
dent upon tidal Influences and freshwater flow to the estuary. Variations
1n salinity generally follow seasonal patterns such that the salt front
will occur further down-estuary during a rainy season than during a dry
season. The salinity profile may also vary from day to day reflecting the
effect of Individual rainfall events, but may also undergo major changes
due to extreme meteorological events.
The location of the salt front 1n a small estuary may be easily displaced
but rapidly restored 1n response to a rainstorm, whereas the effect of the
same size storm on salinity distribution within a larger estuary may be
minor. For a large system, the contribution of a given storm may be only a
fraction of the overall freshwater flow and thus will have no appreciable
effect. For a small system the contribution of a given storm may be very
large compared to overall flow, and the system will respond accordingly.
A rapid Increase 1n flow may have several deleterious effects on a small
estuary: (1) the salinity gradient changes drastically, placing severe
stress on non-motile species and forcing the migration of motile forms, (2)
a sediment and pollutant load which 1s too large to be captured by sur-
rounding wetlands may be transported Into the estuary, and (3) the bottom
may be scoured 1n areas of high flow velocity, destroying floral and faunal
communities and existing habitat, and eliminating the conditions that would
be required for replacement communities to become established.
Major shifts In salinity due to extreme changes 1n freshwater flow are not
uncommon. An excellent example 1s the Impact of Hurricane Agnes on the
Chesapeake Bay 1n 1972. The enormous and prolonged Increase 1n freshwater
flow to the Bay shifted the salinity gradient many miles seaward and had a
devastlng effect on the shellfish population. The flow was so great that
salinity levels did not return to normal for several months, a period far
longer than non-motile species would be able to survive such radical reduc-
tions In salinity. In addition, the enormous quantities of sediment deliv-
ered to the Bay by Hurricane Agnes exerted considerable stress on the Bay
environment.
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Anthropogenic activity may also have a significant effect on salinity In an
estuary. When feeder streams are used as sources of public water supply
and the withdrawals are not returned, freshwater flow to the estuary will
be reduced, and the salt wedge found further up the estuary. If the water
is returned, usually 1n the form of wastewater effluent, the salinity grad-
ient of the estuary may not be affected although other problems might occur
which are attributable to nutrients and other pollutants in the wastewater.
Even when there is no appreciable change In annual freshwater flow or qual-
ity due to water supply uses, the salinity profile may still be affected by
the way In which dams along the river are operated. Flood control dams may
result in controlled discharges to the estuary rather than relatively short
but massive discharge during high flow periods. A dam which Is operated so
as to Impound water for adequate public water supply during low-flow per-
iods may severely alter the pattern of freshwater flow to the estuary. Al-
though annual input to the estuary may remain unchanged, seasonal changes
may have a significant impact on the estuary and its biota.
The discussion of hydrology, meteorology and the effect of hydraulic struc-
tures 1n this section provides only an overview of their possible effects
on the health of an estuary. Hydrologic Impacts will depend upon the uni-
que physical characteristics of the estuary and its feeder streams, In-
cluding structural activity that may have changed flow characteristics to
the estuary. Extreme rainfall events are particularly Important because
they may result In physical damage to wetlands and to the estuarine sub-
strate, and may subject the biota to abnormally low salinities as the salt
wedge is driven seaward. Extreme periods of drought may also have an ad-
verse Impact on the estuary. The operation of hydraulic structures -- dams
and diversions -- can significantly alter the characteristics and the uses
of an estuary. Clearly, these characteristics must be taken into account
in determining the attainable uses of the water body.
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CHAPTER III
CHARACTERISTICS OF PLANT AND ANIMAL COMMUNITIES
INTRODUCTION
Salinity, light penetration and substrate composition are the most critical
factors to the distribution and survival of plant and animal communities 1n
an estuary. This Chapter begins with an overview of the physical phenomena
and biological adaptations which Influence the colonization of the estuary.
Following this, specific Information 1s presented on Estuarlne Plankton
(phytoplankton and zooplankton), Estuarlne Benthos (Infaunal forms,
crustaceans and molluscs), Submerged Aquatic Vegetation, and Estuarlne
F1sh. There 1s also a short discussion of measures of biological health
and diversity. This last subject 1s presented 1n much greater detail 1n
the Technical Support Manual (U.S. EPA, November 1983).
The Information 1n this Chapter (and Its associated Appendices) has been
compiled to provide an overview of the types of habitat, ranges of
salinity, and life cycle and other requirements of plants and animals one
might expect to find 1n an estuary, as well as analyses that might be
performed to characterize the biota of the system.
With this Information having been presented as a base, discussion 1n
Chapter IV will be directed towards how the biological, chemical and
physical data descriptive of the estuary may be synthesized Into an
assessment of the present and potential uses of the estuary.
COLONIZATION AND PHYSIOLOGICAL ADAPTATIONS
The estuarlne environment Is characterized by variations 1n circulation,
salinity, temperature and dissolved oxygen supply. Due to differences 1n
density, the water 1s generally fresher near the surface and more saline
toward the bottom. Colonizing plants and animals must be able to withstand
the fluctuating conditions 1n estuaries. Rooted plants need a stable
substrate to colonize an area. Once established, the roots of aquatic
vegetation help to stabilize the sediment surface, and the stems Interfere
with and reduce local currents so that more material may be deposited.
Thus, small hummocks become larger beds as the plants extend their range.
The depth to which attached plants may become established 1s limited by
turbidity, since they require light for photosynthesis. Estuaries are
typically turbid because of large quantities of detritus and silt
contributed by surrounding marshes and rivers. Algal growths may also
hinder the penetration of light. If too much light 1s withheld from the
lower depths, animals cannot rely heavily on visual cues for habitat
selection, feeding, or In finding ? mate.
Estuarlne animals are recruited from three major sources: the sea,
freshwater environments, and the land. Animals of the marine component
have been most successful 1n colonizing estuarlne systems, although the
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extent to which they penetrate the environment varies (Green 1968).
Estuarlne animals that belong to groups prevalent In freshwater habitats
are presumed to have originated there. Such species comprise the fresh-
water component. The Invasion of estuaries from the land has been
accomplished mainly by arthropods.
When animals encounter stressful conditions 1n an estuary, they have two
alternatives: they can migrate to an area where more suitable conditions
exist, or 1f sedentary or sessile they can respond by sealing themselves
Inside a shell, or by retreating Into a burrow.
Most stenohallne marine animals can survive 1n salinities as low as
10-12 ppt by allowing the Internal environment (blood, cells, etc.) to
become osmotlcally similar to the surrounding water (McLusky 1981). Such
"conformers" often change their body volume. In contrast ollgohallne
animals actively regulate their Internal salt concentration. They do so by
active transport of sodium and potassium Ions (Na , K ). Osmoregulatlon
relies on several possible physiological adaptations. Reduced surface
permeability helps minimize osmotic flow of water and salts. In addition,
the animal's excretory organs serve to conserve Ions or water needed for
osmoregulatlon.
Upper and lower tolerance limits define a range between which environmental
factors are suitable for life (zone of compatibility). The adaptations of
these tolerance limits are referred to as resistance adaptations. In
estuaries, the major environmental factors to which organisms must adjust
are periodic submersion and desiccation as well as fluctuating salinity,
temperature, and dissolved oxygen.
Vernberg (1983) notes several generalizations concerning the responses of
estuarlne organisms to salinity: (1) those organisms living 1n estuaries
subjected to wide salinity fluctuations can withstand a wider range of
salinities than species that occur 1n high salinity estuaries; (2) Inter-
tidal zone animals tend to tolerate wider ranges of salinities than do
subtldal and open-ocean organisms; (3) low 1ntert1dal species are less
tolerant of low salinities than are high intertidal ones; and (4) more
sessile animals are likely to be more tolerant of fluctuating salinities
than those organisms which are highly mobile and capable of migrating
during times of salinity stress. These generalizations reflect the
correlation of an organism's habitat to Its tolerance. Some estuarine
animals are able to survive 1n adverse salinities, provided that the stress
Is fluctuating, not constant. For example, Initial mortalities of the
oyster drill (Urosalplnx dnerea) were very high when exposed to constant
low salinity values. However, little or no mortalities occurred during ten
days of exposure to low fluctuating salinities. Tolerance limits may also
differ between larval and adult stages, as 1n the case of fiddler crabs
(Uca pug11 ator). Adults are able to survive extended periods of 5 ppt
salinity, while larvae cannot tolerate salinities below 20 ppt (Vernberg
1983). The salinity 1n which they were spawned may also Influence larval
responses.
Temperature also has an effect on salinity tolerances of organisms.
Generally, cold-water species can tolerate low salinities best at low
temperatures and tropical species can withstand low salinities best at high
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temperatures. The previous thermal history of an organism Influences Its
resistance to temperature extremes. Acclimation to higher salinities can
also broaden an organism's zone of compatibility for temperature.
The transport of oxygenated surface water to the bottom is greatly In-
hibited when an estuary 1s stratified. In addition, the solubility of
oxygen 1n water 1s suppressed by salinity, so that estuarine DO levels at a
given temperature may not be as high as would be seen 1n freshwater. As a
consequence, many estuaries exhibit consistently low DO levels in the lower
part of the water column, and may become anoxlc at the bottom. This con-
dition may be exacerbated by benthlc DO demand. Many estuarine organisms
must be tolerant of low DO. Those that are able will leave to seek areas
of sufficient dissolved oxygen, while others (such as bivalves) will
respond by regulating metabolic activity to levels that can be supported by.
the ambient DO concentration.
Intertldal organisms experience alternating periods of desiccation and
submersion. These animals, mainly molluscs, are able to resist desiccation
because of morphological characteristics that aid 1n controlling water
losses. Others burrow Into the moist substrate to avoid prolonged exposure
to the air. Small animals with high ratios of surface area to volume are
less resistant to water loss than are larger organisms.
MEASURES OF BIOLOGICAL HEALTH AND DIVERSITY
Estuaries are characterized by high productivity but low species diversity.
Several authors have noted decreased species diversity 1n estuaries when
compared to freshwater or marine systems (Green 1968, McLusky 1971, McLusky
1981, Haedrich 1983). Two major hypotheses explain the paucity of
estuarine species. The first explanation is that of physiological stress
caused by variable conditions 1n estuaries (McLusky 1981). Plants and
animals must be able to withstand considerable changes 1n salinity, DO and
temperature. In addition, because of tidal variation, they may be sub-
jected to periods of desslcation. Variable salinities are especially
challenging to an organism's ability to osmoregulate. Because conditions
in estuaries are not stable, fewer species inhabit estuaries than inhabit
fresh or marine waters.
The second hypothesis explains decreased species diversity by the relative
youth of present-day estuaries (McLusky 1971, McLusky 1981, Haedrich 1983).
The estuaries that we see today probably did not exist several thousand
years ago. Since this is a short period relative to the same scale over
which spedatlon has taken place, few species have been able to adapt to
and colonize the estuarine system. An Investigation by Allen and Horn
(1975) of several small estuarine systems 1n the United States revealed
that a small number of species (<5) comprised more than 75 percent of the
total number of Individuals. Similarly, Haedrich (1983) noted that the
number of fish families characteristic of estuaries comprises only six
percent of the total number of families described.
Investigations of diversity 1n estuarine systems have employed the same
diversity Indices that are commonly used In freshwater systems (see U.S.
EPA, 1983J), Chapter IV-2). The Shannon-Wiener index 1s often employed in
conjunction with the two components that influence its value, a species
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richness index and a measure of evenness (McErlean 1973, Allen and Horn
1975, Hoff and Ibara 1977).
Because seasonal changes are so marked In estuaries, the selected diversity
Index should be sensitive to changes 1n species composition. Thus,
quantitative similarity coefficients and cluster analyses may be used to
determine the extent of similarity between samples. Such measures are
discussed in Chapter IV-2 of the Technical Support Manual: Waterbody
Surveys and Assessments for Conducting Use Attainability Analyses (U.S.
EPA, 1983b).
An equal effort should be expended at each sampling station each time
sampling is done. The results of a fish fauna survey may be biased by the
sampling method employed. For example, the gear used (trawl, gill net,
trap net, seine), the mesh size and the area 1n which fishing occurs
determine the sizes, numbers and kinds of fish caught (McHugh 1967,
McErlean 1973). Sampling gear and technique are also Important in benthlc
and planktonic investigations. Because of the many migratory organisms
found intermittently in estuaries, sampling should occur during each season
of the year.
A major concern in estuarine systems is biological change due to pollution,
especially alterations to commercially important populations. The ratio of
annelids to mollusks and annelids to crustaceans has been used as an
indication of environmental stress. By comparing these ratios to the
Contamination Index (C.) and the Toxlcity Index (T.), described in Appendix
A, areas highly contaminated by metals and organic chemicals can be
characterized (U.S. EPA, 1983a_).
Briefly, contaminant factors (C,) indicate the anthropogenic concentration
of individual contaminants, baled on metal content and S1/A1 ratios in
sediment. The Contamination Index (C.) is a sum of these contaminant
factors, giving equal weight to all metals, and thus has no ecological
significance until combined with blotoxicity data. The map of the
Chesapeake Bay in Figure III-l illustrates the degree of metal
contamination based on C.. The Toxlcity Index (T.) is calculated using
contaminant factors and tPA "acute" criteria for the metals, I.e., the
concentration that may not be exceeded in a given environment at any time.
This index gives information pertinent to the toxicity of sediments to
aquatic life. Figure III-2 Illustrates the results of calculations of
Toxlcity Indices for the Chesapeake Bay.
The Toxlcity Index ranges from values of 1 to 20 where to lowest values
denote the least polluted conditions. Characteristics associated with
various values of T. may also be seen in Chapter IV, Table IV-3. The
Contamination Index Is based on the calculation of the quantity Cf (see
Appendix A) where Cf=0 when observed and predicted metal concentrations 1n
sediment are the same, Cf0 when the observea is greater than the predicted.
The juvenile index is often used to help predict future landings of certain
commercially Important fish 1n estuaries. The Juvenile index is simply the
number of first year fish of a species divided by the number of seine
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Figure III-l. Degrees of metal contamination in the Chesapeake Bay based
on the Contamination Index (C,). (from USEPA 1983O
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Fiaure III-2.Toxicity Index of surface sediments in Chesapeake Bay.
(from USEPA 1983c)
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hauls. This Index Is then compared to juvenile Indices from previous years
along with commercial fisheries landings data.
In summary, species diversity 1n estuaries 1s generally lower than In
adjacent freshwater or marine ecosystems. Either the changing environment
or the youth of estuaries or perhaps a combination of both 1s responsible
for this lack of species diversity. Indices of diversity that are used In
estuaries are the same as those employed 1n freshwater studies and have
been summarized 1n a previous document (U.S. EPA, 1983j>).
ESTUARINE PLANKTON
Plankton Include weak swimmers and drifting life forms. Most planktonlc
organisms are small 1n size, and although they may be capable of localized
movement, their distribution 1s essentially governed by water movements.
Because of their unique salinity conditions and currents, individual
estuaries have characteristic plankton populations.
Phytoplankton
Three principal groups are Included 1n the phytoplankton. They are
diatoms, dlnoflagellates and nanoplankton. Like the phytoplankton of
freshwaters and oceans, estuarlne phytoplankton require nutrients (such as
phosphorus, nitrogen, silicon), vitamins, Iron, zinc and other trace metals
for growth. For photosynthesis to occur, adequate light must be available.
Suitable salinities must also be present for phytoplankton populations to
survive.
Nutrients generally are abundant in estuaries. Seasonal fluctuations in
nitrogen and phosphorus levels are often evident, and are related to
overland runoff and fertilizer application to agricultural lands. External
sources are not entirely responsible for nutrient levels 1n estuaries.
Cycling within estuaries also plays a role 1n plankton productivity. Thus
the turnover, or replenishment time (R), of nutrients is significant 1n
determining their availability. Replenishment time Is defined as R =
[S]/Sp, where [S] 1s the concentration of the nutrient in the phytoplankton
and Sp is the dally production rate measured in terms of partlculate
content of that nutrient 1n the phytoplankton (Smayda 1983). Recycling
mechanisms may be separated Into (l) excretion of rem1neral1zed nutrients
accompanying grazing by herbivorous zooplankton or benthic organisms, (2)
release through sediment rolling and diffusive flux of nutrients from the
interstitial water of sediments following microbial remlneralization, and
(3) kinetic, steady-state exchanges between nutrients present in the
partlculate phase (phytoplankton, bacteria, sedimentary particles) and in
the dissolved phase. The importance of each of the preceding mechanisms 1s
dependent upon characteristics, viz. depth and vertical mixing, of specific
estuaries.
Although the phytoplankton of estuaries 1s an Integral part of the eco-
system, Its role is somewhat less Important than in marine or freshwater
lake ecosystems. This 1s due partly to the large quantities of detritus
and bacteria that serve as an alternative food source for many primary
consumers. Estimates of primary production are generally calculated from
III-7
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the utilization of nutrients (phosphates, C uptake, chlorophyll con-
centration) (Perkins 1974). The phytoplankton contribution to primary
productivity Is often minimal 1n many coastal plain estuaries. Although
nutrients are abundant there, other factors limit phytoplankton production.
At the compensation depth, the amount of oxygen produced by photosynthesis
1s equal to the amount utilized 1n respiration. Because of high tur-
bidity, the compensation depth In estuaries 1s relatively shallow thus
limiting the volume of water 1n which positive production occurs. Several
authors maintain the Importance of phytoplankton In supporting estuarlne
food webs, although the degree of contribution 1s controversial. Boynton,
et al. (1982) provides a review of factors affecting phytoplankton pro-
duction by comparing numerous estuarlne systems.
The flushing time of an estuary also affects the phytoplankton population.
Many estuaries have a relatively long flushing time and stable populations
are able to develop. The Columbia River estuary has a stable system with a
gradation from freshwater to brackish to marine plankton. In contrast, the
Margaree River (the Gulf of St. Lawrence) 1s drained completely at low
water and has no such gradation. Thus, high tide populations are typically
marine, while a freshwater population 1s evident at low tide.
The species composition of an estuary may be unique. Narragansett Bay for
example, 1s a shallow, well-mixed estuary located on the northeastern coast
of the United States. Surface salinity ranges from 20.5 ppt near river
mouths to 32.5 ppt at the mouth of the bay. Flushing time of the bay 1s
estimated at thirty days (Smayda 1983). Because of tidal and wind-Induced
mixing, most of Narragansett Bay has neither a well-defined halocllne or
thermocllne. Seasonal variation of plankton 1s evident, although the
diatom Skeletonema costatum represents about 80% of total numerical
abundance over the annual cycle (Smayda 1983). The major phytoplankton
bloom occurs during December, coinciding with the minimum Incident
radiation and length of day. Blooms are regulated by temperature, light,
nutrients, grazing, hydrographlc disturbances and possibly species Inter-
actions. Neither blue-green algae nor dlnoflagellates are Important In
Narragansett Bay due to Its relatively high salinity. Planktonlc blue-
green algae tend to be more Important 1n reduced salinities. Dlno-
flagellates (viz. Prqrocentrum trlangulatum, Perldlnlum trpchpldeum,
Massartla rotundata, 011sthod1scus~Tuteus) occur sporadically during the
summer months, although diatoms continue to predominate. A succession of
diatom species occurs seasonally, although Skeletonema 1s prevalent during
all months. Detonula confervacea and Thalassloslra nordenskloeldll,
Important secondary species during the winter-spring bloom, are replaced by
Leptocyllndrus danlcus. L^. minimus, Cerataul1na pelaglca, Asterlonella
Japonlca. and Rhlzosolenla fraglllsslma.
Phytoplankton In the Naveslnk River, New Jersey, were studied by Kawamura
(1966). Based on salinity, several zones with characteristic phytoplankton
were defined. Euglenolds dominated below 20 ppt. The zone 1n which
salinity lay between 20 and 22 ppt was populated by Rhlzosolenla.
Cerataul 1na bergonll dominated 1n salinities ranging from 22 to 25 ppt.
Dlnoflagellates,Tncludlng Perldlnlum conlcoldes. P. trocholdes, and
Glenodlnlum danlcum, were prevalent In the outer regTon of the estuary.
Open water beyond the mouth of the estuary was populated mostly by
Skeletonema costatum. For regions with a fairly stable salinity gradient,
Kawamura C1966) noted the dominant forms as presented 1n Table III-l.
III-8
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TABLE III-l. DOMINANT PHYTOPLANKTON IN DEFINED SALINITY REGIONS
Salinlty Dominant Forms
2-5 ppt Anabaenopsis sp., Microcystis sp..
Synedra ulna. Melosira van'ans.
9-10 ppt Anabaena flos-aquae. Helpsira varlans,
Chaetoceros sp., Biddulphia spp.,
Cosdnodfscus sp.
16 ppt Euglenoids
20 ppt Melosira varlans, Chaetoceros deblUs,
D1ty1um"brlghtweni, Perldlnlans.
24-31 ppt Skeletonema costaturn, Rhlzpsolenia
longtseta, Biddulphia aurita,
DTtylum brightwem, Dinophyceans.
from Kawamura (1966).
Zooplankton
Zooplankton commonly found In estuarlne reaches have been divided Into the
following groups based upon thel- origins and salinity tolerances: (1)
Marine Coastal species, (2) Estuarlne, and (3) Freshwater. One of the
dominant copepods 1n estuaries 1s Acartia tonsa. Although 1t 1s not
utilized directly by humans, A. tonsa Is a major food source for fish or
Invertebrates that are consumed by numans (Jones and Stokes Assoc. 1981).
Several surveys of the zooplankton 1n Narragansett Bay have been conducted
and are summarized In Miller (1983). Copepods were the dominant group,
comprising 80% or more of the Individuals on an annual average. Important
species were Acartla clauslI, A^ tonsa, Pseudocalanus mlnutus and Olthona
spp. Rotifers were abundant In late winter, and cladocerans were abundant
In early summer. Flushing reaches a peak in March-April, coinciding with a
low in blomass.
Zooplankton have also been studied extensively in the Chesapeake and
Delaware Bays, resulting In the following list of predominant species:
(1) Coastal:
copepods - Centropages typicus, C_. hamatus, Labidocera aestiva,
Temora iongfcornl s, _Paraca1anus parvus, Pseudo-
calanus mlnutus;
cladocerans - PenlUa avlrostrls, Evadne nordmanni.
(2) Estuarine:
copepods - Acartla tonsa, Acartla clausi, Eurytemora affinis,
Scottolana canadensls (harpacticoid), and Pseuo'o1
diaptomus coronatuT;
III-9
-------
cladocerans - Podon polyphemoides.
(3) Freshwater:
copepods - Cyclops vlrldis;
cladocerans - Bosmina longlrostrls.
Grazing by zooplankton is an Important factor 1n the control of phyto-
plankton populations, although the precise role played Is not yet well-
defined. The population dynamics of zooplankton on the east coast,
Including seasonal cycles and predatlon by ctenophores, 1s covered
extensively by Miller (1983). Ctenophores have not been observed In
Yaquina Bay, Oregon, and It Is probable that fish predators limit
zooplankton densities.
Comparatively less information is available on Gulf coast zooplankton
distributions than for the Atlantic coast. Some references for zooplankton
community structure and distributions In Louisiana estuaries and coastal
waters are: Brice, 1983; Blnford, 1975; Cuzon du Rest, 1963; Drummond,
1976; Gillespie, 1971.
Planktonlc larval forms of organisms such as oysters and crabs are Included
in the temporary zooplankton. The veliger larvae of molluscs become part
of the plankton during the spring and summer. Some estuarine worms also
have planktonic larval forms. The occurrence of these forms is governed by
the breeding season of the adults. Environmental tolerances of the larval
forms of the blue crab (Calllnectes sapidus) and the American oyster
(Crassostrea virglnica) are found In Appendix B (e,f).
To persist in an estuary, zooplankton, like phytopiankton, must have rates
of population increase at least equal to the rates of loss due to tidal
flushing and river flow. High flushing rates generally prohibit the
development of an endemic plankton population, and the plankton found
merely resemble those found 1n the ocean offshore. Studies of population
budgets have been made on a few estuaries (Narragansett Bay, Great Pond,
Moriches Bay) and are mentioned briefly by Miller (1983).
The following articles contain Information on methods in zooplankton
research: Computer and electronic processing of zooplankton (Jeffries
1980); Gear used (Schlndler 1969, Josal 1970); Sampling for blomass-
standing stock (Ahlstrom et al. 1969, Colebrook 1983, Tranter 1968);
Fixation and preservation of zooplankton (Steedman 1976); Icthyoplankton
(Smith and Richardson 1977).
ESTUARINE BENTHOS
Those organisms which live on or in the bottom of any water body are the
benthos. Plants such as diatoms, macroalgae and seagrasses comprise the
phytobenthos, while the zoobenthos includes the animals occupying this
habitat. The estuarine zoobenthos will be discussed in this section. The
zoobenthos is generally divided into macro-, melo- and mlcrobenthos.
Meiobenthos pass through a 1- or 2-mm sieve, but are larger than 100 urn;
111-10
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macro- and mlcrobenthos are respectively larger and smaller than melo-
benthos (Wolff 1983).
Although the diversity of the benthos 1n estuaries is low compared to other
ecosystems, benthic production Is relatively high. A high level of food
(detritus and plankton) and shallow depths contribute to the
characteristically high benthic production noted in estuaries. Detritus is
readily available to the benthos because it sinks through the shallow
water. In addition, waves and tidal currents promote resuspension of
particles, making them available to filter-feeders. The predominance of
relatively opportunistic species, with one or more generations per year,
results 1n a high turnover of blomass and thus high production. Macrofauna
have high blomass and low turnover times and hence have economic and
commercial value. Meiofauna, with low blomass and high turnover rate, play
an essential role as nutrient regenerators and food for higher trophic
levels (Tenore et al. 1977, Mclntyre and Murison 1973, Ajheit and Scheibel
1982).
Infaunal Forms
The benthos comprises invertebrates such as thread worms, bristle worms,
ostracods, and copepods as well as commercially Important species of
crustaceans and molluscs. Nematodes (Nematoda, thread worms) dominate the
shallow water melofauna of estuarine sediments. In addition to nematodes,
permanent meiofauna Include copepods, gastrotrichs, ollgochaetes, rotifers
and turbellarians. Juvenile macrofauna comprise the temporary meiofauna.
Generally, coarser sediments support a greater diversity of species than
finer estuarine sediments (Ferris and Ferris 1979). Polychaetes
(Polychaeta-.Annelida, bristle worms) are abundant 1n the soft bottom,
especially within the sediment of Intertldal mud flats.
Studies have used polychaete populations to characterize water bodies as
having healthy, polluted, or very polluted bottoms. The use of benthic
organisms as indicator species is well-documented for freshwater studies
whereas studies in the estuarine/marine environment are relatively few
(Reish 1979). Although the species composition in freshwater is different
than marine species composition, the concept of using benthic communities
as indicators of pollution remains the same. In estuarine systems,
polychaete species composition changes from zones characterized as healthy
to those classified as polluted. As shown in Table III-2, there is a
concurrent decrease In dissolved oxygen concentration, an Increase in the
organic carbon content of the soil, and a reduction in the number of
organisms until all species are absent (Reish 1979). However, the validity
of using polychaetes as indicator species has been questioned, since
polychaetes such as Capitella capitata, an opportunistic organism whose
presence has often been cited as an Indication of pollution, also occur in
pristine estuarine areas (Reish 1979). The following literature con-
tributions also pertain to the use of benthos as Indicators of pollution:
Sediment bacteria as indicators (Erkenbrecher 1980); Meiofauna as indi-
cators (Coull et al 1981, Raffaelli 1981, Warwick 1981); Macrofauna as
Indicators (Gray and Mirza 1979).
III-ll
-------
TABLE II1-2. SUMMARY OF BIOLOGICAL, CHEMICAL AND PHYSICAL CHARACTERISTICS
OF FIVE ECOLOGICAL AREAS OF THE LOS ANGELES-LONG BEACH HARBORS3'b.
/ Aiir \ i/*IMU\ tnHluih I. /Vhi/nri* hi»lloiit II. lurihim. Very ih'JIuirJ
( mtltffd I ltHl/14/ll /HIM* 1/lftJ'K fcltlfd < t'M/KMIIUI < tl/lllff'it himtmi.
< hurAlrrivlK Hrrrn nit* an Oi'Mi/tYu m lit tt/iiiii lifiMf/«*'i* , ttinttttit IHI jniiiuh
•-pflKTV IJ«CI4fCI
Hulyiluclcs 7 ^ S i |i
I >i\s4ilvril otypcn
Sujljitr ft I) * S ^ S is | ^
III ll .tejxh Ml 1 ; I > 15 > j
ptl niirJuni
Suslu«» 7 ? ) .' 7 • 7 ( 71
Njlurt ul suhslrjd du> inu.1 Mjik Hljik NU||H!C iiiinl IH.uk -ullttlr inwl. Hljik sullnk niuJ Hl^k xullxir niuJ
I in <>( Jr i ul iiiinl |i|*k (,'ljy iljy. sjml. |;u) i b) . M*.lV
•.ulfiJc mod jnd niuJ. N*l niuJ mixl
. LJituMi ui M i ii : 7 : 7 14
\ijit ft i
IllMH
(from Reish 1979)
111-12
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Crustaceans
Crustaceans Include microorganisms such as ostracods., copepods and isopods
along with commercially important macroorganisms such as crabs, shrimp and
lobsters. The crabs (Arthropoda:Crustacea:Decapoda:Brachyura) that have
successfully colonized North American estuarine systems are listed in Table
III-3. Brachyuran crabs have a complex ontogeny. They are released from
the female as zoeae, or free swimming larvae, Into meso- to euhallne
waters. The zoeae undergo a series of molts before reaching the megalopa
stage. The megalopa metamorphoses into the first crab stage, which becomes
the adult following successive molts (Williams and Duke 1983). It has been
noted that above and below the preferred temperature range, the length of
time required for larval development increases. Two species of Cancer that
have commerical value, C^ magister (Pacific Dungeness crab) and C.
Irroratus (Rock crab), normallyenter estuaries only 1n high salinity
regions. Larvae of C. magister and C. irroratus prefer conditions of 25-30
ppt, 10-13°C and 23.1^32.5 ppt, 13°-2T°C, respectively.
CalUnectes sapidus, the blue crab, supports a major fishery in the United
States. Th~e species lives 1n fresh water to salinities as high as 117 ppt
(large males have been recorded 1n salt springs over 180 miles from the sea
in Marion County, Florida) and from the water's edge to 35 meter depths.
Appendix B (Table le) contains information pertaining to the life cycle of
the blue crab. Additional Information on general life histories of crabs
and other commercially Important shellfish 1n Gulf Coast waters 1s compiled
by Benson (1982). The family Portunidae is also represented by Carcinus
maenas in estuaries. The green or shore crab normally inhabits waters
ranging in salinity from 10-33 ppt, and depths of less than 5-6 m (Williams
and Duke 1979). Other crabs commonly found in North American estuaries are
listed in Table III-3. Among the xanthid crabs, only Menippe mercenaria,
the stone crab, has any fishery value. The major commercial fishery for
stone crabs occurs in Florida, where its flesh 1s considered a delicacy.
Most of the information about shrimp pertains to the commercially valuable
penaeid shrimp, Penaeus duorarum (pink shrimp), Penaeus aztecus (brown
shrimp) and Penaeus setiferus (white shrimp). Penaeid shrimp are dependent
upon estuaries durfng their transformation from the postlarval stage to the
juvenile stage. Adults migrate from the estuarine environment to coastal
and nearshore oceanic waters (Couch 1979). The life cycle of the penaeid
shrimp is illustrated in Figure III-3. The range of the brown shrimp
extends from Martha's Vineyard, Massachusetts, through the Gulf of Mexico
to the Yucatan Peninsula, Mexico (Turner, 1983). Brown shrimp spawn 1n
offshore marine waters deeper than 18 m (59 ft). Movement of postlarvae
into estuaries has been observed from January through June in Louisiana. A
peak migration from March to April was noted for Galveston Bay, Texas.
Postlarval brown shrimp prefer salinities of 10 to 20 ppt, and temperatures
above 15°C. Transformation from postlarvae to juveniles occurs four to six
weeks after entering the estuary. Juveniles remain in shallow estuarine
areas (near the marsh-water or mangrove-water interface or in seagrass
beds) that provide feeding habitat and protection from predators until they
reach 60 to 70 mm (2.4 to 2.8 inches) total length (TL). They move into
deeper, open water, and begin gulfward migration when they reach 90 to 110
mm (3.5 to 4.3 Inches) (Turner and Brody, 1983).
111-13
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TABLE III-3.
TAXONOMIC POSITION AND HABITAT OF DECAPOD CRUSTACEAN
SPECIES, INFRAORDER BRACHYURA, OF CONCERN IN ESTUARINE
POLLUTION STUDIES.
Taxon
Habitat
Infnorder Brachyura
Section Cancrtdea
Family Cancnda*
Canctr irrorants Say. Rock crab
Cancrrmatititr Oana. Dunfencstcnb
Section Brachyrhyncha
Superfamily Pominoidea
Family Poftunidae. Swimming" crab*
Subfamily Portvninae
Cailiitfcitt saputnj Rathburn. Blue
crab
Careinut ma* run iLinnaeui). Cratn
or ihorc crab
Superfamily XanthOKka
Family Xanthtdat
Subfamily Xanthinac. Mud crabi
Caialrptodmi I ~Ltp
-------
Figure III-3. Life Cycle of the Penaeid Shrimp, (from Couch 1979)
Postlarval white shrimp migrate Into estuaries from late spring to early
fall, and are most abundant 1n Louisiana estuaries from June through
September. They are generally found 1n lower salinity waters than brown
shrimp and prefer water temperatures higher than 15°C. White shrimp (120
to 140 mm) leave Gulf of Mexico embayments from September to December, as
the water cools.
Finally, the grass shrimp (Paleomonetes sp.) of estuaries commonly live in
patches of grasses growing In shallow water. Because of aquarium suita-
bility, members of palaemonldae are often used 1n pollution studies.
Molluscs
The last major group 1n the estuarlne benthos 1s the molluscs. The
molluscs Include clams, mussels, scallops, oysters and snails. Clams of
major Importance Include Mya arenarla (soft shell clam), Mercenaria
mercenarla (hard shell clam), and Rang1a~cuneata (brackish water clam).
111-15
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The soft shell clam Is common in bays and estuaries on both the east and
west coasts of the United States, although ft Is commercially Important
only on the east coast. Soft shell clams can tolerate a wide range of
salinities and temperatures. Larval development occurs at salinities from
16-32 ppt, and at temperatures of 17-23°C. Mya arenaria occurs In a
variety of substrates, but prefers a mixture of sand and mud (Jones and
Stokes Assoc. 1981). Hard clams (Mercenaria mercenarla) can tolerate high
pollution and low oxygen levels; thus,tKey thrive where other species
cannot compete. Hard clams prefer substrates of sand or sandy clay
(Beccaslo et al. 1980). The llttleneck clam (Protothaca staminea) is a
hardshell species found in estuaries, bays and open coastlines along the
Pacific coast. It ranges from the Aleutian Islands to Socorro Island,
Mexico. Minimum salinity for survival is 20.0 ppt (Rodnlck and L1 1983).
The brackish water clam is found in low salinity bays and estuaries from
the Chesapeake Bay to Mexico (Haven 1978). Rangia cuneata can survive in
fresh water, but needs brackish water for spawning (Menzel 1979).
The bay mussel (fly til us edulis) 1s found worldwide in estuaries and bays.
It is tolerant of variations In temperature, salinity and dissolved oxygen.
Although the bay mussel 1s under stress at salinities less than 14-16 ppt,
it can survive at 4 ppt for short periods of time. This mussel attaches to
any hard substrate and may be found on rocks, stones, shingles, dead
shells, ship bottoms, piers, harbor walls and compacted mud and sand (Jones
and Stokes Assoc. 1981).
Bay scallops (Argopectin irradlans) are usually found 1n shallow estuarlne
eelgrass beds, but may occur In depths to 18 m (Beccaslo et al. 1980).
They ingest detritus, bacteria and phytopiankton. The large amount of
detritus consumed reflects its great avail ability 1n estuarlne systems
(McLusky 1981).
The American oyster (Crasspstrea virglnica) is a permanent resident of
estuaries. It is a valuable component of east coast fisheries. Oysters
prefer salinities between 14.1 ppt and 22.2 ppt, although they are able to
tolerate a wider range, from 4-5 ppt to 35 ppt (Castagna and Chanley 1973).
Within the range of distribution of C_._ virglnica. the species lives in
water temperatures from about 1°C (during the winter In northern states) to
about 36°C (in Texas, Florida, and Louisiana) (Galtsoff 1964). Larvae
develop well in depths from 2 to 8 meters at temperatures of 17.5 to
32.2°C. The oyster population in high salinities 1s limited by oyster
drills (e.g. gastropod Urosalplnx cinerea) and parasites (MSX and
Dermocystidium) (Haven 1978). Spawning by oysters is dependent upon
temperature, and commences when the water reaches from 16-28°C depending
upon geographic area (Bardach et al. 1972, Ingle 1951). After 6-14 days,
the eggs hatch and the free-swimming larvae settle on a suitable hard
substrate. Oysters filter food from the water column and deposit organic
material (feces and pseudofeces) which 1s then available to other benthic
organisms; thus, they play a valuable role in increasing the productivity
of the area in which they live (McLusky 1981).
Temperature tolerances of American oysters differ with latitude. Oysters
at latitudes north of Cape Hatteras can survive at temperatures less than
0°C for 4 to 6 weeks, while Gulf of Mexico oysters die if subjected to such
low temperatures (Cake 1983). Temperatures required for mass spawning also
111-16
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differ with latitude. Apalachlcola Bay reached temperatures of 26-28°C
before mass spawning occurred, while a low of 16.4°C Induced mass spawning
1n Long Island Sound, New York (Ingle 1951). Other oyster species commonly
found 1n estuaries of the United States are Crassostrea glgas (Pacific
oyster) and Ostrea edulls (flat oyster).
Snails (Gastropoda) have not been studied as extensively as the molluscs
discussed above. In general, adult snails are slow moving, benthlc, and
able to endure a variety of temperatures and salinities. After the eggs
are hatched, most snails have a planktonlc stage; a few emerge as crawling
juveniles. Many snails are vegetarians and scrape algae from surfaces.
Some carnivorous snails use their radulas to drill holes In other shelled
animals (e.g., oyster drills). Other snails consume gastropods whole,
digesting the tissue and regurgitating the empty shells (Menzel 1979).
More information about the distributions and habitats of NE Gulf gastropods
is described in Heard (1982).
References on methodology for the study of estuarine mlcroblota and benthos
Include: Holme and Mclntyre 1971, Hullngs and Gray 1971, U.S. EPA 1978,
Uhlig et al. 1973, de Jonge and Bouman 1977, Federle and White 1982, White
et al. 1979, Montagna 1982.
In conclusion, the estuarine benthos play an Important role 1n estuarine
ecosystems. The nematodes and polychaetes, along with the commercially
Important shellfishes, contribute to the high productivity noted 1n most
estuaries. The benthos are generally able to tolerate variations In
temperature and salinity. Thus, they are able to live, and often thrive,
in estuaries.
SUBMERGED AQUATIC VEGETATION
Submerged aquatic vegetation (SAV) plays an Important role in the estuarine
ecosystem, providing habitat, substrate stability and nourishment. These
functions are the subject of discussion 1n this section. However, sub-
merged aquatic vegetation also provides a valuable frame of reference
against which to assess the health of an estuary, or portion of an estuary.
The Importance of SAV to an analysis of the uses of an estuarine waterbody
will be discussed further in Chapter IV, Interpretation.
Role of SAV in the Estuary
Plants increase the stability of bottom sediments and reduce shoreline
erosion. In addition, because the plants help to slow the tidal current,
more materials may settle from suspension, augmenting the substrate and
decreasing turbidity. Species differ in their ability to reduce turbidity.
For example, areas dominated by Potamogeton perfoHatus (a highly branched
species) were more Instrumental 1n Improving water clarity than areas where
Potamogeton pectlnatus (a thin-bladed single leaf species) dominated
IBoynton et a1. 1981).
Aquatic plants serve as both sources and sinks for nutrients. During the
growing season, SAV absorbs nutrients from the water and sediments.
Release of nutrients occurs when the vegetation dies. Submerged aquatic
vegetation also provides valuable habitat for fish and crabs, along with
111-17
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molluscs and other eplfauna. SAV provides shelter, spawning areas and
shade for fish, while roots, stems and leaves provide firm bases for the
attachment of mussels, barnacles, molluscs and other eplfauna. Thus,
vegetated bottoms exhibit a greater species richness than unvegetated
bottoms (U.S. EPA 1982).
Stevenson and Confer (1978) cited a study (Baker 1918) which emphasized the
large number of organisms associated with submerged aquatic vegetation.
Over a 450 sq. mile area, Potamogeton sp. harbored 247,500 molluscs and
90,000 associated animals (total fauna, 337,500) and Myrlophyllum sp.
harbored 45,000 molluscs with 56,250 associated animals (totalfauna,
101,250). Epiphytes and macroalgae constitute a significant and sometimes
a dominant feature of SAV community production and blomass, as can be seen
from Table III-4. F1sh such as sllversldes (Menidia menid1a). foursplne
stickleback (Apeltes quadracus) and pipefish(Syngnathus fuscus) take
advantage of this abundant eplfauna for food.
Eelgrass beds also provide protection for amphipods from predatory flnflsh.
Grass shrimp (Palaeomonetes puglo) seek protection from predatory kHHflsh
(Fundulus heteroclitus)Tn~ eel grass beds. Young and molting crabs find
shelter In areas of submerged aquatic vegetation as well.
Aquatic vegetation enters the food chain though grazing by waterfowl or as
detritus passing through epifaunal and infaunal invertebrates to small and
large fish. The extent to which SAV 1s used as a food source Is determined
mainly by two methods. The first is direct visual Identification of mate-
rial In an organism's digestive system. Such analyses are time-consuming,
and the degree to which food items can be identified is often limited to
largcc Uys that are resistant to digestion. The second techlque 1s based
on C :C ratios 1n plants and associated predators. This method assumes
that animals feeding on a particular plant will, 1n time, reflect the food
source ratio. Problems arise wheAarUpals feed on a variety of species, or
if several plants have similar C :C ratios. In addition, determination
of C :C ratios 1s a relatively expensive procedure.
Submerged aquatic vegetation also plays a role in nutrient cycling in
estuaries. Since plants act as nutrient traps and sinks for dissolved
minerals, SAV communities are capable of removing nutrients from the water
column and incorporating them into blomass. Iron and calcium were found to
be absorbed from the sediment by Myrlophyniim spicatum. The release of
nutrients and minerals occurs by excretion by living plants or by the death
and decomposition of SAV.
Distribution of SAV
The distribution of SAV species is determined largely by salinity. The
degree of flooding also affects vegetation distribution and is particularly
Important for Gulf Coast estuaries (Sasser 1977). In a study of the
Chesapeake Bay, Steenls (1970, cited by Stevenson and Confer 1978) noted
the following tolerance levels for Bay vegetation:
111-18
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-2 -1
TABLE 111-4. DATA FROM SELECTED SOURCES INDICATING THE PARTITIONING OF (a) PRODUCTION (Pa), gCni ~y
AND (b) BIOMASS gni (ORGANIC) BETWEEN VARIOUS AUTOTROPHIC COMPONENTS OF SAV COMMUNITIES
a. Location Species Seagrass tpiphytes
Florida Thalassia
Mass. Zostera
Calif. Ruppia
N.Carolina Zoatera
Ches. Bay Zoatera
P.pectinatua
P.perfoliatus
Dally estimates In aui
b. Location Species
Europe Cymodocea
Alaska Zoatera
Kinzarof
Klawak
Others
N.Carolina Zostera
Ches. Bay P.pectlnatus
P.perfoliatus
1000
28
330
0.48
0.5-2.2
1-3.0
•»er period
Seagrass
400-700
1500
415
113
80
20-60
20-80
200
20
73
0.17
•
Epiphytes
•MM.
25
0.1-0.6
0.1-0.6
Bentldc micro-algae Macro-algae Phytoplankton Reference
Jones 1968
Marshall 1970
— ^o/ yi Uetcel 1964
Penhale 1977
-0.05 — 0.09 Hurray (pers.c
0.3-1.0 Kauaeyer et al
0.5-1.0 Kaiweyer et al
Benthic alcro-algae Macro-algae Phytoplankton Reference
375 Gessner and Ha
1960
393 McRoy 1970
29
2.4
Penhale 1977
Staver et al.
Staver et al.
OBO.)
. 1981
. 1981
mmer
1981
1981
(from USEPA 1982)
111-19
-------
3 ppt
Najas guadalupensis (southern naiad)
3-5 ppt
Chara spp. (muskgrass)
ValHsnerla amerfcana (wildcelery)
12-13 ppt
El odea canadensis (el odea)
Myrfophyllum splcatum (Eurasian watermilfoil)
Ceratopny'Tlum demersum (coontail)
20-25 ppt
Potamogeton perfol1atus (redhead grass)
Potamogetpn pectinatus (sago pondweed)
Zannlchenia palustrls (horned pondweed)
over 30 ppt
Ruppia marltima (widgeongrass)
Zostera marina"(eel grass)
The depth at which vegetation is able to survive is directly related to the
penetration of incident radiation. Plants need light for photosynthesis,
therefore turbidity affects their distribution by decreasing the amount of
sunlight reaching greater depths. Temperature also affects the distribu-
tion of SAV, and exerts considerable influence upon its vegetative growth
and flowering. These factors are considered in more detail in Appendix C
for several east-coast species.
Three associations of submerged aquatic vegetation were described for the
Chesapeake Bay, based on their co-occurrence in mixed beds. The first
association tolerates fresh to slightly brackish water (upper reaches of
the Bay) and includes bushy pondweed, coontail, el odea (waterweed), and
wildcelery. The middle reaches of the Bay have associations of widgeon-
grass, Eurasian watermllfoll, sago pondweed, redhead grass, horned
pondweed, and wildcelery. Finally, in the lower reaches of the Bay,
eelgrass and widgeongrass predominate. The kinds of submerged aquatic
vegetation encountered in the Chesapeake Bay from 1971 to 1981 are listed
in Table III-5.
The major species of SAV found on the eastern coast of the United States
(their distribution, environmental tolerances and consumer utilization) are
listed in Appendix C. The species that are especially important as food
Items for waterfowl are coontail, muskgrass, bushy pondweed, sago pondweed,
redhead grass, widgeongrass and wildcelery. Grazing by waterfowl is a
primary force in the management of aquatic vegetation. Some aquatic
vegetation, although it provides protective cover for wildlife, is con-
sidered a nuisance because of excessive growth and clogging of waterways.
Elodea, Eurasian watermllfoll, and sago pondweed are among those considered
to be pest species.
Information concerning aquatic vegetation In southern U.S. estuaries is
found In literature by Chabreck and Condrey 1979, Beal 1977, and Correll
and Correll 1972.
111-20
-------
TABLE 111-5. A LISTING OF THE SUBMERGED AQUATIC VEGETATION ENCOUNTERED
IN THE CHESAPEAKE BAY FROM 1971 TO 1981.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
Species
Redhead grass (Potamogeton perfoliatua)
Widgeongraaa (Ruppia maritimal
Eurasian vatermilfoil (Myriophyllum epicatum)
Eelgrass (Zosters marina)
Sago pondweed (P. pectinatua)
Horned- pondveed (Zanichellla palustris)
Uildcelery (Valliineria amerlcana)
Common elodea (Elodea canadenaia)
Naiad ( Naj aa guadalupensis)
Muskgraaa (Chara app.)
Slender pondweed (P. puaillua)
Cooncail (Ceratophyllua deaeraua)
Unidentified fragment*
Curly pondweed (Potaaogeton criapua)
Sea lettuce (Ulva app.)
Agardhiella app.
Unidentified filamentous green algae
Unidentified green algae
Gracilaria app.
Uater-atargraaa (Heteranthera dubia)
Unidentified alga
Enteromorpha app.
Ceraaiua
Polyaiphonia
Daaya app.
Unidentified red alga
Unidentified brown alga
Champ ia parvula
Vascular
Plants*
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Macro-
Algael
X
X
X
X
X
X
X
X
X
X
X
X
X
1 An "X" in the column indicates the type of SAV.
{from USEPA 1982)
111-21
-------
Adverse Impacts on SAV
Portions of the estuary may become enriched beyond their flushing and
assimilative capacity and elevated levels of nitrogen and phosphorus begin
to support abnormal algal growth and eutrophlc conditions. Algal growths
are Important because they act to diminish to penetration of sunlight Into
the water. Submerged aquatic vegetation 1s dependent upon sunlight for
photosynthesis, and when light penetration Is diminished too much by algal
growths, the SAV will be affected. These factors are discussed 1n detail
1n Chapter II.
Runoff may also Introduce herbicides to the estuarlne ecosystem. The
magnitude of detrimental effects depends upon the particular herbicide,
and Us persistence in the environment and potential for leaching.
Furthermore, several herbicides have a synerglstlc effect along with
nutrients, its potential for leaching and persistence In the environment.
Several pathogens may attack and diminish the size of submerged aquatic
vegetation beds. Rhlzoctonia solani 1s a fungus that attacks the majority
of duck food plants, but Is especially pathogenic to sago pondweed
(Stevenson and Confer 1978). Lake Venice Disease causes a gradual wasting
away of the host plant; it is manifested as a brownish, silt-like coating
on leaves and stems. Milfoil is attacked by the Northeast Disease, which
gradually causes the leaves to break off, leaving a blackened stem.
Survey Techniques
Aerial, surface and subsurface methods are used to prepare maps delineating
vegetation types and percent cover. Plant growth stage {e.g. season) is
critical when planning a plant survey. For example, early summer is the
optimum time of year to record maximum plant coverage in the Chesapeake Bay
but a different time of year may be more appropriate in other parts of the
Country. Water transparency 1s also Important to show plant growth.
Aerial methods are useful in determining the distribution of plant assoc-
iations, irregular features, normal seasonal changes and perturbations
caused by pollutants. Mapping cameras are designed to photograph large
areas without distortion. Areas of SAV beds may be derived from topo-
graphic quadrangles (Raschke 1983). The Earth Resources Observation System
(EROS) Data Center may be used to obtain listings and photographs already
available for a particular area.
Surface or ground maps can be prepared 1f the area 1s relatively small.
Distances can be determined by ruled tapes, graduated lines, range finders,
or, 1f more accuracy 1s required, surveyor's tools. Field observations of
species may be supplemented by photographs. Divers can mark subsurface
beds with bouys to facilitate determination of bed shapes and areas from
the surface.
Regional surveys of flora give qualitative Information, based upon visual
observation and collection of plant types. To obtain more quantitative
information, line transects, belt transects, or quadrats may be employed
(Raschke 1983). Use of line transects Involves placement of a weighted
nylon or lead cord along a compass line and recording plant species and
linear distance occupied. A belt transect can be treated as a series of
quadrats, with each quadrat defined as the region photographed from a
111-22
-------
standard height or a marked area. The technique of sampling within a
quadrat or plot of standard size 1s applicable to shallow and deep water.
Where visibility 1s poor, eplbenthlc samplers can be used.
A fundamental characteristic of the community structure of submerged
aquatic vegetation is the leaf area Index (LAI). It 1s defined as the
amount of photosynthetlc surface per unit of biomass (U.S. EPA 1982). The
photosynthetlc area is measured by obtaining a two-dimensional outline of
the frond, and determining the area with a planlmeter. Leaf area Index
differences demonstrate the Importance of light in regulating SAY
communities and their adaptability to different light regimes. The
greatest LAI values occur for mixed beds of Zostera and Ruppla; lower
values were found for pure stands of Zostera and Ruppla"(U.S. EPA 1982).
The Information presented here Is a brief overview of survey techniques
used in the sampling of SAV. Supplementary discussions are found in
literature by Kadlec and Wentz (1974), and Down (1983).
ESTUARIME FISH
Systems of Classification
Various authors have attempted to devise systems to classify estuarine
organisms. Because salinity is the most dominant physical factor affecting
the distribution of organisms, it 1s often used as the basis for classi-
fication systems. McLusky (1971, 1981) divides estuarine organisms into
the following categories:
1. Oligohaline organisms - The majority of animals living in rivers
and other fresh waters do not tolerate salinities greater than 0.1
ppt but some, the ol1gohal1ne species, persist at salinities up to
5 ppt.
2. True estuarine organisms - These are mostly animals with marine
affinities which live in the central parts of estuaries. Most of
them are capable of living in the sea but are not found there,
apparently because of competition from other animals.
3. Euryhallne marine organisms - These constitute the majority of
organisms living in estuaries with their distribution ranging from
the sea into the central part of estuaries. Many disappear by
18 ppt but a few survive at salinities down to 5 ppt.
4. Stenohallne marine organisms - These occur 1n the mouths of
estuaries at salinities down to 25 ppt.
5. Migrants - These animals, mostly fish and crabs, spend only a part
of their life in estuaries with some, such as flounder
(Platlchthys) feeding in estuaries, and others, such as salmon
(Salmo salar) or eels (Angullla anguilla) using estuaries as routes
to and from rivers and the sea.
111-23
-------
A similar scheme of classification, shown In Table III-6, was defined by
Recnane. Components of fauna are separated according to the sources from
which they arrived at their present-day habitat, e.g., from the sea, from
freshwater and from the land. Marine and freshwater components are further
divided based on salinity tolerances. The terrestrial component may be
subdivided Into those species which escape the effects of Immersion by
moving upwards when the tide floods the upper shore, and those species
which remain on the shore and are able to survive submersion for several
hours.
Day (1951, cited by HaedMch 1983) divided estuarlne fishes Into five
categories: freshwater fishes found near the head of the estuary,
stenohallne marine forms from the seaward end of the estuary, euryhallne
marine forms occurring over wide areas, the truly estuarlne fishes found
only 1n the estuary, and migratory forms that either pass through the
estuary or enter 1t only occasionally. A modified version of this
classification was presented by McHugh (1967). His categories were:
1. Freshwater fish species that occasionally enter brackish waters.
2. Truly estuarlne species which spend their entire lives 1n the
estuary.
3. Anadromous and catadromous species.
4. Marine species which pay regular seasonal visits to the estuary,
usually as adults.
5. Marine species which use the estuary primarily as a nursery ground,
usually spawning and spending much of their adult life at sea, but
often returning seasonally to the estuary.
6. Adventitious visitors which appear Irregularly and have no apparent
estuarlne requirements.
Day's classification of biota and the Venice System of dividing estuaries
Into six salinity ranges were combined by Carrlker (1967) to develop Table
III-7. The right half of the table shows the blotlc categories and the
approximate penetration of animals relative to salinity zones In the
estuary.
Salinity Preferences
Some freshwater fish species may occasionally stray Into brackish waters.
White catfish (Ictalurus catus) Is a salt-tolerant freshwater form found 1n
estuaries along the east coast of the United States. Three other species
that are primarily freshwater, but have been captured 1n higher salinity
areas are longnose gar (Leplsosteus osseus). blueglll (Lepomls macrochlrus)
and the flier (Centrarchus macropterus) (McHugh 1967).
Very few fish are considered to be truly estuarlne. McHugh (1967) mentions
only two species that he considers endemic to the estuarlne environment.
They are the striped kllHflsh (Fundulus majalls) and the skilletflsh
111-24
-------
TABLE III-6. SUMMARY OF THE COMPONENTS OF AN ESTUARINE FAUNA
1. MARINE COMPONENT
The stenohallne marine component, not penetrating below 30 ppt
The euryhaHne marine component
First grade, penetrate to 15 ppt
Second grade, penetrate to 8 ppt
Third grade, penetrate to 3 ppt
Fourth grade, penetrate to below 3 ppt
Brackish water component, lives In estuaries, but not In sea
II. FRESHWATER COMPONENT
The stenohallne freshwater component, not penetrating above 0.5 ppt
The euryhallne freshwater component
First grade, penetrate to 3 ppt
Second grade, penetrate to 8 ppt
Third grade, penetrate above 8 ppt
Brackish water component, lives 1n estuaries, but not 1n freshwater
III. MIGRATORY COMPONENT migrates through estuaries from sea to freshwater
or vice versa
Anadromous, ascending rivers to spawn
Catadromous, descending to the sea to spawn
IV. TERRESTRIAL COMPONENT
Tolerant of Submersion
Intolerant of Submersion
(from Green 1967)
111-25
-------
TABLE II1-7.
CLASSIFICATION OF ESTUARINE ZONES RELATING THE
VENICE SYSTEM CLASSIFICATION TO DISTRIBUTIONAL
CLASSES OF ORGANISMS.
Divisions
of
Estutry
River
Lower Reaches
Moutk
Venice Syltea
Stltnlty
Zones
0/00
0.5
O.S-5
Upper Retches 5-18
Middle Retches 18-2S
2S-10
30-40
Ecologies) Clttstficttlon
Types of OrgMtMt «nd ApproxtMte R««9e of Distribution
Estutry, RelttUe to division «nd S«l1n>ties
Uwtettc
OU90htltne
MesoKtltne
Polyhtlloe
Polyh«ltne
UMWttC
MIxolMttnt
Tru«
estutrlne
(istu«rtrw
etHtcslcs)
StenorwMnt
•trine
Curyhtl1ne
••rlnt
(frou Carriker 1967]
(Gobiesox strumosus). The foursplne stickleback (Apeltes quadracus) is a
small fTsh that Is abundant 1n estuaries but cannot be considered truly
estuarlne because It enters freshwater occasionally. Beccaslo et al . (I960)
Included kllllflsh, sllverslde, anchovy and hogchoker 1n the category of
truly estuarlne species. Other authors concede the existence of truly
estuarlne species although they fall to mention them as such. Instead,
fish are categorized as spending a major portion of their life cycle in an
estuary, as being dependent on the estuary at some time, or as being the
dominant species present.
A listing of species commonly found 1n North American Atlantic/Gulf coast
estuaries and their salinity tolerances/preferences as adults 1s contained
1n Table I II -8. It should be noted, however, that salinity preferences of
some fish may change at the time of migration. For example, adult stickle-
back (Gasterosteus aculeatus) prefer freshwater 1n March and saltwater 1n
June/July (McLusky 1971).
organism's stage of life.
may be unlike those of the
Salinity tolerances also differ depending on the
Salinity tolerances or requirements of juveniles
adult.
The Gulf of Mexico estuaries support populations of fish that are also
found along the Atlantic coast. For example, spot (Lelostomus xanthurus)
are abundant along the Gulf and the Atlantic coasts. The Atlantic croaker
ranges from the New England States to South America, although It 1s
basically a southern species Important In the Gulf of Mexico and South
Atlantic Bight. Gulf menhaden 1s an estuarlne dependent species that
primarily Inhabits northern Gulf of Mexico waters. Southern klngflsh
(Mentldrrhus amerlcanus) have been collected along the coasts from Long
111-26
-------
TABLE 111-8.
SALINITY TOLERANCE/PREFERENCE OF CERTAIN FISHES
FOUND IN ATLANTIC/GULF COAST ESTUARIES
Scientific Name
Alosa spp.
Brevoortia
patronus
Brevoortia tyrannus
Cy no s c 1 oTTVega 11 s
Ictalurus catus
Tctalurus punctatus
Leiostomu's xanthurus
Menidia menfdla
Micropogonlas undulatus
Morone americana
Morone saxatilis"
Perca flavescens
Pomatomus saltafrlx
(from U.S. EPA, 1983a)
Common Name
Herring, shad, alewife
Gulf menhaden
Atlantic menhaden
Weakfish
White catfish
Channel catfish
Spot
Atlantic silverside
Atlantic croaker
White perch
Striped bass
Yellow Perch
Bluefish
Salinity (ppt)
(Tolerance/Preference)
0-34/-
5-35/5-10
1-36/5-18
-/10-34
3-34/-
0-35/-
0-40/10-34
0-30/4-18
0-35/>12
0-13/5-7
7-34/-
Island Sound, Mew York, to Port Isabel, Texas (Sikora and SL.ora 1982).
They are estuarine dependent, and larval southern kingfish move from
offshore spawning areas to estuarine nursery areas. Salinity preferences
of southern kingfish varies with size. Only the smaller juveniles are
found in waters with salinities of less than 10 ppt. Larger juveniles
(>150 mm or 5.9 inches standard length, SL) are rarely taken 1n wate1*., with
salinities less than 20 ppt, and are usually found in deeper waters such as
sounds, near the mouths of passes, or near barrier islands (Sikora and
Sikora 1982). The most common fish found 1n Gulf of Mexico estuaries are
listed in Table III-9, along with the range of salinities in which they
were captured (Perret et al. 1971). Additional information on the envi-
ronmental requirements of Gulf coast species is presented in Appendix D.
Appendix 3 contains a listing of habitat requirements of major Atlantic
coast estuarine species during their life cycles. More detailed descrip-
tions of habitat requirements of egg, larval and juvenile stages of fishes
of the Mid-Atlantic bight are contained in several publications by the
United States Fish and Wildlife service (1978, Volumes I-VI). Mansueti and
Hardy (1967) also published information regarding fishes of the Chesapeake
Bay region. These reports contain illustrations of the life stages for
many species, along with pertinent information regarding preferred sub-
strate, salinity and temperature. Although the books focus on egg, larval,
and juvenile stages, the adult stage is also addressed.
Annual Cycles of Fish in Estuaries
Annual cycles and abundances of species are important in the ecology of
estuaries. The composition of the estuarine fauna varies seasonally,
reflecting the life histories of species. Anadromous fishes pass through
111-27
-------
TABLE III-9. FISHES COLLECTED IN SAMPLES IN LOUISIANA ESTUARIES
Scientific Name
Common Name
Salinity (ppt)
range where
greatest
range at number of
collection Individuals
sites / captured
Anchoa hepsetus
Anchoa m1tch1111
AHus fells
Bagre marl mis
Brevoortla patronus
dtharlchthys spllopterus
Cynosclon nebulous
Dorosoma cepedlanu*
Dorosoma pentenense
Fundulus s1m111s
Ictalurus furcatus
Lelostomus xanthurus
Membras martinica
Men1d1a beryl Una
Mentldrrhus amerlcanus
Mlcropogonlas undulatus
Mug11 cephalus
Parallchthys lethostlgma
Polydactylus ocfonemus
Prlonotus trlbulus
Sclaenops ocellatus
Sphaeroldes nephelus
Synodus foetens
Trlnectes maculatus
Striped anchovy
Bay anchovy
Sea catfish
Gafftopsail catfish
Menhaden
Bay whiff
Spotted seatrout
Gizzard shad
Threadfln shad
Longnose k1H1f1sh
Blue catfish
Spot
Rough sllverslde
Tidewater sllverslde
Southern klngflsh
Atlantic croaker
Striped mullet
Southern flounder
Atlantic threadfln
Blghead searobln
Red drum
Southern puffer
Inshore Hzardflsh
Hogchoker
7.0-29.9/>15.0
0-31.5/-
0->30.0/>10.0
0-29.9/>5.0
0-30.0/5.0-24.9
0->30.0/>15.0
0.2-30.0A15.0
0-29.9/<10.0
0-29.9/<5.0
0.5-30.7/>10.0
0-4.9/-
0.2->30.0/>10.0
2.0-29.9/>10.0
0->30.0/-
2.0->30.0/>10.0
0->30.0/-
0->30.0/5.0-19.9
0->30.0/-
1.6-29.9/-
2.0->30.0/>15.0
5.0-29.9/-
1.7-30.9/MO.O
4.0-30.9/>10.0
1.7-30.9/>10.0
(from Perret et al. 1971)
111-28
-------
estuaries on the way to spawning grounds. In the Gulf of Mexico, the
Alabama shad and the striped bass are Important anadromous species
(Beccaslo et al. 1982). Both species are sought for sport. Anadromous
species on the Pacific coast Include Chinook salmon, chum salmon, pink
salmon, sockeye salmon, Dolly Varden, river lamprey and cutthroat trout
(Beccaslo et al. 1981, Beauchamp et al. 1983). Studies have shown that
temperature 1s an Important factor governing the timing of migrations and
spawning for some species. Chinook salmon (Oncorhynchus tshawytscha) will
not migrate when temperatures rise above 20°C~!American shad live most of
their lives at sea, but pass through estuaries to spawn 1n fresh water.
Spawning of shad Is dependent on temperature, and commences when the
maximum dally water temperature reaches 16°C. It continues to about 24*C,
peaking at 21°C (Jones and Stokes Assoc. 1980). Additional Information on
Pacific fishes 1s available In Hart (1973). Life history 1s presented
along with certain environmental requirements of the species. However,
salinity tolerances and preferences are noted Infrequently.
Many of these anadromous species are major sport and commercial fish.
Striped bass, for example, occur along the east coast of North America from
the St. Lawrence River, Canada, to the St. Johns River, Florida; along the
Gulf of Mexico; and from the Columbia River, Washington to Ensenada,
Mexico, along the Pacific Coast (Bain and Bain 1982). Temperature was
cited as a key factor 1n their distribution. Striped bass migrate to fresh
or nearly fresh water to spawn. The optimum temperature for egg survival
Is 17° to 20°C. A minimum water velocity of 30 cm/s (1 fps) 1s necessary
to prevent eggs from resting on the bottom. After hatching, the larvae
remain fn nearly fresh water. Striped bass larvae need a minimum of 3 mg/1
dissolved oxygen. Optimum survival of larvae occurs when the temperature
1s between 18°C and 21°C (128-23°C tolerated) and salinity ranges from 3-7
ppt (0-15 ppt tolerated). Juveniles are more tolerant of environmental
conditions and migrate to higher salinity portions of the estuary, feeding
on small prey fish. Optimum temperatures for juveniles are between 14°C
and 21°C, but a range of 10°C to 27°C can be tolerated. Some adult striped
bass may remain In estuaries, while others may embark on coastal migra-
tions. Striped bass populations from Cape Hatteras, North Carolina to New
England may travel substantial distances along the coast, while populations
In the southern portion of the range and on the Pacific Coast tend to
remain 1n the estuary or 1n offshore waters nearby (Bain and Bain 1982/.
It should also be noted that preferred temperatures vary depending on
ambient acclimation temperatures. Striped bass acclimated to 27°C 1n late
August avoided waters of 34°C, while 13°C was avoided by striped bass
acclimated to 5°C In December.
Salmonlds, numerous flatfishes and sturgeon are dependent upon Pacific
coast estuaries at some time during their life cycles. For example, chum
salmon spawn In rivers from northern California to the Bering Sea during
October through December. Adults die after spawning. The young hatch 1n
spring, and move to estuaries and bays where they remain for 3 to 4 months.
They move to deeper waters gradually, as they grow (Beccaslo et al. 1981).
The sand sole, a sport species along the northwest Pacific coastline,
spends up to Its first year In bays and estuaries.
Some fish species utilize estuaries primarily as nursery grounds. Young
fishes feed In the productive estuarine system and then migrate seaward or
111-29
-------
TABLE III-10. FISHES THAT USE ESTUARIES PRIMARILY AS NURSERY AREAS
Scientific Name
Alosa aestivalls
losa pseudoharenga
Brevoortla patronus
Brevoortla tyrannus
Clupea hiaTengus
Clupea Farengus pallas11
Cottu's asper
Cynosdon regal Is
Lelostomus xantfuirys
Mlcropogonias undulatus
Morone amerlcana
Morone saxattlis
Mugll cephalus
Mugll curema
Oncorhynchus gorbuscha
Oncorhynchus kisutch
Osmerus mordax
Perca flavescens
Platlchthys stellatus
Pseudopleuronectes amerlcanus
Salmo saTar
TrTnectes maculatus
Common Name
Blueback herring
Alewife
Gulf menhaden
Atlantic menhaden
Atlantic herring
Pacific herring
Prickly culpln
Weakflsh
Spot
Atlantic croaker
White perch
Striped bass
Mullet (striped)
Mullet (white)
P1nk salmon
Coho salmon
Rainbow smelt
Yellow perch
Starry flounder
Winter flounder
Atlantic salmon
Hogchoker
(from U.S. EPA 1982, Jones and Stokes Assoc. 1981, HaedMch 1983, Beccaslo
et al. 1980)
towards freshwater. Most of the fishes using estuaries as a nursery area
are anadromous, the adults being principally marine. Table 111-10 lists
anadromous fishes (from both the east and west coasts of North America)
which use estuaries primarily as nursery grounds. Although Table 111-10 1s
not a comprehensive listing, 1t contains those fishes mentioned most
frequently 1n the literature (U.S. EPA 1983a, Jones and Stokes Assoc. 1981,
Haedrlch 1983, Beccaslo et al. 1980).
White perch (Morone amerlcana), another commercially Important fish, 1s
also abundant in estuaries on the east coast of North America. Populations
1n the Chesapeake Bay area have been observed to Inhabit the various
tributaries, with some fish entering the Bay Itself. The American eel
(Angullla rostrata) 1s the only catadromous species noted In the litera-
ture!Tt spawns in the Sargasso Sea, then migrates to and lives 1n
estuaries or freshwaters for several years before returning to the sea.
Some fish take advantage of the complex circulation pattern of estuaries,
spawning 1n offshore areas to allow eggs or larvae to drift up Into the
estuary. Most notably, the young of flatfishes (winter and starry
flounder) and some of the drums (croaker, weakflsh and spot) utilize the
estuarlne circulation system (U.S. Oept. of Interior 1970). The juveniles
then feed and mature within the estuary. The gulf menhaden (Brevoortla
111-30
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patronus) supports the largest commercial fishery by weight (Christmas et
aT1982). It 1s an estuarlne-dependent marine species that 1s found
primarily 1n northern Gulf of Mexico waters. Gulf menhaden spawn from
mid-October through March 1n marine waters. Currents transport planktonic
larvae to estuarlne areas, where they transform Into juveniles. As they
grow, juveniles migrate to deeper, more saline waters. Juveniles are able
to tolerate water temperatures from 5°C to 34°C. Adults and juveniles may
Inhabit estuaries throughout the year. The Atlantic croaker also uses the
estuary as a nursery area. Juveniles reside In salinities from 0.5 to 12
ppt, moving to higher salinity waters as they grow. They tolerate a wide
range of temperatures, from 6°C to 20°C. The spot (Lelostomus xanthurus)
1s also estuarlne dependent. Adults spawn 1n nearshore marine waters, but
juveniles spend much of their lives In estuaries. Juvenile spot tolerate
temperatures from 1.2°C to 35.5°C, preferring a range of 6°C to 20°C. They
have been collected 1n salinities from 0 to 60 ppt, but tend to concentrate
near the saltwater-freshwater boundary (Stlckney and Cuenco 1982). Other
estuarlne-dependent species In the Gulf of Mexico are the bay anchovy, sea
catfish, gafftopsoll catfish, spotted and sand seatrout, red drum, black
drum, southern klngflsh and southern flounder.
Some marine species enter the estuary seasonally. The spotted hake
(Urophyds reglns) enters the Chesapeake Bay 1n late fall, and exits before
the warm weather. In Texas estuaries, Urophyds florldanus follows a
similar migration pattern.
The blueflsh (Ppmatomus saltatrlx) Is often considered an adventitious
visitor to Atlantic coast estuaries (McHugh 1967). Although the blueflsh
1s a seasonal visitor, 1t may not appear 1f environmental conditions are
not suitable. Other species may occasionally enter estuaries to feed on
small fish, or If environmental conditions are suitable.
Difficulties often arise because sufficient Information Is not available on
the life cycles of certain species to enable their classification. For
this reason, and because of the many species of fish that enter estuaries
only occasionally, a fully comprehensive 11st of species 1s not available.
However, Haedrlch (1983) compiled a listing of characteristic families
found In estuaries, based upon faunal lists reported 1n various papers. He
divided the fauna Into families found In three zones, that of temperate,
troplcs/subtroplcs, and high latitudes. The families 1n Table III-ll
Include the few resident species, anadromous flsn and marine species that
utilize the estuary as feeding and nursery areas.
Habitat Suitability Index Models
Habitat Suitability Index (HSI) models developed by the U.S. F1sh and
Wildlife Service consider the quality of habitats necessary for specific
species during each life stage. The variables selected for study 1n a
given model are known to affect species growth, survival, abundance,
standing crop and distribution. Output from the models 1s used to
determine the quantity of suitable habitat for a species. The HSI values
produced by the models are relative, and should be used to compare two
areas, or the same area at different times. Thus, the area with the
greater HSI value 1s Interpreted to have the potential to support a greater
number of a species than that with the lower HSI. Values range from 0 to
111-31
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TABLE III-ll. CHARACTERISTIC FAMILIES OF ESTUARINE SYSTEMS
High Latitudes Troplcs/Subtroplcs
Salmon?dae (salmon and trout) Clupeldae (herrings)
OsmeHdae (smelt and capelln) Engraulldae (anchovies)
Gasterosteldae (sticklebacks) Chanldae (m1lkf1sh)
Anwnodytldae (sand lance) Synodontldae Mlzardflsh)
Cottidae (sculplns) Belonldae (silver gars)
Mug111dae (mullets)
Temperate Zones Polynemldae (threadflns)
Anguillidae (freshwater eels) Sdaenldae (crockers)
Clupeldae (herrings) Gob11dae (gobies)
Engraulidae (anchovies) dchlldae (dchelds)
Ariidae (saltwater catfishes) Soleldae (flounders)
Cyprlnodontidae (kllUflshes) Cynoglossldae (flounders)
Gadidae (cods)
Gasterosteldae (sticklebacks)
Serranidae (basses)
Sdaenldae (croakers)
Sparldae (seabreams)
Pleuronectldae (flounders)
(from Haedrlch 1983)
1, with 1 representing the most suitable conditions. HSI models can be
used to provide one value for all life stages, or to calculate HSI values
for each component (e.g. spawning, egg, larvae, juvenile, adult). There Is
some uncertainty in the use of the HSI models, both 1n the form of cal-
culation and the fact that they are unverified models. They have not been
tested to see 1f they work. The form of calculation leads to the possi-
bility of their being Insensitive to environmental changes. An area may
have undergone great degradation before the HSI model drops 1n value. More
information concerning HSI models can be found 1n Chapter IY-1 of the
Technical Support Manual (U.S. EPA 1983b). Models are currently available
for the following estuarlne fish: sTrlped bass (Bain and Bain 1982),
juvenile Atlantic croaker (01az 1982), Gulf menhaden (Christmas et al.
1982), juvenile spot (Stlckney and Cuenco 1982), Southern kingflsh (Slkora
and Slkora 1982), and alewlfe and blueback herring (Pardue 1983). Models
have been developed for several other estuarine organisms. They are
northern Gulf of Mexico brown shrimp and white shrimp (Turner and Brody
1983), Gulf of Mexico American oyster (Cake 1983), and littleneck clam
(Rodnlck and LI 1983).
SUMMARY
The preceding sections touch upon procedures that might be used and
specific phenomena that might be evaluated during the field collection
phase of a waterbody survey.
Strong seasonal changes in estuarlne biological communities compound
difficulties involved in collection of useful data. Because of annual
cycles, important organisms can be totally absent from the estuaries for
111-32
-------
portions of the year, yet be dominant community members at other times.
For example, brown and white shrimp spend part of the year 1n estuaries,
and migrate to deeper, more saline waters as the season progresses.
Furthermore, estuarlne biological communities may also vary from year to
year. Although It has not been mentioned explicitly, 1t 1s understood
that, If at all possible, a reference site will have been Identified and
will have been studied In a manner that 1s consistent with the study of the
estuary of Interest. In addition to whatever field data Is developed on
the estuary and Its reference site, 1t 1s also Important to examine
whatever Information might exist 1n the historical record.
The Importance of submerged aquatic vegetation has not been fully discussed
In this Chapter, nor have any tools been presented by which to digest all
the assessments so far presented. This will be done 1n Chapter IV,
Interpretation.
111-33
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CHAPTER IV
SYNTHESIS AND INTERPRETATION
INTRODUCTION
The basic physical and chemical processes of the estuary are introduced in
Chapter II, with particular emphasis placed on a description of stratifi-
cation and circulation in estuarine systems, on simplifying assumptions
that can he made to characterize the estuary, on desktop procedures that
might be used to define certain physical properties, and on mathematical
models that are suitable for the investigation of various physical and
chemical processes.
The applicability of desktop analyses or mathematical models will depend
upon the level of sophlsticaton required for a particular use attainability
study. These types of analysis are Important to the study 1n three ways: to
help segment the estuary Into zones with homogeneous physical characteris-
tics, to help in the selection of a suitable reference estuary, and to help
in the analysis of pollutant transport and other phenomena in the study
area. Several case studies are presented to illustrate the use of measured
data and model projections in the use attainability study. The selection of
a reference estuary(ies) is discussed later in this Chapter.
Chapter II also offers a discussion of chemical phenomena that are partic-
ularly important to the estuary: the several factors that influence dis-
solved oxygen concentrations in surface and bottom layers and the Impact of
nutrient overenrichment on submerged aquatic vegetation (SAV). Other chemi-
cal evaluations are discussed in the Technical Support Manual (EPA,
November 1983).
The biological characteristics of the estuary are summarized in Chapter
III. Specific information on various species common to the estuary are
presented to assist the investigator in determining aquatic life uses.
Typical forms of estuarine flora and fauna are described and the overall
importance of SAVs--as an indicator of pollution and as a source of habitat
and nutrient for the biota--for the use attainability study is emphasized.
In this Chapter, emphasis ts placed on a synthesis of the physical,
chemical and biological evaluations which will be performed, to permit an
overall assessment of uses, and of use attainability In the estuary. Of
particular Importance are discussions of the selection and analysis of a
reference site, and the statistical analysis of the data that are developed
during the use study.
USE CLASSIFICATIONS
There are many use classifications-navigation, recreation, water supply,
the protection of aquatic 11fe-wh1ch might be assigned to a water body.
These need not be mutually exclusive. The water body survey as discussed in
this volume is concerned only with aquatic life uses and the protection of
aquatic life in a water body. Although the term "aquatic life" usually
refers only to animal forms, the importance of submerged aquatic vegetation
IV-1
-------
(SAY) to the overall health of the estuary dictates that a discussion of
uses Include forms of plant life as well.
The use attainability analysis may also be referred to as a water body
survey. The objectives 1n conducting a water body survey are to identify:
1. The aquatic life uses currently being achieved 1n the water body,
2. The potential uses that can be attained, based on the physical,
chemical and biological characteristics of the water body, and
3. The causes are of any Impairment of uses.
The types of analyses that might be employed to address these three points
are summarized 1n Table IV-1. Most of these are discussed 1n detail else-
where 1n this volume, or 1n the Technical Support Manual.
Use classification systems vary widely from State to State. Use classes
may be based on geography, salinity, recreation, navigation, water supply
(municipal, agricultural, or Industrial), or aquatic life. Clearly, little
Information 1s required to place a water body Into such broad categories.
Far more Information may be gathered 1n a water body survey than 1s needed
to assign a classification, based on existing State classifications, but
the additional data may be necessary to evaluate management alternatives
and refine use classification systems for the protection of aquatic life 1n
the water body.
Since there may not be a spectrum of aquatic protection use categories
available against which to compare the findings of the biological survey;
and since the objective of the survey 1s to compare existing uses with
designated uses, and existing uses with potential uses, as seen 1n the
three points listed above, the Investigators may need to develop their own
system of ranking the biological health of a water body (whether qualita-
tive or quantitative) in order to satisfy the intent of the water body
survey. Implicit In the water body survey Is the development of management
strategies or alternatives which might result 1n enhancement of the bio-
logical health of the water body. To do this it would be necessary to
distinguish the predicted results of one strategy from another, 1n cases
where the strategies are defined 1n terms of aquatic life protection.
The existing state use classifications may not be helpful at this stage,
for one may very well be seeking to define use levels within an existing
use category, rather than describing a shift from one use classification to
another. Therefore, It may be helpful to develop an Internal use classi-
fication system to serve as a yardstick during the course of the water body
survey, which may later be referenced to the legally constituted use categ-
ories of the state.
A scale of biological health classes 1s presented 1n Table IV-2. This 1s a
modified version of Table V-2 presented 1n the Technical Support Manual,
and 1t offers general categories against which to assess the biology of an
estuary. The classification scheme presented 1n Table IV-3, which was
developed In conjunction with extensive studies of the Chesapeake Bay,
associates biological diversity with various water quality parameters. The
Toxldty Index (T.) 1n the table was discussed 1n Chapter III.
IV-2
-------
Table IY-1. SUMMARY OF TYPICAL ESTUARINE EVALUATIONS
(adapted from EPA 1982, Water Quality Standards Handbook)
PHYSICAL EVALUATIONS CHEMICAL EVALUATIONS BIOLOGICAL EVALUATIONS
0 Total volume
0 Reparation rates
0 Temperature
0 Suspended solids
0 Sedimentation
0 Bottom stability
* Substrate composi-
tion and character-
istics
e Channel debris
0 Sludge/sediment
0 Riparian character-
istics
• Dissolved oxygen
0 Size (mean width/depth)
0 Flow/velocity ° Toxics
* Nutrients
- nitrogen
- phosphorus
0 Chlorophyll-a
* Sediment oxygen demand
- Salinity
0 Hardness
• Alkalinity
0 PH
0 Dissolved solids
" Biological inventory
(existing use analysis)
0 Fish
- macroinvertebrates
- microinvertebrates
e Plants
- phytopiankton
- macrophytes
0 Biological condition/
health analysis
- diversity Indices
- tissue analyses
- Recovery Index
• Biological potential
analysis
- reference reach
comparison
IV-3
-------
TABLE IV-2. BIOLOGICAL HEALTH CLASSES WHICH COULD BE USED
IN WATER BODY ASSESSMENT (Modified from Karr, 1981)
Class Attributes
Excellent Comparable to the best situations unaltered by man; all
regionally expected species for the habitat including the
most intolerant forms, are present with full array of age
and sex classes; balanced trophic structure.
Good Fish invertebrate and macroinvertebrate species richness
somewhat less than the best expected situation; some
species with less than optimal abundances or size dis-
tribution; trophic structure shows some signs of stress.
Fair Fewer intolerant forms of plants, fish and invertebrates
are present.
Poor Growth rates and condition factors commonly depressed;
diseased fish may be present. Tolerant macroinvertebrates
are often abundant.
Very Poor Few fish present, disease, parasites, fin damage, and other
anomalies regular. Only tolerant forms of macroinverte-
brates are present.
Extremely Poor No fish, very tolerant macroinvertebrates, or no aquatic
life.
IV-4
-------
TABLE IV-3. A FRAMEWORK FOR THE CHESAPEAKE BAY ENVIRONMENTAL QUALITY
CLASSIFICATION SCHEME
Class Quality Objectives
Quality
II
C*
Note:
Healthy supports maximum
diversity of benthlc
resources, SAV, and
fisheries
Fair moderate resource
diversity, reduction
of SAV, chlorophyll
occasionally high
Fair a significant reduc-
to tlon In resource
Poor diversity, loss of
SAV, chlorophyll
often high, occa-
sional red tide or
blue-green algal
blooms
Poor limited pollution-
tolerant resources,
massive red tides or
blue-green algal
blooms
TT Indicates Toxldty
T*. Indicates Total N1
Index
Very low 1
enrichment
moderate 1-10
enrichment
high 11-20
enrichment
<0.6
<0.08
significant
enrichment
>20
-1
... ii.u.<.«vi.;> iwvw. Nitrogen 1n mg 1 «
T" Indicates Total Phosphorus In mg l"
0.6-1.0 0.08-0.14
1.1-1.8 0.15-0.20
>0.20
* Class C represents a transitional state on a continuum between classes
B and D.
IV-5
-------
ESTUARINE AQUATIC LIFE PROTECTION USES
Even though the estuary characteristically supports a lesser number of
species than the adjacent freshwater or marine systems, 1t may be consider-
ably more productive. Accordingly, uses might be defined so as to recog-
nize specific fisheries (and the different conditions necessary for their
maintenance), and to recognize the Importance of the estuary as a nursery
ground and a passageway for anadromous and catadromous species. Currently
the water body use classification systems of the coastal states distinguish
between marine and freshwater conditions, occasionally between tidal and
freshwater conditions, but seldom make reference to the estuary. Uses and
standards written for marine waters presumably are Intended to apply to
estuarlne waters as well.
It 1s common In these States to Include as a use of marine or tidal waters
the harvesting and propagation of shellfish, frequently with reference to
the sanitary and bacteriological standards Included 1n National Shellfish
Sanitation Program Manual of Operations: Part 1, Sanitation of Shellfish
Growing Areas, published by the Public Health Service .(1965). The term
shellfish applies to both molluscs and crustaceans. Other marine protec-
tion uses which may be applicable to the estuary are worded 1n terms such
as the growth and propagation of fish and other aquatic life, preservation
of marine habitat, harvesting for consumption of raw molluscs or other
aquatic life, or preservation and propagation of desirable species.
In establishing a set of uses and associated criteria to be used 1n the
water body survey, the Investigator might wish to consider examples like
the State of Florida's criteria for Class II (Shellfish Propagation or
Harvesting) and Class III (Propagation and Maintenance of a Healthy, Well-
Balanced Population of Fish and Wildlife) Waters published 1n the Water
Quality Standards of the Florida Department of Environmental Regulation.
The published criteria are extensive and Include the following categories
which are of Importance to the estuarlne water body survey:
Biological Integrity - the Shannon-Weaver diversity Index of benthlc
macrolnvertebrates shall not be reduced to less than 75 percent of
established background levels as measured using organisms retained by a
U.S. Standard No. 30 sieve and collected and composited from a minimum
of three natural substrate samples, taken with Ponar type samplers with
minimum sampling areas of 225 square centimeters.
Dissolved Oxygen - the concentration in all waters shall not average
less than 5 milligrams per liter in a 24-hour period and shall never be
less than 4 milligrams per liter. Normal dally and seasonal
fluctuations above these levels shall be maintained.
Nutrients - In no case shall nutrient concentrations of a body of water
be altered so as to cause an imbalance in natural populations of
aquatic flora or fauna.
IV-6
-------
SELECTION OF REFERENCE SITES
General Approach. There Is a detailed discussion of the selection of
reference or control sites 1n Chapter IV-6 of the Technical Support Manual.
Although this discussion was prepared 1n the context of stream and lake
studies, much of the material 1s pertinent to the study of estuaries as
well. Riverine water body surveys may range 1n scale from a specific well-
defined reach to perhaps an entire stream. One might expect to find a
similar range of scale 1n estuary studies. The lateral bounds of the
riverine study area generally are delineated by but not necessarily limited
to the stream banks. The specification of a reference reach 1s prescribed
by the scale of the study. If a short reach 1s under study, the reference
reach might be designated upstream of the study area. If an entire river
Is under review, another river will have to be Identified that will serve
as an appropriate control.
An estuarlne study may focus on a specific area, but the bounds of the
study area are not easily defined because a physical counterpart to the
river bank may not exist. Other factors compound the difficulties 1n
designing an estuary study compared to the design of a river study. A
major difference is that estuary segments cannot be so easily categorized
because of seasonal changes in the salinity profile. Partitioning the
estuary Into segments with relatively uniform physical characteristics is
an Important first step of a water body survey.
It may be possible to study a small estuary as a single segment, but It
will be necessary to go elsewhere for a reference site. This may be easily
accomplished among the many bar built estuaries of the southeastern coast.
For the large estuary, one may need only to examine a well-defined segment
which has been affected by a point source discharge. If the segment Is an
embayment tributary to the main stem of the estuary, It may not be diffi-
cult to find a suitable control embayment within the same estuary. As the
scale of the study Increases, however, the difficulties associated with the
establishment of a reference site also Increases. It may not make sense to
treat the entire estuary as a single unit for the use attainability survey,
especially 1f use categories are associated with salinity ranges, different
depths, etc. In such a case one would segment the estuary based upon
physical characteristics such as salinity levels and circulation patterns,
and then define the reference site 1n similar fashion. As a practical
matter, it may not make sense to examine an entire estuary as a single
unit, especially a large one. For example, the Chesapeake Bay has been
subjected to a form of use attainability studies for a number of years at a
cost of many millions of dollars. However, Chesapeake Bay 1s so complex
that, despite the intensity of study, clear explanations are not always
possible for the many undesirable changes that have taken place. The
Chesapeake Bay Itself 1s unique and no suitable reference estuary exists.
From the use attainability standpoint, an estuary such as the Chesapeake or
the Delaware or the Hudson 1s best broken down Into segments that are
homogeneous In characteristics and manageable In size.
Statistical Comparisons of Impact Sites With Control Sites. Reference site
comparisons typically rely upon either parametric or nonparametric statis-
tical tests of the null hypothesis to determine whether water quality or
IV-7
-------
any other use attainment Indicator at the Impact site 1s significantly
different from conditions at the control s1te(s).
Parametric statistics, which are suitable for datasets that exhibit a nor-
mal distribution, Include the F (folded)-statlstlc on the difference be-
tween the variances at the Impact site and control site and the t-stat1st1c
on the difference between the means. In order to conclude that there Is no
significant difference between the water quality conditions (or another
Indicator) at the Impact site and the control site, both the F-stat1st1c
and the t-stat1st1c should exhibit probabilities exceeding the 0.05 prob-
ability cutoff for the 95 percent confidence Interval. In cases where the
Impact site 1s being compared with multiple control sites, parametric pro-
cedures such as the Student-Newman-Keuls (SNK) test, the least significant
difference (LSD) test, and the Duncan's Multiple Range test can be used to
test for differences among the grouped means.
Since water quality datasets are often characterized by small sample sizes
and non-normal distributions, 1t 1s likely that nonparametrlc statistical
tests may be more appropriate for the monitoring database. Nonparametrlc
statistics assume no shape for the population distribution, are valid for
both normal and non-normal distributions, and have a much higher power than
parametric statistical techniques for analyses of datasets which are char-
acterized by small sample sizes and skewed distributions. The one-sided
Kolmogorov-Smlrnov (K-S) test can be used to quantify whether each dataset
1s normally (or lognormally) distributed, thereby governing the selection
of either parametric or nonparametrlc procedures. If nonparametrlc pro-
cedures are selected, significant differences 1n distributions can be
evaluated with the two-sided K-S test, while significant differences 1n the
central value can be tested with the Wllcoxon Ranksum test. Both nonpara-
metrlc tests should exhibit probability values exceeding the cutoff for the
95 percent confidence Interval 1n order to conclude that there 1s no signi-
ficant difference 1n water quality conditions at the Impact site and a con-
trol site. For comparisons with multiple control sites, nonparametrlc pro-
cedures such as the Kruskal-Wallls test and the Friedman Ranksum test can
be used to test for significant differences among medians (1f 1t can be
assumed that the distributions of each dataset are not significantly
different.
The same types of statistical tests can be used to evaluate sediment and
biological monitoring data to determine whether suitable conditions for use
attainability exist at the Impact site. Either parametric or nonparametrlc
statistical procedures can be used to compare conditions at the Impact site
and control s1te(s) which are unaffected by effluent discharge or other
pollution sources. In cases where there are no statistically significant
differences 1n distributions and/or control values, 1t may be assumed that
sediment and/or biological monitoring results at the Impact site and con-
trol s1te(s) are similar.
CURRENT AQUATIC LIFE PROTECTION USES
The actual aquatic protection uses of a water body are defined by the resi-
dent flora and fauna. The prevailing chemical and physical attributes will
determine what biota may be present, but little need be known of these at-
tributes to describe current uses. The raw findings of a biological survey
IV-8
-------
may be subjected to various measurements and assessments, as discussed 1n
Section IV (Biological Evaluations) of the Manual. After performing an
Inventory of the flora and fauna and considering a diversity Index or other
Indices of biological health, one should be able adequately to describe the
condition of the aquatic life 1n the water body.
CAUSES OF IMPAIRMENT OF AQUATIC LIFE PROTECTION USES
If the biological evaluations Indicate that the biological health of the
system 1s Impaired relative to a "healthy" reference aquatic ecosystem
(e.g., as determined by reference site comparisons), then the physical and
chemical evaluations can be used to pinpoint the causes of that Impairment.
Figure IV-1 shows some of the physical and chemical parameters that may be
affected by various causes of change 1n a water body. The analysis of such
parameters will help clarify the magnitude of Impairments to attaining
other uses, and will also be Important to the third step 1n which potential
uses are examined.
ATTAINABLE AQUATIC LIFE PROTECTION USES
A third element to be considered 1s the assessment of potential uses of the
water body. This assessment would be based on the findings of the physi-
cal, chemical and biological Information which has been gathered, but addi-
tional study may also be necessary. A reference site comparison will be
particularly Important. In addition to establishing a comparative baseline
community, defining a reference site can also provide Insight Into the
aquatic life that could potentially exist 1f the sources of Impairment were
mitigated.
The analysis of all Information that has been assembled may lead to the
definition of alternative strategies for the management of the estuary at
hand. Each such strategy corresponds to a unique level of protection of
aquatic life, or aquatic life protection use. If 1t Is determined that an
array of uses Is attainable, further analysis which 1s beyond the scope of
the water body survey would be required to select a management program for
the estuary.
One must be able to separate the effects of human Intervention from natural
variability. Dissolved oxygen, for example, may vary seasonally over a
wide range 1n some areas even without anthropogenic effects, but 1t may be
difficult to separate the two In order to predict whether removal of the
anthropogenic cause will have a real effect. The Impact of extreme storms
on the estuary, such as Hurricane Agnes on the Chesapeake Bay 1n 1972, may
completely confound our ability to distinguish the relative Impact of
anthropogenic and natural Influences on Immediate effects and longterm
trends. In many cases the Investigator can only provide an Informed guess.
Furthermore, If a stream does not support an anadromous fishery because of
dams and diversions which have been built for water supply and recreational
purposes, 1t 1s unlikely that a concensus could be reached to restore the
fishery by removing the physical barriers -- the dams -- which Impede the
migration of fish. However, It may be practical to Install fish ladders to
allow upstream and downstream migration. Another example might be a situ-
ation 1n which dredging to remove toxic sediments may pose a much greater
IV-9
-------
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\ier Production
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Figure IV-1.
Potential Effects of Some Sources of
Alteration on Water Quality Parameters;
D » Decrease, I » Increase, C - Change
IV-10
-------
threat to aquatic life than to do nothing. Under the do nothing alterna-
tive, the toxics may remain in the sediment in a biologically-unavailable
form, whereas dredging might resuspend the toxic fraction, making 1t
biologically available and also facilitating wider distribution 1n the
water body.
The points touched upon above are presented to suggest some of the phenom-
ena which may be of importance in a water body survey, and to suggest the
need to recognize whether or not they may realistically be manipulated.
Those which cannot be manipulated essentially define the limits of the
highest potential use that might be realized in the water body. Those that
can be manipulated define the levels of improvement that are attainable,
ranging from the current aquatic life uses to those that are possible with-
in the limitations imposed by factors that cannot be manipulated.
RESTORATION OF USES
Uses that have been impaired or lost in an estuary can only be restored if
the conditions responsible for the Impairment are corrected. Impairment
can be attributed to pollution from toxics or overenrlchment with nutri-
ents. Uses may also be lost through such activities as the disposal of
dredge and fill materials which smother plant and animal communities,
through overflshlng which may deplete natural populations, the destruction
of freshwater spawning habitat which will cause the demise of anadromous
species, and natural events in the sea, such as the shifting of ocean
currents, that may alter the migration routes of species which visit the
estuary at some time during the life cycle. One might expect losses due to
natural phenomena to be temporary although man-made alterations of the
estuarine environment may prevent restoration through natural processes.
Assuming that the factors responsible for the loss of species have been
identified and corrected, efforts may be directed towards the restoration
of habitat followed by natural repopulation, stocking of species 1f habitat
has not been harmed, or both. Many techniques for the Improvement of sub-
strate composition in streams have been developed which might find applica-
tion in estuaries as well. Further discussion on the Importance of sub-
strate composition will be found in the Technical Support Manual (EPA,
November 1983).
Stocking with fish in freshwater environments, and with young lobster in
northeastern marine environments, Is commonly practiced and might provide
models for restocking in estuaries. In addition, aquaculture practices are
continually being refined and the literature on this subject (Bardach et
al., 1972) should prove helpful in developing plans for the restoration of
estuaries or parts of estuaries.
Submerged aquatic vegetation (SAV) 1s considered to be an excellent Indica-
tor of the overall health of an estuary because it is sensitive to environ-
mental degradation caused by physical smothering, nutrient enrichment and
toxics. Because SAY is so important as habitat and as a source of nutrient
for a wide range of the estuarine biota, its demise signals the demise of
its dependent populations. If uses in an estuary have been impaired or
lost, 1t is likely that SAV will also have been affected.
IV-11
-------
Unfortunately, the cause of SAV degradation 1s not always clear. In the
Chesapeake Bay for Instance, controversy persists as to the cause of loss
of SAV and the loss of biota which depend to whatever extent on SAV.
Trends noted over time 1n the demise of these populations may conceivably
be related to trends 1n toxic, sediment and nutrient loadings on the Bay,
and to trends 1n the release of chlorinated wastewaters from POTWs, chlor-
inated effluents from Industry and chlorinated cooling water from power-
plants. Areas 1n which SAV has been adversely Impacted are areas where
there are toxics 1n the sediment and/or where algal blooms prevent light
from reaching SAV communities.
The ability to restore areas of SAV will depend upon the Initial causes of
loss, and the ability to remove the causes. Toxics In sediment may be a
particularly difficult problem because of the Impractical1ty of dredging
large areas to remove contaminated bottom substrate. An Inabilty to remove
toxic sediments which may have caused a decline in SAV and other benthic
communities severely limits the likelihood that these populations may be
restored to past levels.
The control of nutrients may be a much more tractable problem. If nutrient
Inputs to the estuary can be controlled, SAV populations may begin to ex-
pand on their own. In the Potomac River estuary, phosphorus removal at the
Blue Plains wastewater treatment plant, which serves the greater Washing-
ton, D.C. area, has resulted 1n sharp reductions 1n algal blooms which are
considered a major factor in the demise of SAV within the Chesapeake Bay
system.
Apart from natural processes which result In the enlargement of areas of
SAV, SAV may be restored through reseeding and transplanting, depending
upon the species. Generally speaking, reseeding may not be a practical
approach because of the cost of collecting seeds and because one would not
expect all seeds to survive, although VaTMsnerla (wild celery) shows some
promise 1n using seeds to reestablish populations. Some areas may reseed
naturally, but in many cases SAV populations may be too distant for the
natural transport of seeds to be likely. In these cases, plants may be
transplanted 1n order to restore SAV. Reestabllshment 1s accomplished by
transplanting shoots and rhizomes.
Although transplanting may be a more practical alternative, the outcome 1s
not assured. In an effort to reestablish SAV, plugs of Zostera (eelgrass)
and Potamogeton (sage pondweed, redhead grass) were planted in the Potomac
River estuary. These beds showed some measure of success, depending mainly
upon the substrate present. The transplanting of SAV 1s a labor Intensive
operation and as such would require a considerable cost 1n time and re-
sources to restore even a small area.
In Tampa Bay, Florida, stress on the ecosystem, including the disposal of
dredge spoils which have smothered SAV communities, has caused a signifi-
cant loss (25,220 ha, or 81 percent) of submergent wetland vegetation. Ef-
forts to reestablish Spartina (cord grass) and Thalassla (turtlegrass) have
resulted in the restoration of about 11 ha of vegetation (the growth and
spreading of rhlzomateous material is increasing this figure) (Hoffman et
al., 1982). The transplantation of Thalassia and Halodule (shoalgrass)
near the discharge side of a powerplant was less successful, in that
IV-12
-------
Thai assila failed to survive for 30 days where the mean water temperature
was 31"C or greater, and only small patches of shoalgrass survived near the
outer edges of the thermal plume. These differences could not be attri-
buted to differences in sediment composition (Blake et al., 1976). Never-
theless, other transplantation efforts emphasize the importance of
substrate to plant survival. For example, Thai assla prefers a reduced
environment while Halodule prefers an oxidized substrate.
Transplanting oyster spat from "seed" areas which are protected from har-
vesting to areas less favorable for reproduction is a relatively common
practice. Seed areas ideally exhibit optimum salinity and temperature for
oyster reproduction and spat set. Clean shell is deposited as substrate in
seed areas and spat often become very densely populated. Spat are then
moved to areas where an oyster population is desired. Steps may also be
taken to prepare the bottom (often by depositing oyster shells) where an
oyster reef exists, or where attempts will be made to establish an oyster
reef.
Although there has been some progress in the aquacultural sciences towards
rearing species that may be found in the estuary (clam, quahog, oyster,
scallop, shrimp, crab, lobster, flatfish), techniques are not well-advanced
and there is little likelihood that they could be successfully applied on
any scale towards the repopulation of the estuary. As with SAV, the exper-
iments and the successes with the reestablishment of species are limited,
and the more important factor in the restoration of habitat is the control
and reversal of the various forms of pollution which cause the demise of
estuarine populations.
IV-13
-------
CHAPTER V
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Nepthys Incisa. Journal of the Fisheries Research Board of Canada,
34:563-567, 1977.
Thatcher, M.L. and Harleman, D.R.F. Prediction of Unsteady Salinity
Intrusion 1n Estuaries: Mathematical Model and User's Manual. Report
No. 159, Parsons Lab., MIT, Cambridge, Massachusetts, November 1972, pg.
Theillng, D.L. and H.A. Loyacano, Jr. Age and growth of red drum from a
saltwater marsh impoundment in South Carolina. Trans. Am. Fish. Soc.
105(l):41-44, 1976.
V-17
-------
Thomas, D.L. An Ecological Study of the Delaware River In the Vicinity of
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Species of Drum (Sdaenldae) 1n the Lower Delaware River, a Brackish-
Tidal Estuary. Progress Rep. for January-December, 1970. Ichthyologlcal
Assoc. Bull. 3, 1971.
Titus, J., R.A. Goldstein, M.S. Adams, J.B. Mankln, R.V. O'Neill, P.R.
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Myriophyllum spicatum. Ecology 56:1129-1138, 1975.
Tranter, D.J. (ed.). Zooplankton sampling. Unesco Monogr. Oceanogr.
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Turner, R.E. and M.S. Brody. Habitat Suitability Index models: Northern
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Wildl. Serv. FWS/OBS-82/10.54, 1983.
Tutin, T.G. The Percy Sladen Trust expedition to Lake Tlticaca in 1937 the
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Ukeles, R. Nutritional Requirements for Shellfish Culture. In: Arti-
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Maurer, eds. University of Delaware, 1971.
Ungar, I.A. Inland halophytes of the United States, pp. 235-305. In R.J.
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U.S. Environmental Protection Agency. Techniques for sampling and
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V-18
-------
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1983.
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V-19
-------
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August 1977.
V-20
-------
APPENDIX A
DEFINITION OF THE CONTAMINATION INDEX (Cj) AND
THE TOXICITY INDEX (T)
To assess the contribution of anthropogenic sources of metal contamination
over time, sediment cores may be analyzed. The Wedepohl ratio compares the
amount of metal 1n the sediment sample with the concentration 1n an average
shale (or sandstone). In the Chesapeake Bay program, scientists have
measured silicon and aluminum, then correlated metals with S1/A1 ratios. A
contamination factor (Cf) may be computed as follows:
Cf » (Co-Cp)XCp
where: Co = surface sediment concentration
Cp = predicted concentration, derived from the statistical
relation between the S1/A1 ratio and the log metal content of
old, pre-pollutlon sediments from the estuary.
Thus, Cf < 0 when the observed metal concentration 1s less than the pre-
dicted value; Cf = 0 when observed and predicted are the same; Cf > 0 when
the observed 1s greater than the predicted value.
The Contamination Index (C,) 1s found by summing contamination factors for
metals In a given sediment.
Then,
n
Z
n=l
Cf
n
L
n-1
{Co-Cp)/Cp
The Toxldty Index (T.) 1s related to the Contamination Index and Is
expressed by the following equation:
1
TT s V (M,/M.)'Cf4
I Z-» 1 1 1
1=1
where: M. = the "acute" anytime EPA criterion for any of the metals,
but M! 1s always the criterion value for the most toxic of the metals.
The "acute" anytime EPA criterion 1s defined as the concentration of a
material that may not be exceeded 1n a given environment at any time. When
evaluating Toxldty Indices, sampling stations should be characterized by
their minimum salinities. This 1s because the toxldty of metals 1s often
greater \n freshwater than fn saltwater.
A more detailed discussion of the development of the Contamination Index
may be found 1n the U.S. EPA publication, Chesapeake Bay: A Profile of
Environmental Change (1983a) and A Framework for Action (1983c).
A-l
-------
APPENDIX B
LIFE CYCLES OF MAJOR SPECIES OF ATLANTIC COAST ESTUARIES
Contents
I. General Fishery Information
a. Alosa aestivalis (Blueback Herring)
b. Alosa pseudoharengus (Alewife)
c. Alosa sapidissima (American Shad)
d. Brevoortia tyrannus (Atlantic Menhaden)
e. Callinectes sapidus (Blue Crab)
f. Crassostrea virginica (American Oyster)
g. Cynoscion regalis (Weakfish)
h. Cj^ nebulosus (Spotted Seatrout)
i. Ictalurus catua (White Catfish)
j. Ictalurua nebulosus (Brown Bullhead)
k. Ictalurus punctatua (Channel Catfish)
1. Leiostomus xanthurus (Spot)
m. Mercenaria mercenaria (Hard Clam)
n. Micropogonias undulatus (Atlantic Croaker)
o. Morone americana (White Perch)
p. Morone saxatilis (Striped Bass)
q. Mya arenaria (Soft Shell Clam)
r. Perca flavescens (Yellow Perch)
s. Pomatomus saltatrix (Bluefish)
(from U.S.EPA 1983a)
-------
TABLE la. ENVIRONMENTAL TOLERANCES OF ALOSA AESTIVALIS (BLUE BACK HERRING) CAMAOIAM MAI IT IKES TO IT. JOHN'S I1VM. ft
LIFE STAGE
HABITAT
REQUIREMENTS
Tidal-freah and low-
FOOD AND FEEDING
FACTORS
Not applicable
GROWTH t DEVEL-
OPMENT FACTORS
No information
BEHAVIOR
Not applicable
PREDATORS AND
COMPETITORS
No information
SELECTED
REFERENCES
Burbidge 1974
brackiah water.
Ill* Ell* • '• found in
•tream* and river*
with awift current*
and candy or rocky
aubatrata.
Tidal-fre*h and
brackiah water.
Larvae Larva* are found in
tributary «tr*am« and
upper portion* of
river*.
Optimum aalinity
0-5 ppt.
Tidal-freah and
brackiah water.
Juvenile Juvenile* are found
primarily in aurface
watera.
Tolerate aalinity
0-28 ppt.
Optimum aalinity
0-5 ppt.
- copepoda
Selective feeder
during daylight.
- copepod*
- copepodite*
- Bo»min* app.
- macrotoop lank ton
Growth occur*
during warm tem-
perature*.
Growth occur*
during warm tem-
perature*; rate of
growth i* more
rapid than for
alewivc*.
Interspecific
competition with
Bay anchovy in
brackiah water
cau*e* larvae to
aelect food item*
other than the
preferred type.
Young juvenile*
remain in nurcery
area until the
fall, then under-
take a aeaward
migration. Young
may remein in the
lower Bay during
firat or *ecood
winter.
Compete with Bay
anchovy.
Prey of predatory
fiah (ttripcd ba**.
white perch)
Prey of predatory
fiah (atriped baaa.
whit* perch.
blucfith)
Adult* enter the Bay
Adult to tpawn in fre*h-
water; return to the
ocean after (pawning.
- tooplankton
- cru*t*ce*n*
- cru*tacean egg*
- intcct*
- fi*h egg* and
larva*
Blueback herring
mctur* in 3-4 yr*.,
and reach a maii-
mum length of 3B.O
cm.
Hudaon and Hardy 1974
Jonee ct at. 1978
Lippaon ct al. 1979
Domermuth and Reed
1980
Rancy and Maaamann
occur in a narrow
band of coaatal
water; move to the
bottom during winter.
Herring are ana-
dromoua, migrating
into the key to
•pawn in apring.
fiah (atriped
baai, bluefiih,
weakfi(h) in (r**h,
brackiah, i **lt
water. T*rget of
• commercial i
recreational
(tihery.
B-l
-------
TABU Ib. ENVIRONMENTAL TOLERANCES OF ALOSA PSEUDOHARENCUS (ALEWIFE) NEWFOUNDLAND TO SOUTH CAROLINA
LIFE STAGE
Ett*
Larvae
HABITAT
REQUIREMENTS
-0.5 ppt salinity.
Eggs are releaaed in
•low, shallow
portion* of creeka
and rivers over
detritus or sandy
aubstrat*.
0-3 ppt salinity.
Larvae remain in
vicinity ol spawning
area at depth* l*a*
than 3m.
Tolerate salinity
0-J4 ppt.
FOOD AND FEEDING
FACTORS
Not applicable
- rotifer*
- cope pod nsuplii
- copepod*
- ays id shrieip
GROWTH t DEVEL-
OPMENT FACTORS
Hatching period 6
days. Mean water
leap. 60°P.
No information
Crow very rapidly.
possibly due to
BEHAVIOR
Hot applicable
Fora school*
within 1-2 days
after hatching.
Young juveniles
•igrat* toward the
PREDATORS AND
COMPETITORS
No information
Prey of predatory
fish (white perch
and striped b*ss)
Prey of predatory
fish (bluefish.
SELECTED
REFERENCES
Jones et el. 1971
Shea et al
Lippson et
Hildebrand
Schroeder
. 1980
al. 1979
and
1921
Optimum salinity
O.S-S ppt.
Juvenile Young juveniles are
found in nursery
area* from *hor* to
shore; •• the fish
grow, there is • clow
downstream movement.
0-3* ppt salinity.
Adult* enter the
Adult Bay to spawn in
freshwster; return
to ocesn by mid-
entering s*lt water,
average lOi mm.
Mid-water feeder
- copepod•
- young fish
- looplankton
- mycid*
Alewife mature in
V
-------
TABLE Ic. ENVIRONMENTAL TOLERANCES OF ALOSA SAP1D1SSIMA (AMERICAN SHAD) CULF OF ST. LAURENCE TO FLORIDA
LIFE STAGE
*•••
Larvae
Juvenile
Adult
HABITAT
REQUIREMENTS
0-0.$ ppt ealinity.
Streaae and river*
with (wife current*
and *andy or rocky
aubatrate.
Optiajum aaliaity
0-5 ppt.
Larva* are foumd at
depth* greater the*
3».
Tolerate aalinity
0.5-12 ppt.
Optiewei aalinity
i-12 ppt.
Young juvenile*
gradually move into
•ore **lioe water*.
Tolerate aalinity
0-J* ppc.
Adult* enter the Bay
to *pawn in freah-
water or on flat* in
tidal water*; return
to ocean after
•pawning.
FOOD AND FEEDING
FACTORS
Not applicable
Ho information
Feed at or
beneath *urfac*
- daphnid clado-
ceran*
- boaaunid clado-
ceran*
- other cladoceran
•pp.
- copepod*
Feed in aurface
layer
- copepod*
- ••*!! fi*h
- plankt ivorou*
cructaceana
- inacct*
GROWTH 4 DEVEL-
OPMENT FACTORS
Temperature* above
21°C and low D.O.
level* decreaae
hatching auccea*.
At D.O. level* of
$ pp». *o«e *tre**
and •ortality occur*;
at D.O. level* of
4 ppa, high Mortality
•ay occur.
Young grow rapidly
during the firat
Growth rate de-
createa after 3
year* of age.
Reach aexual
•aturity in 4-)
yeara.
BEHAVIOR
Hoc applicable
Ho iaforaatioe,
Juvenile* remain
in natal atreaaa
and rivera until
the fall, then
undertake a aeaward
•igration. Some
remain in the lower
Bay during the
firat winter.
Shad are anadromoua,
• igrating into the.
Bay to apawn in
•pring. Meet* are
built, but no
parental care ia
given to egga.
rREDATORS AND
COMPETITORS
Ho information
Preyed upon by top
predatory specie*
(atriped ba**,
bluefiah, white
perch, other herring
•PP-)
Competition with
•pecie* *uch aa
the alewife or
blueback herring
influence location
of feeding fiih 4
•election of prey.
Prey of top preda-
tory apecie*.
Prey of top pre-
datory fiah (klue-
fiih, itriped ba**).
Target of a commar~
cial and recrea-
tional fiahary.
SELECTED
REFERENCES
Hildebrand and
Schroeder 1921
Shea et «1. 1»BO
Domermuth and Bead
1«BO
Lippao* et al. 1*7*
Cilia et al. 1947
B-3
-------
TABLE Id. ENVIRONMENTAL TOLERAMCCS OF BREVOORTIA TTRANNUS (ATLANTIC HENHADEN) NOVA SCOTIA TO CULF OF MEXICO
LIFE STAGE
£««•
Larvae
Juvenile
HABITAT
REQUIREMENTS
Egg* are released in
the ocean, probably
not far (ae far aa
64 »•) fro* th«
•outb at the fay.
Early larvae tolerate
16-34 ppt salinity.
Oft imam aalinity
2*-M ppt. Latar
tKay concentrate in
tidal fresh to low
brackish water*
(0-3 ppt salinity).
Tolerate salinity
0-14 ppt.
Optimum salinity
0-1) ppt. Young* r
fish concentrate in
tidal-fresh to low-
brackish waters.
FOOD AMD FEEDING GROWTH 4 DEVEL-
FACTORS OPMENT FACTORS
Not applicable No information
Sight-selective No information
feeder*
- copepods
site of fish
influences site
of copepods
taken.
Filter feeder No infonaation
- phytoplankton
BEHAVIOR
Not applicable
Larvae enter the
Bay in spring when
they are about 10- JO
mm long; any reach
nursery areas in
larval or juvenile
stage.
You ng-of-t he-year
juveniles remain
in the Bay during
summer; My leave
in fall or over-
winter in Bay.
PREDATORS AND SELECTED
COMPETITORS REFERENCES
No information Priste* and Willie
1971
Shea ec al. I9M
June and Carlson 1*71
No information
Durbin and Durbin 197}
Lippaoo et al. 1979
Prey of top prefa-
tory fish including
bluefish and striped
bass.
Tolerate salinity
1-36 ppt concentrate
in areas of i-lfl ppt
Adulc salinity where food
patches occur. One
end two year old
adults utilise the
Bay; older fish
remain off the
coast.
Filter feeder
- cooplanfctun
- larger phyto-
plankton
- longer chains
of chain-
forming diatoms.
Feeding behavior
is linked to food
density and par-
ticle siie.
Some fiih may reach
maturity in one ycjr;
all fish sre mature
by age 3. Maximum
length around 47.0
cm.
Schooling marine
fish which enter
the Bay in spring
to feed; moat
migrate seaward in
the fall, though
some may overwinter
in the lower Bay.
Prey of top pre-
datory fish in-
cluding bluefish
and striped bass.
Target of a com-
mercial fishery.
B-4
-------
TABLE U. ENVIRONMENTAL TOLItANCCS OF CALLINECTES SAPIDUS (BLUE CRAB) NEW JERSEY TO FLORIDA
HABITAT
LIFE STAGE IEQUUEMENTS
Hitch at aalinitiea
of 10.1-32.6 ppt;
Egg* oft imam ealinitiea
for hatch are 23-10
ppt. Female* carry
the egg* until hatch
occur*.
Tolerate aalinitiea
of 1S.S-32.3 ppt;
Zoeae optimum talinitiee
•r« 21-28 ppt.
Zoeae ara found in
the upper aurfaca
water.
FOOD AND FEEDING
FACTORS
Hot applicable
- rotifera
- Hauplii larvae
- aea urchin
larvae
- polychaete
larvae
GROWTH k DEVEL-
OPMENT FACTORS BEHAVIOR
Salinity affecti Not applicable
hatching success.
Zoeae molt at leaat Zoeae ahow an
three time*, with attraction to
the final Bold pro- light.
due ing a meg* lops.
Molting it affected
by salinity, temper-
ature, larval con-
centration*, and
light intensity.
PREDATORS AND SELECTED
COMPETITORS REFERENCES
No information Van Engel at al.
Shea et al. 1980
Bulkin 1*7)
Van local 1958
No information Sandoa and Roger*
Lippton 1971
1973
1944
Lippaoo et el. 1979
Optimum aalinitte*
of 20-3} ppt. Mega-
Megalop* lop* may be found in
•urface water* or on
the bottom.
Omnivorou*
- plant*
- fiah and ahell-
fi*h piece*
- detritus
Availability of
prey affecta diet.
Salinity and temper-
ature affect the
durat ion of the
megalop* *t*ge.
Hegalop* metamorpho*e
into a *mall juvenile
crab.
Hegalop* and juven-
ile* move into the
Bay through the
entrainmenc in bottom
water*, beginning in
fel 1. In winter
young crab* cea*e
migration* and burrow
into channel bottom*.
No information
Juvenile*
and
Adult*
Juvenile* concentrate
in brackiah water
with aalinitie* lea*
than 20 ppt. Adult
malea concentrate
in aalinitie* of
3-1} ppt. Female*
concentrate in
salinities of 10-28*
ppt.
- benthic organ-
i*m*
- *mall fi*h
- plant*
- (hellfiih
- amall cruat-
aceana
- detritu*
Availability of
prey affecta diet.
Craba reach sexual
maturity in 12-20
month* depending on
timing of hatch.
Growth occur* by
«hedding the shell.
and is regulated by
water temperature.
In warm weather,
juvenile* move in-
shore. When temper-
aturea drop, juven-
ile* move to channel
araaa to overwinter
in aemi -hibernation.
Adulta have cimilar
movement pattern*.
- predatory fish
•uch a* striped
b*s* and bluefiab
- bird* such a*
heron* and herring
• gull*
- a commercial and
recreational
f iahery.
B-5
-------
TABLE If. ENVIRONMENTAL TOLERANCES OP CRASSOSTREA VIRCINICA (AMERICAN OYSTER) NEW ENGLAND TO GULF COAST
LIFE STAGE
Ell.
Larvae
Juveni lea
(spat)
AdulCl
HA* I TAT
REQUIREMENTS
Optimum salinity of
22.5 ppt. below 10
ppt , aurvival it poor.
Pelagic «n> released
in open water.
Optimal growth occur*
•t salinities of
12.S-25.0 ppt.
Salinity 5-35 ppt.
Oysters ire found
in shallow water leas
than 10 meters deep.
Optimum survival of
oysters occurs on
hard substrate such
as rocks, pilings.
and oyiter (hells in
the intertidal and
sub-tidal zones.
FOOD AND FEEDING
FACTORS
Not applicable
Filter feeder
- phytoplankton
- bacteria
The site of food
particles taken is
a funct ion of the
mouth aize.
Filter feeder
- phytoplankton
- bacteria
- detritus
Filter feed on
1-12 micron prey
- phytoplankton
- bac t e r la
- detritus
Turbidity and low
temperatures in-
fluence feeding
and digestion.
GROWTH 4 DEVEL-
OPMENT FACTORS
Turbidity levels of
1?5 •{ L"' or more
eggs.
Turbidity levels of
100 >g L~' cause
high larval mortality.
Salinity, tempera-
ture, and available
food influence
larval development.
Spat exhibit rapid
growth during the
first year. Growth
rates are affected
by avai 1 abi 1 it y of
food, salinity, and
water temperature.
Growth is affected
by substrate type,
salinity, tempera-
ture , t idal f low,
and crowding. Oysters
reach aeiual maturity
during the second
year of growth. |A
few reach maturity
at one year (Haven))
BEHAVIOR
Not applicable
Oyater larvae
move within the
estuary by entrain-
ment in bottom
waters. Larvae search
for suitable substrate
on which to attach
in about two weeks.
At setting, larvae
metamorphose tp spat.
Oysters initially
develop as males,
yet by the second
breeding setson
many change into
females.
Epibenthic with
frequent alternation
of sei. Font com-
munities or "bars."
Oyiter distribution
in higher salinity
areas is restricted
by predators and
parasite*.
PREDATORS AND
COMPETITORS
Ho information
Prey of ptanktonic-
feeding fish and
invertebrates.
Compel I tors
- boring sponges
and clan*
- slipper shell
- sea squ i r t
- barnacles
- spirochaetes
- perlorating
algae
Prcdatora
- oyster drills
- blue crabs
- starfish
- bird*
- commercial fishery
Di seates
- Perkinsus man nut
(Dermo)
- Menchinia nelsoni
(MSX)
SELECTED
REFERENCES
Calt*off 1964
Haven and Morales-
Alamo 1970
Korringa 19)2
Davis and Calabrese
1964
Ukalcs 1971
Andrews 1967, 1968
Haven, personal
communicat ion
B-6
-------
TABLE 1|. ENVIRONMENTAL TOLERANCES OP CYNOSCION BECAL1S (UEAKFISH) HASSACHUSETTS TO FLORIDA
LIFE STAGE
EM*
Larvae
Juvenile
Adult
HABITAT
REQUIREMENTS
Tolerate salinities
of 5-34 ppt.
Buoyant egg* are re-
leaeed in Che near-
•hore and eatuarine
tone* along the coaat.
Tolerate aalinitiea
12-31 ppt.
Larvae remain in the
general vicinity of
•pawning.
About 0-34 ppt
•alinity. Young-of-
the-year fish move
into low falinity
areaa over toft,
•uddy bottoaia.
Tolerate salinities
of 10-34 ppt.
Adulti remain in the
lower portion of the
Bay.
FOOD AND FEEDING
FACTORS
Not applicable
Ho information
- ahriaip
- other crust-
acean app.
- bay anchovy
- young Menhaden
- other lull fnh
Primarily pisci-
vorout
- sienhaden
- herring Iversides
- c r u tt acvans
- annelids
GROWTH I DEVEL-
OPMENT FACTORS
Eggs are
-------
TABLE Ih. ENVIRONMENTAL TOLERANCES OF CYNOSCIOM NEBULOSUS (SPOTTED SEATKOUT) DELAWARE TO HCXICO
HABITAT
LIFE STAGE REQUIREMENTS
Spawning occur* at
salinities of 30- Ji
Egg* ppt . Hatched in 40
hr. at 2i°C.
Egg* reported a*
both demersal and
pelagic, released
in deeper channel*
and hole* adjacent
to gra**y bays and
f lata.
Growth of larvae
is rapid, about
Larvae 4.4 m*i in 1) daya
after hatching.
Young fish spend
their juvenile
life in vegetated
flats, moving to
deeper water in
winter.
Fish larger than
2 inches show a
Juvenile tendency to con-
gregate in schools.
Reaain in grassy,
anal low water flats
until colder weather
causes thea to move
to deeper water.
FOOD AND FEEDING
FACTORS
Hot applicable
Very small in-
vertebrates.
including cope-
pod a, ay a id
ahrimp, and post-
larval penacid
shrimp.
As the trout grow,
diet changes to
include larger por-
portiona of cari-
dean ahriap and
then to pcnaeid
ahrimp.
GROWTH 4 DEVEL-
OPMENT FACTORS
Egga arc susceptible
to low D.O. and sudden
changes in salinity
or teaperature.
Highly sensitive to
changes in tempera-
ture. Winter-t ime
cold shock and high
temperature change*
causes kills.
Females grow faster
than males but males
attain sexual maturity
at a smaller site.
Growth i* rapid in
first year with
length* of 11 ca
attained by the firat
winter and 2) ca
their second winter.
BEHAVIOR
Not applicable
Tend to remain
close to site
of (pawning
in graiay
f lata.
Start to
school as
young fiah
but reaain in
general area
of nursery
ground* until
cold weather
cauie* them to
move to deeper
water.
PREDATORS AND SELECTED
COMPETITORS REFERENCES
Tabb 1961
No information Arnold at al. 1978
Fable at al. 1978
Idyll and Fatty 197)
Lorio and Perret
1980
No information
Reported a*
highly can*
nibalist ic
in the post-
larval atage.
(continued)
B-8
-------
TABLE Ih. (CONTINUED)
LIFE STAGE
HABITAT
REQUIREMENTS
FOOD AND FEEDING
FACTORS
GROWTH 4 DEVEL-
OPMENT FACTORS BEHAVIOR
PREDATORS AND
COMPETITORS
SELECTED
REFERENCES
While tagging etudiea
•how that tern* •«•-
Adult trout travel aa much
aa 31) oilee, matt
•tudiea ahow that
few (tab leave their
natal eituary.
C^ nebulo»ua occu-
piea a »or* aouthern.
warmer water habitat
than do*a C. regalia.
Liated aa the top
carnivore in moat
eatuarine commoni-
tiea. Aa an adult,
will eat all other
fiah of a aa>aller
aite aa well aa
ehrimp and aetall
craba.
Longevity indicated
to be 8 to 9 year* of
age. Generally nature
at one to three yeara
with SOX acKually
mature by end of
accond year (25 c«
in length). All fiah
appeared to have
apawned by age three.
A 1978 report citea
the largest aeatrout
caught waa 16 pound*.
Hoveeweit pal-
term have
been traced to
the preaence
or abaence of
penaeid
ahrieip.
Seatonal auveawnta
correspond to water
temperature and
•pawning aeaaon.
A top predator
which would be
in competition
with other pre-
dator* auch aa
bluefiih and
atriped ba».
both coaawrcial
and recreational
f ianeriea.
B-9
-------
TABLE li. ENVIRONMENTAL TOLERANCES OF 1CTALUHUS CATUS (UNITE CATFISH) NEW YORK TO FLORIDA
LIFE STAGE
HAIITAT
REQUIREMENTS
Freshwater
Eggs deposited
rOOO AMD FEEDING
FACTORS
Not applicable
in o«at*
GROWTH 4 DEVEL-
OPMENT FACTORS
Egg* need to be
••rated.
•EHAVIOR
Not applicable
rtEDATORS AND
COMPETITORS
No information
SELECTED
REFERENCES
JOM* «t al. 197«
built near sand or
gravel bank* in at ill
or running water.
Larvae
In freshwater, may No information
move into tidal
water.
Yolk sac larvae No information
bypass larval
stage, develop
directly to
juvenile stage.
No information
Lip**om et al. 1979
Daiber et al. 1976
Kendall and Scbwarti
I9M
No information
No information
Juvenile
Growth continue*
at II ppt aalinity
or leaa.
Remain
until end of
tint aummer;
initially guarded
by parent a.
Adult
Minimum aalinity of
14.5 ppt
Widespread in Bay.
Prefer heavily ailtcd
bottom.
Omnivorous, toll- Fith mature in one
tary, bottom feeder to two years.
-plant material
-•mall fish Haiimum length
-clams and snail* 61.0 cm.
Inhabit river channel* -worms
and streams with slow -insects
current, ponds, and -dead material
lake*.
Stay in waters
greater than ) m,
overwinter in
deeper water (15 •
move upstream to
spawn in fresh-
water.
Hales guard and
aerate egg masses.
No information
B-10
-------
TABLE Ij. ENVIRONMENTAL TOLERANCES OF ICTALURUS NEBULOSUS (Bh MM IULLHEAO) SOUTHERN CANADA TO SOUTHERN FLMIDA
LIFE STAGE
EM
Larvae
Juvenile
Adult
HABITAT FOOD AND FEEDING
REQUIREMENTS FACTORS
Freshwater Not applicable
Egg* deposited in
nest* in (and or
gravel at depth* of
•evcral inche* to
•everal feet.
Freshwater Ho Information
Found at bottom
Found among vegetation Ho information
or other cover over
muddy kottoma.
Adult* are widespread Omnivorous,
throughout most of the solitary bottom
Bay area, occurring in feeder
GROWTH 4 DEVEL-
OPMENT 'ACTORS
Egg* exposed to
direct aunlight
produce poor
hatches.
Egga need to be
agitated.
Yolk-sac larvae
bypass larval
stage, develop
directly to juvenile
•tage.
Mo information
Nature at 1 year*.
Maximum length
around W.I en.
PREDATORS AND
ICHAVlOt COMFETITOIS
Not applicable No information
Grouped in a No information
tight maaa at
bottoo.
Young juvenile* Ho information
herded in school*
by parent*; may
remain in schools
throughout first
A schooling frottoei ito information
specie* which is
active primarily at
SELECTED
urcuNCcs
Jones et al. IW
Lippaon et al. 1979
Daibcr at al. 1976
channel* and (hallow,
muddy water around
aquatic vegetation.
Maximum aalinity 10
ppt.
- plant material
- small fun
- clam* and snails
- worn*
* insects
- dead Material
night. Fish may
burrow in toft *edi-
swnt*. Adult* attend
egg* and orally
agitate.
B-ll
-------
TABLE Ik. ENVHUNBCNTAL TOLttANCU OP ICTALUtUS PUNCTATUS (CHANNEL CATFISH) HUDSON BAY ICC ION TO NOtTHMN HCXICO
LIFE STAGE
HABITAT
(F.qUKCNENTS
tit* 1 to 2 daya old
FOOD AND FEEDING
FACTOtS
Not applicable
CBOVTH i DEVtL-
OPHENT FACTO* S
No informac ion
BEHAVlOt
Not applicable
PkCDATOBS AND
CONPETlTOtS
No information
SELECTED
UFEUNCCS
Jonee
-------
TABLE 1 1. ENVIRONMENTAL TOLERANCES OT LEIOSTOHUS XANTHURUS (SPOT) MASSACHUSETTS TO FLORIDA
LIFE STAGE
Eta
HABITAT FOOD AND FEEDING GROWTH 4 OtVEL-
REQUIREMENTS FACTORS OPHENT FACTORS BEHAVIOR
tha continental shelf.
PREDATORS AND
COMPETITORS
Jellyfish, such as
the sea walnut
(HncMiopsis leidyi).
predatory Marine
fish.
SELECTED
REFERENCES
Hudson and Hardy 1974
Shea at al. 1980
Lippaon et al. 1979
Tolerat* salinity 0-35 Sight-selective
Larvae ppt. OptiMuw salinity feeder
0-5 ppt in the estuary. - planktonic cope-
pods
Ho inforution
No information
Prey of predatory
fi*h and bird*
Tolerate taltnity
0-34.2 ppt. Poit-
Juwenilt larva* and young
fith concentrate at
•alinitiea of O.J-J.O
ppt; during years o(
high population density
young My awve into
freshwater. Prefer
•toddy substrate.
•atto* feeder
- benthic karp-
•cticoid cope-
pods
- annelids
- plant Material
Growth during
tint suawer is
rapid, juveniles
•ay awasure 13 ca
by late (all.
Post-larvae are
carried into the lay
in April through
entrainatent in bottoai
waters. School along
shore during suaaMr.
Young awve downstreaai
as they grow.
as above
TnoMas 1971
Chao and Husick 1977
Petera and Kjelaon
Adult
8- 14 ppt salinity.
Occur at depths greater
than I • over soft
•uddy bottoai; larger
fish prefer channel
waters.
Bottoai feeder
- burrowing poly-
chaetes
- annelids
- taiall crusta-
ceans
- MOlluSCS
Reach sexual Matu-
rity by the third
year; minimum
length around 11-li
CM.
Adults enter the Bay
in Apri 1 and Nay,
leave for spawning
grounds offshore fro*
Aug. through Nov.
Prey of large gaaM-
fish (ttriped bass),
sharks, and the
target of recreational
and coas*ercial fish-
eries.
- aacroiooplankton
B-13
-------
TABLE !•. ENVIRONMENTAL TOLCIUNCCS OF MERCENAR1A MERCENARIA (HARD CUM) NOVA SCOTIA TO YUCATAN
H All TAT FOOD AND FEEDING
LIFE STAGE REQUIREMENTS FACTORS
Tolerate 20-3) ppt Not applicable
Eggs salinity, prefer 26.)-
?7.J ppt.
Salinities greater than No information
17.) ppt. Larvae are
Larvae pelagic, found in the
surface waters.
CftOWTH 4 DEVEL-
OPMENT FACTORS
Salinity affect*
egg development.
Larval development
i* affected by
aalinity, tempera-
ture, turbidity,
and circulation
pattern*.
IEHAVIOR
Eggs are carried on
currents in lit* tay.
Larvae are initially
pelagic, but toward
the end of this
ttsge, they slternate
between a planktonic
and bent hi c existence.
PREDATORS AND
COMPETITORS
No information
Clam larvae are prey
of other filter
feeding organisms.
SELECTED
REFERENCES
Lippson 1973
Daiber et al. 1976
Shea et al. I960
CastagM as>d Chanley
1973
Adult
Optimum salinity 24-28 Filter feeder
ppt, survive salinities - algae apecies
as low as 12.) ppt. - detritus
Growth rstes vary Young clams hsve bi-
with the type of
•ubetrate u««d.
faiter growth
occur* in coaraer
aedimenta.
•exual gonad*,
uiually dominated by
•ale characteriat ica.
After the firtt
•pawning season,
about )OI of the juve
nile* become female.
Sslinities greater than Filter feeder
1) ppt. Hard clams
occur in aubtidal
or intertidal waters
with solid substrate
(•hell or rock).
- algae species
Large clams measure
12-13 cm in length.
Adults spawn during
neap tides; spawning
•ay be both thermally
and chemically
stimulated.
Predators include
- oyster drills
- blue craba
- moon snails
- conchs
- horseshoe crabs
- sea stara
- puffers
- waterfowl
- cow nosed rays
- drum fish
- man
B-14
-------
TABLE In. ENVIRONMENTAL TOLERANCES 07 M1CROPOCONIAS UNPULATUS (ATLANTIC CROAKER) CAPE COO. MA TO FLORIDA
HABITAT FOOD AND FEEDING
LIFE STAGE
»•••
Larva*
Juvcni It
Adult
REQUIREMENTS
Efgi «r« rele**ed in
the ocean near th«
mouth of the My fro*
Augu*t through
December.
Larva* which enter the
Bay in fall remain in
channel water* at
depth* greater than
1m; carried to the
•alt water interface.
Young juveniles are
found in channel water*
of 0-21 ppt lalinity.
Older fith tend to be
down-river fro* the
younger fi*h.
Tolerate salinity
0-40 ppt . Optimum
salinity 10-34 ppt.
Hard bottoei at depth*
greater than 3m.
FACTORS
Not applicable
Mo information
Juvenile* lea*
than 10 cm
- harpacticoid
cope pod*
Older juvenile*
- polychaete*
- cruitaccan*
- fiih
- other inverte-
brate*
- ••ill cruata-
ceana
- annelid*
- ma\ lu*c*
- »all fiah
GROWTH 4 DEVEL-
OPMENT FACTORS
Ho information
No information
No growth occur*
during the winter
•caaon; young f i ah
have been killed
during incentive
cold periodi on
the nuraery ground*.
Croaker reach a
maximum length of
around 50 cai.
BEHAVIOR
Not applicable
Larvae begin entering
the Bay in fall
through entrainment
in bottoai water*.
Ye* r ling croaker
leave in the fall.
Crocker enter the
Bay in *pring,
remaining in the
lower cituary until
fall, then they
•igrate back to *ea.
Water temperature
influence* croaker
migration*.
PREDATORS AND SELECTED
COMPETITORS REFERENCES
No information Shea et at. 1980
Hildebrand and
Schroeder 1921
Lippaon et al. 1979
No information
Stickney ct al. 1975
Chao and Muaick 1977
Haven 19)7
Striped batt preda- Joteph 1972
tion on overwintering
juvenile* may depre** Wallace 1940
the population;
juvenile* al*o preyed
on by bluefiih.
Prey of top preda-
tory *pccie* (itriped
baa* and bluefiah).
The target of a
commercial and recre-
ational fiahery.
B-15
-------
TA»LE lo. ENVIRONMENTAL TOLERANCES Or MORONE AMERICANA (WHITE PERCH) NOVA SCOTIA TO SOUTH CAftOLINA
LIFE STAGE
ESS
Larvae
Juvenile
Adult
HABITAT
REQUIREMENTS
Tolerate ••Unity 0-6
PP'- ESS* arc released
in tidal-fre*h to low-
brackiah watera in
aha How* along the.
• nor*.
Tolerate ((Unity 0-8
ppt, prefer 0-1.} ppt.
Maximum depth 12 ft.
Larva* arc found in
•hallow water over
aand or gravel bare or
mud bottom.
Tolerate salinity 0-13
ppt, prefer 0-J ppt.
Found in (hallow
•luggi*h water over
•ill, mud, or vege-
tation; move to *andy
thoalt and beache* at
night .
Tolerate ••Unity 0-30
ppt, prefer 4-18 ppt.
In aummer, concentrate
near ihoal*, occasion-
ally in channel area*.
In winter, found in
deeper water; move to
channel* during coldest
period*.
FOOD AND FEEDING
FACTORS
Not applicable
Sight-selective
feeder*
- rotifer*
- cope pod*
- cope pod*
- cladoceran*
- iniecr. larvae
Bottom oriented,
pile ivorou*
- yel low perch
- young eel*
- young (triped
bass
- insects
- cru(t*ceana
CRUWTH » DEVEL-
OPMENT FACTORS
Suspended icdiment
level* about 1>OO
ppm mcreaae incu-
bation period.
Temperature and
availability of
rotifer* affecta
development of
yolk-sac larvae.
Growth positively
correlated with
temperature and
•olar radiation.
Growth influenced
by population
density.
Growth ratea
decrease with age
•nd high population
density. Hales
mature in J years,
female* in 3.
•EHAVIOR
Not applicable
Remain in (pawning
area, settle to
bottom. General
oownatremm movement
a* larvae develop.
Juvenile* remain in
nuraery area at lead
until 20 mm long, may
remain until I year
old. Juvenile* may
form large achoola.
Schooling *dult*
are reaident to the
•ay. White perch
•re (emi-anadromou*,
making apawning
migration* upstream
in ipring.
PREDATORS AND SELECTED
COMPETITORS REFERENCES
No information Shea at al. 19SO
Lippaoo at al. 1979
Mildebrand and
Schroeder 1928
Compete with itnped Hud eon and Hardy 1974
bas« larvae in
nuriery «r««i. Looa 197)
Preyed upon by
fish (striped baas) Hancuati 1961
and bird*.
Compete with *trip*d
bast juveniles-
Preyed upon by fish
(striped bass, blue-
fish) and bird*.
Preyed on by larger
fish (striped bass,
bluefish). Also the
target of a commercial
and recreational
fishery.
B-16
-------
TASLS If. EHV!SOS9=KTAi. TOISSAMCES OF MOaOig SASATILiS {STSIPSB BASS) ST. LAUKESCS BI¥ES. CANADA TO ST. JOSS'S BiVES. R,
HABITAT rOOD AND FEEDING
LIFE STAGE
Egg
Larvae
Juvenile
REQUIREMENTS
Tolerate aalinity 0-10
ppt. 1.5-3 ppt optimal.
1.0-2.0 m aec-1
optimum flow rat*. Semi-
buoyant egg* released
in fresh to bracki*h
water.
Tolerate **linity 0-1}
ppt. 5-10 ppt optimal.
0.3-1.0 • sec"1
optimal flow rat*.
- open water*
- at 13 aaa, move
inshore for firat
summer
Juvenile* 50-100 mm.
Tolerate salinity 0-35
ppt. Optimal 10-20
ppt. 0-1 • sec"1
optimal flow rate.
- prefer sandy sub-
it rate but found
over gravel bottoms
as well in shallow
watera.
FACTORS
Not applicable
Sight selective
feeder
- copepoda
- rotifers
- cladocerans
Nigh prey concen-
tration* oeceaaary
for successful
first feeding.
Non-selective
feeder
- insect larva*
- polychaetes
- larval fish
- amphipoda
- myaid*
GROWTH 4 DEVEL-
OPMENT FACTORS
Salinity and temp-
erature influence
development.
Temperature and
adequate iood
influence growth.
Temperature and
population density
influence growth.
PREDATORS AND
SEHAVIOa COMPETITORS
Mot applicable Prey of whit* perch.
Positively photo- Compete with white
trophic; newly- perch lerv** in
hatched larvae sink nursery area.
between swimming
efforts; at 2-1
daya of age larvae
can swim continuously.
Downstream movement Compete with white
of young-of -the-year perch in nursery
(ish. Yearlings Prey of predatory
school in river* or fish, bird*, mammals,
move into lower and man.
estuary in summer.
SELECTED
-""-"
Setaler st a!. 19*0
BoyntOB er si, 19(1
Msven and Hitwrakv
19M
Hollia 1952
Doroshev 1970
Shea et al. 1980
Hd. Dept. Nat. Res.
1981
Tolerate 0-3} ppt.
usually in salinities
Adult greater than 12 ppt.
Suaater habitat include*
high energy shorelines
with * current. Over-
winter in channels in
estuary or oil shore
al depths below 6 •.
Piscivorous
alewife
blueback herring
while perch
spot
axnhaden
bay anchovy
croaker
Temperature, age,
population density,
and oxygen level*
influence growth.
Androatous, migrate
to freshwater to
spawn, return to
lower **tu*ry or
ocean after spawning.
Young fcmal** (2-3
yr) migrate along
coast in summmr with
older fish.
Compete with blue-
fish, weakfish, and
white perch. Com-
mercial and recre-
ational fishery for
atriped bass.
B-17
-------
TABU
ENVI
KTAL TOUIANCCS OF NY* AMMAKIA (SOFT SHELL CLAN) LABIADOB TO WORTH CAKOLIKA
LIFE STAGE
HABITAT
UQU1UWMTS
FOOD AMD FECOINC
FACTMS
CtOUTH 4 KVEL-
OFHENT FACTORS
BEHAVIOB
PIEDATOIS AMD
OOMPETITOtS
SELCCTED
BZFEUKCES
I||* are released by
•edantary adult* ia
Eft* two •pawning peak*,
•pring •Mml 1*11.
Larvae
Juvenile
Mot applicable
Ma information
Hot epplicabl*
Ma information
Minimum ••Unity for
larval aurvival i*
• ppt.
Fllt«r
(U«*l-
- och«r •iero-
•copic plankton
T**p«r*turc inMu-
cncci l«rv«l dcvcl-
Ofment ; •( 10°C,
il (low.
After the planktonic
larvae develop •<•(-
ficientty. they
metamorphoae to
adult form and
tattle to the bottom.
No inforvctto*
Juvenile* occur owcr
• bro«d«r dcptb
than »dulti.
Su*p*n«io« f***«r
- pnycoplcokton
- •icrosooplMfctoa
- bccttri*
- dctritu*
Juvenile clam* arc Juvenile* can move
•en*itive to lalin- about by mine, the
ity fluctuation*. autaculir foot or by
current*. They
Ktabliah a permanent
burrow when one inch
long.
Tolerate aalinity 3-35
ppl. Optinwei 16-32 ppt.
Adult Claaa occur on (hallow
•ubtidal bed* to (table
•ubttrate* at depth*
lea* than 6-10 •.
Su*pen*ion feeder
- phytoplankton
- aicrotooplanktoo
- bacteria
- detritu*
Claai* reach (enual
•aturity in one
year. Growth 11
influenced by water
current!, lood
•upply, temperature,
and aediaent type.
Adult* occur in deep,
permanent burrow* in
•haltow water.
Predator* include:
- blue cr«b
* oyiter drill*
- hor*e*hoe crab*
- cow-noted ray*
- herrinf, gull*
- waterfowl
- bottom feeding
fiah
- commercial and
recreational
litnerie*.
Sbea et al. 19M
Lucy 1977
Merrill and Tubiaah
1970
Uallace ct al. 196}
Caatagnaj and Chan ley
1971
Nattnietacn I9b0
B-18
-------
TABLE Ir. ENVIRONMENTAL TOLERANCES OF PEiCA fLAVESCENS (VELUM PERCH) EAST COAST RANGE Of NOVA SCOTIA TO SOUTH CAROLINA
LIFE STAGE
H All TAT
REQUIREMENTS
u-u.3 ppt salinity.
FOOD AND FEEDING
FACTORS
Not applicable
GROWTH 4 DEVEL-
OPMENT FACTORS
Low teaperaturr*
*E HA VI OR
Not applicablt
PREDATORS AND
COMPETITORS
Ho intonation
SELECTED
REFERENCES
Settler it al.
1980
til
Non-tidal and tidal-
fresh water.
during (pawning
season cause in
extended incubation
period (2-1 wki),
larvae BOre devel-
oped at hatch than
other anadroBoua
apeciea.
Lippaoa «t al. 1979
Auld and Scbufc*! 1474
Daiber at al. 197*
Muocy 1*62
Tolerate salinity 0-2
ppt . Opt i BUM 0-0.) ppt.
Larvae Shallow, frcahwater;
lurvival reduced when
aediBent concent rat iona
exceed }00 Bg L'1.
0.5-10 ppt, concentrate
at aalinitiea of i-7
Juvenile ppt in tuBBer. Found
in vegetated area* near
ihore.
Tolerate 0-13 ppt
salinity, prefer 5-7
Adult ppt in suBBer. Prefer
higher aalinicy, tidal
watera with Buddy
•ubitrate.
- plankton
- small cruata-
ccana
- inaecta
- worai
- BO 1 LutC*
- bay anchoviea
- ail vert idea
- Binnowa
- iiupoda
- anphipodi
- anaila
- cruataccana
Salinitiea greater
than 2 ppt inter-
fere with larval
development .
Crowa quickly
during firat year;
growth rale
decreaaea with age.
Feaate* hjve greater
growth rate than
Bale •.
Malet mature at 1
year of age,
ttmtlet Bature at
age ? or 3; grow
to 5) CB. Large
populationi cause
atunting of adulta.
Larvae Bove down-
atreaa after
hatching; concentrate
near surface, for*
•c hoo 1 a .
Initially concentrate
at surface, becooe
draeraal at about 25
Spring Bigration
upstreaB to spawn;
return downstreaai
after spawning.
Preyed upon by white
perch, striped baaa,
chain pickerel.
Preyed upon by fish
such as white perch
and striped base,
birds, BiBBsts.
CoBpete with white
perch and atriped
bass.
CoBpetcs with saaller
fish and invertebrate*
for food. Preyed
upon by birds
(Bcrgansera), fiah
(gar* and pike*), and
Ban.
B-19
-------
TAIL! It. Lirt HISTORY OP NMATOHUS SALTATRIX (ILUEFISH) NOVA SCOTIA TO ARCtKTINA
LIFE STAGE
HAIITAT
uqutRCMCNTS
FOOD AMD FEEDIMC
FACTORS
GROWTH i. DEVEL-
OPMENT FACTORS
UHAVIOR
PREDATORS AND
COHPET 1 TORS
SELECTED
UFIRENCES
Cgg* released off-shore
in two distinct wave*;
Egga spring (pawning occur*
in the Gulf Stream,
while cummer spawning
occur* over the
continental shelf.
Not applicable
No information
Not applicable
No inloTBAtion
Lippto* «t •!. 1*7*
(ckro«4«r
JOM* «t •!. 1971
Daiktir ct •!.
Larvae
Juvenile
No information
0-37.5 ppt ••Unity.
The larger the juvenile
population, the (fester
the penetration into
the lay.
No information
- copepods
- molluscs
- planktivorou*
crustacean*
- any fish smaller
than thamaelve*
No information
Juveni les grow
quickly during
the first summer.
No information No infon
Juvenile* from spring No inton
spawning enter the
lay in early summer;
leave the lay by
late fall, heading
off chore and couth-
ward.
tat ion
tat ion
ppt ealinity.
Both •eiuelly mature
and immature adulti
Adult enter the lay; the
larger the adult
population, the greater
the penetration into
the lay.
Voraciou* predator
- menhaden
- lilveriidc*
- bay anchovy
- herring »pp.
- cruataceana
- annelid*
•luefiah are ••*-
u*lly mature at
about 10.0 cm,
and reach a ma»imu
length of »J.* cm.
Bluefiah, a marine
• p*cie>, enter* the
•ay in cpring and
•ummer to feed.
School* of »lue(i*h
move (eaaonally in
relation to food
abundance.
Compete wttb other
top predator* *uch
•* ttriped **•*.
Target of a com-
mercial and recre-
ational fiahary.
B-20
-------
APPENDIX C
SUBMERGED AQUATIC VEGETATION
Compiled from Stevenson and Confer 1978.
-------
APPENDIX C
SUBMERGED AQUATIC VEGETATION
CeratophyTlum demersum (Coontall)
Characea: Chara, Nltella, Toypellas
Elodea canadensls (Common el odea)
Myrlophyllutn spfcatum (Eurasian watermllfon
Najas guadalupensls (Bushy pondweed)
Potamogeton pectinatus (Sago pondweed)
Potamogeton perfollatus (Redhead grass)
Ruppia marftlma (Wldgeongrass)
ValHsnerla americana (Wild celery)
ZannlchelUa palustrls (Horned pondweed)
Zostera marina (Eelgrass)
C-l
-------
Ceratophyllum deroersum (Coontall)
Distribution
References
Frequents quiet, freshwater pools and
slow streams. Also 1n the Maryland
portion of the Chesapeake Bay.
Mason 1969
Temperature
Critical minimum temperature for
vegetative growth of 20°C, with
optimum growth at 30°C.
Wilkinson 1963
Salinity
Essentially freshwater, but grows
normally 1n salinities under 6.5*/o<»<
Bourn 1932
Substrate
Often grows Independently of substrate
material.
Sculthorpe 1967
Light, Depth and Turbidity
Shade tolerant, requiring a minimum of
2 percent full sunlight for optimum
growth. Not considered to be depth
limited due to Its rootless nature.
Turbidity 1s not as detrimental for
coontan as for rooted vegetation
because of shade tolerance and water
surface habitat.
C-2
Chapman et al. 1974
-------
Ceratophyllurn demersum (Coontail)
Continued
References
Consumer Utilization
Foliage and seeds rated as having great Sculthorpe 1967
importance to ducks, coots, geese, grebes,
swans, waders, shore and game birds.
Moderate importance as fish food, shade,
shelter and spawning medium.
C-3
-------
(copied from HotchMss 1967)
Flgurt 1. Coontall (CtratophyTlum dtmtrsum)
C-4
-------
Characea: Chara, Nitella. TolypelTas
Distribution
References
Primarily found In freshwater environments.
Some species Inhabit brackish waters but
are not found In truly marine enviromaents.
Found 1n temperate and tropical regions of
all the continents.
HutchInson 1975
Cook et al. 1974
Temperature
Germination of Characea occurs after main-
tenance at 40°C for one to three months.
Hutchlnson 1975
Salinity
Certain species ranged 1n salinities up to
15°/oo with growth cessation and limited
survival at 20°/0o.
Oawson 1966
Substrate
Most species of Characea grow in silt or
mud substrate though a small number of
species tend to grow In shallow water on
sandy bottoms.
Hutchlnson 1975
Light, Depth and Turbidity
The Characea are capable of surviving in
low light intensities. Have been found
Inhabiting fresh water at depths up to
65.5 m (Lake Tahoe), with Incident
C-5
Hutchlnson 1975
-------
Characea: Chara, NUella, Tolypellas
Continued
References
radiation of slightly more than 2 percent
of that reaching the lake surface.
Consumer Utilization
Consumed by many kinds of ducks, especially Martin and Uhler 1939
diving ducks. Also provides habitat for
aquatic fauna.
C-6
-------
(cooled from Hotchklss 1967)
Figure 2. Muskgrass (Chara sp.)
C-7
-------
El odea canadensls (Common el odea)
Distribution
Endemic to North America and naturalized
to Many Industrialized nations of Europe
and the southern healsphere.
Temperature
References
Water temperatures of 15 to 18*C are
necessary for successful growth.
Yeo 1965b
Salinity
Salinity range of fresh Mater to brackish
water of 10*/..-
U.S. Army Corps of
Engineers 1974
Substrate
Prefers a soil to sand substrate. Grows
better when rooted than when suspended.
Yeo 1965b
Hutchlnson 1975
Light. Depth and Turbidity
Maximum frequency of elodea Is between
3.0 • and 7.5 • depth. Capable of
quickly growing up through covering
layers of silt.
Hutchlnson 1975
C-8
-------
Elodea canadensls (Comon elodea)
Continued
References
Consumer Utilization
Has Uttle value to water fowl. Generally
unpalatable to aquatic Insects. Epiphytes
grow abundantly between the teeth on the
leaf Margins and on the upper leaf surfaces.
Martin and Uhler 1939
Hutchlnson 1975
C-9
-------
(copied from Hotchkiss 1967)
Figure 3- Common elodea (Elodea canadensis)
C-10
-------
Myriophyllum spicatum (Eurasian watermllfoil)
Distribution
References
Native to Europe and Asia, is widespread
In Europe, Asia and parts of Africa.
Found in Chesapeake Bay area, also infested
many lakes in New York, New Jersey and
Tennessee.
Anonymous 1976
Springer 1959
Springer et al. 1961
Stotts 1961
Temperature
Found growing in temperatures ranging from
0.1° to 30*C.
Anderson 1964
Anderson et al. 1965
Salinity
Found 1n salinities ranging from 0 to
20e/oo. Grows best 1n salinities of
0 to 5 °/o*. Inhibition starts at 10°/*o
and becomes severe from 15 to 20°/00.
Rawls 1964
Boyer 1960
Substrate
Grows best in soft muck or sandy muck
bottoms. Maximum density coincides with
fine organic ooze while minimum density
1s found In sand.
Patten 1956
Anderson 1972
Steenis et al. 1967
PhlUpp and Brown 1965
Springer 1959
Light, Depth and Turbidity
Sensitive to turbidity and grows In water
more than 2 m deep, 1f clear. Limited to
1.5 m in extremely turbid waters.
C-ll
Southwlck 1972
Titus et al. 1975
-------
m splcatua (Eurasian watermllfoll)
Continued
References
Consult Utilization
Low grid* duck food. Found In digestive Florschutz 1973
tracts of 27 Canada Geese, 6 species of Martin et al . 1951
dabbling ducks, 4 species of divers and Springer 1959
31 coots 1n the vicinity of Back Bay and Springer et al. 1961
Currltuck Sound. Offers support for
aufwuchs wMch later becone food for higher
life foras. Crowds out vore desirable
foods.
C-12
-------
(copied from Hotchklss 1967)
Figure 4- Eurasian watermlIfoil (MyHophynum splcatum)
C-13
-------
Najas guadalupenses (Bushy pondweed)
Distribution
References
Essentially freshwater or brackish water
species, ranging fn-m ' --egon to Quebec,
and California to Florida.
Hotchkiss 1967
Martin and Uhler 1939
Temperature
Mo information
Sa Ijfjr ty
Prefers 3°/0o salinity. Found in Potomac
River at salinities of 6 to 9°/oo.
Steenis 1970
Substrate
Prefers soils containing a predominance of
sand, but tolerates substrate of pure muck.
Light, Depth and Turbidity
Usually found in depths ranging from 0.3 to
1.2 m, but has been recorded at depths over
6 m.
USOI 1944
Martin and Uhler 1939
Martin and Uhler 1939
Consumer Utilization
Excellent in food value for waterfowl. Birds
eat both the seeds and the leafy plant parts.
Martin and Uhler 1939
C-14
-------
(redrawn after Hotchkiss 1967)
Figure 5. Naiad (Najas sp.)
C-15
-------
Potamogeton pectinatus (Sago pondweed)
Distribution
References
Range Includes freshwater streams and
ponds, also brackish coastal waters of
the United States and portions of Canada.
Most abundant 1n the northwestern states
and the Chesapeake Bay in the United States.
Reported to be a pest species of irrigation
systems In the west, and 1n cranberry bogs
of Massachusetts.
Martin and Uhler 1939
Hodgeson and Otto 1963
Devlin 1973
Temperature
Germination shown to occur when water
temperature reaches 15 to 18°C.
Yeo 1965b
Salinity
Maximum seed production, seed germination
and vegetative growth occurs in freshwater.
Salinities of 8 to 9°/0« generally decreased
growth and germination rates by 50 percent.
Teeter 1965
Substrate
Grows on both mud and sand bottoms. Prefers
sllty bottoms.
Sculthorpe 1967
Rlckett 1923
Light, Depth and Turbidity
Requires at least 3.5 percent total sunlight
for growth. Shading produces yellowed,
sparse foliage, elongated nodes and rigid
unbranched stems. _
Bourn 1932
-------
Potamogeton pectlnatus (Sago pondweed)
Continued
References
Consumer Utilization
One of the more Important waterfowl plant Martin and Uhler 1939
foods. Nutlets and tubers reported to be Fassett 1960
excellent food source for ducks; rootstocks
and stems are consumed to a lesser degree.
Also provides protective habitat for fish,
oysters, and benthic creatures.
C-17
-------
(copied from Hotchkiss 1967)
Figure 6. Sago pondweed (Potamogeton pectinatus)
C-18
-------
Potamogeton perfollatus (Redhead grass)
References
Distribution
Fresh and moderately brackish waters.
It has been found In Labrador, Quebec,
New Brunswick and extends to Eurasia,
northern Africa and Australia. Its
presence has been recorded 1n the
Chesapeake Bay through 1976.
Ogden 1943
USFWS Migratory Bird and
Habitat Research
Laboratory 1976
Temperature
Experiments showed that respiration and
0- consumption Increased as temperatures
increased from 25 to 40*C, with death
occurring at 45*C.
Anderson 1969
Salinity
1.5 to 19°/oo, tolerant to 25°/,0
Anderson 1969
Substrate
Grows best on a mixture of organic material
and silt with a minimum carbon to nitrogen
ratio, a high capacity to recycle ammonia
and a low redox potential. Moderately
organic muds fairly rich In nitrogen and
exchangeable calcium are more suitable
than highly organic muds.
Misra 1936
C-19
-------
Potamogeton perfollatus (Redhead grass)
Continued
References
Light. Depth and Turbidity
Usually found In still or standing water
ranging from 0.6 to 1.5 m depth. Maximum
rate of photosynthesis attained where
n
light Intensity was about 1.1 g cal/ctn .
Felfoldy 1960
Martin and Uhler 1939
Consumer Utilization
Seeds, rootstocks and portions of the stem
are consumed by Black Ducks, Canvasbacks,
Redheads, Rlngnecks and other duck species,
Also eaten by geese, swans, beaver, deer,
muskrat. Provides protective cover for
various aquatic organisms.
Martin and Uhler 1939
Fassett 1960
C-20
-------
(copied from Hotchkiss 1967)
Figure 7. Redhead grass (Potamogeton perfoliatus)
C-21
-------
Ruppla marltlma (Wldgeongrass)
Distribution
References
Inhabits a wide range of shallow, brackish
pools, rivers and estuaries along the
Atlantic, Gulf and Pacific Coasts. Also
occurs 1n fresh portions of estuaries,
alkaline lakes, ponds and streams and 1n
shallow, saline ponds and river deltas of
the Great Salt Lake region.
Martin et al. 1951
Radford et al. 1964
Ungar 1974
Chrysler et al. 1910
Temperature
R_. marltlma appeared to have two growing
seasons within the temperature range of
18° to 30°C. Growth ceased outside this
range although some fruiting and flowering
occurred at temperatures higher than 30°C.
Joanen and Glasgow 1965
Salinity
Tolerant of a broad salinity range, from
5.0 to 40.0°/oo. Tension zone of over
30°/oo. Flowering and seed set occurs
1n range of tapwater to 28V»o.
Steenls 1970
Anderson 1972
McMillan 1974
Substrate
Prefers soft bottom muds or sand. Has been
found growing on shallow sand shell gravel
soils 1n Russian rivers and streams.
Anderson 1972
Zenkevltch 1963
C-22
-------
Ruppla mar1t1ma (Wldgeongrass)
Continued
Light, Depth and Turbidity
References
Optimum production 1n laboratory studies
occurred at depth of 60 cm. Is found at
depths of a few Inches to several feet.
Turbidity tolerance less than 25-35 ppm In
small ponds; turbidity Is especially harm-
ful to young plants prior to the stems
reaching the surface.
Joanen and Glasgow 1965
Consumer Utilization
Serves as food for numerous species of
ducks, coots, geese, grebes, swans, marsh
and shore birds of the Atlantic, Pacific
and Gulf Coasts. Also used as nursery
grounds and as a fish spawning medium and
cover for marine organisms.
Sculthorpe 1967
Martin and Uhler 1939
Kerwln 1975b
C-23
-------
(copied from Hotchkiss 1976)
Figure 8. Widgeongrass (Ruppia maritima)
C-24
-------
Vallisneria americana (Wildcelery)
Distribution
References
Freshwater macrophyte occurring 1n the
tidal streams of the Atlantic Coastal
Plain.
Martin and Uhler 1939
Temperature
Grows best In temperature range of 33 to
36°C. Arrested growth occurs below 19°C.
Wilkinson 1963
Salinity
Laboratory tests showed that ValHsnerla
could not be maintained 1n salinities
greater than 4.2°/o0.
Bourn 1934
Substrate
Grows equally well in sandy soil and mud.
Hutchinson (1975) found that Y_. americana
thrived best in a soil of 6.5 percent
organlcs, 8.78 percent gravel, 21.46
percent sand, 47.90 percent silt, 14.26
percent clay.
Light, Depth and Turbidity
Schuette and Alder 1927
Hutchinson 1975
Able to tolerate muddy, roiled water.
Usually found in shallow water (0.5 to
1.0 m).
Steenis 1970
C-25
-------
Yanisneria amerlcana (Wlldcelery)
Continued
References
Consumer Utn fzatlon
All parts of the plant structure are Sculthorpe 1967
consumed by fish, ducks, coots, geese,
grebes, swans, waders, shore and game
birds. Also serves as a shade, shelter
and spawning medium for fish.
C-26
-------
(copied from rtotchklss 1967)
Figure 9. VMIdcelery (Va111sner1a amerlcana)
C-27
-------
Zannlchellla palustrls (Horned pondweed)
Distribution
References
This species has been documented In every
state 1n continental United States; however,
1t Is not a commonly occurring submerged
aquatic. Reported occasionally 1n brackish
marshes along the Mew England coast, rarely
found Inland. Recorded 1n Chesapeake Bay
and south to CurMtuck and Pamllco Sound
area, North Carolina.
Deane 1910
Fassett 1960
Temperature
In the Chesapeake Bay, the ZannlchelUa
populations decline rapidly when tempera-
tures reach 30°C. Reported to exist 1n
temperatures as low as 10.5 to 14.8°C.
Tutln 1940
Salinity
Tolerates freshwater, but prefers brackish
waters to 20°/oo.
Radford et al. 1964
Substrate
Tends to grow 1n clay to sandy sediments.
Light, Depth and Turbidity
Prefers shallower water than other submerged
aquatics. May need higher light Intensities
than others; good growth obtained at 4 to 7
percent of the maximum noon summer sunlight.
C-28
Correll et al. 1977
-------
ZannlchelUa palustrls (Horned pondweed)
Continued
References
Consumer Utilization
Fruits and sometimes foliage are good for Fassett 1960
waterfowl In brackish pools.
C-29
-------
(copied from Hotchkiss 1967)
Figure 10- Homed pondweed (Zannichellia palustris)
C-30
-------
Zostera marina (Eelgrass)
Distribution
References
On the Pacific Coast of North America,
eel grass extends from Grantly Harbor,
Alaska, to Agiahampo Lagoon in the Gulf
of California. On the Atlantic Coast of
North America, eelgrass extends from
Hudson Bay, Canada, the southern tip of
Greenland, and one locality in Iceland,
to Bogue Sound, North Carolina.
Me Roy 1968
Steinbeck and Picketts
1941
Cottam 1934]>
Ostenfeld 1918
Phillips 1974a
Temperature
Tolerate temperatures from -6°C to 358C.
Photosynthesis decreased sharply above
35°C. Death occurred after exposure to
-98C.
Biebel and McRoy 1971
Salinity
Can tolerate salinities ranging from
8°/oo to full strength seawater (35Voe)
Phillips 1974a
Arasaki 1950^, 1950b
Martin and Uhler 1939
Substrate
Found growing on a wide variety of sub-
strates, from pure firm sand to pure fii
mud.
Phillips 1974a
C-31
-------
Zostera marina (Eelgrass)
Continued
Light. Depth and Turbidity
References
Has been found growing from about 2 m above
MLW (minimum low water) to depths down to
30 m. Low light Intensity conditions
Inhibit flowering and turlon (young branch)
density 1s decreased In shaded plots.
Cottam and Munro 1954
PhllMps I974a_
Backman and Barllottl 1976
Consumer Utilization
The only groups of animals that consume
eel grass directly are waterfowl and sea
turtles. Eel grass beds provide Important
habitats and nursery areas for many forms
of invertebrates and vertebrates, which
then serve as food sources of species at
higher levels.
Cottam 193413
*ddy and toward 19W
Gutsell 1930
C-32
-------
(copied from Hotchklss 1967)
Figure 11. Eelgrass (Zostera marina)
C-33
-------
APPENDIX D
Environmental Requirements of certain fish 1n Gulf of Mexico estuaries
Contents
Anchoa hepsetus (striped anchovy)
Ancfioa mjtchllll (bay anchovy)
Arlus fells (sea catfish)
ParaTlchthys Tethpslgma (southern flounder)
Mugll cephalus (striped mullet)
Pomatomus saltatrlx (blueflsh)
Pooonlas "cromls (black drum)
Sciaenops ocellatus (red drum)
from Benson 1982
D-l
-------
Anchoa hepsetus (striped anchovy)
The distribution of all life stages of striped anchovy appears to be
limited primarily by salinity. Christmas and Waller (1973) reported this
species in salinities ranging from 5.0 ppt to 3.5 ppt. Perry and Boyes
(1978) collected 95.6% of their specimens in salinities between 20 and 30
ppt, largely in waters south of the Gulf Intracoastal Waterway. This fish
is most abundant at temperatures ranging from 20° to 30°C (68° to 86'F)
(Perry and Boyes 1978).
Anchoa mitchilli (bay anchovy)
Although the distribution of the bay anchovy 1n Mississippi Sound waters 1s
not greatly affected by differences 1n salinities, low winter temperatures
appear to cause some movement to deeper, wanner offshore waters (Springer
and Woodburn I960; Christmas and Waller 1973). Swingle (1971) found them
to be nearly equally distributed in salinities between 5 and 19 ppt in
Alabama coastal waters. Highest catches were 1n salinities ranging from
20.0 to 29.9 ppt. In Mississippi Sound, Christmas and Waller (1973)
established no relationships between the distribution of anchovies and
salinities above 2 ppt. Perry and Christmas (1973) found larvae in
Mississippi waters in salinities ranging from 16.6 to 27.8 ppt. Bay
anchovies were taken at temperatures from 5.0° to 3A.9°C 141.0° to 94.8*F),
but the largest numbers were In water temperatures between 10.0* and 14.9*C
(50.0° and 58.8°F) (Christmas and Waller 1973).
Arius fells (sea catfish)
Sea catfish in estuaries in the summer are most abundant in water
temperatures from 19° to 25°C (66° to 77°F). Year round, they have been
taken in the range of 5.0° to 34.9°C (41.0° to 94.8°F) (Perret et al. 1971;
Adkins and Bowman 1976; Drummond and PellegHn 1977; Johnson 1978). This
euryhaline species is common in salinities from 0 to 45 ppt, but some
tolerate 60 ppt. A preference of higher salinities has been suggested
(Gunter 1947; Johnson 1978; Lee et al . 1980). Breeding occurs in waters
having a salinity range of 13 to 30 ppt.
The developmental stage of larvae incubating in the oral cavity may
determine the location of the parent male (Harvey 1971). Younger larvae
tolerate salinities up to 12.8 ppt, but more developed larvae tolerate
salinities of 16.7 to 28.3 ppt (Harvey 1971). Juveniles are most numerous
in low salinities (Johnson 1978).
Although minimum dissolved oxygen requirements of sea catfish are not
known, this fish sometimes lives in dredged semi closed and closed canals
that are characterized by low oxygen concentrations (Adkins and Bowman
1976). They are found in moderately turbid water (Gunter 1947; Lee et al.
1980).
Sea catfish principally live at depths from 4 to 7 m (13 to 23 ft), but may
occupy waters as deep as 36 m (118 ft) (Lee 1937; Johnson 1978). Major
substrates are muddy or sandy bottoms rich 1n nutrients (Etchevers 1978;
Shipp 1981).
D-2
-------
ParaHchthys lethostigma (southern flounder)
The southern flounder Is euryhaline, occurring 1n waters with salinities
from 0 to 60 ppt. The normal range 1s from about 10 to 31 ppt. They live
at water temperatures from 9.9° to 30.5°C (49.8" to 66.9°F), but are most
common between 14.5° and 21.6°C (58.1° and 70.9°F) (Stokes 1973). The
temperatures and salinities where southern flounder were collected in
Mississippi Sound by Christmas and Waller (1973) ranged from 5.0° to 34.9°C
(41.0° to 94.8°F) and 0.0 to 29.9 ppt. The Juveniles may live in fresh-
water for short periods.
Juveniles are usually most abundant in shallow areas with aquatic
vegetation (shoal grass and other sea grasses) on a muddy bottom. Adults
also tend to favor aquatic vegetation such as Spartlna alternlflora. Some
flounders overwinter in the deeper holes and channels of estuaries, but
most (adults and second-year juveniles) migrate to Gulf waters in the fall
(Gunter 1945).
Mugil cephalus (striped mullet)
Striped mullet live 1n freshwater and 1n salinities up to 75 ppt. In Texas
estuaries the mullet were about equally distributed In water of all salin-
ities (Gunter 1945). They have been taken in Mississippi in salinities
ranging from 0.0 to 35.5 ppt (Christmas and Waller 1973).
Fish less than 3.6 cm (1.4 inches) long are most abundant in salinities
from 0.0 to 14.9 ppt. Juveniles (up to 7.9 cm or 3.1 Inches long) prefer
lower salinities and warmer waters than larger fish. Juveniles are mostly
taken in salinities from 0 to 10 ppt when temperatures range from 25° to
30°C (77° to 86°F). F1sh up to 11 cm (4 Inches) long are abundant at
salinities from 0 to 20 ppt at temperatures of 7° to 30°C (45° to 86°F)
(Etzold and Christmas 1979). Highest catches 1n samples from Mississippi
Sound were in the range of 7° to 20°C (45° to 68'F). Mullet are often
killed in water temperatures less than 5°C (41°F) (J.C. Parker 1971), and
they tend to aggregate i/i sheltered areas before the arrival of cold
weather.
Pomatomus saltatrlx (bluefish)
Temperature and salinity are the only factors cited by Wilk (1977) as
determinants of the distribution of bluefish on the Atlantic coast.
Extensive data from egg and larval collections on the outer continental
shelf of Virginia showed that maximum spawning occurred at 25.6°C (78.1°F)
with none below 18°C (64°F) (Norcross et al. 1974). Minimum spawning
temperature is about 14°C (57°F) (Hardy 1978). Bluefish seem to prefer
salinities from 26.6 to 34.9 ppt. Limited larvae collections 1n the Gulf
of Mexico were found in a temperature range of 23.2° to 26.4°C (73.8° to
79.6°F) and a surface salinity range of 35.7 to 36.6 ppt (Barger et al.
1978). In estuaries they rarely live In salinities below 10 ppt. Hardy
(1978) suggested 7 ppt as the minimum salinity. Lacking are data on the
effects of substrate, turbidity, tides, or dissolved oxygen on bluefish
distribution. Bluefish activity patterns are highly oriented to vision
(Olla and Studholme 1979), however, and bluefish are not likely to frequent
turbid areas.
0-3
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Pogonlas cromls (black drum)
Black drum are euryhallne during all life stages, I.e., they occur in
salinities from 0 to 35 ppt. The species is most common at salinities
ranging from 9 to 26 ppt (Gunter 1956; Etzold and Christmas 1979), but some
inhabit water with salinities as high as 80 ppt. The black drum is usually
taken at water temperatures from 12° to 30°C (54° to 86°F). This fish
inhabits areas with sand or soft bottoms as well as brackish marshes and
oyster reefs (Etzold and Christmas 1979). The preferred habitat of
juveniles during the first 3 months are muddy, nutrient-rich, marsh
habitats such as tidal creeks.
Sciaenops ocellatus (red drum)
The general salinity range for red drum is 0 to 30 ppt, but some tolerate
salinities up to 50 ppt (Theiling and Loyacano 1976). Larvae and Juveniles
were taken at salinities between 5.0 and 35.5 ppt 1n one study (Christmas
and Waller 1973), but most occur at salinities from 9 to 26 ppt. The
larger fish seem to prefer higher salinities. Red drum are most abundant
in salinities from 20 to 25 ppt (Etzold and Christmas 1979), and from 25 to
30 ppt (Kilby 1955). Overall, red drum prefer moderate to high salinities.
Red drum have been observed 1n water temperatures ranging from 2° to 29°C
(36° to 84°F). Some young fish were found in a temperature range of 20.5°
to 31°C (68.9° to 87.88F). The highest catches were at temperatures
between 20° and 258C (68° and 778F) (Etzold and Christmas 1979). Large
numbers of red drum have been reported killed in severe cold spells (Adkins
et al. 1979).
Red drum thrive in waters over sand, mud, or sandy mud bottoms and
occasionally in and among aquatic vegetation.
D-4
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Technical Support Manual:
Waterbody Surveys and
Assessments for Conducting
Use Attainability Analyses
Volume III: Lake Systems
-------
TECHNICAL SUPPORT MANUAL:
WATERBODY SURVEYS AND ASSESSMENTS FOR
CONDUCTING USE ATTAINABILITY ANALYSES
VOLUME III: LAKE SYSTEMS
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF WATER REGULATIONS AND STANDARDS
CRITERIA AND STANDARDS DIVISION
WASHINGTON, D.C. 20460
NOVEMBER 1984
-------
FOREWORD
The Technical Support Manual; Water Body Surveys and Assessments for
Conducting Use Attainability Analyses, Volume III; lake Systems contains
outdance prepared by EPA to assist states fn implementing the revised Water
Quality Standards Regulation (48 FR 51400, November 8, 1983). This docu-
ment addresses the unique characteristics of lake systems and supplements
the two previous Manuals for conducting use attainability analyses (U.S.
EPA, 1983b, 1984).TRe~pun>o$e of these documents 1s to provide guidance
to as$1st~5tates 1n answering three central questions:
(1) What are the aquatic protection uses currently being achieved In
the water body?
(2) What are the potential uses that can be attained based on the
physical, chemical and biological characteristics of the water
body?
(3) What are the causes of any Impairment of the uses?
Consideration of the suitability of a water body for attaining a given use
Is an Integral part of the water quality standards review and revision
process. EPA will continue to provide guidance and technical assistance to
the States In order to Improve the scientific and technical bases of water
quality decisions. States are encouraged to consult with EPA at the
beginning of any standards revision project to agree on appropriate methods
before the analyses are Initiated, and to consult frequently as they are
conducted.
Any questions on this guidance may be directed to the water quality
standards coordinators located In each of the EPA Regional offices or to:
El Hot Lomn1t2
Criteria and Standards Division (WH-585)
401 H Street, S.W.
Washington, D.C. 20460
Edwin L. Johnson, Director
Water Regulations and Standards
-------
CONTENTS
FOREWORD
CHAPTER I
INTRODUCTION
CHAPTER II PHYSICAL AND CHEMICAL CHARACTERISTICS
INTRODUCTION
PHYSICAL CHARACTERISTICS
Physical Parameters
Physical Processes
CHEMICAL CHARACTERISTICS
Overview of Physlco-Chemlcal Phenomena 1n Lakes
Phosphorus Removal by Precipitation
Dissolved Oxygen
Eutrophicatlon and Nutrient Cycling
Significance of Chemical Phenomena to Use
Attainability
TECHNIQUES FOR USE ATTAINABILITY EVALUATIONS
Introduction
Empirical Models
Computar Models
CHAPTER III BIOLOGICAL CHARACTERISTICS
INTRODUCTION
PLANKTON
Phytoplankton
Zooplankton
AQUATIC MACROPHYTES
Response to Macrophytes to Environmental Change
Preferred Conditions
BENTHOS
Composition of Benthlc Communities
General Response to Environmental Change
Qualitative Response to Environmental Change
Quantitative Response to Environmental Change
FISH
Trophic State Effects
Temperature Effects
Specific Habitat Requirements
Stocking
Page
I-l
II-l
II-l
II-l
II-l
II-6
11-23
11-23
11-27
11 -28
11-29
11-31
11-32
11-32
11-33
11-48
III-l
III-l
III-l
III-l
111-10
III-ll
III-ll
111-12
111-13
111-13
111-14
111-14
III-22
111-31
111-31
II1-32
111-32
111-34
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CHAPTER IV SYNTHESIS AND INTERPRETATION
IY-1
CHAPTER V
APPENDIX A
APPENDIX B
APPENDIX C
APPENDIX D
INTRODUCTION IY-1
USE CLASSIFICATIONS IY-1
REFERENCE SITES IY-4
Selection IY-4
Comparison IY-7
CURRENT AQUATIC LIFE PROTECTION USES IY-8
CAUSES OF IMPAIRMENT OF AQUATIC LIFE PROTECTION USES IY-8
ATTAINABLE AQUATIC LIFE PROTECTION USES IY-8
PREVENTIVE AND REMEDIAL TECHNIQUES IY-10
Dredging IV-11
Nutrient Precipitation and Inactlvatlon IV-16
Aeration/Circulation IY-22
Lake Drawdown IY-30
Additional In-Lake Treatment Techniques IV-34
Watershed Management IY-39
REFERENCES Y-l
PALMER'S LISTS OF POLLUTION TOLERANT ALGAE A-l
U.S. ENVIRONMENTAL PROTECTION AGENCY'S PHYTOPLANKTON
TROPHIC INDICES B-l
CLASSIFICATION, BY VARIOUS AUTHORS, OF THE TOLERANCE
OF VARIOUS MACROINVERTEBRATE TAXA TO DECOMPOSABLE
WASTES C-l
KEY TO CHIRONOMJD ASSOCIATIONS OF THE PROFUNDAL ZONES
OF PALEARCTIC AND NEARCTIC LAKES D-l
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CHAPTER I
INTRODUCTION
EPA's Office of Water Regulations and Standards has prepared guidance to
accompany changes to the Water Quality Standards Regulation (48 PR 51400).
This guidance has been compiled and published 1n the Hater Quality Stand-
ards Handbook (U.S. EPA, December I983a). Sections 1n the Handbook present
discussion of the water quality review and revision process; general
guidance on Mixing zones, and economic considerations pertinent to a change
In the use designation of a water body; the development of site specific
criteria; and the elements of a use attainability analysis.
One of the major pieces of guidance 1n the Handbook 1s "Water Body Surveys
and Assessments for Conducting Use Attainability Analyses." This guidance
presents a general framework for designing and conducting a water body sur-
vey whose objective Is to answer the following questions:
1. What are the aquatic life uses currently being achieved In the
water body?
2. What are the potential uses that can be obtained, based on the
physical, chemical and biological characteristics of the water
body?
3. What are the causes of Impairment of the uses?
In response to requests from several states for additional Information,
technical guidance on conducting water body surveys and assessments has
been provided In two documents:
1. Technical Support Manual; Water Body Surveys and Assessments for
"Conducting Use Attainability Analyses (U.S. EPA. November 1983bTr"
2. Technical Support Manual: Water Body Surveys and Assessments for
'Conducting Use Attainability Analyses. Volume II: Estuarlne
Systems (U.S. EPA. June 1984).
The first volume 1s oriented towards rivers and streams and presents
methods for freshwater evaluations. The second volume stresses those con-
siderations which are unique to the estuary. The current Manual. Volume
III, focuses on the physical, chemical and biological phenomena of lakes
liuf Is presented so as not to repeat Information that Is common to other
freshwater systems that already appears 1n one of the earlier volumes.
Apart from the rare Impoundment that Is fed only by surface runoff or
underground springs, rivers and lakes are linked physically and exhibit a
transition from riverine habitat and conditions to lacustrine habitat and
conditions. Because of this physical link, the biota of the lake will be
essentially the same as the biota of the stream, although there are few
species that are primarily lake species. Given the ties that exist between
like and stream under natural conditions, It Is Important that those who
dill be conducting lake use attainability studies refer to Volume I on
rivers and streams for additional perspective.
1-1
-------
Each of the Technical Support Manuals provides extensive Information on the
plants and animals characteristic of a given type of water body, and
provides a number of assessment techniques that will be helpful 1n per-
forming a water body survey. The methods offered 1n the guidance documents
are optional, however, and states may apply them selectively, or may use
their own techniques for designing and conducting use attainability
studies.
Consideration of the suitability of a water body for attaining a given use
Is an Integral part of the water quality standards review and revision
process. The data and other Information assembled during the water body
survey provide a basis for evaluating whether or not the water body 1s
suitable for a particular use. Since the complexity of an aquatic eco-
system does not lend Itself to simple evaluations, there 1s no single
formula or model that will serve to define attainable uses. Rather, many
evaluations must be performed, and the professional judgment of the
evaluator Is crucial to the Interpretation of data that 1s reviewed.
This Technical Support Manual on lakes will not tell the biologist or
engineer how to conduct a use attainability study, per se, rather, It will
lay out those chemical, physical and biological phenomena that are char-
acteristic of lakes, and point out factors that the Investigator might take
Into consideration while designing a use study, and while preparing an
assessment of uses from the Information that has been assembled. The
chapters 1n this Manual focus on the following aspects of lakes:
Chapter II. Physical and Chemical Characteristics
o Circulation, stratification, seasonal turnover
o Nutrient cycling
o Eutrophlcation processes
o Computer and desktop procedures for lake evaluations
Chapter III. Biological Characteristics
o Benthos
o Zooplankton
o Phytoplankton
o Macrophytes
o Fish
Chapter IV. Synthesis and Interpretation
o Aquatic life use classifications
o Impairment of uses
o Reference site comparisons
o Preventive and remedial techniques
Chapter V. References
1-2
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CHAPTER II
PHYSICAL AMD CHEMICAL CHARACTERISTICS
INTRODUCTION
The aquatic life uses of a lake are defined 1n reference to the plant and
animal life 1n the lake. The types and abundance of the biota are largely
determined by the physical and chemical characteristics of the lake. Other
contributing factors Include location, cllmatologlcal conditions, and
historical events affecting the lake.
Each lake characteristic such as depth, length, Inflow rate and temperature
contributes to the physical processes of the Mater body. For example,
circulation may be the dominant physical process In a lake that 1s large
and shallow while for a deep medium size lake the dominant process may be
the annual cycle of thermal stratification.
The chemical characteristics of a lake are affected by Inflow water quality
and by various physical, chemical and biological processes which provide
the biota with Us sustaining nutrients and required dissolved oxygen.
OverenHchment with nutrients may accelerate the natural processes of the
lake, however, and lead to major upsets In plant growth patterns, dissolved
oxygen profiles, and plant and animal communities. The physical and
chemical attributes of lakes as well as the Influence of physical processes
on chemical characteristics are discussed In this chapter.
In addition to a discussion of physical parameters and processes, and the
chemical characteristics of lakes, several techniques for use attainability
evaluations are presented In this chapter. These Include empirical
Input/output models, computer simulation models, and data evaluation
techniques. For each of these general categories specific methods and
models are presented with references. Illustrations of some techniques are
also presented.
The objective 1n discussing the physical and chemical properties of lakes
Is to assist the states to characterize a lake and select assessment
methodologies that will enable the definition of attainable uses.
PHYSICAL CHARACTERISTICS
Physical Parameters
The physical parameters which describe the size, shape and flow regime of a
lake represent the basic characteristics which affect physical, chemical
and biological processes. As part of a use attainability analysis, the
physical parameters must be examined In order to understand non-water
quality factors which affect the lake's aquatic life.
Lakes can be grouped according to formation process. Ten major formation
processes presented by Wetzel (1975) Include:
II-l
-------
o Tectonic (depression due to earth movement)
o Volcano*
o Landslides
o Glaciers
o Solution (depressions fro* soluble rock)
o River activity
o Wind-formed basins
o Shoreline activity
o Dans (man-Made or natural).
The origins of a lake determine Us morphologic characteristics and
strongly Influence the physical, chemical and biological conditions that
will prevail.
Physical (morphological) characteristics whose measurement may be of
Importance to a water body survey Include the following:
o Surface area, A (measured In units of length squared, L2)
o Volume, V (measured 1n units of length cubed, I )
o Inflow and outflow, Q. and Qrtlli. (measured 1n units of length
cubed per time, L3/T) 1n out
o Mean depth, 9
o Maximum depth
o Length
o Length of shoreline
o Depth-area relationships
o Depth-volume relationships
o Bathymetry (submerged contours).
Some of these parameters may be used to calculate other characteristics of
the lake. For example:
II-2
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o The Mass flow rate of a chemical, say phosphorus, may be calcu-
lated as *** product of concentration [P. ] and Inflow, Q4_, pro-
vided the units are compatible. in in
mass flow rate » [?1n, M/L3] x (Q1n, L3/T) • M/T
where M denotes units of mass
o The surface loading rate Is calculated as the quotient of Inflow
and surface area, or the quotient of mass flow rate and area,
e.g.,
liquid surface loading rate - (Q1n, L3/T)/(A, L2) - L3/L2-T
mass surface loading rate • [C1n, M/L3] x (Q1n. L3/T)/(A, L2) - M/L2-T
o The detention time 1s given by the quotient of volume and flow
rate, e.g.,
detention time - (V, L3)/(Q1n, L3/T) • T
The reciprocal of the detention time Is the flushing rate, T
o Mean depth Is the quotient of volume and surface area, e.g.,
9 • (V, L3)/(A, L2) • L
The first seven parameters of the above 11st describe the general size and
shape of the lake. Mean depth has been used as an Indicator of produc-
tivity (Wetzel. 1975; Cole, 1979) since shallower lakes tend to be more
productive. In contrast, deep and steep sided lakes tend to be less
productive.
Total lake volume and Inflow and outflow rates are physical characteristics
which Indirectly affect the lake aquatic community. Large Inflows and
outflows for lakes with small volumes produce low detention times or high
flow through rates. Aquatic life under these conditions may be different
than when relatively small Inflows and outflows occur for a large lake
volume. In the latter case the detention time 1s much greater.
Hand (1975) has recommended a shape factor—the lake length divided by the
lake width—for lake studies. This shape factor was applied by Hand and
McClelland (1979) as a variable 1n a regression equation used to predict
chlorophyll-a 1n Florida lakes. Other parameters 1n that regression
equation are phosphorus, nitrogen, and the mean depth.
For the requirements of a more detailed lake analysis, Information describ-
ing the depth-area and depth-volume relationships and Information
describing the bathymetry may be required. An example of a bathymetrlc map
Is shown 1n Figure II-l for Lake Harney, Florida (Brezonlk and Fox, 1976).
The roundness of this particular lake 1s typical of many lakes 1n Florida
whose morphometry has been affected by limestone solution processes (Baker,
et al., 1981). A typical reh-esentat1on of the depth-area and depth-volume
relationships for a lake 1s shown 1n the graph of Figure II-2 for the Fort
II-3
-------
1HAXIOH
Shaded araa raprasaats marsh airaa
Contour lina« showing dtpth in f««t at
••an low vatar
Figure II-l. Bathyrotrlc Maip of Lake Harney, Florida (from flrezonlk. 1976)
II-4
-------
740
7JO
40 10 120 110 200 240 210 320 JCO 400
VOIUMC-IOOO ACAC rccr
7)0
Figure II-2. Fort Loudoun Reservoir Areas and Volumes (from Water
Resources Engineers, 1975)
II-5
-------
Loudoun Reservoir, Tennessee (Hall, et al., 1976). Depth-area relation-
ships can be Important to the biological activity In a lake. If the
relationship 1s such that with a slight Increase In depth the surface area
1s greatly Increased, this then produces greater bottom and sediment con-
tact with the water volume which 1n turn could support Increased biological
activity.
In addition to the physical parameters listed above, It Is also Important
to obtain and analyze Information concerning the lake's contributing water-
shed. Two major parameters of concern are the drainage area of the con-
tributing watershed, and the land use(s) of that watershed. Drainage area
will aid 1n the analysis of Inflow volumes to the lake due to surface run-
off. The land use classification of the area around the lake can be used
to predict flows and also nonpolnt source pollutant loadings to the lake.
The physical parameters presented above may be used to understand and
analyze the various physical processes that occur In lakes. They can also
be used directly 1n simplistic relationships which predict productivity to
aid In aquatic use attainability analyses.
Physical Processes
There are many complex and Interrelated physical processes which occur 1n
lakes. These processes are highly dependent on the lake's physical param-
eters, geographical location and characteristics of the contributing water-
shed. Individual physical processes are usually highly Interdependent.
Five major processes—lake currents, heat budget, light penetration,
stratification and sedimentation—are discussed below. Each process can
affect the ecological system of a lake, especially the biota and the dis-
tribution of chemical species.
Lake Currents
Water movement 1n a lake affects productivity and the biota because It
Influences the distribution of nutrients, microorganisms and plankton
(Wetzel, 1975). Lake currents are propagated by wind, Inflow/out flow and
CoMolls force (a deflecting force which Is a function of the earth's
rotation). The types of currents developed 1n lakes are dependent upon the
lake size and Its density structure.
For small, shallow lakes (especially those that are long and narrow),
Inflow/outflow characteristics are most Important and the predominant cur-
rent 1s a steady-state flow through the lake. For very large lakes, wind
Is the primary generator of currents and, except for local effects, Inflow
and outflow have a relatively minor affect on lake circulation. The
Cor1ol1s force Is another Important determinant of circulation 1n larger
lakes such as the Great Lakes (L1ck, 1976^).
Wind. Wind Induced turbulence on the lake surface results In a variety of
current patterns that are characteristic of the lake's physical properties.
For shallow lakes, the wind Induces vertical mixing throughout the water
column. Steady-state currents formed in deep lakes that have a constant
density are characterized by top and bottom boundary layers where vertical
11-6
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mixing 1s Important, and by horizontal boundary layers near the shore where
horizontal mixing Is Important (L1ck, 1976±).
Under severe or prolonged wind conditions, the stress on the water surface
can cause circulation In the upper epIHmnlon region of a stratified lake
because of the Inclination of the water surface. This then can cause a
counter flow 1n the lower hypollmnlon region of the reservoir. This
condition 1s demonstrated by Fischer (1979) 1n Figure II-3. The flow
patterns are turbulent enough to disrupt the thermocllne by tilting 1t
toward the leeward side of the lake. After the wind stops, Internal water
movement causes the tilted upper and lower water regions, which are
separated by the thermocllne, to oscillate back and forth jntll the pre-
wlnd stress steady-state condition returns (Wetzel, 1975). This type of
water movement caused by wind stress and subsequent oscillations Is known
as a seiche.
Simply stated, an external seiche Is a free oscillation of water, In the
form of long standing surface wave, reestablishing equilibrium after having
been displaced. The external seiche attains Us maximum amplitude at the
surface while the Internal seiche, which Is associated with the density
gradient In stratified lakes, attains It maximum amplitude at or near the
thermocllne (Figure II-4). In stratified waterbodles, the layers of
differing density oscillate relative to each other, and the amplitude of
the Internal standing wave or Internal seiche of the metallmnlon 1s much
greater than that of the external or surface seiche. Because of the
extensive water movement associated with Internal seiches, the resulting
currents lead to vertical and horizontal transport of heat and dissolved
substances (Including nutrients) and significantly affect the distribution
and productivity of plankton (Wetzel, 1975).
Inflow and Outflow. Lake currents and the resultant mixing and horizontal
transport of the water mass may also be a function of Inflow and outflow
patterns and volumes. Influent velocity generally decreases as the flow
enters the lake. Inflowing water of a given temperature and density tends
to seek a level of similar density In the lake. Three types of currents
may be generated by river Influents, as shown In Figure II-5. Overflow
occurs when Inflow water density 1s less than lake water density.
Underflow occurs when Inflow density 1s greater than lake water density.
Interflow occurs when there 1s a density gradient In the lake, as during
periods of stratification, where Inflow Is greater 1n density than the
epIHmnlon but Is less dense than the hypollmnlon.
For a completely mixed lake where no density gradient exists, the outflow
draws on the totally mixed volume with little consequence to the net flow
within the lake. In stratified Impoundments, where outflows could be from
different levels (e.g., reservoir release or withdrawal operations), the
discharge comes from only a limited zone (or layer) within the lake or
reservoir. The thickness of the withdrawal layer 1s a function of the
density gradient In the region'of the outlet.
Corlolls Effect. For very large lakes, like the Great Lakes, the Corlolls
effect can Influence the currents within the lake. This effect Is caused
by the Inertlal force created by the earth's rotation. It deflects a
moving body (water In this case) to the right (of the line of action of the
II-7
-------
Figure II-3,
Formation of barocHnlc motions 1n a lake exposed to wind
/ft*8"?*?* th! surface: («) Initiation of motion,
jbj position of maximum shear across the thermocllne
(c; steady-state barocHnlc circulation (from Fischer, 1979)
II-8
-------
• •»*•*••<•» • •_• ^p* *_? **"^******* f
Figure II-4.
Movement caused by (1) wind stress and (11) a subseqvwnt
Internal seiche In a hypothetical two-layered lake,
neglecting friction. Direction and velocity of flow are
approximately Indicated by arrows, o - nodal section.
(from Mortimer, 1952)
ri-g
-------
FIGURE II-5. Types of inflow into lakes and reservoirs
(from Wunderllch, 1971) Avoirs
11-10
-------
earth's rotation) In the Northern Hemisphere and to the left In th«
Southern Hemisphere. The Cor1ol1s effect causes the surface water to movt
to the right of the prevailing direction of the wind. Under these con-
ditions In a stratified lake, less dense water tends to fom on the right
side of the predominant current while denser water collects on the left
side of the current (Uetzel, 1975).
Heat Budget
The temperature and temperature distribution within lakes and reservoirs
affect not only the water quality within the lake but also the thermal
regime and quality of a river system downstream of the lake. The thermal
regime of a lake 1s a function of the heat balance around the body of
water. Heat transfer modes Into and out of the lake Include: heat trans-
fer through the air-water Interface, conduction through the mud-water
Interface, and Inflow and outflow heat advectlon.
Heat transfer across the mud-water Interface 1s generally Insignificant
while the heat transfer through the air-water Interface 1s primarily
responsible for typical annual temperature cycles In lakes.
Heat Is transferred across the air-water Interface by three different
processes: radiation exchange, evaporation, and conduction. The Individ-
ual heat terms associated with these processes are shown 1n Figure II-6 and
are defined 1n Table II-1 along with typical ranges of their magnitudes 1n
northern latitudes.
The expression that results from the summation of these various energy
fluxes Is:
- (Hb * He ±
where
HM « net energy flux through the air-water Interface,
N Btu/ft2-day
H « net short-wave solar radiation flux passing through the
Interface after losses due to absorption and scattering
In the.atmosphere and by reflection at the Interface,
Btu/fr-day
H » net long-wave atmospheric radiation flux passing through
*" the Interface after reflection, Btu/ft -day
2
Hb > outgoing long-wave back radiation flux, Btu/ft -day
H. • convectlve energy flux passing back and forth between
the Interface and the atmosphere, Btu/ft-day
He • energy loss by evaporation, Btu/ft-day
11-11
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H,
t
t
"c
AIR-WATER
INTERFACE
Figure II-6. Heat Transfer Terms Associated with Interfadal Heat Transfer
(from Roesner, 1981}
11-12
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TABLE II-l
DEFINITION OF HEAT TRANSFER TERMS
ILLUSTRATED IN FIGURE II-6
Magnitude
Heat Teni Units (BTU ft"2 day"1)
H.
H,,
H.
Hir
"b
H,
Hc
where
H
L
T
• total Incoming solar or 9 .
short-wave radiation HL T*1
, • reflected short-wave radiation HL"2^1
> total Incoming atmospheric 9 .
radiation HL'^T"1
» reflected atmospheric radiation HL^T"1
* back radiation from the water ? .
surface HL" T"
» heat loss by evaporation HL^T"1
• heat loss by conduction to 9 .
atmosphere HL'^T"1
• units of heat energy (e.g., BTU)
• units of length
• units of time
400-2800
40-200
2400-3200
70-120
2400-3600
150-3000
-320 to +400
SOURCE: Roesner, et al., 1981.
11-13
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These mechanisms by which heat 1$ exchanged between the water surface and
the atmosphere are fairly well understood and are documented In the litera-
ture (Edlnger and Geyer, 1965). The functional representation of these
terms has been defined by Hater Resources Engineers, Inc. (1967).
The heat flux of the air-water Interface Is a function of location (lati-
tude, longitude and elevation), season of the year, time of day and
meteorological conditions 1n the vicinity of the lake. Meteorological
conditions which affect the heat exchange are cloud cover, dew-point
temperature, barometric pressure and wind.
Light Penetration
The heat budget discussed above 1s also descriptive of the light flux at
the air-water Interface. The transmission of light through the water
column Influences primary productivity, growth of aquatic plants,
distribution of organisms and behavior of fish.
The reduction of light through the water column of a lake Is a function of
scattering and absorption where absorption 1s defined as light energy
transformed to heat. Light transmission 1s affected by the water surface
film, floatable and suspended partlculates, turbidity, dense populations of
algae and bacteria, and color.
The Intensity at a given depth 1s a function of light Intensity at the
surface and the parameters mentioned above which attenuate the light.
Attenuation 1s usually represented by the use of a light extinction co-
efficient.
An Important physical parameter based on the transmission of light Is the
depth to which photosynthetic activity 1s possible. The minimum light
Intensity required for photosynthesis has been established to be about 1.0
percent of the Incident surface light (Cole, 1979). From the depth at
which this Intensity occurs to the surface 1s called the euphotlc zone.
Percent light levels can be measured by a subsurface photometer which can
be used to establish the depth of 1.0 percent Illumination. A simple
measurement of light penetration depth Is made with the Secchl disc which
1s lowered Into the water to record the depth at which 1t disappears to the
observer. The depth of the 1.0 percent surface light Intensity may be
estimated as 2.7 to 3.0 times the Secchl disk transparency (Cole, 1979).
The percent of the surface Incident light which reaches different depths 1s
highly variable for Individual lakes. Cole (1979) presents examples of the
percent Incident light by depth for various bodies of water, as shown In
Figure II-7.
Lake Stratification
Lakes 1n temperate and northern latitudes typically exhibit vertical
density stratification during certain times of the year. Stratification 1n
lakes 1s primarily due to temperature differences (I.e., thermal strati-
fication), although salinity and suspended solids concentration may also
affect density.
11-14
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a
a
3 -
5 -
0.1
50 100
Percent incident light
FIGURE II-7.
Vertical penetration of light 1n various bodies of
water showing percentage of Incident light remaining
at different depths (from Cole, 1978)
11-15
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Lake stratification 1s best explained by a discussion of a generalized
annual temperature cycle. For a period 1n spring, lakes commonly circulate
from surface to bottom, resulting 1n a uniform temperature profile. This
vernal mixing has been called the spring overturn. As surface temperatures
war* further, the surface Mater layer becomes less dense than the colder
underlying water, and the lake begin* to stratify. This stratified
condition, called direct stratification, exists throughout the summer, and
the Increasing temperature differential between the upper and lower layers
Increases the stability (resistance to mixing) of the lake.
The upper mixed layer of warm, low-density water 1s termed .the epHlmnlon,
while the lower, stagnant layer of cold, high-density water 1s termed the
hypo11mn1on. The transition zone between the epIUmnlon and hy poll union
has been called, among other names, the metalImnlon. This narrow
transition zone Is characterized by rapidly declining temperature with
depth, and 1t contains the thermocHne which Is the plane of maximum rate
of decrease 1n temperature. The region In which the temperature gradient
exceeds 1*C per meter may be used as a working definition of the thermo-
cllne. A diagram of the three zones and the thermocllne 1s presented 1n
Figure II-8, and Figure II-9 1s a diagram of an annual temperature cycle 1n
which direct stratification occurs.
As surface water temperatures cool 1n the fall, the density difference
between Isothermal strata decreases and lake stability U weakened.
Eventually, wind-generated currents are sufficiently strong to break down
stratification and the lake circulates from surface to bottom (fall
overturn). In warmer temperate regions, a lake may retain this completely
mixed condition throughout the winter, but 1n colder regions, particularly
following the formation of Ice, Inverse stratification often develops
resulting 1n winter stagnation. In this condition, the most dense, 4*0
water constitutes the hypol1mn1on which 1s overlled by less dense, colder
water between 0*C and 4*C. The difference 1n density between 0*C and 4*C
1s very small, thus Inverse stratification results 1n only a minor density
gradient Just below the surface. Hence, the stability of Inverse
stratification 1s low and, unless the lake 1s covered with Ice, Is easily
disrupted by wind mixing.
During stratification, the presence of the thermocllne suppresses many of
the mass transport phenomena that are otherwise responsible for the ver-
tical transport of water quality constituents within a lake. The aquatic
community 1s highly dependent on the thermal structure of such stratified
lakes.
Retardation of mass transport between the hypolImnlon and the epIUmnlon
results 1n sharply differentiated water quality and biology between the
lake strata. For example, If the magnitude of the dissolved oxygen
transport rate across the thermocllne Is low relative to the dissolved
oxygen demand exerted In the hypolImnlon, vertical stratification of the
lake will occur with respect to the dissolved oxygen concentration.
Consequently, as ambient dissolved oxygen concentrations 1n the hypol1mn1on
decrease, the life functions of many organisms are Impaired and the biology
and biologically mediated reactions fundamental to water quality are
altered. Major changes occur 1f the dissolved oxygen concentration goes to
zero and anaerobic conditions result. Large diurnal fluctuations of
11-16
-------
10
20
E
•
z
H
0.
UJ
0
30
40
50
c
o
"c
o
a
10
15
20
25
30
TEMPERATURE, °C
FIGURE I1-8. Vertical temperature profile showing direct
stratification and the lake regions defined
by it (from Cole, 1979).
11-17
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LATC FAU.-VINTC*
fAU.
\
•MIIM
r-**"-** y **im»*-j
y»«n.»« g «mn»»
'" • - • ——^- ttu*»** • •
I-
in
1
( • * M M *
Figure II-9. Annual Cycle of Thermal Stratification and Overturn In an Impoundment (from Zlson et al, 1977)
11-18
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dissolved oxygen concentrations In the eplllmnlon can also occur due to
daytime photosynthetlc oxygen production superimposed over the continuous
oxygen demand from blotlc respiration.
Vertical stratification of a lake with respect to nutrients can also occur.
In the euphotlc zone, dissolved nutrients are converted to partlculate
organic material through the photosynthetlc process. Because the euphotlc
zone of an ecologically advanced lake does not extend below the thermo-
cllne, this assimilation of the dissolved nutrients lowers the ambient
nutrient concentrations In the epIUmnlon. Subsequent sedimentation of the
partlculate algae and other organic matter then serves to transport the
organically bound nutrients to the hypollmnlon where they are released by
decomposition. In addition, the vertical transport of the released
nutrients upward through the thermccline Is suppressed by the same
mechanisms that Inhibit the downward transport of dissolved oxygen. Thus,
several processes combine to reduce nutrient concentrations 1n the eplllm-
nlon while simultaneously enriching the hypollmnlon.
In addition to the effect of the temperature structure on the movement of
water quality constituents, the temperature at any point has a more direct
Impact on the biology and therefore the water quality structure of an
Impoundment. All life processes are temperature dependent. In aquatic
environments, growth, respiration, reproduction, migration, mortality and
decay are strongly Influenced by the ambient temperature. According to the
van't Hoff rule, within a certain tolerance range, biological reaction
rates approximately double with a 10*C Increase 1n temperature.
Annual Circulation Pattern and Lake Classification
Lakes can be classified on the basis of their pattern of annual mixing as
described below.
Amlxls Amlctlc lakes never circulate. They are permanently covered
with Ice, and are mostly restricted to the Antarctic and very
high mountains.
Holomlxls In holomlctlc lakes, wind-driven circulation mixes the entire
lake from surface to bottom. Several types of holomlctlc lakes
have been described.
OUgomlctlc lakes are characterized by circulation that Is
unusual, Irregular, and In short duration. These are generally
tropical lakes of small to moderate area or lakes of very great
depth. They may circulate only at Irregular Intervals during
periods of abnormally cold weather.
Monomlctlc lakes undergo one regular period of circulation per
year. Cold monbmlctlc lakes are frozen 1n the winter (and
therefore stagnant and Inversely stratified) and mix throughout
the summer. Cold monomlctlc lakes are Ideally defined as lakes
whose water temperature never exceeds 4*C. They are generally
found In the Arctic or at hlih altitudes. Harm monomlctlc
lakes circulate 1n the winter at or above 4"C and stratify
directly during the summer. Warm uomomlxis Is common to warm
11-19
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regions of temperate zones, particularly coastal areas, and to
•ountalnous areas of subtropical latitudes. Mam monom1ct1c
lakes are prevalent In coastal regions of North America and
northern Europe.
Dlmlctlc lakes circulate freely twice a year In spring and
fall, and are directly stratified 1n summer and Inversely
stratified In winter. Dlmlxls Is the most common type of
annual nixing observed In cool temperate regions of the world.
Most lakes of central and eastern North America are dlmlctlc.
Polymlctlc lakes circulate frequently or continuously. Cold
polymlctlc lakes circulate continually at temperatures near or
slightly above 4*C. Ham poiyafctlc lakes circulate frequently
at temperatures well above « wc. These lakes are found 1n
equatorial regions where air temperatures change very little
throughout the year.
Meromlxls Meromlctlc lakes do not circulate throughout the entire water
column. The lower water stratum 1s perennially stagnant and 1s
called the monlmollmnlon. The overlying stratum, the mlxo-
llmnlon, circulates periodically, and the two strata are
separated by a severe salinity gradient called the chemocllne.
Internal Flow and Lake Classification
Experience with prototype lakes (Roesner, 1969) has revealed that with
respect to Internal flow structure there are basically three distinct
classes of lakes. These classes are:
o The strongly-stratified, deep lake which 1s characterized by
horizontal Isotherms.
o The weakly stratified lake characterized by Isotherms which are
tilted along the longitudinal axis of the reservoir.
o The nonstratlfled. completely mixed lake whose Isotherms are
essentially vertical.
The single most Important parameter determining which of the above classes
a lake will fall Is the denslmetrlc Froude number, F, which can be written
for the lake as:
F • (LQ/DY) { P^g/J) (2)
where
0
V
lake length, m
volumetric discharge through the lake, ar/$
mean lake depth, m
lake volume, m3
reference density, taken as 1.000 k.;'m 4
average density gradient In the lake, Icg/m
gravitational constant, 9.81 m/sz
11-20
-------
This number 1$ the ratio of the Inertia! fore* of the horizontal flow to
the gravitational forces within the stratified Impoundment; consequently,
It Is a measure of the success with which the horizontal flow can alter the
Internal density (thermal) structure of the lake froo that of Its gravi-
tational static equilibrium state.
In deep lakes, the fact that the Isotherms are horizontal Indicates that
tht Inertia of the longitudinal flow Is Insufficient to disturb the overall
gravitational static equilibrium state of the lake except possibly for
local disturbances In the vicinity of the lake or reservoir outlets and at
points of tributary Inflow. Thus, It Is expected that F tould to be small
for such lakes. In completely mixed lakes, on the other hand, the Inertia
of the flow and Its attendant turbulence Is sufficient to completely upset
the gravitational structure and destratlfy the res»ivolr. For lakes of
this class, F will be large. Between these two extremes lies the weakly
stratified lake 1n which the longitudinal flow possesses enough Inertia to
disrupt the reservoir Isotherms from their gravitational static equilibrium
state configuration, but not enough to completely mix the lake.
For the purpose of classifying lakes by their Froude number, 0 and p in
equation (2) may be approximated as 10"3 kg/a and 1000 kg/m , respec-
tively. Substituting these values and g Into equation (2) leads to an
expression for F as:
F « (320) (LQ/DY) (3)
where L and D have units of meters, Q Is In rn^/s, and V has units of m3.
It Is observed from this equation that the principal lake parameters that
determine a lake's classification are Its length, depth, and discharge to
volume ratio (Q/Y).
In developing some familiarity with the magnitude of F for each of the
three lake classes, It Is helpful to note that theoretical and experimental
work In stratified flow Indicates that flow separation occurs 1n a strati-
fied fluid when the Froude number Is less than 1/r, I.e., for F < 1A, part
of the fluid will be In motion longitudinally while the remainder Is
essentially at rest. Furthermore, as F becomes smaller and smaller, the
flowing layer becomes more and more concentrated 1n the vertical direction.
Thus, In the deep lake It Is expected that the longitudinal flow Is highly
concentrated at values of F « 1/r while In the completely mixed case F
must be at least greater than 1/r since the entire lake Is In motion and It
may be expected In general that F » 1/r. Values of F for the weakly
stratified case would fall between these two limits and might be expected
to be on the order of 1/r. As an Illustration, five lakes are listed In
Table II-2 with their Froude numbers. It Is known that Hungry Horse
Reservoir and Detroit Reservoir are of the deep reservoir class and can be
effectively described with a one-dimensional model along the vertical axis
of the lake. Lake Roosevelt, which has been observed to fall Into the
weakly stratified class Is seen to have a Froude number on the order of
1A, which 1s considerably larger than F for either Hungry Horse or Detroit
Reservoirs. Finally, Priest Rapids and Wells Daras, which are essentially
completely mixed along their vertical axes, show Froude n"ibers much larger
than 1A, as expected.
11-21
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TABLE II-2
IMPOUNDMENT FROUDE NUMBERS
RESERVOIR
Hungry Hors«
Detroit
Lake Roosevelt
Priest Rapids*
Hells*
LENGTH
( Meters)
4.7xl04
l.SxlO4
2.0xl05
2.9x10*
4.6xl04
AVERAGE
DEPTH
(meters)
70
56
70
18
26
DISCHARGE TO
VOLUME RATIO
(sec*1)
1.2xlO"8
3.5xlO'8
S.OxlO"7
4.6xlO'6
6.7xlO'6
F CLASS
0.0026 Deep
0.0030 Deep
0.46 Weakly
Stratified
2.4 Completely
Mixed
3.8 Completely
Mixed
*R1ver run dans on the Columbia River below Grand Coulee Dan.
SOURCE: Roesner, 1969.
11-22
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Sedimentation 1n Lakes
One physical process that 1s particularly Important to the aquatic
community Is the deposition of sediment which Is carried from the
contributing watershed Into the body of the lake. Because of the low
velocities through a lake, reservoir or Impoundment, sediments transported
by Inflowing waters tend to settle to the bottom before they can be carried
through the lake outlets.
Sediment accumulation rates are strongly dependent both on the unique
physiographic characteristics of a specific watershed and upon vaMojs
characteristics of the lake. Although sediment accumulation rates can be
transposed from one lake to another, this should be done with a careful
consideration of watershed characteristics (Department of AgricuUure,
1975, 1979). Apart from the use of predictive computer models, sediment
accumulation rates may be determined In one of two basic ways: {1} by
periodic sediment surveys on a lake; or (2) by estimates of watershed
erosion and bed load. Watershed erosion and bed load may be translated
Into sediment accumulation rate through use of the trap efficiency, defined
as the proportion of the Influent pollutant (1n this case sediment) load
that Is retained 1n the basin. The second method usually employs the
development of sediment discharge rate as a function of water discharge.
Such a sediment-rating curve Is Illustrated In Figure 11-10. From such
relationships, annual sediment transport to the IcHe 1s developed and
applied to the lake or reservoir trap efficiency functions to develop the
sediment accumulation rates. Trap efficiencies have been developed as a
function of the lake capacity-Inflow ratio, as shown In Figure 11-11.
Other methods for predicting trap efficiency are described by Movotny and
Chester* (1981) and Uhlpple et al. (1983).
Accumulated sediment In lakes can, over many years, reduce the life of the
water body by reducing the water storage capacity. Sediment flow Into
lakes also reduces light penetration, eliminates bottom habitat for many
plants and animals, and carries with It adsorbed chemicals and organic
matter which settle to the bottom and can be harmful to the ecology of the
lake. Where sediment accumulation Is a major problem, proper watershed
management Including erosion and sediment control must be put Into effect.
CHEMICAL CHARACTERISTICS
Overview of Physlco-Chemical Phenomena In Lakes
Water chemistry phenomena that are characteristic of freshwater have been
discussed In Section III, Technical Support Manual; Water Body Surveys and
Assessments for Conducting use Attainability Analyses tu.s. EPA. I983b).
The material 1n Section III Is applicable to lakes as well as rivers and
streams. The reader should refer to this Manual for a discussion of hard-
ness, alkalinity, pH and salinity, and for a discussion of a number of
Indices of water quality. It would also be helpful to refer to Volume II
of this series, Technical Support Manual; Water Body Surveys and Assess-
ments for Conducting Use Attainability Analyses. Volume II; EstuarTn?
Systems, for a discussion of eutrophlcatlon and the Importance of aquatic
vegetation. Even though the flora and fauna of estuaries have adapted to
11-23
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10.000
i
10
1.000
10,000 100,000
in ton* p«f doy
Figure 11-10. Sediment-rating curve for the Powder River at Arvada,
Wyoming (from Fleming, 1969)
(00
:
i»
I
L
_ «./» l/wC;*f w i»*ft*f
Offftlrtfl * , "
0.001 O.COJ 000/001 001 00* OJ Oi 03 05 Or 1 21 S f K)
Capoeiiy• iflflo« rai« (wri-lMi capacity p«r wrt-fool OMHIOI *Wlo»)
Figure 11-11. Reservoir trap effldenty as a function of the capacity-
Inflow ratio (from Brune, 1953)
11-24
-------
higher salinities than win be found In the lake, many of the Interrela-
tionships of biology and nutrient cycling 1n the estuary have their
counterparts 1n the lake.
The discussion to follow will be United to chemical phenomena that are of
particular Importance to lakes. This will focus on nutrient cycling and
eutropMcation, but will of necessity also be concerned with the effects of
variable pH, dissolved oxygen, and redox potential on lake processes.
Water chemistry In a lake and stages In the annual lake turnover cycle are
closely related. Turnover was discussed 1n greater detail earlier 1n this
chapter 1n the section on physical processes. For the current discussion
on lake water chemistry, we shall refer primarily to the stratified lake
that undergoes the classic lake turnover cycle. Since the patterns of lake
stratification and turnover vary widely, depending upon such factors as
depth, and prevailing climate as characterized by altitude and latitude,
the discussion to follow on water chemistry may not be applicable to all
lakes.
Once a thermocllne has formed, the dissolved oxygen (DO) concentration of
the hypo11anion tends to decline. This occurs because the hypollmnlon Is
Isolated from surface waters by the thermocllne, and there Is no mechanism
for the aeration of the hypollmnlon. In addition, the decay of organic
matter In the hypollmnlon as well as the oxygen requirements of fish and
other organisms In the hypollmnlon serve to deplete DO.
With the depletion of DO, reducing conditions prevail and many compounds
that have accumulated In the sediment by precipitation are released to the
surrounding water. Compounds that are solublllzed under such conditions
Include compounds of nitrogen, phosphorus, Iron, manganese and calcium.
Phosphorus and nitrogen are of particular concern because of their role 1n
eutrophlcatlon processes 1n lakes.
Nutrients released from bottom sediments under stratified conditions are
not available to phytoplankton In the eplllmnlon. However, during overturn
periods, mixing of the hypollmnlon and the eplllmnlon distributes nutrients
throughout the water column, making them available to primary producers
near the surface. This condition of high nutrient availability Is short-
lived because the soluble reduced forms are rapidly oxidized to Insoluble
forms which repreclpltate. Phosphorus and nitrogen are also deposited
through sorptlon to particles that settle to the bottom, and are trans-
ported from the eplllmnlon to the hypollmnlon 1n dead plant material that
Is added to sediments.
A special case occurs for 1ce covered lakes, esepdally when a layer of
snow effectively stops light penetration Into the water. Under these
conditions winter algal photosynthesis Is curtailed and dissolved oxygen
(DO) concentrations may decline as a result. A declining DO may affect
both the chemistry and the biology of the system. The curtailment of
winter photosynthesis may not pose a problem for a large body of water.
For a small lake, however, respiration and decomposition processes may
deplete available DO enough to result In fish kills.
11-25
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The chemical processes that occur during the course of an annual lake cycle
are rather complex. They are driven by pH, oxidation- reduction potential,
concentration of dissolved oxygen, and by such phenomena as the carbonate
buffering system which serves to regulate pH while providing a source of
Inorganic carbon which may contribute to the many precipitation reactions
of the lake. The water chemistry of the lake may be better appreciated
through a detailed review of such references as Butler (1964), and Stum*
and Morgan (1981).
Of the many raw Materials required by aquatic plants (phy topi ank ton and
microphytes) for growth, carbon, nitrogen and phosphorus are of particular
Importance. The relative and absolute abundance of nitrogen and phosphorus
are Important to the extent of growth of aquatic plants that may be seen 1n
a lake. If these nutrients are available In adequate supply, massive algal
and macrophyte b loons My occur with severe consequences for the lake.
The concept of the existence of a Uniting nutrient 1s the crux of Liebig's
"law of the nlnlnum" which basically states that growth 1s United by the
essential nutrient that 1s available In the lowest supply relative to
requirements. This applies to the growth of prlnary producers and to the
process of eutrophlcatlon In lakes where either phosphorus or nitrogen 1s
usually the Uniting nutrient.
Algae require carbon, nitrogen and phosphorus 1n the approximate atonic
ratio of 100:15:1 (Uttoroark, 1979), which corresponds to a 39:7:1 ratio on
a nass basis. The source of carbon 1s carbon dioxide which exists 1n
essentially unllnlted supply In the water and In the atmosphere. Nitrogen
also Is abundant 1n the environment and 1s not realistically subject to
control. Nitrate Is Introduced to the water body In rainfall, having been
produced electrochenlcally by lightening; 1n runoff to the water body; and
nay be produced In the water body Itself through the nitrification of
ammonia by sedlnent bacteria (Hergenrader, 1980). In contrast, nany
sources of phosphorus to a lake are anthropogenic.
There are some lakes that are nitrogen United, for which nitrogen controls
offer a means of controlling eutrophlcatlon. This Is unusual, however,
and phosphorus Uniting situations are much more prevalent than nitrogen
Uniting conditions. As stated above, a N:P mass ratio of 7:1 1s commonly
assumed to be required for algal growth; a N:P ratio less than 7:1
Indicates that nitrogen Is limiting, while a N:P ratio greater than 7:1
Indicates a phosphorus limiting situation.
The growth of aquatic plants 1s United when low phosphorus concentrations
prevail 1n a water body. Adequate control of phosphorus results 1n
nutrient limiting conditions that will hold the growth of aquatic plants 1n
check. Most Inputs of phosphorus to a lake are anthropogenic, thus control
of this nutrient offers the best means of regulating the trophic condition
of the lake. The focus of the discussion to follow will be an overview of
the chemistry of phosphorus and Its Interactions with pH, dissolved
oxygen, carbonates and Iron In the water body.
A discussion of phosphorus chemistry nay be approached through our under-
standing of the control of phosphorus 1n wastewater treatment plants by
precipitation reactions. As will be seen 1n Chapter IV, the principles of
11-26
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phosphorus control In wastewater processes My have application to lakes as
well. The chemistry of phosphorus Is very coup lex and will not be dis-
cussed In great detail In this Manual. The reader who would like further
Insight Into the fine points of phosphorus chemistry should refer to texts
such as Butler (1964), and Stumm and Morgan (1981).
Phosphorus Removal by Precipitation
Phosphorus removal Is discussed 1n detail In Process Design Manual for
Phosphorus Removal (U.S. EPA, 1976). Chapter 3 of that Manual . "Theory of
Phosphorus Removal by Chemical Precipitation," forms the basis of dis-
cussion for this section.
Ionic forms of aluminum, Iron and calcium have proven most useful for the
removal of phosphorus. Calcium In the form of Hrne 1s commonly used to
precipitate phosphorus. Hydroxyl Ions produced when Hme Is added to water
also play a role 1n phosphorus removal. Because the chemistry of phos-
phorus reactions with metal Ions 1s complex, 1t will be assumed for the
sake of simplicity that phosphorus reacts In the form of orthophosphate ,
Aluminum
Aluminum and phosphate Ions combine to form aluminum phosphate. The
principal source of aluminum 1s alum, or hydrated aluminum sulfate, which
reacts with phosphate as follows:
3~ 2"
A12(S04)3 ' 14H20 + 2P04~ - -2A1P04 + 3S04" * 14H20 (4)
The solubility of aluminum phosphate varies with pH and reaches a minimum at
pH 6. Greater than stolchlometrlc amounts of alum generally are required
for phosphorus removal because of competing reactions, one of which produces
aluminum hydroxide and reduces pH as well. Alum addition has often been
used as a means of controlling phosphorus problems 1n lakes. This Is
discussed 1n greater detail In Chapter IV In the section on lake restoration
techniques.
Lime
Calcium or magnesium and phosphate Ions react In the presence of hydroxyl
1on to form hydroxyapatlte, Cac(OH)(P04)v The reaction 1s pH dependent,
but the solubility of the precipitate Is so low that even at pH 9
appreciable amounts of phosphorus are removed. L1me addition has
occasionally been used to treat phosphorus problems 1n lakes, but the high
pH required to form and maintain hydroxyapatlte generally precludes this as
a practical method of control .
Iron
Iron, which 1s a mlcronutrlent required by algae, has been shown to be
limiting In some lakes (Wetzel, 1975) and could be an Important factor In
the eutrophlcatlon of lakes. When a lake 1s well oxygenated, most Iron In
the system 1s tied up In organic, suspended and parti cul ate matter, and very
little exists In soluble form (Hergenrader, 1980). Under anoxlc conditions
11-27
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1n the hypollmnlon, Iron tends to be released fro* bottom sediments along
with phosphorus that has been tied up 1n the for* of Iron and manganese
precipitates.
Both ferrous (Fe2*) and ferric (Fe3*) Ions way be used to precipitate
phosphorus. Ferric Iron salts are effective for phosphorus removal at pH
4.5 to 5.0 although significant removal of phosphorus may be attained.at
higher pH levels. Good phosphorus removal with the ferrous 1on 1s
accomplished at pH 7 to 8.
Lazoff (1983) examined phosphorus and Iron sedimentation rates during and
following overturn to evaluate the removal of phosphorus through adsorption
and copreclpltatlon with Iron compounds. At overturn, ferrous Iron which
has been released along with phosphorus from the sediment, precipitates as
ferric hydroxides. Iron precipitation at overturn has been observed as the
formation of reddish brown floe particles. Phosphorus 1s removed from the
water column by these floe particles, either through adsorption or through
copreclpltatlon and settling. Thus, large amounts of phosphorus may be
removed from the water column and, therefore, become unavailable for
phytoplankton growth.
The removal of phosphorus by this mechanism may be aided by phytoplankton
and other sources of turbidity In the water. To the extent that these limit
light penetration Into the water, photosynthesis and phosphorus uptake are
Inhibited, thus permitting effective removal by ferric Iron (Lazoff, 1983).
Dissolved Oxygen
Lake turnover, and mechanical aeration of bottom waters, leads to re-
oxygenatlon of the hypollmnlon. If the bvpollmnlon was previously anoxlc,
oxygenatlon will cause a reduction 1n PO,^" levels through the formation of
Iron and manganese complexes and precipitates (Pastorok et al., 1981). The
limited ability of Iron, manganese and also calcium to tie up phosphorus In
a lake 1s regulated by DO levels and by oxidation-reduction (redox)
potential. As the 00 of the hypollmnlon falls, the redox potential
decreases and phosphorus 1s released during the reduction of metal pre-
cipitates that formed when the redox potential was higher. This may not be
a problem while the lake remains stratified, but once stratification ends
and the lake becomes mixed, the soluble phosphorus becomes available to
aquatic plants living near the surface. L1me does not reliably remove
phosphorus from the aquatic system because effective removal occurs at pH
levels greater than those found 1n natural waters.
Aluminum complexes are much less susceptible to redox changes and, there-
fore, are effective 1n permanently removing partlculate and soluble phos-
phorus from the water column. Removal of phosphorus by aluminum occurs by
precipitation, by sorptlon of phosphates to the surface of aluminum
hydroxide floe and by the entrapment and sedimentation of phosphorus con-
taining participates by aluminum hydroxide floe. Once deposited, the floe
of aluminum hydroxide appears to consolidate and phosphorus 1s apparently
sorbed from Interstitial water as 1t flows through the floe (Cooke, 1981).
Oxygen depletion leads to low redox potentials In the sediment and a net
release of phosphorus Into the water column. With aeration, the redox
11-28
-------
potential Increases causing phosphorus to be precipitated and to be sorted
by the sediment. Low pH values 1n the hypollmnlon may be attributed to high
carbon dioxide associated with decay processes 1n the sediment. With
oxygenatlon, C02 levels decrease and pH Increases (Fast. 1971).
Eutrophlcatlon and Nutrient Cycling
Eutrophlcation
There are two general ways 1n which the tern "eutrophlcation" Is used. In
the first, eutrophlcation 1s defined as the process of nutrient enrichment
In a water body. In the second, "eutrophlcation" 1s used to describe the
effects of nutrient enrichment, that Is, the uncontrolled growth of plants,
particularly phytoplankton, In a lake or reservoir. The second use also
encompasses changes In the composition of animal communities 1n the water
body. Both of these uses of the term eutrophl cation are commonly found 1n
the literature, and the distinction, If Important, must be discerned from
the context of use 1n a particular article.
Eutrophlcatlon Is the natural progression, or aging process, undergone by
all lentlc water bodies. However, eutrophlcatlon 1s often greatly
accelerated by anthropogenic nutrient enrichment, which has been termed
"cultural eutrophlcatlon/
In lakes nutrient enrichment often leads to the Increased growth of algae
and/or rooted aquatic plants. For many reasons, however, excessive algal
growth will not necessarily occur under conditions of nutrient enrichment;
thus, the presence of high nutrient levels may not necessarily portend the
problems associated with the second use of the term eutrophlcatlon. For
example, the water body may be nitrogen limited or phosphorus limited,
toxics may be present that Inhibit the growth of algae, or high turbidity
may Inhibit algal photosynthesis despite an abundance of nutrients.
The three basic trophic states that may exist In a lake (or a river or
estuary) may be described In very general terms as follows:
o OUgotrophlc - the water body Is low In plant nutrients, and may be
well oxygenated
o Eutrophlc - the water body 1s rich In plant nutrients, and the
hypollmnlon may be deficient 1n 00
o Hesotrophlc - the water body Is In a state between ollgotrophlc and
eutrophlc.
What specific range of phosphorus or nitrogen concentration to ascribe to
each of these trophic levels Is a matter of controversy since the degree of
response of a water body to enrichment may be controlled by factors other
than nutrient concentrations, 1n effect making the response site specific.
As will be seen In Chapter III, In a discussion of various measures of the
trophic state of a lake, eutrophlcatlon 1s a complex process and whether or
not a water body 1s eiitrophic 1s not always clear, although the consequences
are.
11-29
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Nutrients are transported to lakes from external sources, but once 1n the
lake «ay be recycled Internally. A consideration of attainable uses 1n a
lake mist Include an understanding of the sources of nitrogen and phos-
phorus, the significance of Internal cycling, especially of phosphorus, and
the changes that might be anticipated 1f eutrophlcation could be controlled.
Nutrient Cycling In Lakes
There are many sources of nitrogen 1n the lake ecosystem. Significant
amounts of this nitrogen stem fro* natural sources and cannot be controlled.
Many anthropogenic sources, such as agricultural runoff, also are not
readily controlled. This 1s true In large part because the policy Issues
surroundlna nitrogen (and phosphorus) control through Best Management
Practices (BMPs) have not been resolved even though technical Implementation
of BMPs could appreciably reduce nutrient loadings to a water body. Once In
the aquatic system nitrogen nay undergo several bacterlally Mediated trans-
formations such as nitrification to nitrite and nitrate or den1tr1f1cation
of nitrate to nitrogen. Proteins undergo ammonlflcation to ammonia which 1n
turn Is oxidized to nitrate. Also, some Cyanophyta (blue-green algae) are
capable of using atmospheric nitrogen. Unlike phosphorus, nitrogen 1s not
readily removed from a system by complexatlon and precipitation reactions.
Whereas nitrogen Inputs to a water body are predominantly non-point sources,
phosphorus Inputs are predominantly point sources that arc mere readily
Identified and controlled. There are some parts of the country, as 1n
Florida, where extensive phosphorus deposits are found which could be the
source of significant natural Inputs to a lake and Its feeder streams. Such
lakes may be nitrogen limited. With the exception of runoff, the anthro-
pogenic sources (particularly the point sources) of phosphorus can be
controlled to a large extent. Control of the external Inputs of phosphorus
to a lake may not necessarily end problems of eutrophl cation, however,
annual fluctuations In 00, pH and other parameters may result In the
recycling of significant amounts of phosphorus within the system.
Uttormark (1979) has noted that most lakes are nutrient traps, on an annual
basis, and that the trophic status of a lake can be dependent on the degree
of Internal nutrient cycling that occurs. There 1s typically a seasonal
release from and deposition of nutrients to the sediment, and the effect of
this Internal nutrient cycling 1s dependent upon physical characteristics
such as morphology, mixing processes and stratification.
As discussed earlier, phosphorus that has been released from sediments to
anoxlc bottom waters under stratified conditions may become temporarily
available to primary producers during overturn periods. This often causes
phytopiankton blooms 1n spring and fall. During winter and summer,
stratification limits vertical cycling of nutrients and nutrient
availability may limit phytopiankton growth.
Macrophytes derive phosphorus directly from lake sediment or from the water
column. The release of some of this phosphorus to the surrounding water has
been reported for some macrophytes (Landers, 1982). In addition, signifi-
cant amounts of phosphorus and nitrogen are released to the surrounding
water by macrophytes as they die and-decompose. Landers has estimated that
about one-fourth of the phosphorus and one-half of the nitrogen within a
11-30
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decaying plant will remain as a refractory portion, while the rest 1s
released to the surrounding water.
In response to soluble phosphorus released by decomposing Microphytes, the
algal blomass (as Measured by chlorophyll-a concentration) nay show a
significant Increase. When these algae laler die, phosphorus will be
returned to the system In soluble for*, as precipitates that form with Iron,
calcium and manganese, or will be tied up In dead cells that settle to the
bottom to become part of the sediment.
Significance of Chemical Phenomena to Use Attainability
The most critical water quality Indicators for aquatic use attainment In a
lake are dissolved "xygen (DO), nutrients, chlorophyll-a and toxicants.
Dissolved oxygen 1s an Important water quality Indicator Tor all fisheries
uses and, as we have seen above, Is an Important factor In the Internal
cycling of nutrients In a lake. In evaluating use attainability, the
relative Importance of three forms of oxygen demand should be considered:
respiratory demand of phytoplankton and macrophytes during non-
photosynthetlc periods, water column demand, and benthlc demand. If use
Impairment Is occurring, assessments of the significance of each oxygen sink
can be useful In evaluating the feasibility of achieving sufficient pol-
lution control, or In Implementing the best Internal nutrient management
practices to attain a designated use.
Chlorophyll-^ Is a good Indicator of algal concentrations and of nutrient
overenrlchment. Excessive phytoplankton concentrations, as Indicated by
high chlorophyll-.a levels, can cause adverse DO Impacts such as: (a) wide
diurnal variation In surface 00 due to daytime photosynthetlc oxygen pro-
duction and nighttime oxygen depletion by respiration and (b) depletion of
bottom DO through the decomposition of dead algae and other organic matter.
Excessive algal growth may also result In shading which reduces light
penetration needed by submerged plants.
The nutrients of concern In a lake are nitrogen and phosphorus. Their
sources typically are discharges from Industry and from sewage treatment
plants, and runoff from urban and agricultural areas. Increased nutrient
levels may lead to phytoplankton blooms and a subsequent reduction 1n DO
levels, as discussed above,
Sewage treatment plants are typically the major point source of nutrients.
Agricultural land uses and urban land uses are significant non-point sources
of nutrients. Wastewater treatment facilities often are the major source of
phosphorus loadings while non-point sources tend to be the major con-
tributors of nitrogen. It Is Important to base control strategies on an
understanding of the sources of each type of nutrient, both In the lake and
In Its feeder streams.
Clearly the levels of both nitrogen and phosphorus can be Important deter-
minants of the uses that ran be attained In a lake. Because point sources
of nutrients are typically wore amenable to control than non-point sources,
and because phosphorus removal for municipal wastewater discharges 1s
typically less* expensive than nitrogen removal, the control of phosphorus
11-31
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discharges 1s often the Method of choice for the prevention or reversal of
use Impairment 1n the lake.
Discussion of the Impact of toxicants such as pesticides, herbicides and
heavy metals 1s beyond the scope of this volume. Nevertheless, the presence
of toxics In sediments or In the water column may prevent the attainment of
uses (particularly those related to fish propagation and maintenance 1n
water bodies) which would otherwise be supported by water quality criteria
for 00 and other parameters.
TECHNIQUES FOR USE ATTAINABILITY EVALUATIONS
Introduction
In the use attainability analysis. 1t must Initially be determined 1f the
present aquatic life use of a lake corresponds to the designated use. The
aquatic use of a lake Is evaluated In terms of biological measures and
Indices. If the designated use 1s not being achieved, then physical, chem-
ical and biological Investigations are carried out to determine the causes
of Impairment. Physical and chemical factors are examined to explain the
lack of attainment, and they are used as a guide 1n determining the highest
use level the system can achieve.
Physical parameters and processes must be characterized so that the study
lake can be compared with a reference lake. Physical parameters to be
considered are average depth, surface area, volume and retention time. The
physical processes of concern Include degree of stratification and
Importance of circulation patterns. Once a reference lake has been
selected, comparisons can be made with the lake of Interest 1n terms of
water quality differences and differences 1n biological communities.
Empirical (desktop) and simulation (computer-based mathematical) models can
be used to Improve our understanding of how physical and chemical char-
acteristics affect biological communities. Desktop analyses nay be used to
obtain an overall picture of lake water quality. These methods are usually
based on average annual conditions. For example, they are used to predict
trophic state based on annual loading rates of nutrients. They are simple,
Inexpensive procedures that provide a useful perspective on lake water
quality and 1n many cases will provide sufficient Information for the use
study. For a more detailed analysis of lake conditions, computer models can
be employed to analyze various aspects of a lake. These models can simulate
the distribution of water quality constituents spatially (at various
locations within the lake) and temporally (at various times of the year).
Desktop calculations and larger simulation models may both be used to
enhance our understanding of existing lake conditions. More Importantly,
they can be used to evaluate the lake's response to different conditions
without actually Imposing those conditions on the lake. This 1s of great
benefit In determining the cause of Impairment where, for example, the model
can predict the lake response to the removal of point and nonpolnt loads to
the lake system. Models can also be used to assess potential uses by simu-
lating the lake's response to various design conditions or restoration
activities. A good discussion of model selection-and use 1s provided by the
U.S. EPA (1983c).
11-32
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Empirical Models
In contrast to the complex computer models available for the study of lake
processes, there are a number of simple empirical, Input/output models that
have proven to be widely applicable to lake studies. Most of these models
consider phosphorus loadings or chlorophyll-ja concentrations 1n order to
estimate the trophic status of a lake.
Vollenwelder Model
Vollenwelder (1975) proposed an empirical fit to a simplified phosphorus
mass balance model, using the factor:
-------
10-
CD
S
.1-
.01-
EUTROPHIC
DANGEROUS
PERMISSIBLE
OLIGOTROPHIC
i
10
100
Figure II-12a. The Vollenwelder Model (from Z1son, et al., 1977)
1000
11-34
-------
10
: EUTROPHIC
E
a
<
o
a.
wi
o
r
a.
o.J
ooi
f
/PERMISSIBLE
• .
• •
O i
ST4TC :
a>
OUGOTROPHIC .
01
1 10 tOO
MEAN DEPTH Z/ HYDRAULIC RESIDENCE TIME . T,
( m/yr }
1000
ui
Figure II-12b. The Vollenwe1der-OECD Model (from Rast and Lee, 1978).
11-35
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An example application of this type of approach 1s given by Z1son, et al.
(1977), where the characteristics of a reservoir are given as:
B1gge:- Reservoir
Available Data (all values are means):
Length 20 ml « 32.2 km
Width 10 ml « 16.1 km
Depth (z) 200 ft « 61 •
InHow (0) 500 cfs
Total phosphorus concentration 1n Inflow 0.8 ppm
Total nitrogen concentration 1n Inflow 10.6 ppm
First determine whether phosphorus Is likely to be growth Halting. Since
data are available only for influent water, and since no additional data
are available on Impoundment water quality, N:P for Influent water will be
used.
M:P « 10.6/0.8 - 13.25
Thus, recalling that a N:P mass ratio of 7:1 1s required for algal growth,
Bigger Reservoir is probably phosphorus limited.
Compute the approximate surface area, volume and the hydraulic residence
time.
Volume (V) - (20 ml) (10 mi) (200 ft) (5280 ft/mi)2 •
1.12 x 10l2ft3 » 3.16 x 1010m3
Hydraulic residence time (rj • v/Q •
1.12 x 1012ft3/500 ft3sec"1 -2.24 x 109sec « 71 yr
Surface area (A) « (20 ml) (10 ml) (5280 ft/ml)2 -
5.57 x 109ft2 • 5.18 x 108m2
Next, compute hydraulic loading, qs
qs « 2/rw
qs - 61 m/71 yr » 0.86 m yr"1
Compute annual Inflow, Qy
Qy « (Q) (3.25 x 107sec yr'1)
Qy - 1.58 x 1010ft3 yr"1
Phosphorus concentration In the Inflow 1s 0.8 ppm, or 0.8 mg/1. Loading
(L.) 1n grams per square meter per year is computed from the phosphorus
concentration (C ), the annual Inflow (Q ), and the surface area (A):
Ii-36
-------
(1.58XlQ10ftV)(0.8igP/1)(2832 1/ft3)(1 % 1Q-3
p b
(5.18 x 10b if)
Lp • 0.70
Referring to the plot In Figure II-12a, we would expect that Bigger Reser-
voir. with Lp • 0.7 and q$ • 0.86," Is eutrophlc, possibly with severe
summer algal blooms.
The Vollenwelder type of approach has many useful and varied applications.
For example, a phosphorus loading model was used to evaluate three pro-
spective reservoir sites for eutrophl cation potential (Camp Dresser &
McKee, 1983). Since this evaluation was part of a study to select a future
dan site, and an Impoundment did not exist, there was very little Infor-
mation available with which to work. While such an evaluation was not a
use attainability study per se, the application 1s Instructive because 1n
many cases there may be virtually no data available for use 1n evaluating
an existing lake or Impoundment for attainable uses. For these cases where
few historical data are available, use of a computer model would require
simulation predictions without the benefit of a calibrated model, unless
considerable resources are available to conduct a sampling program to
characterize the water body from season to season In order to generate the
data required by such a model. There are few options 1n this case other
than use of an empirical model which, nevertheless, may provide very
Instructive results.
In the reservoir site study, phosphorus loading was estimated from water
quality data for the streams that would feed each of the prospective
reservoirs, and from an evaluation of land use practices 1n the watersheds.
Streamflow data and an analysis of rainfall-runoff relationships provided
an estimate of flow (Q) to each of the three reservoirs, and topographic
maps were used to determine reservoir volume, average depth (z), and
surface area (A).
In the analyses, the quantity II r^ *ay be calculated as:
zAw - ZP« (V/AHQA) « Q/A
where />, the flushing rate, 1s equal to the reciprocal of r, the hydraulic
residence time.
The quantity Q/A 1s the hydraulic loading rate— the amount of water added
annually per unit area of lake surface. This may be Interpreted to Imply
that lakes with the same hydraulic and phosphorus loadings should have the
same In-lake phosphorus concentration regardless of differences 1n flushing
rates (Uttormark and Hutchlns, 1978).
The flushing rate 1s a very Important characteristic of a lake, and *« an
Important determinant of trophic state. If the 'flushing rate Is high, as
11-37
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•1ght be the case In a run-of-river Impoundment, algal growth problems may
be much 1*5s for a given phosphorus loading than for the same phosphorus
loading to a lake with a low flushing rate. Although hydraulic loading
serves as a'surrogate for flushing rate 1n the Vollenweider model, the
model still represents an Important advancement beyond static loading
estimations, such as were presented In Vollenweider In 1968 (Table 11-3)
where estimates for trophic state are based solely on mass loading.
Vollenwe1der-OECD Model
The Organization for Economic Cooperation and Development (OECD)
Eutrophlcatlon Stuay was conducted In the early 1970's to quantify the
relationship between the nutrient (phosphorus) load to a water body (lake,
reservoir, or estuary) and the eutrophlcatlon-related water quality
response of the water body to that load. Rast and Lee (1978) applied the
Vollenweider (1975) model to the OECD water bodies 1n the United States.
The results are plotted In Figure II-12b. It Is apparent that the
eutrophlc water bodies are clustered In "one area of the plot and the
o11gotroph1c water bodies 1n another. Between those two zones, the authors
delineated rough boundaries of permissible and excessive phosphorus loading
with respect to eutrophlcatlon-related water quality. This model can be
used 1n the same way as the Vollenweider model discussed previously.
Dillon and Rlgler Model
In 1974, Dillon and Rlgler (as reported by Uttormark and Hutchlns) pub-
lished an empirical model, similar to that of Vollenweider, 1n which a
phosphorus retention coefficient (R) was proposed to account for phosphorus
retention In the lake.
Incorporation of R Into the phosphorus mass balance equation leads to
Equation 7 for the D11lon-R1g1er model which 1s analogous to Equation 5 for
the Vollenweider model.
[P] » L(l-R)/(zp) (7)
Dillon and Rlgler used values of 10 and 20 mg-P/m3 to define acceptable and
excessive loading values to derive Figure 11-13. Figure 11-13 may be used
to estimate trophic state by plotting the quantity:
L(1-R)/P vs. z
where
L « annual phosphorus loading,
R « retention coefficient, (P|M
ft « flushing rate » Q/V. yr"lin
z • mean depth, m
11-38
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TABLE II-3
SPECIFIC NUTRIENT LOADING LEVELS FOR LAKES
(EXPRESSED AS TOTAL NITROGEN AND
TOTAL PHOSPHORUS IN g/m -yr}*
Mean Depth
Up To:
5 •
10 n
50 •
100 m
150 m
200 •
Permissible
Loading
Up To:
N
1.0
1.5
4.0
6.0
7.5
9.0
P
0.07
0.10
0.25
0.40
0.50
0.60
Dangerous
Loading In
Excess of:
N
2.0
3.0
8.0
12.0
15.0
18.0
P
0.13
0.20
0.50
0.80
1.00
1.20
*fron Yollenwelder (1968)
SOURCE: Uttomark and Hutchlns, 1978.
11-39
-------
6
01
c
OLIQOTROPHIC
10
M*an d»pth, i . In met«r«
Figure 11-13. The Dlllon-Rlgler Model (from Dillon and Rigler. 1974).
11-40
-------
The lines of Figure 11-13 represent equal predictive phosphorus concentra-
tions, Indicating that the prediction of the trophic state of a lake 1s
based on a measure of the predictive phosphorus concentration 1n the lake
rather than on the phosphorus loading (Tapp, 1978).
Larsen and Herder Model
Larsen and Herder (as reported 1n Tapp, 1978) used the phosphorus mass
balance model to describe the relationship between the steady state lake
and mean Input phosphorus concentrations. Again using values of 10 and 20
mg/nr (ug/1), Larsen and Herder developed the curves of Figure 11-14 to
distinguish ollgotrophlc, mesotrophlc and eutrophlc conditions. To use
Figure 11-14, one needs to estimate the mean Influent lake phosphorus
concentration, P, 1n g/m , and JLxn, the fraction of phosphorus retained In
the lake. The Larsen and HercVer formula plots mean tributary total
phosphorus concentration against a phosphorus retention coefficient,
thereby addressing the criticism of other models that no distinction Is
made between phosphorus Increases due to Influent flows or concentrations
or both (Hern, et al., 1981). In effect, the Larsen and Herder model
predicts the mean tributary phosphorus concentration which would cause
eutrophlc or mesotrophlc conditions.
In a comparative test of these three phosphorus loading models, using data
collected under the National Eutrophlcatlon Survey on 23 water bodies (most
In the northeastern and north central United States), 1t was found that the
D1llon-R1gler and Larsen-Hercler models fit the data much better than the
Vollenwelder model (Tapp, 1978). This 1s probably because the Vollenwelder
model considers only total phosphorus loading without regard to 1n-lake
processes that reduce the effective phosphorus concentration. In a similar
comparison on data from southeastern water bodies, however, all three of
the models generally fit the data.
Of the empirical models, the Vollenwelder Is the most conservative because
It does not account for phosphorus In the outflow from a lake. This model
should be used 1n a first level of analysis, 1n the absence of sufficient
data to establish a phosphorus retention coefficient. If the retention
coefficient can be derived, the 01llon-R1gler or Larsen-Merder models
would be preferable (Tapp, 1978).
Reckhow (1979) cautions that the application of empirical phosphorus lake
models may not be appropriate for certain conditions or types of lakes.
These Include conditions of heavy aquatic weed growth, violation of model
assumptions (for example, no outlet from a lake), or because the lake type
(such as extremely shallow lakes) was not Included 1n the data sets used to
develop each of the models.
Sedimentation rates are apt to differ 1n a closed lake from sedimentation
1n a lake with an outlet. Based on a consideration of the phosphorus mass
balance equation with the outflow term removed, and upon settling rates
discussed by Dillon and Klrchner (1975) and Chapra (1977), Reckhow (1979)
proposed the following expression for predicted phosphorus concentration:
11-41
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1000
100
to.
10
EUTROPHIC
/
x /
/
OLIQOTROPHIC
J I I I I I I I I
0.1 0.2 0.3 0.4 0.6 0.6 0.7 0.8 0.9 1.0
Figure 11-14. The Larsen-Merder Model (from Tapp, 1978).
11-42
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L/(16 + 1 0 ) < P < L/13.2 (8)
Shallow lakes present a problem because the potential for mixing of the
sediments results In phosphorus concentrations that may be more variable
than In deeper lakes. On the other hand, these sane conditions may prevent
the development of anaerobic conditions and serve to reduce concentration
variability. Modeling of lakes with heavy weed growth 1s problematic
because thick growths may restrict mixing, while Interacting directly with
the sediment.
Modified Larsen and Herder Model
Hern, et al. (1981) note the assumption Inherent to each of the phosphorus
iKXtels discussed above that the relationship of phytoplankton blomass to
phosphorus Is the same for all lakes, yet point out that the utilization
and Incorporation of phosphorus Into phytoplankton blomass varies sig-
nificantly from lake to lake, depending on availability of light, supply of
other nutrients, bloavallablllty of the various species of phosphorus, and
a number of other factors. They go on to evaluate the factors affecting
the relationship of phytoplankton blomass to phosphorus levels and show how
the phosphorus models may be modified to base trophic state assessments on
chlorophyll-^ rather than phosphorus.
In their analysis of sampling data from a number of lakes, Hern et al .
determined that the response ratio of chlorophyll-^ (CHLA) to high summer
phosphorus concentrations decreases as total phosphorus Increases^ Tn
contrast to the findings of other authors (Vollenwelder, Dillon, etc.)
whose work Is based on data collected In lakes that were free of major
Interferences. Hem, et al., Indicate a belief that the reason most lakes
do not reach maximum production of chlorophyll-a 1s because of Interference
factors. Factors which may prevent phytopTankton chlorophyll-^ from
achieving maximum theoretical concentrations based on ambient total
phosphorus (TP) levels 1n a lake Include:
1. Availability of light (for example, limitations due to turbidity
or plankton self shading);
2. Limitation of growth by nutrients other than total phosphorus,
e.g., nitrogen, carbon, silica, etc.;
3. Biological availability of the TP components;
4. Domination of the aquatic flora by vascular plants rather than
phytoplankton;
5. Grazing by zooplankton;
6. Temperature;
7. Short hydraulic retention time; and
8. Presence of toxic substances.
II-43
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Tht response ratio (RA) 1s defined as the amount of chlorophyll-a formed
per unit of total phosphorus. A strong relationship betweentHLA fa
•easure of phytopiankton blomass) and IP 1n lakes has been established by a
number of authors, as discussed by Hern et al. (1981). A log-log trans-
formation of the response ratio and total phosphorus concentration yields a
straight line (Figure 11-15} which provides a basis of comparison between
the theoretical RA and the actual RA at a given phosphorus level. This
relationship was used to modify the Larsen-Mercler model to accomplsh the
following objectives:
1. Change the trophic classification based on an ambient TP level to
one based on the biological manifestation of nutrients as measured
by chlorophyll-^;
2. Determine the "critical" levels of TP which will result In an un-
acceptable level of CHLA concentration so that the level of TP can
be manipulated to achieve the desired use of a given water body;
and
3. Account for the unique characteristics of a lake or reservoir
which affect the RA.
The Larsen and Herder (1976) model predicts the mean tributary TP concen-
tration which would cause eutrophic or mesotrophlc conditions as follows:
TF- » ETP or (9)
TF « MTP (10)
I _B
where
TP"£ • the minimum mean tributary TP concentration In ug/1 which will
cause a lake to be eutrophic at equilibrium,
TP~M • the minimum mean tributary TP concentration 1n ug/1 which will
cause a lake to be mesotrophlc at equilibrium,
ETP • a constant equal to 20, which Is the theoretical minimum
ambient ug/1 of TP In a lake resulting In «utrophic conditions
and Is the level which 1f not equaled or exceeded will result
1n meso- or oil gotrophic conditions,
11-44
-------
<
ff
-6 :
-8
-e
-4 -2
Log TP In jig/I
Figure 11-15. The relationship between summer log RA and log TP based
on Jones and Bachmann's (1976) regression equation (from
Hern, et al., 1981).
11-45
-------
MTP » a constant equal to 10, which 1s the theoretical minimum
ambient ug/1 of TP In a lake resulting 1n mesotrophlc condi-
tions and 1s the level which If not equaled or exceeded will
result In oil gotrophic conditions, and
R « fraction of phosphorus retained In the lake.
The Larsen and Herder equations (I.e., Equations 9 and 10) can be
corrected to account for the RA of a specific lake as follows:
TP.- • EWERA/AERA) (11)
^ • MTP(MRA/AMRA) (12)
where
TP»£ » the minimum mean tributary TP concentrations In ug/1 which will
cause a lake to be eutrophlc at equilibrium corrected to
account for the lake's RA,
^AM " t*16 minimum mean tributary TP concentrations In ug/1 which will
cause a lake to be •«sotrophic at equilibrium corrected to
account for the lake's RA,
ERA * a constant equal to 0.32 which 1s the RA predicted from 20 ug/1
of ambient TP utilizing Jones and Bachmann's (1976) regression
equation,
MRA • a constant equal to 0.23 which 1s the RA predicted from 10 ug/1
of ambient TP utilizing Jones and Bachmann's (1976) regression
equation,
AERA * the mean summer RA for the lake corrected to what It would be
at the 20 ug/1 level of TP, I.e., the ambient eutrophlc level,
and
AMRA • the mean summer RA for the lake corrected to what It would be
at the 10 ug/1 level of TP, I.e., the ambient mesotrophlc
level.
The ERA constant of 0.32 was determined from utilizing the ETP constant of
20 ug/1 of ambient TP 1n the Jones and Bachmann (1976) regression equation:
log ug/1 CHLA « -1.09 + 1.46 log ug/1 TP (13)
11-46
-------
Substituting 20 ug/1 for TP, log CHLA Is equal to 0.81 and CHLA 1s equal to
6.4. Therefore, the ERA 1< equal to 6.4/20 or 0.32. Similarly, the MRA
constant of 0.23 was determined utilizing the MTP constant of 10 ug/1 of
ambient TP.
The AERA 1s determined from the following equation:
-B |>9 HP - B ] + A (14)
where
ORA » the observed summer ambient RA 1n the lake,
OTP • the observed summer ambient TP In the lake,
A • -4.77 which Is the log of the RA determined from Equation 13
utilizing a TP concentration at approximately 0 (since log 0 Is
undefined, an extremely low TP concentration, I.e., 0.00000001
ug/1, was used to approximate 0 on the log scale), and
B - -8 which 1s the log of the TP (I.e., 0.00000001 ug/1, which Is
used to approximate 0 In Equation 13).
Substituting Into Equation 14:
The AMRA Is determined from the following equation:
: B]
Substituting Into Equation 16:
109 AH«A • ' (9) - 4.77 (17)
The constants used In Equations 14 and 16 are used to establish the slope
of a line (Figure 11-15) which begins at -4.77 (log RA) and -8 (log TP).
Using the ORA and the OTP, the RA Is adjusted using the relationship shown
1n Figure 11-15, which was determined from the Jones and Bachmann (1976)
regression equation (Equation 13) to one which would cause eu trophic (AERA)
or mesotrophlc conditions In the lake (AMRA).
A comparison of trophic state predictions using the Larsen and Herder
equations (Equations 9 and 10) with the modified equations to account for a
lake's RA (Equations 11 and 12) war made using lake field data (Hern, et
al., 1981). Those data showed that tht lake had:
11-47
-------
OTP » 36.3 ug/1,
observed mean summer CHLA (OCHLA) * 6.3 ug/1,
1-R » 0.71,
ORA • 0.17, and
observed mean tributary TP (OTTP) - 57.3 ug/1.
Substituting Into Equation 9 (the La r sen-Herder equation that yields the
minimum Man tributary TP that will cause a lake to be eu trophic), we find:
TP. « 20 • 28.2 ug/l (9)
E
Since 28.2 ug/1 of TP represents the theoretical minimum mean tributary
concentration which will cause the lake to be eu trophic under steady state
conditions and the OTTP Is 57.3 ug/1. the use of Equation 9 would classify
the lake as eu trophic. Substituting Into Equation 11 which gives the mean
tributary TP that will cause a lake to be eutrophlc, when this TP Is
corrected for the lake's response ratio, RA:
TP.F » 20(0.32/0.13) • 69.3 ug/1 (11)
** cm
Since 69.3 ug/1 1s greater than 57.3 ug/1, we find 1f we use the Modified
equation which accounts for the lake's RA, the lake could be classified as
•esotrophic and could possibly be ollgotrophlc. To determine whether 1t Is
•esotrophic or ollgotrophlc, we substitute Into Equation 12 to determine
the mean tributary TP, corrected for the lake's RA, that will support
•esotrophic conditions.
TPau - 10(0.23/0.10) - 32.4 ug/1 (12)
** 0771
Since 32.4 ug/1 1s less than 57.3 ug/1, we would classify the lake as
mesotrophlc.
Computer Models
For many lakes, desktop evaluations and the analysis of field data may not
be sufficient for an analysis of attainable uses. When a more sophisti-
cated analysis 1s Indicated, computer-based mathematical models can be used
to simulate physical and water quality parameters, as well as various life
forms and their Interrelationships. The model predictions can be used to
determine whether physical and water quality cond1'4ons are adequate for
11-48
-------
use attainment. For example, using the Information on biological requv
ments presented later 1n this manual 1n conjunction with predicted watt
quality conditions, judgments can be made regarding *hat type of aquatic
life community a lake 1s likely to be capable of supporting. Computer
models have the great advantage that they can predict the lake's ecological
system rapidly under various design conditions and In addition, many
computer models can simulate dynamic processes 1n the water body. In
contrast, the phosphorus loading empirical models are suited only to steady
state assumptions about the lake.
Which computer model to select will depend on the Itvel of sophistication
required In the analysis to be conducted. The selection will also depend
highly on the size of the lake and Its particular physical characteristics.
For example, a long, narrow lake which Is fully nixed horizontally and
vertically can be modeled by a one-dimensional model. Two-dimensional
models may be required where lake currents In a very large, shallow lake
are the dominant factor affecting lake processes. In deep lakes where the
vertical variations 1n lake conditions are most Important, one-dimensional
models In the vertical direction are appropriate.
In many cases lake water quality and ecological models have been developed
to high degrees of sophistication, but these models do not provide the same
degree of sophistication for the mechanisms that describe transport
phenomena In the lake. On the other hand, models developed to simulate the
hydrodynamics of a lake did not Include the simulation of an extensive
array of chemical and biological conditions. One of the major weaknesses
In current water quality models as perceived by Shanahan and Harleman
(1982) 1s the linkage of hydrodynamlc and biochemical models.
Hydrodynamlc Modeling
Shanahan and Harleman (1982) have described various types of models for
lake circulation studies. They Included two major groups: simplified
models and true circulation models.
The simplified models Included zero-dimensional models 1n which a lake Is
represented by a fully-mixed tank or continuous- flow stirred tank reactor.
For a larger lake, representation with the zero-dimensional model Is accom-
plished by treating different areas of the lake as separate fully mixed
tanks. Simplified models also Include longitudinal and vertical one-
dimensional models. These models consider a series of vertical layers or
horizontal segments.
True circulation models are those which employ two- and three-dimensional
analysis. Two-dimensional models have been developed with a single or with
multiple layers where It Is assumed that the lake Is vertically homogeneous
within a layer. While lake circulation Is modeled In each layer, the
Interactions between layers must be considered separately. The fully
three-dimensional model, which also handles vertical transport between
layers, 1s the most complex, and most expensive to set up and run.
Although there are some examples of this type of model In use, Shanahan and
Harleman believe that these models have not reached a point of practical
application.
11-49
-------
ce circulation models have been Investigated 1n detail by
of the Case Western Reserve University. In a report for the
tental Protection Agency, Lick (1976b) describes his work on
onal nodels. The three-dimensional"models developed by Lick.
a steady-state, constant-density Model; (2) a t1we-dependent,
1ty »ode1; and (3) a t1 Me-dependent, variable-density Model.
teraged Models are also presented which average the three-
dimensional equations over the depth, thus reducing the Model to a two-
dimensional model.
Lake Hater Quality Modeling
Many one-, two- or three-dimensional lake water quality models have been
developed for various applications. As part of an EPA technical guidance
Manual for performing wasteload allocations (U.S. EPA, 1983d, available
water quality Models were reviewed. Information concerning model
capability, model developers, and technical support were presented.
Descriptions of lake models from Book IV - Lakes and Impoundments, Chapter
2 - Eutrophlcatlon (U.S. EPA, 1983c) are provided In Tables II-4 through
11-8 to present an overview of soW~of the models that have been developed
for lake studies.
Lake water quality models such as those described 1n Tables I1-4 through
11-8 generally a-e stand-alone models, however, some lake quality models
have been linked to sophisticated hydrodynamlc models. For example, In one
special study for Lake Ontario, Chen and Smith (1979) developed a three-
dimensional eco1og1ca1-hydrodynam1c Model. The hydrodynamlc model
calculated currents and the temperature regime throughout the lake using a
horizontal grid with eight layers of thickness. The water quality model
Included a coarser horizontal grid with seven layers. The hydrodynamlc
Information was transferred through an Interface program to the water
quality model.
Much of the focus 1n water quality models developed for deep lakes and
reservoirs has centered around the prediction of the thermal energy
distribution, and has led to the development of one-dimensional ecological
models such as LAKECO and WQRRS as described 1n Tables II-7 and 11-8,
respectively. This type of model 1s described 1n more detail 1n the
following section.
One-Dimensional Lake Modeling
Development of LAKECO, WQRRS and other variations of these ecological
models such as EPAECO (Gaume and Duke, 1975) began 1n the late sixties with
studies on the prediction of thermal energy distribution (Water Resources
Engineers, 1968, 1969). From some of their earlier work, Chen and Orlob
(1972) developed a model of Ecological Simulations for Aquatic Environments
which was used as the basis for many of the subsequent lake and reservoir
models.
One-dimensional lake models assume that mass and energy transfers only
occur along the vertical axis of a lake. To facilitate application of the
necessary mass and energy balance equations, the lake 1s represented as a
one-dimensional system of horizontal elements with uniform thickness, as
11-50
-------
YABLE II-4
DESCRIPTION OF WATER ANALYSIS SIMULATION PROGRAM
Name of Model:
Respondent:
Developers;
Year Developed:
Capabilities;
Avail ability;
Applicability;
Support;
Water Analysis Simulation Program (WASP)* -
LAKE1A, ERIE01, and LAKE3
William L. Richardson
U.S. Environmental Protection Agency
Large Lakes Research Station (LLRS)
9311 Groh Road
Grosse Isle, Michigan 48138
(313) 226-7811
Robert V. Thomann, Dominic DIToro, Manhattan College, N.Y.
1975 (LAKE1)
1979 (LAXE3)
Model Is one (LAKE1) or three (LAJCE3) dimensional and
computes concentration of state variable 1ri each com-
pletely nixed segment given Input data for nutrient
loadings, sunlight, temperature, boundary concentration,
and transport coefficients. TJ-.e kinetic structure In-
cludes linear and non-linear Interactions between the
following eight variables: phytopiankton chlorophyll,
herbivorous zooplankton, carnlverous zooplankton. non-
living organic nitrogen (partlculate plus dissolved),
ammonia nitrogen, nitrate nitrogen, non-living organic
phosphorus (partlculate plus dissolved), and available
phosphorus (usually orthophosphate). Also, a refined
biochemical kinetic structure which Incorporates two
groups of phytoplankton, silica and revised recycle
processes Is available.
Models are In the public domain and are available from
Large Lakes Research Station.
The model 1s general, however, coefficients are site
specific reflecting past studies.
User's Manual
A user's manual titled "Water Analysis Simulation Program"
(WASP) Is available from Large Lakes Research Station.
Technical Assistance
Technicalassistance would be provided If requested 1n
writing through an EPA Program Office or Regional Office.
*The Advanced Ecosystem Model Program (AESOP) described next 1s a modified
version of WASP.
SOURCE: U.S. EPA. 1983c.
11-51
-------
TABLE II-5
DESCRIPTION OF WATER ANALYSIS SIMULATION PROGRAM
AND ADVANCED ECOSYSTEM MODELING PROGRAM
Nuw of Model
Respondent.•
Developers;
Capabilities:
Verification:
Avail ability:
Applicability;
Mater Analysis Simulation Program (HASP)
Advanced Ecosystem Modeling Program (AESOP)
John K St. John
HydroQual, Inc.
1 LethbHdge Plaza
Mihwah. N.J. 07430
(201) 529-5151
WASP
UoiTnlc M. DIToro, James J. Fltzpatrlck. John L. Manc1n1,
Donald J. 0'Conner, Robert V. Thomann (Hydrosclence, Inc.)
(1970)
AESOP
UoiTnlc DIToro, Janes J. Fltzpatrlck, Robert V. Thomann
(Hydrosclence, Inc.) (1975)
The Water Quality Analysis Simulation Program, WASP, may be
applied to one-, two-, and three-dimensional water bodies,
and models may be structured to Include linear and non-
linear kinetics. Depending upon the modeling framework the
user formulates, the user may choose, via Input options, to
Input constant or time variable transport and kinetic
processes, as well as point and non-point waste discharges.
The Model Verification Program, MVP, may be used as an
Indicator of "goodness of fit" or adequacy of the model as
a representation of the real world.
AESOP, a modified version of WASP, Includes a steady state
option and an Improved transport component.
To date WASP has been applied to over twenty water resource
management problems. These applications have Included
one-, two-, and three-dimensional water bodies and a number
of different physical, chemical and biological modeling
frameworks, such as BOD-DO, eutrophlcation, and toxic sub-
stances. Applications Include several of the Great Lakes,
Potomac Estuary, Western Delta-Sulsun Bay Area of San
Francisco Bay, Upper Mississippi, and New York Harbor.
WASP Is 1n public domain and code 1s available from USEPA
(Gross* Isle Laboratory and Athens Research Laboratory).
AESOP 1s proprietary.
Models are general and may be applied to different types of
water bodies and to a variety of water quality problems.
11-52
-------
TABLE II-5
DESCRIPTION OF HATER ANALYSIS SIMULATION PROGRAM
AND ADVANCED ECOSYSTEM MODELING PROGRAM (Concluded)
Support: User's Manual
WASP and MVP documentation 1s available from USEPA (Grosse
Isle Laboratory). AESOP documentation 1s available from
HydroQual.
Technical Assistance
Technical asssfstance of general nature from advisory to
Implementation (model set-up, running, calibration/
verification, and analysis) available on contractual
basis.
SOURCE: U.S. EPA, 1963c.
11 -53
-------
TABLE II-6
DESCRIPTION OF CLEAN PROGRAMS
Name of Model;
Respondent:
Developers:
Supporting Agency;
Year Developed;
Capabilities;
CLEAN, CLEANER. MS. CLEANER, MINI. CLEANER
Richard A. Park
Center for Ecological Modeling
Rensselaer Polytechnic Institute
NRC-202, Troy, N.Y. 12181
(518) 270-6494
Park, O'Neill, Bloonfleld, Shugart, et al.
Eastern Deciduous Forest 81 owe
International Biological Program
(RPI, ORNL, and University of Wisconsin)
ThOMS 0. Barnwell, Jr.
Technology Development and Application Branch
Environmental Research Laboratory
Environmental Protection Agency
Athens, Georgia 30605
1973 (CLEAN)
1977 (CLEANER)
1980 (MS. CLEANER)
1981 - estimated completion date for MINI. CLEANER
The MINI. CLEANER package represents a complete re-
structuring of the Multl-Segment Comprehensive Lake
Ecosystem Analyzer for Environmental Resources (MS.
CLEANER) 1n order for It to run 1n a memory space of
22K bytes. The package Includes a series of simula-
tions to represent a variety of distinct environments,
such as well mixed hypereutrophlc lakes, stratified
reservoirs, fish ponds and alpine lakes. MINI. CLEANER
has been designed for optimal user application—a turn-
key system that can be used by the most Inexperienced
environmental technician, yet can provide the full
range of Interactive editing and output manipulation
desired by the experienced professional. Up to 32
state variables can be represented 1n as many as 12
ecosystem segments simultaneously. State variables
Include 4 phytoplankton groups, with or without surplus
Intracellular nitrogen and phosphorus; 5 zooplankton
groups; and 2 oxygen, and dissolved carbon dioxide.
The model has a full set of readily understood commands
and a machine-Independent, free-format editor for
efficient usage. Perturbation and sensitivity analysis
can be performed easily. The model has been calibrated
and 1s being validated. Typical output 1s provided for
11-54
-------
TABLE II-6
DESCRIPTION OF CLEAN PROGRAMS (Concluded)
a set of test data. File and overlay structures are
described for Implementation on virtually any computer
with at least 22K bytes of available memory.
Verification:
Availability;
Applicability:
Support;
The MINI. CLEANER model is being verified with data
from OeGray Lake, Arkansas; Coralvilie Reservoir, Iowa;
Slapy Reservoir, Czechoslovakia; Ovre Helmdalsvatn,
Norway; Vorderer Finstertak See, Austria; Lake Balaton,
Hungary; and Lago Hergozzo, Italy. The phytoplankton/
zooplankton submodels were validated for Vorderer
Flnstertaler See.
Models are in public domain and code Is available from
Richard A. Park (RPI) and Thomas 0. Barnwell (EPA/
Athens).
Model Is general.
User's Manual
A user's manual for MS. CLEANER Is available from
Thomas 0. Barnwell, Jr. A user's manual for MINI.
CLEANER Is In preparation.
Technical Assistance
Assistance may be available from the Athens Laboratory;
code and initial support is available for a nominal
service charge from RPI; additional assistance is
negotiable.
SOURCE: U.S. EPA, 1983c.
11-55
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TABLE 11-7
DESCRIPTION OF LAKECO AND ONTARIO MODELS
Name of Model;
Respondent:
Developers:
User Developed:
Capabilities;
Verification;
Availability;
Applicability:
Support;
LAKECO*, ONTARIO
Carl U. Chen
Carl U. Chen
Tetra Tech Inc.
3746 Mount Diablo Blvd., Suite 300
Lafayette, California 94596
(415) 283-3771
(Original version developed when Dr. Chen was with Mater
Resources Engineers)
1970 (original version)
LAKECO
Model Is one-dimensional (assumes lake Is horizontally
homogeneous) and calculates temperature, dissolved oxygen,
and nutrient profiles with dally time step for several
years. Four algal species, four zooplankton species, and
three fish types are represented. The model evaluates the
consequences of wasteload reduction, sediment removal, and
reaeration as remedial measures.
ONTARIO
Same as above but 1n three-dimensions for application to
Great Lakes.
The models have been applied to more than 15 lakes by Dr.
Chen and to numerous other lakes by other Investigators.
The model is in the public domain and the code is avail-
able from the Corps of Engineers (Hydrologlc Engineering
Center), EPA and NOAA.
General
User's Manual
User's manuals are available from Tetra Tech, Corps of
Engineers, EPA and NOAA.
Technical Assistance
Technical assistance 1s available and would be negotiated
on a case-by-case basis.
*A version of LAKECO, contained in a model referred to as Water Quality for
River Reservoir Systems (WQRSS) and supported by the Corps of Engineers
(Hydrologlc Engineering Center), 1s described separately.
SOURCE: U.S. EPA, 1983c.
11-56
-------
TABLE II-8
DESCRIPTION OF HATER QUALITY FOR
RIVER RESERVOIR SYSTEMS
Name of Model: Water Quality for River Reservoir Systems (WQRRS)
Respondent:
Developers:
History;
Capabilities;
Verification:
Avail ability;
Applicability;
Support:
Mr. R.G. Wllley
Corps of Engineers
609 Second Street
Davis. California 95616
(916) 440-3292
Carl W. Chen, G.T. Orlob. W. Norton, 0. Smith
Water Resources Engineers, Inc.
1970 (original version of lake eutropMcation model)
1978 (Initial version of WQRRS package)
1980 (updated version of WQRRS)
See description of LAKECO In Table 11 -7 (model also can
consider river flow and water quality).
Chattahoochee River (Chattahoochee River Water Quality
Analysis, April 1978, Hydrologlc Engineering Center Project
Report)
Model 1s In public domain and code 1s available from Corps.
Model Is general.
User's Manual
A user's manual 1s available from Corps.
Technical Assistance
Advisory assistance Is available to all users. Actual exe-
cution assistance Is available to federal agencies through
an Inter-agency funding agreement.
SOURCE: U.S. EPA, 1983c.
11-57
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shown In Figure 11-16. Each hydraulic element 1s treated as a continuous-
TIOW stirred tank reactor (CFSiiO with completely uniform properties.
The Implicit assumption of this .geometric structuring of the problem Is
that mass concentration and thermal gradients 1n the horizontal plane are
Insignificant In determining the ecological responses and thermal behavior
of the Impoundment along the vertical axis. Therefore* simulated results
are Interpreted as being average conditions across the lake at a particular
elevation.
These models solve a set of equations representing the water quality of a
lake and the interactions of the lake biota with water quality. In
reality, an aquatic ecosystem exhibits a delicate balance of a'muTtfpllclty
of different aquatic organisms and water quality constituents. 'Of neces-
sity, lake ecological models account only for the more significant Inter-
actions in this balance.
An aquatic ecosystem is comprised of water, its chemical impurities, and
various life forms: bacteria, algae, zooplankton, benthos and fish, among
others. The biota responds to nutrients and to other environmental con-
ditions that affect growth, respiration, recruitment, decay, mortality and
predatlon. Abiotic substances derived from air, soil, tributary waters and
the activities of man, are Inputs to the system that exert an influence on
the blotic structure of the lake. Figure 11-17 provides a conceptual
representation of an aquatic ecosystem.
The fundamental bull!ding blocks (nutrients) for all living organisms are
the same: carbon, nitrogen and phosphorous. With solar radiation as the
energy source, these Inorganic nutrients are transformed into complex
organic materials by photosynthetic organisms. The organic products of
photosynthesis serve as food sources for aquatic animals. It 1s evident
that a natural succession up the food chain occurs whereby inorganic
nutrients are transformed to biomass.
Biological activities generate wastes which Include dead cell material and
excreta which Initially are suspended but may settle to the bottom to
become part of the sediment. The organic fraction of the bottom sediment
decays with an attendant release of the original abiotic substances. These
transformations are Integral parts of the carbon, nitrogen and .phosphorous
cycles and result in a natural "recycling" of nutrients wlth'ln an aquatic
ecosystem.
The water quality and biological productivity of a lake vary 1n both time
and space, Temporal variations are associated with a wide variety of
external Influences on a lake. Examples of these Influences are atmos-
pheric energy exchanges, tributary contributions and lake outflows.
Spatial variations occur both in the horizontal plane and with depth.
Variations In the horizontal plane are normally due to local conditions,
such as distance from shoreline, depth of water and circulation patterns.
Many times these variations do not affect the overall ecological balance of
a lake and are not modeled by the one-dimensional lake model.
11-58
-------
tributary
inflow
evaporation
tributary
vertical
\ aavdction
-control slice
outflow
Figure 11-16.
Geometric Representation of a Stratified Lake
.(from Gaune and Duke, 1975).
11-59
-------
NAN-INDUCED
WASTE LOADS
DETRITUS
SEDIMENT
Figure 11-17.
Conceptual Model of an Aquatic Ecosystem
(from Chen and Orlob, 1972).
11-60
-------
Variations of water quality along the vertical axis of a lake have a wore
general effect. The hydrudyrtamlc behavior of a well-stratified lake 1s
density-dependent and, therefore, 1s related closely to the vertical tem-
perature structure of the impoundment. The vertical temperature structure,
In turn, 1s governed by the same external environmental factors as the
temporal variations, I.e., atmospheric energy exchanges, tributary con-
tributions and lake outflows.
EPA Center for Water Quality Modeling
The Center for Water Quality Modeling, located at the Environmental
Research Laboratory In Athens, Georgia, has long been Involved In the
development and application of mathematical models that predict the
transport and fate of water contaminants. The Center provides a central
file and distribution point ror computer programs and documentation for
selected water quality and pollutant loading models. In addition, the
Center sponsors workshops and seminars that provide both generalized train-
Ing 1n the use of models and specific Instruction In the application of
Individual simulation techniques.
The water quality model supported by U.S. EPA for well-mixed lakes 1s the
Stream Water Quality Model QUAL-II (Roesner, et al., 1981). The model
assumes that the major transport mechanisms—advectfon and dispersion—are
significant only *long the main direction of flow (longitudinal axis of the
lake). It allows for multiple waste discharges, withdrawals, tributary
flows, and Incremental Inflow. Hydraullcally, QUAL-II 1s limited to the
simulation of time periods during which the flows through the lake are
essentially constant. Input waste loads must also be held constant over
time. QUAL-II can be operated as a steady-state model or a dynamic model.
Dynamic operation makes 1t possible to study water quality (primarily
dissolved oxygen and temperature) as 1t Is affected by diurnal variations
In meteorological data.
The Army Corps of Engineers have developed a numerical one-dimensional
model (CE-QUAL-R1), of reservoir water quality (U.S. Army Corps of
Engineers, 1982). The reservoir model Is a direct descendant of the
reservoir portion of a model called "Water Quality for River-Reservoir
Systems" (WQRRS) which was assembled for the Hydrologlc Engineering Center
of the Corps of Engineers by Water Resources Engineers, Inc. (Camp Dresser
I McKee). The definitive origin of WQRRS was the work of Chen and Orlob
(1972).
The aquatic ecosystem and geometric representation of this model are sim-
ilar to those discussed In the previous section on one-dimensional lake
modeling. A summary of the model capabilities of CE-QUAL-R1 Is given In
Table II-9.
Example Application of Mathematical Modeling
Mathematical modeling of natural phenomena allows planners, engineers,
biologists, and the general public to s*e the effects on the lake system of
changes In the environment which are planned or predicted to occur In the
future. This Insight allows a stavt to assess the environmental responses
11-61
-------
TABLE II-9
CE-QUAL-R1 MODEL CAPABILITIES
Factors considered by CE-QUAL-R1 Include the following:
a. Physical Factors
(1) Shortwave and longwave solar radiation at the water surface.
(2) Net heat transfer across the air-water Interface.
(3) Convectlve and radiative heat transfer within the water body.
(4) Convectlve Mixing due to density Instabilities.
(5) Placement of Inflowing waters at aepths with comparable
density*
(6) Withdrawal of outflowing waters from depths Influenced by the
outlet structure and density stratification.
(7) Conservative substance routing.
(8) Suspended sol Ids routing and settling.
b. Chemical and Biological Factors
(1) Accumulation, dispersion, and depletion of dissolved oxygen
through aeration, photosynthesis, respiration, and organic
demand.
(2) Uptake-excretion kinetics and regeneration of nitrogen and
phosphorus and nitrification processes under aerobic condi-
tions.
(3) Carbon cycling and dynamics and alkallnlty-pH-CO* Inter-
actions.
(4) Phytoplankton dynamics and trophic relationships.
(S) Transfers through higher trophic levels of the food chain.
(6) Accumulation, dispersion, and decomposition of detritus and
sediment.
(7) Conform bacteria die-off.
(8) Accumulation, dispersion, and reoxldatlon of manganese, Iron,
and sulflde when anaerobic conditions prevail.
SOURCE: U.S. Army Corps of Engineers, 1982.
11-62
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of the lake and help It to analyze alternative plans for protecting the
present use or determining what uses cr*"1H be attained.
External factors, such as Increased nutrients which accelerate the growth
of algae, may destroy the delicate balance of nature, and cause consider-
able ham to the lake and Its biology. Therefore, It Is Important to be
able to predict what the lake response will be to external factors without
actually Imposing those conditions on 1t. The mathematical portrayal of
the lake ecosystem by the computer model helps us toward that end.
As an example, the lake ecological model EPAECO (Gaume and Ouke, 1975) pro-
vided a tool to mathematically represent the aquatic ecological system 1n
the Fort Loudoun Lake, Tennessee. This study was conducted as part of the
208 plan for the Knoxvllle/Knox County Metropolitan Planning Commission
(Hall, et al., 1976). The 208 study aree map is shown 1n Figure 11-18. In
general, the model EPAECO Is designed to simulate the vertical distribution
of the following constituents over an annual cycle:
1. Temperature 10. Total Inorganic Carbon
2. Total Dissolved Solids 11. Carbon Dioxide
3. Alkalinity 12. Hydrogen Ion (pH)
4. Conforms 13. Dissolved Oxygen
5. Carbonaceous Biochemical 14. Algae (two classes)
Oxygen Demand (CBOO) 15. Zooplankton
6. Ammonia Nitrogen 16. Fish (three classes)
7. Nitrite Nitrogen 17. Benthlc Animals
8. Nitrate Nitrogen 18. Organic Sediment, and
9. Phosphorus 19. Suspended Detritus.
The general approach to use of the mathematical model EPAECO Is to obtain
data which describe the geometric properties of the lake and Its past
history of water quality and hydrodynamics. Data on water quantity and
quality of tributary Inputs to the lake (streams and/or waste loads) and
meteorological data are also necessary. Initially, the lake must be
described as a mathematical system of depths, areas, volumes, tributary
Inputs and releases. A site-specific model must be developed which
properly describes the environmental community and Its Interactions for
Fort Loudoun Lake. This Is done by a procedure called calibration. A
calibrated model gives the user greater confidence that the simulation
model will react as would the lake Itself to changes In external factors
such as Increased tributary nutrient concentrations.
Examples of calibration results are shown 1n Figures 11-19 through 11-21.
Figure 11-19 presents the observed and simulated reservoir elevations for
the year 1971; Figure 11-20 shows the vertical temperature profiles,
observed and simulated, for the months of April, Hay and July, 1971; and
Figure 11-21 gives the observed and simulated profiles for several water
quality constituents for a single day 1n September 1971.
One of the main considerations 1n the study of Fort Loudoun Lake was an
evaluation of present and future trophic states. Lakes which become en-
riched with excessive nutrients may be defined as eutrophlc. Eutrophlca-
tlon produces large algal communities which affc't the taste and odor of
the lake's waters. Bacteria which degrade the large amounts of dead
11-63
-------
LEGEND
Knox County (208 Area)
Fort Loudoun Drainage
Area
QAM
Figure 11-18. 208 Study Ai from Hall et al. 1976)
11-64
-------
ir.5-
27 -
265-
M
I1"
t»
H
255-
<
25 -
245-
24 -
O
X
0
- 0 0 xox
X xox °0 °x>°0 On Qo 00
x & 0* **QX °x^xQ
x Ox
0 *
0
^m
«
O
X
x x K *O
O O O x° x oo ° <
»
x
OATC
Si*
C ? >
5 S | f 5
814
812
-810 .
1
^
J
2
-808
-806
0 50 100 ISO 200 250 300 350
JULIAN DAYS, 1971
KEY:
O OBSERVED
SIMULATED
Figure 11-19.
Fort Loudoun Reservoir Elevations 1971 Observed vs.
Simulated (from Hall et al, 1976)
II-65
-------
•o o
o
oo
3
O
o
tn
C
O |3
jj I.
OO
*o
o
o
-?-
0
o
00
00
.0
o
fc A
TEMPERATURE *C
c.c
o o
o o
« 0
O o
•o
o
o
o
o
00
o
oc.
KEY-
O CSSCRVCO FROM
STATIONS SOU a 615.8
• SIMULATED
a
c/t/n
Figure II- 2Q Temperature Profile for -t Loudoun (from Hall et al, 1976)
11-66
-------
'^ 1
2S.
20-
I
i»i
i
o
I
£
-.—*-
o » 10
oo (••/•*!
4 J UJ
4d>
KEY*
OOCh
Q STATION2flM.603 2J
• STATIOMlRM.6l3.ai
SIMULATED
00:
O STAT10N2IRM.603 2)
• STATION JW.M6I3.B)
SIMULATED
PHOSPHORUS:
O STATION2RU.6OJ 2)
• STATION JtRU.613 A)
SIMULATED
NITROGEN:
O STATION2O.M.603 2)
• STATION 3IRM.6I30I
SIMULATED
ALGAE:
O STATION2HM.6O32)
• STATION 3MU.6I5 8)
SIMULATED
/IOTE.
•MTROCEN 'NH3N»NO3N»NO2 N
Figure 11-21. DO and BODs, Inorganic Phosphorus and Nitrogen, and Algae
September 10, 1971 Fort Loudoun (from Hall et al, 1976)
11-67
-------
organic Mtter In the lake deplete the oxygen supply, which 1n turn results
1n a loss of some types of fish. Excessive aquatic weed growth 1s also
detrimental to swimming, boating and fishing.
The Model EPACCQ was used to assess algal growth as a result of various
nutrient loads (high, medium and low) to the lake during the period of May
through September. This type of Model application not only quantified the
degree of expected algal growth as a function of the availability of
nutrients but also predicted the alga! population and total lake ecology
for future nutrient loads to the lake.
Since phosphorus was the Uniting nutrient for algal growth In this lake
study, the total available phosphorus was compared to the maximum seasonal
algal concentrations simulated for the sensitivity study. Figure 11-22
snow4; this comparison. The curve Is derived from the maximum algal con-
centrations resulting from the following sensitivity conditions: high P,
medium P, and low P. This curve represents the maximum algal concentra-
tions reached by a constant Inflow concentration of phosphorus during the
algal growing season.
A limited amount of phosphorus Is required 1n the Inflows to the stratified
portion of the reservoir to support a desirable algal community without
producing excess growth and thus undesirable conditions. As shown on the
graph In Figure 11-22, Fort Loudoun Lake phosphorus concentrations In the
range of 0.013-0.037 mg/1 produced algal concentrations which were suitable
for a well-balanced ecosystem with good water quality as observed In 1971
by the Tennessee Valley Authority.
11-68
-------
RANGE OF VALUES REPORTED
DURING APRIL-SEPT. 1971
BY TVA AT T.R. MILE €24.6
.02 .03
TOTAL AVAILABLE
PHOSPHORUS (mg/t)
04
.05
Figure II- 22 Maximum Seasonal Algae vs. Total Available Phosphorus
Lake Model Sensitivity Study - Fort Loudoun
(from Hall et al, 1976)
11-69
-------
CHAPTER III
BIOLOGICAL CHARACTERISTICS
INTRODUCTION.
This chapter contains Information about the characteristic plants and
animals found 1n lakes and provides an overview of the water quality and
the types of habitat that they require. The chapter Is divided Into major
sections: Plankton, Aquatic Macrophytes, Benthos, and Fish.
Particular emphasis Is placed on changes 1n species composition as lakes
progress from oilgotrophy to eutrophy. The biota of lakes 1s often studied
to assess the trophic state or biological health of the water body. Thus,
Indicator organisms are also discussed In this chapter, along with
qualitative and quantitative methods of assessing the biological health of
a lake. The reader 1s referred to the Technical Support Manual: Water
Body Surveys and Use Attainability Analyses (U.S. EPA. 1983b) where an
extensive discussion on species diversity and other measures o7 community
health will be found.
PLANKTON
Planktonic plants and animals are Important members of the lacustrine food
web. Phytopiankton, which comprise plgmented flagellates, green and blue-
green algae, and diatoms, are lowest on the food chain and serve as a
primary food source for higher organisms. Zooplankton may be grazers
(consuming phytopiankton) or predators (feeding on species smaller than
themselves). The zooplankton, In turn, serve as the primary food source
for the young of many fish species. The findings of various authors who
have studied the effects of organic pollution and nutrient enrichment on
the lacustrine plankton are summarized below.
Phytopiankton
The growth of phytoplankton 1s normally limited by the amount of nitrogen
and/or phosphorus available. When Increased quantities of nutrients enter
the lake In runoff or effluents, eutrophlcatlon with Its attendant
uncontrolled algal growth and Its consequences may begin. For example, the
production of toxic substances by some algae may cause human gastrointes-
tinal, skin and respiratory disorders, while blooms of Mlcrocystls and
Nostoc rlvulare may poison wild and domestic animals, causing unconsclous-
ness, convulsions and sometimes death (Mackenthun, 1969).
Algal blooms affect the dissolved oxygen (00) content of the water.
Diurnal fluctuations of 00 and pH become more pronounced with large algal
populations. In addition, the dissolved oxygen In the hypollmnlon 1s
depleted through algal death and decay, leading to anoxlc conditions. F1sh
may die because of anaerobic conditions or the production of toxic
substances. Water quality problems caused by algae, such as taste and
odor, are especially troublesome 1f the water body 1s used as a source of
drinking water. Finally, scums and mats of the algae destroy the aesthetic
value of the lake.
III-l
-------
Since some species are able to compete better than others. Increased
nutrients cause changes In phytoplankton community composition. Thus,
specific algal associations say be Indicative of eutrophic conditions.
Indices of trophic state based on phytoplankton taxon are also related to
the degree of eutrophy. The use of phytoplankton as Indicators of
eutrophlcation Is discussed below.
Qualitative Response to Environmental Change
The Identification of phytoplankton that are commonly found In eutrophlc
and cllgctrophlc lake waters his resulted In lists of pollution tolerant/
Intolerant genera and species. Palmer (1969) developed several lists of
pollution tolerant algal genera and species by compiling Information In 269
reports by 165 authors. The eight most tolerant genera were Euglena.
~7tc
Osclllatorla. Chlaaydoaonas. Scenedesaus. Chi ore1, la. Mltzchla. Mivlcula,
and StlgeocTonium. The five most tolerant species were Euglena vlrldls.
MltzcETapaiea. Osc 11 la tori a 1 laosa. Scenedesaus quacricaudl^and
and Stlgeocionlum.The five most tolerant species were Euglena vlrldls.
~~^ paiea. Osc 11 la tori a 1 laosa. Scenedesaus quacr
Osclllatorla tenuls!Palaer used the following aethod to combine the works
of the various authors: A score of 1 or 2 points was given for each algae
reported by an author as tolerating organic enrichment, the larger figure
being reserved for the algae that an author emphasized as being typical of
waters with high organic pollution. The compilation by Palmer 1s presented
In Appendix A, pollution-tolerant genera and pollution-tolerant species.
Palmer's listings have been criticized because the Information used to
compile them came from a broad range of sources and geographical areas. In
addition, the compilation Is restricted to algae tolerating high organic
pollution. Thus, the listing may not be valid for other types of pollu-
tants. Nevertheless, It does provide an Indication of relative tolerance
to organic pollution.
Taylor, et al. (1979) studied the environmental conditions associated with
phytoplankton genera. The occurrence of 57 genera was related to total
phosphorus levels, total KJeldahl nitrogen levels, chlorophyll-^ levels,
and M/P ratio values. Most genera were found to occur over extremely wide
ranges or conditions. The seven genera associated with levels of phos-
phorus greater than 200 ug/1 were found to also represent seven of the
eight highest chlorophyll-^ values. Taylor designated this group con-
taining Actlnastrum, Anabaenopsls. Schroederla. Raphldlopsls. Chlorogonlum.
SolenkinTTj and Lagerhelmla as~the "nutrient rich genera". All seven
genera were summer and fall forms, while Actlnastrum and Lagerhelmla also
occur in spring.
The "nutrient-poor" group, containing five genera, were associated with
total phosphorus levels less than 70 ug/1. Asterlonella. Dlnobryon.
Tabellarla. Per1d1n1um, and Cerat1urn make up this group.Xsterlonella Is
the only genus occurring solely in spring. The other genera occur 1n
summer and fall; Dlnobryon and Tabellarla also occur equally in spring,
summer and fall.
Taylor, et al. (1979) also noted which genera achieved numerical dominance
most frequently in the lakes studied. Meloslra was the most dominant
genus, followed by Oscillatoria *?d Lyngbya. Asterlonella was considered
spring dominant, whileStephanodiscus. SynedraanHTabellaria were
III-2
-------
categorized as spring and summer dominant. Fragilarla occurred equally
throughout the seasons as a dominant, and the remaining genera were summer
and fall dominant. Additional Information about the environmental
conditions associated with the presence of the 20 phytoplankton aenera most
frequently recorded as dominants 1s available 1n Taylor, et al. (1979).
The study by Taylor, et -al.. (1979) concluded the following: (1) Phyto-
plankton genera survive over such a broad range of environmental conditions
that they cannot be used as Indicator organisms; (2) No phytoplankton
genera emerged as dependable Indicators of any one or combination of the
environmental parameters measured; (3) Preliminary analyses suggest that
phytoplankton community composition shows promise for use In water quality
assessment; (4) Some taxa, e.g., Pediastrum and Euglena, were very frequent
components of phytoplankton communities, but rarely achieved high relative
numerical Importance within those communities; (5) Flagellates and diatoms
were the most common springtime plankton genera, while the blue-green and
coccold green genera were most common 1n the summer and fall; and (6) Blue-
green algal forms, Including several not known to fix elemental nitrogen,
contributed 9 of the 10 genera which attained numerical dominance 1n water
with a mean Inorganic nitrogen/total phosphorus ratio (N/P) of less than 10
(generally suggestive of nitrogen-limitation).
Similarly, Bush and Welch (1972) concluded that phosphorus availability was
most critical to the blomass formation of blue-green algae. They found
that Aphanizomenon and Microcystis formed mats on the water surface during
warm summer daysT~and were typical of shallow, hypereutrophic lakes such as
Clear Lake (California), Klamath Lake (Oregon) and Moses Lake (Washington).
Their study showed that the blomass of blue-green algae was related to in-
organic phosphate even when nitrate was low and Invariable.
Harris and Vollenwelder (1982) noted some diatoms that are characteristic
of oligotrophlc lakes. Species of Tabellarla, Fragilarla, and Asterlonella
indicated oligotrophlc conditions. In sediment cores of Lake Erie, species
of Melosira showed the transition from oligotrophlc to eutrophic condi-
tions. The succession of species was as follows: Melosira distans and M.
Itallca were present prior to 1850 and are considered indicative of oligo-
trophy; after 1850, H. distans and M. Itallca populations dwindled, and M.
islandica (moderate enrlchmeriD and"R. "granulata (eutrophlcatlon Indicator)
appeared In the core; 1n the next phase, around 1960, M_. distans disap-
peared and was replaced by M_. binderana.
Quantitative Response to Environmental Change
Because phytoplankton exhibit such a broad range of tolerance to environ-
mental conditions, the presence or absence of a single species is not
necessarily indicative of trophic state. In contrast, indices based on
dominant genera, community composition, cell count, or chlorophyll-a^
provide a useful assessment of lake trophic levels and are better suited to
the classification of lakes than single species evaluations.
Chlorophyll-a. Chlorophyll-a is a widely accepted index of algal blomass.
In lakes ana" reservoirs with" retention times greater than 14 days, It Is
highly correlated with phosphorus. The correlation does not hold for
III-3
-------
systems with less than 14-day retention times (U.S. EPA, 1979a). Estimates
of chlorophyll-a values Indicative of trophic state are sfcown 1n Table
III-l.
Carlson's Trophic State Indices. Carlson (1977) developed three Indices of
trophic state, based upon Secchl depth, total phosphorus and chlorophyll-ji.
The three Indices are defined below:
Carlson's Secchl Depth Index, TSI(SO) • 10(6 - 1^) (1)
Carlson's Chlorophyll-a Index, TSI(CHL) • 10(6 - 2.04-0.68^1n CHL} (2)
Carlson's Total Phosphorus Index, TSI(TP) • 10(6 - 1n^8^TP) (3)
where
SO • Secchl disc depth, •
CHL » Concentration of chlorophyll-ji, ug/1
TP • Concentration of total phosphorus, ug/1.
The scale of values for Carlson's Secchl Depth Index ranges from zero to
greater than 100. A Secchl depth transparency of 64 m, which 1s greater
than the highest value reported for any lake 1n the world, yields a value
of zero. A Secchl depth of 32 m corresponds to an Index value of 10. An
Index value of 100 represents a transparency of 0.062 m. Using empirically
determined relationships between total phosphorus and transparency, and
chlorophyll-a and transparency, Carlson developed equations (1), (2) and
(3). These equations arrive at the same trophic state Index value, regard-
less of whether Secchl depth, total phosphorus, or chlorophyll-^ Is the
parameter used. However, It Is desirable to evaluate all three Indices
because of non-nutrient related factors (temperature, Inorganic turbidity,
toxics) which may affect productivity and cause disagreement among the
Indices.
Based on observations of several lakes, most ollgotrophlc lakes had TSI
below 40, wesotrophic lakes had TSI between 35 and 45, and most eutrophic
lakes had TSI greater than 45. Hypereutrophic lakes may have values above
60 (Novotny and Chesters, 1981; lit to mark and Hutch 1ns, 1978).
Nyqaard's Trophic State Indices. Nygaard (cited by Sullivan and Carpenter,
1982)developedfivephytoplankton Indices (myxophycean, chlorophycean,
diatom, euglenophyte, and compound) based on the assumption that certain
algal groups are Indicative of various levels of nutrient enrichment. He
assumed that Cyanophyta, Euglenophyta, centric diatoms, and members of
Chlorococcales are typical of eutrophic waters, while desmlds and many
pennate diatoms are generally found 1n ollgotrophlc waters. Nygaard's
Indices are listed 1n Table II1-2. In applying these Indices, the number
of taxa 1n eact. major group Is determined from the species 11st for each
sample (U.S. EPA
III-4
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TABLE III-1
TROPHIC STATE VS. CHLOROPHYLL-^
Chlorophyll-^ (ug/1)
Trophic
Condition
Sale aao to,
1966
National Academy
of Sciences,
1972
Dobson, et al., U.S. EPA,
1974 1*74-
Ollgotrophlc 0.3-2.5
Mesotrophlc 1-15
Eutrophlc 5-140
0-4
4-10
0-4.3
4.3-8.8
>8.8
<7
7-tt
SOURCE: U.S. EPA, 1979±.
III-5
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TA.BLE II1-2
MYfiAARO'S TROPHIC STATE IMQICES
Index Calculation Oil gotrophic Eutrophlc
Myxophycean Myxophyceae 0.0-0.4 0.1-3.0
Desatdeae
Chiorophycean Chlorococcales 0.0-0.7 0.2-9.0
Desaldeae
01ato« Centric Dlatons 0.0-0.3 0.0-1.75
Pennate Diatoms
Euglenophyte Euglenophyta 0.0-0.2 0.0-1.0
IMyxophyceae * Chlorococcales)
Cowpound (Myxophyceae + Chlorococcales > 0.0-1.0 1.2-25
Centric Ofatoas •*• Euglenophyta)
Desaldeae
SOURCE: U.S. EPA, 1979a.
II1-6
-------
Nygaard's ranges show considerable overlap between trophic states.
Sullivan and Carpenter (1982) sampled 27 lakes and reservoirs and found
that Nygaard's Indices did not differentiate between trophic states. In
addition, an Index value 1s undefined whenever the denominator 1s zero.
Palmer's Organic Pollution Indices. Palmer (1969) developed two algal
pollution Indices (genus and species) for rating water samples with high
organic pollution. After reviewing reports of 165 authors, Palmer prepared
two lists of organic pollution-tolerant forms, one containing 20 genera
(Table III-3), and the other, 20 species (Table III-4).
In analyzing a water sample, any of the 20 genera or species present 1n
concentrations of 50/ml or more are recorded. The pollution Index numbers
of the algae present are then totaled, giving a genus score (Palmer's Genus
Index) and a species score (Palmer's Species Index). A score of 20 or more
1s taken as evidence of high organic pollution, while a score of 15 to 19
Is taken as probable evidence of high organic pollution. Lower figures
Indicate that the organic pollution of the sample 1s not high, or that some
substance or factor Interfering with algal persistence Is present or active
(Palmer, 1969).
Use of Palmer's Indices In a study of Indiana lakes and reservoirs showed
that the Genus Index was more sensitive to differences among samples than
the Species Index. The Genus Index was correlated with the degree of
eutrophlcatlon, reflecting the abundance of eutrophic Indicator genera.
Another advantage of the Genus Index 1s that genera are easier to Identify
than species. However, a study of 250 lakes In the eastern and south-
eastern states showed that Palmer's Indices were poorly correlated with
summer mean phosphorus and chlorophyll-^ levels, although the Genus Index
ranked higher (Spearman's rank correlation coefficient) than the Species
Index (U.S. EPA, 1979a).
U.S. EPA Proposed Phytopiankton Indices of Trophic State. Using a test set
of 44 lakes In the eastern and southeastern states, EPA compared the
abilities of several Indices to measure trophic state (U.S. EPA, 1979^).
The same report Introduced 10 additional Indices that used a combination of
data Including total phosphorus, chlorophyll-^, Kjeldahl nitrogen, phyto-
pi ankton genera counts and cell counts/ml.
Each genus was assigned "trophic values" based on mean parameter values
associated with the dominant occurrence of that genus. The data used to
assign trophic values was taken from studies of 250 lakes that were sampled
during spring, summer and fall of 1973. Trophic values used 1n the general
formulas of the new Indices (Table 111-5) are presented 1n Appendix B,
along with sample problems using the Indices.
When the newly developed Indices were compared to Nygaard's and Palmer's
Indices, they showed a consistently stronger correlation with summer mean
phosphorus levels and chlorophyll-a levels. When applied to the dominant
phytopiankton community components, the Indices generally had higher
correlations than the analogous Indices applied to all phytoplankton
community components, although the differences were small (U.S. EPA 1979aK
III-7
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TABLE II1-3
TABLE II1-4
VALUES USED IN ALGAL
GENUS POLLUTION INDEX
VALUES USED IN ALGAL
SPECIES POLLUTION INDEX
Genus
Anacystls
Ank1 strodesaus
Cnla^ydooonas
Chi orel la
Closterlua
Cyclotella
Euglena
GoMphoneaa
Lepoc1ncl1$
Meloslra
Mlcractlnlua
Navlcula
N1tzsch1a
OsclllatoHa
Pandorlna
Phacus
Phorvldlua
Scenedesaus
St1geoc1on1ua
Synedra
Pollution
Index
1
2
4
3
I
1
5
1
1
1
1
3
3
5
1
2
1
4
2
2
Species
Pollution
Index
SOURCE: Palner, 1969.
Anklstrodesnus falcatus 3
Arthrosplra Jennerl 2
Cnlorella vulgarls 2
Cyclotella »enegh1n1ana 2
Euglena gracllls 1
Euglena vlrldls 6
Gowphoneaa parvulua 1
Meloslra varlans 2
Navlcula cryptocephala 1
N1tz$ch1a aclcularls 1
Nltzschla palea 5
OsclllatoHa chlorlna 2
Osc1llator1a I1«osa 4
OsclllatoHa prlnceps 1
OsclllatoHa putHda 1
OsclllatoHa tenuls 4
Pandorlna «oru« 3
Scenedesnus quadrlcauda 4
StlgeoclonluM tenue 3
Synedra ulna 3
SOURCE: Palner, 1969.
III-8
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TABLE II1-5
EPA PROPOSED PHYTOPLANKTON INDICES TO TROPHIC STATE
Phytopiankton Trophic State Index (TSI) Calculations Without Cell Counts:
TSI » 2 Vn
1-1 1
n * number of dominant genera In the sample (Concentration - 10 percent of
the total sample concentration).
V<* • the trophic value for each dominant genus 1n the sample; TOTALP (PD),
CHLA (PD), KJEL (PD), MY (PD); MY - Log TOTALP * Log CHLA + Log KJEL -
Log SECCHI
Phjloplankton Trophic State Index (TSI) Calculations with Cell Counts:
TSI • 2
1-1
Total Community:
n • the number of genera 1n the sample (entire phy topi ante ton community)
C • the concentration of the genus In the sample (units/ml)
Y • the trophic value for each genus;
TOTALP/CONC(P). CHLVCONC(P), KJEL/CONC(P)
Dominant Community:
n - the total number of dominant genera 1n the sample
C • the concentration of the genus 1n the sample (units/ml)
Y » the trophic value for each genus;
TOTALP/COHC (P), CHLA/CONC (PO), KJEL/COMC (PO)
*The parameters TOTALP, CHLA, etc. are defined In Appendix B.
SOURCE: U.S. EPA, 19/9_?.
III-9
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loop!ankton
As lakes become enriched, phytopiankton and (to a large degree) herbivorous
zooplankton populations Increase. Changes 1n species composition also
occur, although 1t 1s difficult to classify the trophic state of a water
body on the basis of a 11st of zooplankton species living 1n It.
Generally, larger species of zooplankton dominate In oilgotrophic waters.
This 1s probably largely due to predatlon pressure. In eutrophic waters,
where the fish stock 1s heavy, the larger zooplankton are eaten first.
Thus, the number of zooplankters that attain a large size 1s Halted.
Species of Bosmlna have been commonly accepted as Indicators of enrichment.
Hutchlnson (1967) observed that Bosmlna coreqonl longlsplna appeared to be
characteristic of larger and less productive lakes, and B. Iong1rostr1s of
smaller and more productive lakes. Studies on the sediments of Llnsley
Pond, Connecticut (Oeevy, 1940), Indicated that the disappearance of B.
coregonl longlsplna was concurrent with the appearance of B. longlrostrTs
as the lake oecame enriched. However, the collection of ¥• longlrostrTs
from the ep111mn1on, and £. coregonl from the hypollunion of another lake
shows the uncertainty of using BosiTna spp. as Indicators.
Studies of zooplankton In the Great Lakes showed the following:
1. A decreased significance of calanolds and an Increased predomi-
nance of cyclopolds and cladocerans were seen as a general trend
from ollgotrophlc Lake Superior to eutrophic Lake Erie (Ratalas,
1972; Watson, 1974).
2. Larger zooplankton were observed 1n Lakes Superior and Huron,
although Lake Erie had an Increased blomass of zooplankton
(Patalas, 1972; Watson, 1974).
3. In Lake Michigan. Bosmlna coregonl has been replaced by B. longl-
rostrls, Dlaptomus oregonensls has become an Important copepod
species. Eurytemora afflnls appeared (Beeton, 1969).
4. Dlaptomus s1c1lo1des, usually found In eutrophic waters has become
a dominant zooplankton 1n Lake Erie (Beeton, 1969).
Some rotifers have been considered Indicators of eutrophled waters. How-
ever, these organisms (1n particular, Brachlonus and Keratella quadrata)
have also been collected from ollgotrophlc lakes. Other zooplankton are
difficult to Identify and thus are not practical to use as Indicators of
water quality. For example, Cyclops scutlfer 1s principally an ollgotro-
• • - ..--- ,^
phlc form while Cyclops scutlfer wlgrensis lives 1n meso- and eutrophlc
lakes (Ravera, 1980).
Sprules (1977) developed a technique for predicting the llmnologlcal
characteristics of a lake which Is based on Its midsummer limnetic crus-
tacean zooplankton community. The results Indicated that northwestern
Ontario lakes characterized by Cyclops blcuspldatus thomasl. and Dlaptomus
cte<
_ apt '
water clarity. Acidic, small and clear lakes of the KUlarney region,
mlnutus are generally large and clear, whereas Tropocyclops "prasinus
aexlcanus and Dlaptomus mlnutus are typical of smaller lakes with lower
111-10
-------
Ontario, are dominated by Dlaptomus mlnutus. while Olaphanosoma leuch-
tenberglanum. Bosmlna longirostrl's and Mesocyclops edax dominate in lakes
that are less clear, larger ana have a higher pH. Finally, In the
Hallburton region of Ontario, small and productive lakes are characterized
by Olaptomus oregonensls. M. edax. and Cerlodaphnla lacustrls. Those lakes
with P. mTnutus. D. slcllTs. B. longlrostrls and Daphnla duba are larger
and less productive. . ~~
Thus, the direct effects of nutrient enrichment on the zooplankton are
unclear. Although a few qualitative changes have been Mentioned, the only
quantitative Information refers obliquely to diversity Indices. The
diversity of the zooplankton community generally decreases with Increasing
enrichment, as do the other organism communities. Diversity Indices are
discussed 1n the Technical Support Manual: Water Body Surveys and Assess-
ments for Conducting use Attainability Analyses U9B3b).
AQUATIC MACROPHYTES
Aquatic plants play several roles In the lake ecosystem. They produce
oxygen through photosynthesis, shade and cool sediments, diminish water
currents and provide habitat for benthlc organisms and fish (Boyd, 1971).
Carlgnan and Kalff (1982) found that water milfoil (Myrlophyllum splcatum
L.) was Important as physical support for mlcroblal communities.Submersed
macrophytes serve as food and nest sites for aquatic Insects and fish, and
provide protection from predatlon. The plants also play a role 1n nutrient
cycling, especially In the mobilization of phosphorus from sediments.
Barko and Smart (1980) Investigated the uptake of phosphorus from five
different sediments by Egerla densa, Hydrl11 a verticillata. and Myrlo-
phyl1 urn splcatum. The amount of sediment phosphorus mobilization differed
among species and sediments, but It was demonstrated that the plants were
able to obtain their phosphorus nutrition exclusively from the sediments.
Release of phosphorus from the macrophytes occurred primarily through death
and decay rather than through excretion. Landers (1982) showed that decom-
posing Myrlophyllum splcatum supplied significant amounts of nitrogen and
phosphorus to surrounding waters. Nitrogen Inputs accounted for less than
2.2 percent of annual allochthonous Inputs, but phosphorus recycling from
decaying plants equaled up to 18 percent of the total annual phosphorus
loading for the reservoir studied.
Response of Macrophytes to Environmental Change
Major environmental changes In lakes generally occur In response to nutri-
ent Increases (which accelerate eutrophlcatlon), suspended sediment, and
sediment deposition. Suspended sediment attenuates light penetration,
resulting 1n reduced photosynthesis by submerged aquatic macrophytes, and a
possible decrease In the coverage by plants. Reed, et al. (1983) noted
that the growth of Chara 1n a test pond was restricted during years when
the turbidity was high, but luxurious stands developed when the water was
clearer. Sediment deposition smothers some plants. For example, Isoetes
lacustrls Is not present 1n areas with rapid silting, but HI tell a and
Juncus often occur Instead (Farnworth, 1979). Potamogeton perfojlatus may
also replace Isoetes where silting occurs. The composition of the sub-
strate 1s Important In the growth of .racrophytes. Potaroogeton perfol1atus,
El odea canadensls. and Myrlophyllum splcatum reportedly grew more rapidly
III-ll
-------
1n natural sediment than In sand. Lobelia dortmanna grew only In sand
containing organic matter (Famworth, 1979).
Although aquatic macrophytes are vital to the ecosystem, eutrophlcation and
the subsequent overgrowth of plants may be detrimental to the water body.
Diurnal DO fluctuations driven by photosynthesis and respiration may be so
extreme that oxygen deficits occur. Oxygen depletion In the hypo11mn1on
may also be caused by decaying macrophytes. Low DO may cause fish kills
and eliminate sensitive species (Boyd, 1971).
Although eutrophlcatlon 1s often considered the cause of changes 1n macro-
phyte composition, management techniques may also be responsible. Nicholson
(1981) argued that techniques such as herblddal poisoning and mechanized
cutting were primary reasons for the replacement of native Potamogeton
species 1n Chautagua Lake, New York, by Potamogeton crlspus and Myr^
phyllum splcatum.
Preferred Conditions
Certain aquatic plants are able to "out-compete" others and In large popu-
lations become established under eutrophlc conditions. Such excessive
growth Is usually undesirable, and the plants are considered aquatic weeds.
Aquatic plants that cause difficulty In the United States Include Myrlo-
phyllum splcatum var. exalbescens (water milfoil), Potamogeton crlspus
(curly-leavedpondweed). Elchornfa crasslpes (water hyaclnthT, Plstla
stratioles (water lettuce), Alternanthera phlloxeroldes (alligator weed),
Heterantnera dubla (water stargrass). Hyriophyiium braslllcnse (parrot
feather),R. splcatum var. splcatum (euraslanwatermilfoil), Najas
?uadalupensTs (southern na1 adrr"Potampgeton pectlnatus (sago pondweed),
lodea cana3ens1s (elodea), and Phragmltes communls tcomion weed).
Seddon (1972) Investigated the environmental tolerances of certain aquatic
macrophytes found 1n lakes. He grouped the species Into the following:
1. Tolerant species that occur over a wide range of solute concentra-
tions - Potamogeton natans, Nuphar lutea. Nymphaea alba, Glycerla
flultansTTlttorella un1 flora;
2. Highly eutrophlc species - Potamogeton pectlnatus, Myrlophyllua
splcatum;
3. Moderately eutrophlc species - Potamogeton crlspus. Lemna trisulca;
4. Species tolerant of mesotrophic as well as eutrophlc conditions -
Ranunculus clrclnatus. Lemna minor, Polygonum amphlblum. Cera-
tophyllum'a'emersum, Potamogeton~obtus1follusi
5. Species of oilgotrophic tolerance - Potamogeton perfollatus,
Ranunculus aquatllls, Aplum Inundatum, El odea canadensls, Pota-
"mogeton berchtoldH.
Plants occurring only 1n eutrophlc conditions were considered restricted to
such areas by physiological demands. It should be noted that the last
group, although classified as of ol1gotroph1c tolerance, may also be found
111-12
-------
1n «utrophic waters. 011gotroph1c species, while shown to have a wide
tolerance, are thought to be exclude- by competition rather than by
physiological limitation from sites with higher trophic status. The last
group In effect Includes those species that can adapt to the relatively
nutrient free conditions of oHgotrophlc water.
BENTHOS
Benthlc Mcrolnvertebrates are often used as Indicators of water quality.
Because they are present year-round, are abundant, and are not very motile,
they are well-suited to reflect average condition* at the sampling point.
Many species are sensitive to pollution and die 1f at any time during their
life cycle they are exposed to environmental conditions outside their
tolerance Units.
There are also disadvantages to basing the evaluation of the blotlc Integ-
rity of a water body solely on macrolnvertebrates. Identification to the
species level Is time-consuming and requires taxonomlc expertise. Further-
more, the results may be difficult to Interpret because life history In-
formation 1s lacking for many species and groups, and because a history of
pollution episodes 1n the receiving water may not be available to provide
perspective for the Interpretation of results.
Certain organisms and associations of organisms point to various stages of
eutrophy. Decay of organic material often decreases the DO (dissolved
oxygen) content of the hypollmnlon below the tolerance of the Inverte-
brates. Attempts to translate the results of studies Into meaningful
values have yielded lists (presented later 1n this section) of tolerant and
Intolerant groups of macrolnvertebrates. In addition, mathematical for-
mulas have been developed which assign numerical values to various trophic
states depending upon the benthos present. However, factors other than
organic pollution (e.g., substrate, temperature, depth) may also Influence
the species composition of benthlc populations. Parameters such as these
which govern species distribution are discussed 1n Merrltt and Cumins
(1978).
Composition of Benthlc Communities
The composition of the benthos In littoral and profundal areas of a lake 1s
mostly dependent upon substrate, but Is also Influenced by depth, temper-
ature, light penetration and turbidity. The littoral regions of lakes
usually support larger and more diverse populations of benthlc Inverte-
brates than profundal areas (Moore, 1981). Benthlc communities In the
littoral regions consist of a rich fauna with high oxygen demands.
The vegetation and substrate heterogeneity of the littoral zone provide an
abundance of mlcrohabltats occupied by a varied fauna. By contrast, the
profundal zone Is more homogeneous, becoming more so as lakes become more
eutrophlc (Wetzel, 1975). One of the best Illustrations of the differences
of littoral and profundal benthos Is seen In studies of Lake Esrom, a
dlmlctlc lake 1n Denmark (Jonasson, 1970). The bottom fauna found on sub-
surface weeds (depth about 2m) comprises thirty-three groups and species,
totaling 10,810 Individuals per square meter. Tn contrast, only five
species are found 1n the profundal zone of Lake Esrom, although the density
111-13
-------
1s high (20,441 per square meter). The animals 1n this region burrow Into
the bottom Instead of living on or near the surface.
The factors Mentioned above should be considered 1n the design of a study
of lake benthos. Because substrates of deep waters generally have finer
sediment particles than substrates of shallow waters, depth, should be
considered 1n quantitative calculations to help compensate for substrate
differences. Adjustments for depth will be discussed 1n greater detail 1n
the section on quantitative measures of the effects of pollution on
benthos.
General Response to Environmental Change
The benthos of freshwater Is composed largely of larvae and nymphs of
aquatic Insects (Arthropoda: Insecta). The benthos also comprises fresh-
water sponges (PoHfera: Sponglllldae), flatworms (Platyhelmlnthes:
Tr1c1ad1da), leeches (Annelida: H1rud1nea), aquatic earthworms (Annelida:
Ollgochaeta), snails (Molluscs: Gastropoda), clams and mussels (Mollusca:
B1va1v1a). Particular groups of Insects are most abundant 1n specific
kinds of freshwater habitat. Damsel files and dragonflies (Odonata) are
generally found 1n shallow lakes, but some species occur In running water.
StonefUes (Plecoptera) and mayflies (Ephemeroptera) are predominantly
running water forms, although certain Ephemeroptera dwell 1n lakes and
ponds. Caddlsflles (Trlcoptera) abound In likes and streams where the
water 1s well-aerated. The other groups also occur In both streams and
lakes (Edmondson. 1959).
Aquatic Insects can be Identified by using various keys (Pennak, 1978;
Edmondson, 1959; Needham and Needham, 1962; Nerrltt and Cummins, 1978).
Merrltt and Cummins (1978) also provide lists of the species and habitats
(lentlc or lotlc) where they are most often found.
The species composition and number of Individuals of the benthlc community
change In response to Increased organic and Inorganic loading. Organic
pollution generally causes a decrease 1n the number of species of
organisms, but an Increase 1n the number of Individuals. Inorganic pol-
lution, such as sediment, causes a decrease 1n the number of Individuals,
as well as a decrease In species. The following sections focus on
qualitative and quantitative changes 1n freshwater benthlc populations that
are Indicative of types of pollution and of trophic state 1n lakes and
reservoirs.
Qualitative Response to Environmental Change
The most sensitive macrolnvertebrate species are usually eliminated by
organic pollution. Because decay of organlcs often depletes oxygen, the
surviving species are those that are more tolerant of low dissolved oxygen
content. The predominant bottom conditions can be Inferred by observing
which species are present at a specific site.
Suspended sediment and silt deposition may Influence macrolnvertebrates by
causing:
(a) Avoidance of adverse conditions by migration and drift;
111-14
-------
(b) Increased mortality due to physiological effects, burial, and
physical destruction;
(c) Reduced reproduction rates because of physiological effects, sub-
strate changes, loss of early life stages;
(d) Modified growth rates because of habitat Modification and changes
1n food type and availability (Farnworth, et al., 1979).
Indicator Organisms
The macrolnvertebrate classes that are most often used as Indicator organ-
isms are the Insecta and Annelida. These organisms are Illustrated In
Figure III-l. Stonefly nymphs, mayfly naiads, and heUgraomltes are
generally considered to be relatively sensitive to environmental changes.
The Intermediately tolerant macrolnvertebrates Include scuds, sowbugs,
blackfly larvae, dragonfly nymphs, damsel fly nymphs, and leeches. Blood-
worms (midge larvae) and sludgeworms make up the group of very tolerant
organisms.
Anaerobic environments are tolerated by sewage fly larvae and rat-tailed
maggots. Table 111-6 lists those aquatic Insects that have been found at
dissolved oxygen concentrations of less than 4 ppm. The greatest number of
tolerant species are members of the order Dlpteri.
Sponges are affected by pollution although they are not usually considered
Indicator organisms. Of the freshwater sponges, Ephydatla fluvlatlHs. E.
muellerl, Heteromeyenla tublsperma. and Eunalus fragl11s 'may be found Tn
eutrophlc waters. Also, Ephydafla robusta can survive very low dissolved
oxygen levels and has been collected at DO tensions of 1.00 ppm (Harrison,
1974). Of the Mollusca, Unlonld clams (B1valv1a) are considered sensitive
to environmental changes. Snails.(Gastropoda) commonly occur In moderately
polluted environments. The most resistant species are Physa heterotropha.
P. Integra. P_. gyrlna, Gyranulus parvus. Hellsoaa anceps. and H. trlvolvTs.
But almost every common species has been found in polluted areas (Harman,
Weber (1973) compiled a 11st of tolerances of freshwater macroInvertebrate
taxa to organic pollution (Appendix C). Organisms that occur In streams
and lakes are Included. The tolerances of the organisms listed In the
appendix are based upon classification by various authors.
Trends 1n macrolnvertebrate populations have been shown In studies of
eutrophlc lakes, A collection of studies report the following responses of
macrofauna to Increasing eutrophlcation:
o OUgochaetes, chlronomlds, gastropods and sphaerlds Increase and
Hexagen1 a (mayfly nymph) decreases (Carr and Hlltunen, 1965);
o Numbers of ollgochaetes relative to chlronomlds Increase as organic
enrichment Increases (Peterka, 1972);
111-15
-------
a
fi
A. Stonefly nymph CPlecoptera) 0.
B. Mayfly naiad (Ephemeroptera) *•
C. Hellgrammfte or DoBsonfly L.
larvae (Corydaltdae) M.
0. Caddlsfly larvae (THchoptera)
E. Blackfly larvae (SimulUdae) N.
F, Scud (Amphlpoda) 0.
6. Aquatic sow bug (Isopoda) P.
H. Snail (Gastropoda) Q.
Fingernail clam (Sphaer11dae)
Damsel fly nymph (Zygoptera)
Dragonfly nymph (Anisoptera)
Bloodworm or midge fly larvae
(Tend1ped1dae)
Leech (H1rund1nea)
Sludgeworm {Tublflcldae)
Sewage fly larvae (Psychoda)
Rat-tailed maggot (Tublfera-
Erlstalis)
Figure III-l. Representative bottom fauna (from Keup, et al., 1966).
111-16
-------
TABLE II1-6
SPECIES FOUMD AT DISSOLVED OXYGEN LESS THAN 4 PPM
Odcnata - dragonfiles and dasselflies
Ischnura poslta (Hagen)
Pachydlplax longlpennls (Burn.)
Epheaeroptera - aayfiies
Paraleptophlebla sp.
Caenls sp.
Heniptera - true bugs
Motonecta Irrorata Uhl.
Pica strTola Fleb.
^anatrrTusTral 1 s Hung.
Ranatra kirkaldyl Bueno
Pelocorls feaoratus P. de B.
Beiostoaa fluainea Say
Trepobates sp.
Rhagovella" obesa Uhl.
Megaloptera - alder flies, dobsonfUes,
and fish files
Chaullodes sp.
Coieoptera - beetles
Hallpi us spp.
Peltodytes spp.
coeiaabus spp.
Laccophiius spp.
HydroporuTspp.
oineutes spp.
Gyrlnus"~spp.
Troplsternus spp*
:nrpnycT"
StenelBis grossa Sand.
MacnronycHu? glabratus Say
Lepldoptera - butterflies and «oths
Parapoynx sp.
Trlchoptera - caddlsflles
Polycentropus reaotus (Banks)
Oecetls eddlestonl Ross
Dlptera - true flies
ProclacHus bell us (Loew)
Cllnotanyp'us plnguls (Loew)
Ablabesmyla monllls (L.)
Trtchociadius sp. Roback
Chlronomus attenuatus (Walk.)
Chlronomus rlparlus (Me1g.)
CryptocniFonomus nr. fulvus (Joh.)
Olcrotendlpes nervosus (Stasger)
Harnlschia nr."aoortlva (Mall.)
MlcrotendTpes pedellus DeGeer
Trlbelos Jucundus (Walk.)
Rheotanytarsus exlguus (Joh.)
Calopsectra nr.~guerla Roback
PalpomylaTp. spp.
Tublfera tenax (L.)
SOURCE: Roback, 1974.
111-17
-------
o The smallest Insect larvae are characteristic of ollgotrophlc
waters, and 4u= to a shift In species composition, larval size
Increases with Increasing eutrophlcatlon (Jonasson, 1969);
o Tanytars1n1 are replaced by Ch1ronom1n1 1n positions of dominance
with Increasing eutrophlcatlon (Paterson and Fernando, 1970).
The study of four reservoirs (Salt Valley Reservoirs) In eastern Nebraska
revealed several trends 1n macrobenthlc communities as eutrophlcatlon pro-
gressed. Contrary to the observation frequently reported that ollgochaete
populations Increase as eutrophlcatlon progresses, Hergenrader and Lesslg
(1980b) observed a decrease 1n Tublfex. They noted, however, that the deep
hypolTmnetlc waters of the Salt Valley reservoirs do not become anaerobic,
as 1s the case 1n lakes where ollgochaetes have Increased. The Tanytarsinl
(family Chlronomldae) present 1n the less eutrophic reservoirs disappeared
In the most eutrophic. Finally, Sphaerlum (order Hollusca) Increased
during the early stages of eutrophlcatlon but declined as eutrophy pro-
gressed.
Chlronomld Communities as Indicators
Instead of using a single organism to Indicate water quality, Saether
(1979, 1980) suggests studying Chlronomld communities. By looking at
profundal, littoral and subllttoral Chlronomld communities, Saether was
able to delineate 15 characteristic communities found 1n environments
ranging from ollgotrophlc to eutrophlc. The communities, 6 In each of the
oilgotrophic and eutrophlc and 3 1n the mesotrophic range, are lettered
from alpha to omlkron. The Greek letters emphasize that the 15 sub-
divisions are not trophic level divisions, but are recognizable Chlronomld
communities. The species found 1n a lake or part of a lake can be used to
determine the associations and hence the extent of eutrophy. The key to
Chlronomld associations and the species 11st noted by Saether are presented
1n Appendix 0. By using this system, Saether found significant
correlations between Chlronomld associations and the ratios of
chlorophyll-a to mean depth (Figure III-2) and total phosphorus to mean
depth (Figure II1-3).
Sediment Effects
The distribution of macrolnvertebrates will be much less affected by
currents and drift 1n a lake than 1n a river. However, at those points
where rivers enter a lake, or where a river forms at the outlet from a
lake, one might expect to find macrolnvertebrate populations that are
similar to the population of the connecting river. The distribution of
macrolnvertebrates found In the littoral zone will be less affected by
drift (since rooted plants 1n the littoral tend to slow currents and
thereby Inhibit drift) and more by the physical effects of suspended sol Ids
and sedimentation. As concentrations of suspended and settleable solids
Increase, Invertebrates tend to release hold of the substrate to be
transported by currents or to migrate elsewhere. Migration from those
areas affected by sediment changes the structure of the benthlc community.
The effects of suspended solids on benthlc macrolnvertebrates are
-------
10 IS 20 2.S DO
Chlorophyll a/ } ^ug /i/m
35
Figure III-2. Ch1orophyl1-a/ Mean Lake Depth 1n relation to 15 lake
types based "on Ch1ronom1d Communities (From Saether, 1979)
111-19
-------
UJ
0123 456789 10 11 12
Tot- P/2 /*g/l/m
Figure III-3. Total Phosphorus/Mean Lake Depth 1n relation to 15 lake
rigure ^ ^^ ^ Chtronomld communities (From Saether, 1979)
^
III-30
-------
TABLE II1-7
SUMMARY OF SUSPENDED SOLIDS EFFECTS ON AQUATIC MACROINVERTEBRATES
MtMtf hfnUliMM Lovw
Uft
Mb* PofMteUoM
M
Uta*il
Elfcrt •oH<
CMOMMM«&
T«MAddM
HoraulfMMM-
CoJtory
Ok«MM«0wdto
tnttoM)
QlMUiy
Triooty
HtoMQuony
LfaiMloMQinny
Mb**
40-200 m»
Abo can**4 rfciMM fa
SfatSutotT*
SOURCE: Sorenson, et al., 1977.
111-21
-------
Deposition of sediment In the profundal zone My provide a stable sub-
strate. In contrast deltas where streams enter the lake or reservoir May
be subject to continuing deposition and erosion. Such areas will support
fewer species and fewer numbers of organises than the More stable profundal
zone.
Sediment deposition Modifies Mcrolnvertebrate habitat and alters the type,
distribution and availability of food. Substrate preference of macro-
Invertebrates 1s related to a variety of factors. In addition to particle
size, the colonization of an area 1s dependent on the amount and type of
detritus, the presence of vegetation, the degree of compaction and the
amount of perlphyton (Farnworth et al.( 1979). Sediment preferences My
change with an organism's life history stage, thus compounding the problem
of categorizing associated substrate. Nonetheless, certain groups such as
Ch1ronom1dae and Trlcorythodes. are recognized as preferring fine sediment.
Quantitative Response to Environmental Change
Quantitative techniques that are used to assess the biological Integrity of
lakes Include a number of Mthematlcal Indices, or focus on the abundance
of certain benthlc organisms. These methods are summarized 1n the fol-
lowing sections. Other measures of community health, such as diversity
Indices, are discussed 1n the Technical Support Manual: Water body Surveys
and Assessments for Conducting use Attainability Analyses (U.S. EP&.
1983b), and 1n a review by Washington (1984).
OUgochaete Populations
OUgochaetes, particularly members of the family Tublflcldae, are present
1n large numbers 1n polluted areas. Aston (1973) found that Llmnodrllus
hoffmelsterl and Tublfex tublfex predominate In areas receiving heavy
sewage pollution. In a review of the relationship between tublfldds and
water quality, Aston (1973) noted several Investigations that have used the
population density of tublfields as an Index of pollution. Surber (cited
by Aston, 1973), studied a number of lakes 1n Michigan and concluded that
areas with an ollgochaete density of more than 1,100 per square meter were
truly polluted. Carr and HUtunen (1965) used the following numbers of
olfgochaetes per square meter to Indicate pollution 1n western Lake Erie:
light pollution, 100 to 999; moderate pollution, 1,000 to 5,000; and heavy
pollution, more than 5,000. This means of classification falls to consider
seasonal variation In population density and the organic content and
particle size of the bottom substrate. Since the population density 1s
likely to vary, this method has limited utility (Aston, 1973).
VUederholm (1980) noted that a simple depth adjustment could make ollgo-
chaete abundance more applicable. By dividing the number of ollgochaetes
per square meter by the sampling depth, he found that the correlation with
chlorophyll was Increased. This adjustment may account for factors that
are affected by depth such as food supply, predatlon pressure (which
declines as depth Increases), and possible oxygen deficits.
Tt"» relative abundance of ollgochaetes may be a better Indication of
organic pollution than the population density. In a stream study, Good-
night and WhUley (1961) suggested that a population of BO percent or more
111-22
-------
of ollgcchsetes In the total aacroInvertebrate population Indicates a high
degree of organic enrichment. They hypothesized that percentages fro» 60
to 80 Indicate doubtful conditions and below 60 percent, the area Is In
good condition. howmlller and Beeton (1971) used this Index In a study of
Green Say, Lake Michigan, and concluded that In 1967 the lower bay was 1n a
highly polluted state, and the Middle bay had "doubtful conditions."
BMnkhurst (1967) suggested that the relative abundance of the tublflcld
Llmnodrllus hoffmelsteH (as a percentage of all ollgochaetes) may be a
useful measure of organic pollution. Increased percentages of L. hpff-
melsterl are often Indicative of organic pollution. Lower Green "Bay 1731
L. hoffmelsterl) was Identified as being wore polluted than Riddle Green
fay (50% and 421 L. hoffmelsterl) by reference to the relative abundance of
this oUgochaclo Ttowmiiier and Scott, 1977).
011gochaete/Chlronomld Rat1o
Another proposed Indicator uses the ratio of ollgochaetes to chlronomlds.
Generally, the ratio Increases as the lake becomes More eutrophlc.
Hlederholm (1980) advocates Including a depth adjustment (ratio divided by
sampling depth) when using the ollgochaete/chlronomld ratio since ollgo-
chaetes tend to Increase In dominance at greater depths. Studies of
Swedish lakes showed a high correlation between depth-adjusted ollgochaete/
chlronomld ratios and trophic state, but very little correlation of the
non-adjusted ratio with trophic state. Table III-8 shows that the depth-
adjusted ollgochaete/chlronomld ratio had low values (from 0-1.5) In
oilgotrophic lakes, and progressively higher values for mesotrophic
(1.5-3.0), eutrophlc (3.0-7.4) and hypereutrophlc (>18) lakes. Hlederholm
suggests that the ollgochaete/chlronomld ratio may be used directly when
comparing data from a single site over time or different lakes over time,
but a general application needs some adjustment for depth.
Mathematical Indices
A survey of the literature reveals at least four mathematical Indices 1n
addition to diversity Indices that may be applicable In freshwater lake
studies. These Indices are described In Table III-9.
Based on their studies of rivers and streams receiving sewage, Kolkwltz and
Marsson (1908, 1909) proposed their saproplc system of zones of organic
enrichment. They suggested that a river receiving a load of organic matter
would purify Itself and that 1t could be divided Into saproblc zones
downstream from the outfall, each zone having characteristic biota.
Kolkwltz and Marsson published long lists of the species of plants and
animals that one could expect to be associated with each zone. The zones
were defined as follows:
o Polysaproblc; gross pollution with organic matter of high molecu-
lar weight, very little or no dissolved oxygen and the formation of
sulphides. Bacteria are abundant, and few species of organisms are
present.
111-23
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TABLE III-8
BENTHIC COMMUNITY MEASURE
WITH AND WITHOUT ADJUSTMENT FOR DEPTH
Lake
Approximate
Trophic
State4
Chlorophyll-*
(ug/1)5 ~
Ollgochaete/
Chlronoald Ratio
(I)
without with
depth adj. depth adj.c
Vattem, 20-40«
Yattern, 90-llOa
Yanern. 40-80 •
Skaren, 10-26«
Innaren, 14-19*
Somen, 16-49*
Malaren, area C, 30«
Malaren, area C, 45-50*
Malaren, area B, 15»
Hjalaaren, area C, 6-18»
S. Bergundasjon, 3-5«
Yaxjosjon, 3-5«
Hjalaaren, area B, 2-3«
0
0
0
0
M
M
M
M
E
E
HE
HE
HE
1.1
1.1
1.7
2-2.5
2.5-3
3-4
5.5
5.5
17.5
9.4
25-75
50-100
102
38.9
90.1
86.0
25.9
19.8
44.3
85.5
96.4
69.0
71.9
69.0
87.4
66.8
1.3
0.9
1.5
1.5
1.2
1.9
2.9
2.0
4.6
7.4
18.5
21.6
34.4
a. 0 » ol1gotroph1c, M • »esotrophic, E • eutrophic, HE • hypereutrophic
b. May-October, 1»
c. Ol1gochaete/Ch1ronoa1d ratio divided by sampling depth
SOURCE: Ulederhola, 1980.
111-24
-------
TABLE 111-9
MATHEMATICAL INDICES
Index Name and Description
Saproblc Index
Reference
Saether, 1979
.
" TTT
s • 1-4, 011 go - to polysaproblc
h • occurrence value; J, occasional
3, common; 5, Mass occurrence.
BentMc Quality Index
5 N, . k
BQI
1
1
based on Indicator species of
ch1ronom
-------
o Hesosaproblc; simpler organic molecules and Increased 00 content.
Upper zone lalpha-mesosaproblc) has many bacteria and often fungi,
with more types of animals and lower algae. Lower zone
(beta-mesosaproblc) has conditions suitable for many algae,
tolerant animals and some rooted plants.
o 01 Igosaproblc: oxygen content 1s back to normal and a wide range
of plants and animals occur.
As stated, the saproblc system was designed for rivers and streams.
Nevertheless, the concept could be applied to riverine Impoundments that
have a predominant longitudinal flow. More Importantly, however, 1s the
Impetus generated by the saproblc 'system for the development of subsequent
biological Indices.
Pintle and Buck (1955, cited by Saether, 1979) applied the Ideas of Kolk-
wltz and Marsson In the Saproblc Index (Table III-9), which was proposed
for use In stream studies. Further extensions of the saproblc system were
made by Sladecek (1965) and these modifications are summarized 1n Nemerow
(1974).
Wlederholm proposed the Benthlc Quality Index (BQI) In 1976 for studies of
Swedish Lakes (cited by Saether, 1979). The value of ki (Table 111-9)
represents the empirical position of each species In the range from oil go-
trophic to eutrophic conditions. The Indicator species used by Ulederholm
were given the following values for k,: 5. Heterotrlssoclad1us subpllosus
(K1eff.); 4, Mlcropsectra spp. and ParacladUpcima spp., specmcany tC
nigrltula (Goetgh.); 3. Phaenospectra coraclna (Zett.) and St1ctoch1ronomus
rosenschoeldl (Zett.); Z, Chlronomus anthracinus (Zett.V;1, Chlronomus
piumpsus L.; o. absence of these indicator species. The BQI was related to
total phosphorus/mean lake depth as shown 1n Figure III-4. The value of
the Index approaches 0 as the lakes become more eutrophlc, and Is nearly 5
In ollgotrophlc lakes. With the Indicator species used here, the BQI
applies to Palearctlc lakes (e.g., Europe, Asia north of the Himalayas,
Northern Arabia, Africa north of the Sahara). However, the species used as
Indicators may be redefined for Nearctlc lake studies (e.g., lakes 1n
Greenland, arctic America, northern and mountainous parts of North America)
by using the species lists given 1n Appendix D.
The Trophic Condition Index (TCI) 1s the only commonly used Index that was
developed In North America specifically for lake studies. This Index
(Table III-9) was designed by BMnkhurst (1967) for use on Great Lakes
waters. It Is based on ollgochaetes which are classified according to the
degree of enrichment of the environments where they are typically found
(Table III-IO). The TCI ranges from 0 to 2, with the higher values associ-
ated with more eutrophlc conditions.
In a study of Green Bay, Howmlller and Scott (1977) compared the TCI with
four other Indices. Only the Trophic Condition Index showed a significant
difference between the three areas of Green Bay shown 1n Figure III-5. The
other Indices used were Species Diversity, OUgochaete worms per square
meter, OUgochaete worms (!) and L. hoffmeslterl (I). As shown 1n Table
III-11, these Indices show no statistical difference between Areas II and
III, and sometimes no significant difference from values for Area I.
111-26
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Figure III-4. Total phosphorus/mean lake depth in
relation to a benthic quality Index (BQI) based
on Indicator species of chlronomids (From Wiederholm, 1980)
111-27
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TABLE 111-10
A CLASSIFICATION OF OLIGOCHAETE SPECIES
ACCORDING TO THE DEGREE OF ENRICHMENT OF THE ENVIRONMENTS
IN WHICH THEY ARE CHARACTERISTICALLY FOUND
Group 0
Species largely restricted to oilgotrophic situations:
StylodHlus her1ng1anus
Peloscolex varlegatus
P. superlorensls
L1mnodr1lus profundlcola
Tublfex kesslerl
Rhyacodrllus coccineus
R. Montana
Group 1
Species characteristic of areas which are mestropMc or only slightly
enriched:
Peloscolex ferox
P. freyl
Ilyodrllus tempietonl
Potatothrlx moldavlensls
P. vejdovskyl
Aulodrllus spp.
Arcteonals lomondl
Dero dlgltata
Nals ellnguls
Slavlna appendlculata
Unc1na1s unclnata
Group 2
Species tolerating extreme enrichment or organic pollution:
L1«nodr11us angu1st1pen1s
L. cervix
L. claparedelanus
L. hoffMlsterl
L. maumeensls
L. udekenlanus
Peloscolex aultlsetosus
Tublfex tublfex
SOURCE: HoMlller and Scott, 1977.
111-28
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Figure I1I-5. Map of Lower and Hlddle Green Bay showing
9 location of benthos sampling stations and
areas designated I. II. and III (from Howmlller
and Scott. 1977).
111-29
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TABLE III-ll
AVERAGE VALUES OF FIVE INDICES OF POLLUTION
COMPARED FOR THREE AREAS OF GREEN 3AY
Species Diversity
OUgochaete woms/r
Ollgochaete woms, %
L. noff«e1ster1. t
Trophic Index
I
1.00
1085
63
73
1.92
Area
II
1.62
1672
53
bti
1.84
III
1.66
1152
53
42
1.53
NOTE: Values underscored with a comon line are not
significantly different fro* each other.
SOURCE: HoMriller and Scott, 1977.
II1-30
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FISH
Although fish species In many Instances show no preference for either
lacustrine or riverine habitat, certain environmental components (e.g.,
velocity, substrate, dissolved oxygen and temperature) render one habitat
•ore suitable than another. The following paragraphs highlight the habitat
requirements of certain fish species that are predominantly lacustrine.
Trophic State Effects
Ollgotrophlc and eutrophlc lakes have characteristic fish populations
because of their contrasting habitats. Briefly, Ollgotrophlc lakes are
generally deep and often large In size, and are located In regions where
the substratum Is rocky. These lakes usually stratify In summer, but the
cool profundal zone contains sufficient oxygen year-round for fish sur-
vival. Ollgotrophlc lakes support less than 20 pounds of fish per surface
acre, and characteristic fish are salmons, trouts, chars, clscoes, and
graylings (Bennett, 1971).
Eutrophlc lakes support fish populations of largemouth bass, white bass,
white and black crapples, blueglll and other sunflsh, buffalo, channel
catfish, bullheads, carp, and suckers (Bennett, 1971). Such lakes have
shallow to Intermediate depths, may have large or small surface areas, and
are located 1n regions with more fertile soil than Ollgotrophlc lakes.
Hypollmnetlc waters of eutrophlc lakes frequently exhibit reduced oxygen
levels during summer stratification.
Nutrient enrichment which causes Increased production In lakes accelerates
the natural progression of trophic state from oilgotrophy to eutrophy.
Initially, eutrophlcation and the subsequent abundance of food organisms
may cause Increased growth of fish. However, undesirable conditions of
temperature and dissolved oxygen 1n later stages force some fish to leave
the affected area or perish. F1sh commonly respond to changes associated
with eutrophlcation by shifting their horizontal and vertical distribution.
In Lake Erie, whiteflsh and clscoes became restricted to the eastern basin
as the environment became more unsuitable (Beeton, 1969). Perch and
whiteflsh may move from the littoral zone Into the pelagic zone, where they
are not usually found (Larkln and Northcote, 1969). The restriction of
coldwater fishes to a thin layer between the oxygen deficient hypollmnlon
and the warm eplllmnlon may lead to mortalities. This may have contributed
to the disappearance of clscoes from Lake Mendota, Wisconsin.
As eutrophlcatlon proceeds, there 1s a general pattern of change 1n fish
populations from coregonlnes to coarse fish. One of the best examples of
population changes Is In the Great Lakes. Although factors other than
eutrophlcatlon may have contributed to the loss of some species, enrichment
Is recognized as being an Important cause. Commercial fisheries provide
Information on the species composition of catches. In Lake Erie, the major
species In the 1899 catch were lake herring (cisco), blue pike, carp,
yellow perch, sauger, whiteflsh and walleye. By 1940, the lake herring and
sauger fisheries had collapsed, and the catch was dominated by blue pike,
whiteflsh, yellow perch, walleye, sheepshead, carp, and suckers. Blue pike
and whiteflsh populations have since declined, and the catch has become
111-31
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•ore concentrated on the warmwater species such as freshwater drum, carp,
yellow perch and smelt (6«*U*n, 1969; Larkln and Northcote, 1969).
Temperature Effects
Temperature as well as trophic state plays a role 1n determining the fish
species Inhabiting a lake. Trout are generally considered representative
of coldwater species. Rainbow trout and brook trout thrive 1n water with a
•ax1MUM summer temperature of about 70*F. Rainbow trout are More tolerant
of higher temperatures than brook trout. Prolonged exposure to tempera-
tures of 77.5*F 1$ lethal to brook trout (Bennett, 1971).
Fish typical of warmer waters Include largemouth bass, blueglll, black and
white crapple, and black and yellow bullhead. These species are fairly
tolerant of high, naturally occurring, water temperatures, and generally
suffer mortality only when additional adverse factors (e.g., anoxlc
conditions, toxics, thermal plumes) prevail. Species such as smallmouth
bass, rock bass, walleye, northern pike, and muskellunge are more sensitive
to Increased temperatures than the more typical warmwater fish, but are not
as sensitive as trout.
Warmwater fish and coldwater fish may live 1n the same lake. For example,
a two-tier fishery may exist In a stratified lake, wherein warmwater fish
live 1n the eplllmrlon and the metal 1union, while coldwater fish survive In
the cooler waters of the hypollmnlon.
Specific Habitat Requirements
Specific habitat requirements for some lake species are published In a
series of documents (Habitat Suitability Index Models) prepared by the Fish
and Wildlife Service and available through the National Technical
Information Service. These publications summarize habitat suitability
Information for many lake species Including: rainbow trout, longnose
sucker, smallmouth buffalo, blgmouth buffalo, black bullhead, largemouth
bass, yellow perch, green sunflsh, and common carp. The following
Information on the habitat requirements of these species Is contained
within the Fish and Wildlife Service reports.
Rainbow Trout
Rainbow trout prefer cold, deep lakes that are usually ollgotrophlc. The
size and chemical quality of the lakes may vary. Rainbow trout require
streams with gravel substrate In riffle areas for reproduction. Spawning
takes place In an Inlet or outlet stream, and those lakes with no tributary
streams generally do not support reproducing populations of rainbow trout.
The optimal water velocity for rainbow trout redds Is between 30 and 70
cm/sec. Juvenile lake rainbow trout migrate from natal streams to a
freshwater lake rearing area.
Adult lake rainbow trout prefer temperatures less than 18"C, and generally
remain at depths below the 18"C Isotherm. They require dissolved oxygen
levels greater than 3 mg/1 (Raleigh, et al., 1964).
111-32
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Longnose Sucker
This species Is most abundant In cold, ollgotrophlc lakes that are 34-40 •
deep. These lakes generally have very little littoral area. They are also
capable of Inhabiting swift-flowing streams, but longnose suckers In lake
environments enter strews and rivers only to spawn or to overwinter. The
longnose sucker spawns 1n riffle areas (velocity 0.3-1.0 m/sec), where the
adhesive eggs are broadcast over clean gravel and rocks (Edwards, 1983a).
Smallmouth Buffalo
Although smallmouth buffalo typically Inhabit large rivers, preferring
deep, clear, warn waters with a current, they can do well 1n large reser-
voirs or lakes. Lake or reservoir populations spawn In embayments or along
recently flooded shorelines. Although smallmouth buffalo will spawn over
all bottom types, they prefer to spawn over vegetation and submerged ob-
jects. Juveniles frequent warm, shallow, vegetated areas with velocities
less than 20 cm/sec. Adults are found 1n areas with velocities up to 100
cm/sec (Edwards and Twomey, 1982^).
Blgmouth Buffalo
Bigmouth buffalo prefer low velocity areas (0-70 cm/sec), and Inhabit large
rivers, lowland lakes and oxbows, and reservoirs. Populations In reser-
voirs reside 1n warn, shallow, protected embayments during the summer, and
move Into deeper water In the fall and winter. Fluctuations of reservoir
water levels reduce buffalo populations due to slltatlon, erosion and loss
of vegetation (Edwards, 1983b).
Black Bullhead
Bullheads live In both riverine and lacustrine environments. Optimal
lacustrine habitat has an extensive littoral area (more than 25 percent of
the surface area), with moderate to abundant (more than 20 percent) cover
within this area. Bullhead nests are located In weedy areas at depths of
0.5-1.5 m. Black bullheads are most common In areas of low velocity (less
than 4 cm/sec). They prefer Intermediate levels of turbidity (25-100 ppm),
and can withstand low dissolved oxygen levels (as low as 0.2-0.3 mg/1 In
winter, 3.0 mg/1 In summer) (Stuber, 1982).
Largemouth Bass
Largemouth bass prefer lacustrine environments. Optimal habitats are lakes
with extensive shallow areas (more than 25 percent of the surface area less
than 6 m depth) for growth of submergent vegetation, but deep enough (3-15
m) to successfully overwinter bass. Current velocities below 6 cm/sec are
optimal, and velocities above 20 cm/sec are unsuitable. Temperatures from
24-30'C are optimal for growth of adult bass. Largemouth bass will nest on
a variety of substrates, Including vegetation, roots, sand, mud, and cob-
ble, but they prefer to spawn on a gravel substrate. Adult bass are con-
sidered Intolerant of suspended solids; growth and survival of bass Is
greatest In low turbidity waters (less than 25 ppm suspended solids). Bass
show signs of stress at oxygen levels of 5 mg/1, and DO concentrations less
than 1.0 mg are lethal (Stuber, et al., 1982aK
111-33
-------
Yellow Perch
Yellow perch prefer *reas with sluggish currents or slack water. They
frequent littoral areas In lakes and reservoirs, where there are Moderate
amounts of vegetation present. Riverine habitat resembles lacustrine
areas, with pools and slack-water. Perch spawn 1n depths of 1.0 m to 3.7
•, and In waters of low (less than 5 en/sec) current velocity. Littoral
areas of lakes and reservoirs provide both spawning habitat and cover
(KMeger, et al., 1983).
Green Sunflsh
Green sunflsh thrive In both riverine and lacustrine environments. Optimal
lacustrine environments are fertile lakes, ponds, and reservoirs with
extensive lUtural areas (more than 25 percent of the surface area).
Preferred environmental parameters are: velocities less than 10 cm/sec,
moderate turbidities (25-100 JTU) and DO levels of more than 5 mg/1 (lethal
levels of 1.5 mg/1) (Stuber, et al., 1982b).
Common Carp
This species prefers areas of slow current. In both riverine and lacus-
trine environments, carp prefer enriched, relatively shallow, warm, slug-
gish and well-vegetated waters with a mud or sllty substrate. Adults are
generally found In association with abundant vegetation. The common carp
Is extremely tolerant of turbidity and Its own feeding and spawning
activities over sllty bottoms Increase turbidity. Adults are also tolerant
of low dissolved oxygen levels, and can gulp surface air when the dissolved
oxygen Is less than 0.5 mg/1 (Edwards and Twomey, 1982}>).
Stock1ng
The most common fish management technique used Is stocking. The purpose of
stocking Is to Improve the fish population, and certain fish are used more
often than others. The following description 1s based on Information 1n
Bennett (1971).
Bass and bluegllls have often been stocked In the same pond or lake. The
theory behind stocking these species 1n combination Is that both largemouth
bass and bluegllls would be available for sport-fishing. The role of the
bluegllls 1s to convert Invertebrates Into blueglll flesh. The bass then
feed on small bluegllls and thereby control the population. Problems may
be caused from an overpopulation of one species, especially since the
bluegllls overpopulate more often than the bass. Stocking ratios (numbers
of bass : numbers of bluegllls) as discussed by Bennett (1971), Influence
the outcome of such stocking endeavors.
Because largemouth, small mouth, and spotted bass are omnivorous, any of
these three species stocked alone may be fairly successful. They feed on
crayfish, large aquatic Insects and their own young. These species do well
In warmwater ponds 1f they do not have to compete with prolific species
such as bluegllls, green sunflsh, and black bullheads. Largemouth bass
111-34
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have been stocked In war»water ponds In combination with Minnows, chub-
suckers, red-ear sunflsh or waraouths. These combinations have proved to
be successful.
Walleye stocking reportedly has variable success except In waters devoid of
other fishes. In waters such as new reservoirs and renovated lakes, satis-
factory survival rates for walleye occur. Bennett (1971) noted that,
generally, walleye stocking was unsuccessful In acid or softwater lakes.
111-35
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CHAPTER IV
SYNTHESIS AMD INTERPRETATION
INTRODUCTION
Tht basic physical and chemical processes of the lake were introduced in
Chapter II. Chapter II also Includes a discussion of desktop procedures
that night be used to characterize various lake properties, and a dis-
cussion of mathematical models that are suitable for the Investigation of
various physical and chemical processes.
The applicability of desktop analyses or mathematical models will depend
upon the level of sophistication desired for a use attainability study.
Case studies were presented to Illustrate the use of measured data and
model projections In the use attainability study. The selection of a
reference site 1$ discussed later In Chapter IV.
Chapter II also provides a discussion of chemical phenomena that are of
Importance 1n lake systems. Most Important of these are the processes that
control Internal phosphorus cycling, and the processes that control dis-
solved oxygen levels 1n the epIUmnlon and the hypollmnlon of * stratified
lake. Chemical evaluations are also discussed In the earlier Technical
Support Manuals (U.S. EPA, 1983b, 1984).
The biological characteristics of the lake are summarized In Chapter III.
Specific Information on plant, fish and macrolnvertebrate lake species Is
presented to assist the Investigator 1n determining aquatic life uses.
The emphasis In Chapter IV 1s placed on a synthesis of the physical, chemi-
cal and biological evaluations which will be performed to permit an overall
assessment of aquatic life protection uses In the lake. A large portion of
this discussion 1s devoted to lake restoration considerations.
Like the two previous Technical Support Manuals (U.S. EPA, 1983£, 1984),
the purpose of this Manual 1s not to specifically describe how to conduct a
use attainability analysis. Rather. It Is the desire of EPA to allow the
states some latitude In such assessments. This Manual provides technical
support by describing a number of physical, chemical, and biological
evaluations, as well as background Information, from which a state may
select assessment tools to be used In a particular use attainability
analysis.
USE CLASSIFICATIONS
There are many use classifications—navigation, recreation, water supply,
the protection of aquatic life—which might be assigned to a water body.
These need not be mutually exclusive. The water body survey as discussed
1n this volume Is concerned only with aquatic life uses and the protection
of aquatic life In a lake.
IY-1
-------
The objectives In conducting « u»e attainability survey are to Identify:
1. The aquatic life use currently be survey Is the development of
IV-2
-------
TABLE IV-1
SUMMARY OF TYPICAL HATER BODY EVALUATIONS
PHYSICAL EVALUATIONS
CHEMICAL EVALUATIONS
BIOLOGICAL EVALUATIONS
o Size (wan width/depth)
o Flow/velocity
o Total volume
o Reaeratfon rates
o Temperature
o Suspended solids
o Sedimentation
o Bottom stability
o Substrate composi-
tion and character-
Istlcs
o Sludge/sediment
o Riparian character-
istics
o Downstream
characteristics
o Dissolved oxygen
o Nutrients
- nitrogen
- phosphorus
o Chlorophyll-a
o Sediment oxygen demand
o Salinity
o Hardness
o Alkalinity
o pH
o Dissolved solids
o Toxics
o Biological Inventory
(existing use analysis)
o Fish
o Macrolnvertebrates
o Microlnvertebrates
o Plants
- phytopi ankton
- macrophytes
o Biological condition/
health analysis
- diversity Indices
- primary productivity
- tissue analyses
• Recovery Index
o Biological potential
analysis
o Reference reach
comparison
SOURCE: Adapted from EPA 1982±, Water Quality Standards Handbook
IV-3
-------
management strategies or alternatives which might result 1n enhancement of
th. biological health ef the water body. A clear definition of uses Is
necessary to weigh the predicted results of one strategy against another 1n
cases where the strategies are deflntd In tens of protection of aquatic
life.
Since one My very well be seeking to define use levels within an existing
use category, rather than describe a shift from one use classification to
another, the existing state use classifications nay not be helpful. There-
fore, It aay be necessary to develop an Internal use classification system
to serve as a yardstick during the course of the water body survey, which
•ay later be referenced to the legally constituted use categories of the
state.
A scale of biological health classes 1s presented 1n Table IV-2 that offers
general categories against which to assess the biology of a lake. A
descriptive scale 1s found In Table IV-3 that nay be used to assess a water
body. This scale was developed by EPA 1n conjunction with the National
Fisheries Survey.
REFERENCE SITES
Selection
Chapter IV-6 of the Technical Support Manual (U.S. EPA. 1983£) presents a
detailed discussion on the concept of ecological regions and "the selection
of regional reference sites. This process Is particularly applicable to
small and medium size lakes. Use attainability studies for very large
lakes are more likely to be concerned with specific segments of the lake
than with the lake 1n Us entirety. Resource requirements are an Important
consideration as well for very large lakes. For example, New York State
•ay be prepared to Investigate uses 1n Lake Ontario near Buffalo, but May
not be prepared to study the entire lake. A study of this Magnitude could
not be done without federal participation, or In the case of Lake Ontario
or Lake Erie, International participation. For the scale of study that a
state nay embark upon, reference sites could well be segments of the sane
or other large lakes.
The concept of developing ecological regions that are relatively homo-
geneous can be applied to lakes. This concept 1s based on the assumption
that similar ecosystems occur 1n definable geographic patterns. Although
the biota of particular lakes 1n close proximity may vary, 1t 1s more
likely to be similar 1n a given region than In geographically dissimilar
regions.
Within each region various lakes are Investigated to determine which sites
have a well balanced ecosystem and to note watershed land use and land
cover characteristics and the effects of man's activities. A major
characteristic to look for 1n the selection of a reference lake 1s the
level of disturbance In the watershed that feeds the lake. Good reference
site candidates are lakes located away from heavily populated areas, such
as 1n protected park land.
IV-4
-------
TABLE IV-2
BIOLOGICAL HEALTH CLASSES WHICH COULD BE USED
IN WATER BODY ASSESSMENT
Class
Attributes
Excellent
Good
Fair
Poor
Very Poor
Extremely Poor
Comparable to the best situations unaltered by nan; all
regionally expected species for the habitat Including the
most Intolerant forms, are present with full array of age
and sex classes; balanced trophic structure.
Fish Invertebrate and macrolnvertebrate species richness
somewhat less than the best expected situation; some
species with less than optimal abundances or size dis-
tribution; trophic structure shows some signs of stress.
Fewer Intolerant forms of plants, fish and Invertebrates
are present.
Growth rates and condition factors commonly depressed;
diseased fish may be present. Tolerant macrolnvertebrates
are often abundant.
Few fish present, disease, parasites, fin
anomalies regular. Only tolerant forms
brates are present.
damage, and other
of macrolnverte-
No fish,
life.
very tolerant macrolnvertebrates, or no aquatic
SOURCE: Modified from Karr, 1981
IV-5
-------
TABLE IV-3
AQUATIC LIFE SURVEY RATIMG SYSTEM
A water body that 1s rated a five has:
•A fish coamunlty that 1s Mil balanced among the different levels of the food
chain.
- An age structure for most species that Is stable, neither progressive (leading to
an Increase In population) or regressive (leading to a decrease 1n population).
• A sensitive sport fish species or species of special concern always present.
- Habitat which will support all fish species at every stage of their life cycle.
• Individuals that are reaching their potential for growth.
• Fewer Individuals of each species.
- All available niches filled.
A water body that 1s rated a four has:
• Many of the above characteristics but some of then are not exhibited to the full
potential. For example, the water body has a well balanced fish community; the age
structure Is good; sensitive species are present; but the fish are not up to their
full growth potential and *ay be present In higher numbers; an aspect of the
habitat Is less than perfect (I.e., occasional high temperatures that do not have
an acute effect on the fish); and not all food organises are available or they are
available 1n fewer numbers.
A water body that Is a three has;
• A community 1s not well balanced, one or two trophic levels dominate.
- The age structure for many species Is not stable, exhibiting regressive or
progressive characteristics.
• Total number of fish 1s high, but Individuals are saall.
• A sensitive species May be present, but 1s not flourishing.
• Other less sensitive species Mice up the Majority of the blomass.
- Anadromous sport fish Infrequently use these waters as a Migration route.
A water body that 1s rated a two has:
• Few sensitive sport fish are present, nonsport fish species are more conmon than
sport fish species.
- Species are acre common than abundant.
• Age structures may be very unstable for any species.
- The composition of the fish population and dominant species 1s very changeable.
- Anadromous fish rarely use these waters as a migration route.
- A saall percent of the reach provides sport fish habitat.
A water body that 1s a one has;
- The ability to support only nonsport fish. An occasional sport fish may be found
as a transient.
A water body that 1s rated a zero has;
• No ability to support a fish of any sort, an occasional fish may be found as
transient.
IV-6
-------
For the selection of a reference lake, it is important to seek compara-
bility In physical parameters such as surface area, volume, and mean depth,
and In physical processes such as degree of stratification and sedimenta-
tion characteristics. It will be Important also to seek comparability in
detention time, which plays a role 1n determining the chemical and
biological characteristics of the lake. Detention time is determined by
lake volume and rate of flow into the lake from both point and nonpoint
sources.
The selection of a candidate reference lake could be based on an analysis
of existing data. Data for many lakes throughout the country are available
from the National Eutrophication Survey conducted by the U.S. EPA in
cooperation with state and local agencies. National computerized data
bases such as WATSTORE and STORE! can provide flow and water quality data.
Many states and counties have their own water quality and biological
monitoring programs which should be used to obtain the most up-to-date
information on the lake.
In addition to the historical data that may be available through UATSTORE
or the National Eutrophication Survey. It 1s very Important to obtain
current information on a lake in order to evaluate its present character-
istics. One must be careful to note trends that may have occurred over
time so as to fully understand the extent to which the reference lake
represents natural conditions.
Comparison
The reference site will have been selected on the basis of physical simi-
larity with the study area, and upon the determination that it reflects
natural conditions or conditions as close to natural as can be found.
Subsequent comparisons for the purpose of describing attainable uses will
be based on comparisons of the chemical and biological properties of the
two water bodies. Similarities and differences In chemical and biological
characteristics can be examined to identify causes of use Impairment, and
potential uses can be determined from an analysis of the lake's response to
the abatement of the identified causes of Impairment.
Comparisons of Individual chemical and biological parameters can be made by
using simple statistics such as mean values and ranges for the entire data
base or that part of the data base which Is considered appropriate to re-
flect present conditions. Seasonal and monthly statistics can also be used
for lakes which demonstrate major changes throughout the year.
In addition to Individual parameters, water quality and biological indices
are useful for comparisons. Hater quality Indices summarize a number of
water quality characteristics into a single numerical value which can be
compared to standard values that are indicative of a range of conditions.
The National Sanitation Foundation Index, the Dinius water quality Index,
and the Harkins/Kendall water quality index, each of which may provide
insight Into the study site, are discussed in Chapter III of the Technical
Support Manual 'U.S. EPA, 1983b_).
Biological Indices to be considered include: diversity indices which
evaluate richness and composition of species; community comparison indices
IV-7
-------
which Measure similarities or dissimilarities between entire communities;
recovery Indices which Indicate the ability of an ecosystem to recover from
pollutant stress; and the Fish and Wildlife Service Habitat Suitability
Index which examines species habitat requirements. These Indices are dis-
cussed In detail In Chapter IV of the Technical Support Manual (U.S. EPA,
I983j>). Another useful tool which 1s qeseripcq in that Manual 1s cluster
analysis, which 1s a technique for grouping similar sites or sampling
stations on the basis of the resemblance of their attributes (e.g., number
of taxa and number of Individuals).
Statistical tests can be used to determine whether water quality or any
other use attainment Indicator at the study site 1s significantly different
from conditions at the reference site or sites. Several of these tests are
described in Volumes I and II of the Technical Support Manual (U.S. EPA,
1983b, 1984).
CURRENT AQUATIC LIFE PROTECTION USES
The actual aquatic life protection uses of a water body are defined by the
resident flora and fauna. The prevailing chemical and physical attributes
will determine what biota may be present, but little need be known of these
attributes to describe current uses. The raw findings of a biological sur-
vey may be subjected to various measurements and assessments, as discussed
In Section IV (Biological Evaluations) of the Technical Support Manual
(U.S. EPA, 1983b). After performing an Inventory or the flora and fauna
(preferably an~h1stor1cal Inventory to reflect seasonal changes) and
considering diversity indices or other measures of biological health, one
should be able to adequately describe the condition of the aquatic life in
the lake.
CAUSES OF IMPAIRMENT OF AQUATIC LIFE PROTECTION USES
If the biological evaluations Indicate that the biological health of the
system is Impaired relative to a "healthy" reference aquatic ecosystem (as
might be determined by reference site comparisons), then the physical and
chemical evalutions can be used to pinpoint the causes of that impairment.
Figure IV-1 shows some of the physical and chemical parameters that may be
affected by various causes of change in a water body. The analysis of such
parameters will help clarify the magnitude of impairments to attaining
other uses, and will also be Important to the third step in which potential
uses are examined.
ATTAINABLE AQUATIC LIFE PROTECTION USES
A third element to be considered 1s the assessment of potential uses of the
water body. This assessment would be based on the findings of the physi-
cal, chemical and biological information which has been gathered, but
additional study may also be necessary. A reference site comparison will
be particularly important. In addition to establishing a comparative
baseline community, the reference site provides Insight into the aquatic
life that could potentially exist 1f the sources of Impairment were
mitigated or removed.
IV-8
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The analysis of all Information that has been assembled may lead to the
definition of alternative strategies for the management of the lake at
hand. Each such strategy corresponds to a unique level of protection of
aquatic life, or aquatic life protection use. If It Is determined that an
array of uses 1s attainable, further analysis which 1s beyond the scope of
the water body survey would be required to select a management program for
the lake.
One must be able to separate the effects of human Intervention from natural
variability. Dissolved oxygen, for example, may vary seasonally over a
wide range In some areas even without anthropogenic effects, but 1t may be
difficult to separate the two In order to predict whether removal of the
anthropogenic cause will have a real effect. The Impact of extreme storms
on a water body, such as the effect of Hurricane Agnes on Pennsylvania
lakes and streams 1n 1972, may completely confound our ability to
distinguish the relative Impact of anthropogenic and natural Influences on
Immediate effects and long term trends. In many cases the Investigator can
only provide an Informed guess.
If a lake and stream system does not support an anadromous fishery because
of dams and diversions which have been built for water supply and recre-
ational purposes, 1t Is unlikely that a concensus could be reached to
restore the fishery by removing the physical barriers—the dams—which
Impede the migration of fish. However, 1t may be practical to Install fish
ladders to allow upstream and downstream migration. Another example might
be a situation 1n which dredging to remove toxic sediments may pose a much
greater threat to aquatic life than to do nothing. Under the do nothing
alternative, the toxics may remain 1n the sediment 1n a biologically-
unavailable form, whereas dredging might resuspend the toxic fraction,
making It biologically available while facilitating wider distribution In
the water body.
The points touched upon above are presented to suggest some of the phenom-
ena which may be of Importance 1n a water body survey, and to suggest the
need to recognize whether or not they may realistically be manipulated.
Those which cannot be manipulated essentially define the limits of the
highest potential use that might be realized In the water body. Those that
can be manipulated define the levels of Improvement that are attainable,
ranging from the current aquatic Hfe uses to those that are possible
within the limitations Imposed by factors that cannot be manipulated.
PREVENTIVE AND REMEDIAL TECHNIQUES
Uses that have been Impaired or lost can only be restored If the conditions
responsible for the Impairment are corrected. In most cases, Impairment 1n
a lake can be attributed to toxic pollution or nutrient overenMchment.
Uses may also be lost through such activities as the disposal of dredge and
fill materials which smother plant and animal communities, through
overflshlng which may deplete natural populations, and the destruction of
freshwater spawning habitat which will cause the demise of various fish
species. One might expect losses due to natural phenomena to be temporary
although man-made alterations of the environment may preclude restoration
by natural processes.
IY-10
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Assuming that the factors responsible for the loss of species have been
Identified and corrected, efforts nay be directed toward the restoration of
habitat followed by natural repopulatlon, stocking of species 1f habitat
has not been named, or both. Many techniques for the Improvement of
substrate composition 1n streams have been developed which might find
application In lakes as well. Further discussion on the Importance of
substrate composition will be found 1n the Technical Support Manual (U.S.
EPA, November 19836).
The U.S. EPA National Eutrophlcation Study and companion National Eutro-
phlcatlon Research Program resulted In the development and testing of a
number of lake restoration techniques. In the material to follow, an
overview 1s provided of a number of projects sponsored by the U.S. EPA 1n
which these techniques were applied. This Is an overview that Is not
Intended to be exhaustive 1n detail. For further Information, the reader
1s referred to a manual on lake restoration techniques that 1s currently In
preparation by U.S. EPA and the North American Lake Management Society.
Dredglng
Introduction
Dredging to remove sediments from lakes has several objectives: to deepen
the lake, to remove nutrients associated with sediment, to remove toxics
trapped In bottom sediment, and to remove rooted aquatic plants. Dredged
lakes generally show Improved aesthetics, and often enjoy Improved fish
habitat as shown by Increased growth of fish (Peterson, 1981). The
following sections summarize the objectives of lake dredging programs, the
environmental concerns associated with sediment removal, and the methods
used In Implementing dredging projects.
Lake Conditions Most Suitable for Sediment Removal. Dredging to Improve
lake conditions Is better suited for some lakes than others. Obviously, a
lake with a sediment-filled basin 1s a prime candidate for dredging. Other
considerations are lake size, the presence of toxics In the sediment,
dredging cost, and sedimentation rate. Toxics are of concern because they
may be released to the water column during the dredging operation. Because
of dredging costs, the dredging of large areas 1s not feasible. Lakes that
have been dredged In whole or In part range In size from 2 hectares (ha) to
1.050 ha (Peterson, 1981).
The practicality of sediment removal as a lake restoration technique also
depends on the depth of sediment to be removed. Lakes with surface sedi-
ment that Is highly enriched relative to underlying sediment are best
suited for dredging projects. Dredging will not be cost effective In lakes
with high sedimentation rates. The effect of sediment removal lasts longer
In water bodies with smaller ratios of watershed area to lake surface area
(Peterson, 1981). One other consideration 1n dredging projects 1s the dis-
posal of the dredged material. "Clean" sediment may be sold as landfill to
offset the cost of dredging. However, the disposal of contaminated
sediment may add considerably to the overall cost of the restoration
program.
IV-11
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Purpose
Lakes 1n colder sections of the United States require a mean depth of about
4.5 a or greater to avoid winter fish kills; thus, lake deepening projects
may help assure fish survival (Peterson, 1981). Removal of sediment con-
taining high concentrations of nutrients helps to control algal growth.
The resultant decreased algal growth Is also beneficial for fish popula-
tions. These purposes are explained In greater detail 1n the following
sections. Examples of lakes that have been dredged for the aforementioned
purposes are summarized 1n a separate section, Case Histories.
Removal of Nutrients. The primary nutrient of concern In dredging opera-
tlons Is phosphorus. Removal of enriched sediment reduces the Internal
phosphorus load, as Internal phosphorus cycling can amount to a major
portion of the total loading. Peterson (1981) cited these examples of
lakes In which a large percentage of the total phosphorus was attributed to
Internal sources:
(1) Llnsley Pond, Connecticut—Internal phosphorus was about 45 per-
cent of the total phosphorus loading (Livingston and Boykln,
1962);
(2) Long Lake, Washington—phosphorus loading from sedlnent was 25-50
percent of the external loading (Welch, et al., 1979); and
(3) White Lake, Michigan—about 40 percent of the total phosphorus
loading was contributed by sediment phosphorus regeneration (Jones
and Bowser, 1978).
Because such large amounts of phosphorus are found within the sediments,
dredging may be a feasible means by which to greatly reduce Internal
loading.
Lake Deepening. Summer stratification and vertical mixing characteristics
change with Increasing depth. In addition, a larger volume of hypol1mnet1c
water, and a larger quantity of dissolved oxygen, are present 1n deeper
lakes (Stefan and Hanson, 1981). Therefore, assuming Identical rates of
benthlc oxygen uptake per unit area, the hypol1mn1on of a shallow lake will
be depleted sooner than the hypollmnlon of a deeper lake. Summer overturn
due to wind-Induced mixing may be frequent In shallow lakes. Therefore,
dredging to Increase depth may help to reduce the frequency of overturn.
Increased lake volume may also help reduce water temperature. Reduced
water temperature Increases oxygen solubility and decreases metabolic rates
of organisms. Therefore, algal growth rates and hypol1mnet1c oxygen deple-
tion may be slowed (Stefan and Hanson, 1981).
Removal of Toxics. The bottom sediment may be a sink for toxic and hazard-
ous materials as well as nutrients. Toxics 1n sediments pose a potentially
serious problem, although there 1s a paucity of Information concerning the
direct effects of contaminated sediment on organisms. Another major con-
cern about sediments containing toxics 1s the possible Introduction of
toxics Into the food web, and the bloaccumulatlon and b1omagn1f1cat1on of
toxics that may follow.
IV-12
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Macrophyte Removal. Rooted aquatic macrophytes can be removed by dredging.
Aquatic plants are most often removed for reasons of aesthetics or Inter-
ference with recreational uses. However, the role of racrophytes In
Internal nutrient cycling also Justifies their removal. Barlco and Smart
(1980) demonstrated that Egerla densa, Hydrllla verticil!ata. and Myrlo-
phyTlum sp lea turn could obtain their phosphorus nutrition exclusively from
the sediments.When the plants die and decompose, nutrients In soluble
form may be released to the water column, or be returned to the sediments
as partlculate matter.
Some researchers contend that healthy aquatic macrophytes obtain nutrients
from the sediment and excrete them to the surrounding water (Twllley, et
al., 1977; Carlgnan and Kalff, 1980). There 1s considerable evidence to
show that large quantities of nutrients are recycled to the lake when
plants die and decay (Barko and Smart, 1980; Landers, 1982). Landers
(1982) found that senesclng stands of Myrlophyllum splcatum contained up to
18 percent of the annual total phosphorus loading In an Indiana reservoir.
Because aquatic macrophytes cause mobilization of nutrients from the soil,
their removal Is a key to reducing the Internal phosphorus load.
Environmental Concerns of Lake Dredging
Many of the environmental problems caused by dredging are associated with
resuspenslon of fine partlculates. Increased turbidity reduces light
penetration; consequently, photosynthesis and pnytoplankton production are
Inhibited. Suspended sediments absorb radiation from the sun and transform
It Into heat, thereby Increasing the water temperature. Increases In
temperature affect the metabolic rate of organisms, In addition to reducing
the oxygen-holding capacity of the water. Dredging may also cause
Increased nutrient levels 1n the water column, and potentially favorable
conditions for algal blooms (Peterson, 1981).
Toxic substances may also be liberated during dredging operations. For
example, the aldrln concentration 1n Vancouver Lake, Washington, was 0.012
mg/1 prior to dredging and Increased by three times at one site and ten
times at another site during dredging (Peterson, 1979). Return flow from
settling ponds reached even higher concentrations, at times up to 0.336
mg/1.
Resuspended organic matter may present a different type of problem. Rapid
decomposition may deplete the available dissolved oxygen. This may be
especially Important since the organic content of lake sediments can reach
80 percent on a dry weight basis (Wetzel, 1975). Although Peterson (1981)
noted that no lake dredging projects have caused this problem, the poten-
tial should be recognized.
Implementation of Lake Dredging Projects
Sediment Removal Depth. After It has been determined that sediment removal
fs a viable Take restoration technique, a removal depth and method must be
selected. Sediment removal depth has been determined by several different
methods. The following paragraphs briefly describe two methods by which to
determine removal depth.
IV-13
-------
Sediment Characterization. Studies of chemical and physical character-
istics of a lake bottom say show distinct stratification of sediment. The
greatest concentration of nutrients My be In a single layer, so that
removal of the layer will significantly affect the Internal nutrient
loading. The sediment removal depth may be determined on the basis of
nutrient content and release rates for the layers of sediment.
For example, sediment In Lake Tnimrwn, Sweden, was characterized chemically
and physically, horizontally and vertically. The study showed a definite
layer of Fes-colored (black) fine sediment deposited on * bijown layer.
Based on aerobic and anaerobic release rates of P04 -P and NHA -N, 1t was
decided that the black layer would be removed (Peterson, 1981). Born
(1979) noted that the ecosystem of Lake Trummen was restored following
dredging.
Lake Simulation. Another approach to determining sediment removal depth
uses a lake model to predict the lake depth necessary to prevent summer
destrat1f1cat1on (Stefan and Hanson, 1980). This method of computation 1s
generally used for shallow lakes.
Stefan and Hanson (1981) modeled the Fairmont Lakes, Minnesota, to
determine the lake depth that would be required to prevent phosphorus
redrculatlon from the sediments. Using air temperature, dew point
temperature, wind direction, solar radiation, and wind speed, plus a
consideration of lake morphology, the model predicts temperature with
depth. Lake simulation helps determine the appropriate temperature and,
therefore, minimum depth for stable seasonal stratification. This method
of determining removal depth Is based on the concept that shallow eutrophlc
lakes can be dredged to such a depth that a stable system 1s formed. In
theory, phosphorus released from the sediment Into the hypollmnlon will be
recycled to the photic zone with diminished frequency. By controlling and
reducing the phosphorus concentration of the epIUmnlon, the standing crop
of algae will be decreased. The simulation results agreed with the
hypothesis of phosphorus release and recycling and the anticipated effects
of dredging (Stefan and Hanson, 1981).
The method of lake simulation does not consider sediment release rates.
Removal of the upper sediment layer may reduce nutrient levels 1n the
overlying water even though stratification 1s not stable. Therefore,
sediment release rates should also be examined along with the modeling
approach (Peterson, 1981).
Dredging Equipment. Barnard (1978) and Peterson (1979) describe various
dredges 1 ncludlng the Mud Cat, the Bucket Wheel, and others, and their
advantages and disadvantages, the reader should refer to these sources,
especially Barnard (1978), for more detailed Information.
The typical dredges are grab, bucket, and clamshell dredges which are
generally operated from a barge-mounted crane. These systems remove
sediment at nearly Us 1 TV site density, but removal volumes are limited to
less than 200,000 m . Turbidity 1s created due to bottom Impact of the
bucket, the bucket pulling free from the bottom, bucket overflow and
leakage both below and above the water surface, and the Intentional over-
flow of water from receiving barges to Increase the sol Ids content,
IY-14
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Cutterhead dredges are the most commonly used 1n the United States. The
cutterhead dredge removes material In a slurry that Is 10 to 20 percent
solids. These hydraulic dredges can remove larger volumes of sediment than
bucket dredges. Turbidity from hydraulic dredges Is largely dependent on
pumping techniques and cutterhead configuration, size and operation.
Sediment Disposal. Dredged material disposal must also be considered In
sediment removal projects. Fill pemlts are required for the filling of
low-lying areas when the area exceeds 4.0 ha (10 acres) (Section 404,
Public Law 92-500).
Upland disposal sites, which do not require Federal permits, commonly
employ dikes to retain dredged material. Dike failure and underdeslgned
capacity are two major problems with upland disposal areas.
Several documents prepared by the U.S. Army Corps of Engineers contain
useful Information about dredged material disposal. They Include: Treat-
ment of Contaminated Dredged Material (Barnard and Hand, 1978), Evaluation
of Dredged Material Pollution Potential (Brannon, 1978), Confined Disposal
Area Effluent and Leachate Control (Chen, et al., 1978), Disposal Alterna-
tives for Contaminated Dredged Material as a Management Tool to Minimize
Adverse Environmental Effects (Gambrell, et al., 1978), Upland and Wetland
Habitat Development with Dredged Material: Ecological Considerations
(Lunz, et al., 1978), Guidelines for Designing, Operating, and Managing
Dredged Material Containment Areas (Palermo, et al., 1978), and Productive
Land Use of Dredged Material Containment Areas (Walsh and Malkasaln. 1978).
Lake Dredging Case Studies
Peterson (1981) lists 64 sediment removal projects In the United States
that are In various stages of Implementation. Several of these projects
will be considered In more detail In the following section.
Lilly Lake, Wisconsin. Lilly Lake has a surface area of 35.6 ha, a maximum
depth of 1.8 m and a mean depth of 1.4 m. The main problem In Lilly Lake
was excessive macrophyte growth, resulting In an accumulation of organic
detritus and bottom sediment. Macrophytes also curtailed recreational
activities such as boating and fishing. Winter fish kills were common In
Lilly Lake.
Dredging began In July 1978 and continued through October of the same year.
During dredging operations, the 5-day BOD Increased by 1-2 mg 02/Hter, and
turbidity rose by 1-3 formazln units. Ammonia concentration Increased from
0.01 ng/liter to a high of 5.5 mg/llter when dredging was halted In Octo-
ber. Prior to dredging, chlorophyll HI levels averaged 2.5 ug/llter to 3.0
ug/llter, Immediately after dredging commenced, chlorophyll-a reached a
concentration of 27 ug/Hter, and then decreased to levels of 12-18
ug/Hter. _ Productivity also Increased from pre-dredg1ng levels of about
200 mg C/nT/d to an average of 750 mg C/nT/d In 1978 (Peterson, 1981).
Dredging began again 1n May 1979 and was completed by September. Maximum
depth was Increased to 6.5 m following dredging. The water quality In 1980
was Improved over previous-years, and the macrophyte blomass was reduced
from 200-300 g dry welght/ra to nearly zero.
IV-15
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Ste
-------
research 1s needed on direct toxldty and general health effects before
this technique receives large-scale use.
Suitable Lake Types. Certain lake types are better suited to nutrient
precipitation and Inactlvatlon than others. Lakes should have moderate to
high retention tines (several months or longer), since the treatment will
not be effective 1f there Is a rapid flow-through of water. A water-
phosphorus budget Is useful In assessing the significance of retention
time.
Nutrient precipitation and Inactlvatlon Is generally Implemented following
nutrient diversion, but this method of lake restoration will not be effec-
tive If the diversion Is Insufficient. Lakes with low alkalinity will
exhibit excessive pH shifts unless the lake 1s buffered or a mixture of
alum and sodium alumlnate Is used as precipitant. Finally, In lakes with
large littoral areas, phosphorus that 1s derived from groundwater, trans-
located from sediments by macrophytes, or resuspended by some activity that
stirs up sediment deposits may cause higher phosphorus concentrations than
expected.
Purpose
Phosphorus precipitation and Inactlvatlon techniques are used In water
bodies with high concentrations of phosphorus In the water column and the
sediment. Such a condition 1s generally Indicated by nuisance algal
blooms. Immediate results of phosphorus precipitation Include decreased
turbidity and algal growth. Application of aluminum compounds, primarily
aluminum sulfate and sodium alumlnate, may also effectively control the
release of phosphorus from the sediment.
Environmental Concerns of Nutrient Precipitation
One Immediate response of phosphorus precipitation Is a reduction 1n tur-
bidity. The Increased light penetration could stimulate Increases In
rooted plant blomass. Other undesirable side-effects Include reduced
planktonlc mlcrocrustacean species diversity and toxic effects of residual
dissolved aluminum (ROA) on aquatic biota. Laboratory research Is cur-
rently underway to enlarge the aquatic toxldty data base available for the
U.S. EPA to develop water quality criteria for aluminum for the protection
of aquatic life. Aluminum toxldty 1s pH dependent and 1t becomes
extremely toxic below pH 5. Cooke and Kennedy (1981) cited the following
laboratory studies regarding the possible toxic effects on the biota of
phosphorus precipitation using aluminum compounds:
(1) Daphnla roagna had a 16 percent reproductive Impairment at 320 ug
Al/l (Blesfnger and Christian, 1972);
(2) A few weeks exposure to 5,200 ug Al/l seriously disturbed rainbow
trout tested 1n flow through bloassays (Everhart and Freeman,
1973);
(3) No obvious effect on rainbow trout after long-term exposure to 52
ug Al/l (Kennedy, 1978; Cooke, et al., 1978);
IV-17
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(4) Daphnla magna survival was reduced 60 percent In 96-hr tests of
concentrations to 80 ug Al/1 (Peterson, et al., 1974. 1976); and
(5) Mo negative effects on fish (Kennedy and Cooke, 1974; Bandow,
1974; Sanvllle, et al., 1976) or benthlc Invertebrates (Narf.
1978) after full-scale lake treatments. Cooke and Kennedy (1981)
noted that there were no toxic effects on fish as long as the pH
regains In an acceptable range and the RDA 1s less than about 50
ug Al/1.
Implementation of Nutrient Precipitation Projects
The following factors should be considered for phosphorus precipitation/
Inactlvatlon through chemical application: dose, choice of dry or liquid
chemical, depth of application, application procedure, and season (Cooke
and Kennedy. 1981).
Pose Determination. Cooke and Kennedy (1980) and Cooke and Kennedy (1981)
describe some Methods for determining dose. A dose of aluminum that re-
duces pH to 6.0 1s considered "optimal." The residual dissolved aluminum
should remain below 50 ug Al/1, the level at which aluminum begins to
elicit toxic effects. A simplified method for dose determination Is
outlined 6*1ow (Cooke and Kennedy, 1980).
Procedure:
(1) Obtain representative water samples from the lake to be treated.
Care should be exercised In selecting sampling stations and depths
since significant heterogeneities, both vertical and horizontal,
commonly occur 1n lakes. Samples should be collected as close to
the anticipated treatment date as possible.
(2) Determine the total alkalinity and pH of each sample. Total
alkalinity, an approximate measure of the buffering capacity of
lake water, will dictate the amount of aluminum sulfate (or
aluminum) required to achieve pH 6 and thus optimum dose. Addi-
tional chemical analyses can be performed, depending on the
specific needs of the Investigator. For example, phosphorus
analyses before and after laboratory treatment would allow
estimation of anticipated phosphorus removal effectiveness.
(3) Determine the optimum dose for each sample. Initial estimates of
this dose, based on pH and alkalinity, can be obtained from Figure
IV-2. More accurate estimates should be made by titrating samples
with fresh stock solutions of aluminum sulfate of known aluminum
concentration using a standard burette or graduated pipette. The
concentration of stock aluminum solutions should be such that pH 6
can be reached with additions of 5 to 10 mil 111 Hers per liter of
sample. Samples must be mixed (about 2 minutes) using an overhead
stirring motor and pH changes monitored continuously using a pH
meter. Optimum <
-------
ALUMINUM DOSE (mg Al/l) TO OBTAIN pH 6.0
S
o
to
O
at
250
200
150
<
O
100
Figure 1V-2. Estimated aluminum sulfate dose (mg/1) required to
obtain pH 6 In treated water of varying Initial alkalinity
and pH (from Cooke and Kennedy, 1980).
IV-19
-------
(4} The relationship between total alkalinity and optimum dose can be
determined using Information from each of the above tltratlons by
plotting optimum dose as a function of alkalinity. This relation-
ship will allow determination of dose at any alkalinity with the
range tested.
Liquid alum and liquid sodium alumlnate generally form a better floe and
are more effective than the dry forms (Cooke and Kennedy, 1981). If only
dry alum 1s available, 1t can be mixed 1n tanks to form a slurry before
application.
Depth of Application. Aluminum salts can be applied to surface water, or
at predetermined depth(s), depending upon treatment objectives. A surface
application is generally needed to remove phosphorus from the water column,
whereas hypolimnetic treatment controls the release of phosphorus from
sediments.
Time of Application. Both partlculate and dissolved forms of phosphorus
are efficiently removed by the aluminum floe as It settles to the bottom.
Whether there 1s an optimum season for the application of aluminum salts
for the removal of various forms of phosphorus Is debatable, as discussed
by Cooke and Kennedy (1981).
Nutrient Precipitation Case Studies
Although at least 28 lakes have been reported In the literature that have
been treated by the phosphorus inactlvatlon/precipitation technique, there
Is a paucity of Information regarding post-treatment effects. The
following sections summarize five case histories that are representative of
different approaches, have long-term monitoring, or illustrate strengths
and shortcomings of this technique. Information concerning dose, method of
application, cost, and long-term effects on additional restoration projects
employing inactivatlon/precipitation techniques is found in Cooke and
Kennedy (1981).
Horseshoe Lake, Wisconsin. Horseshoe Lake has a surface area of 8.9 ha, a
maximum depth of 16.7 m, and a mean depth of 4.0 m. It is the first
reported full scale 1n-1ake inactlvation experiment in the United States
(Funk and Gibbons, 1979). Prior to treatment, the lake exhibited algal
blooms, dissolved oxygen depletions and fish kills. High nutrient levels
were attributed to agricultural and natural drainage, and to waste dis-
charges from a cheese-butter factory prior to Its closing 1n 1965.
Alum was applied, Just below the water surface, 1n May 1970. No decrease
In phosphorus level was observed until after fall circulation, when con-
centrations decreased substantially. Reduced phosphorus concentrations
were observed in both the epilimnion and the hypollmnlon. Although hypo-
limnetic phosphorus Increased slightly every year following treatment. It
was controlled for about 8 years. Secchi disc transparency also increased
and no fish kills have occurred since the alum application. Additional
information about the restoration of Horseshoe Lake is provided by
Peterson, et *i. (1973).
IV-20
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Medical Lake. Washington. Medical Lake covers an area of 64 ha. It has a
maxima depth of 18 m and a mean depth of 10 n. Prior to treatment, the
lake exhibited nuisance algal bloons, summer anoxia and high nutrient con-
centrations, primarily because of Internal nutrient cycling. Treatment
with alum was chosen as the best method for Inactivating phosphorus 1n
Medical Lake.
Alum was applied at the surface or at 4.5 meters, depending upon whether
the area was shallow or deep. Application began In August 1977 and con-
tinued over a 5-week period.
Hater quality monitoring through June 1980 showed that alum treatment
successfully reduced phosphorus levels, eliminated algal blooms and In-
creased water clarity. Total and orthophosphorus levels prior to alum
treatment were 0.47 mg/llter and 0.32 mg/llter, respectively. These levels
decreased about 87 and 97 percent, respectively. Chlorophyll-a decreased
from.a mean monthly value of 25.2 mg/m prior to alum treatment, to 3.2
mg/nr following treatment. Seech1 disc transparency Improved from a mean
depth of 2.4 meters to 4.9 meters. Whereas the lake did not support a
fishery prior to treatment, a rainbow trout population flourished after
phosphorus preclpltatlon/lnactlvatlon. No negative Impacts on biota were
observed although the concentration of dissolved aluminum Increased to 700
ug Al/1 during treatment. Post-treatment levels fell to 30-50 ug/1 (Cooke
and Kennedy, 1981). Detailed results of water quality monitoring following
phosphorus preclpltatlon/lnactlvatlon treatment are presented In Gasperlno,
et al. (198pa) and Gasperlno, et al. (1980£).
Annabessacook Lake. Maine. Annabessacook Lake, located In central Maine,
covers an area of about 575 ha, and has a hypollranetlc area of 130 ha. The
mean lake depth 1s 5.3 m and the maximum depth Is 14.9 m. High levels of
phosphorus In the water column and sediments were believed to be respon-
sible for blue-green algal blooms. Industrial and municipal wastewater
Inputs contributed to high phosphorus levels prior to 1972, and Internal
nutrient cycling caused continued high nutrient levels In the lake
(Dominie, 1980).
Annabessacook Lake underwent an extensive lake restoration program, In-
cluding nutrient diversion, agricultural waste management and 1n-lake
nutrient 1nact1vat1on. Point sources were diverted from the lake and
agricultural waste management plans were Implemented. Laboratory testing
showed that aluminum treatment was a feasible alternative for lake res-
toration. Because the lake water has a low alkalinity, a combination of
aluminum sulfate and sodium alumlnate was used to provide sufficient buf-
fering capacity to moderate potential. pH shifts.
After the aluminum application and commencement of waste management pro-
grams, the following changes were observed (Dominie, 1980):
o Total phosphorus mass In the lake was reduced from over 2,200
kilograms (kg) In 1977 to 1,030 kg 1n 1978.
o Internal recyclable phosphorus was reduced 65 percent from 1,800
kg 1n 1977 to 625 kg 1n 1979.
IV-21
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o The average June chlorophyll-a concentration decreased from 11.5
ug/l (1977) to 6,2 ug/1 (1978 IT
o Secchl dise depth for June (monthly mean) increased from 2 = 0 m
(1977) to 3.1 m (1978).
Additional Information on the restoration of Annabessacook Lake 1s found In
Dominie (1980), Gordon (1980), Cooke and Kennedy (1981), and U.S. EPA
(1982).
Liberty Lake. Washington. Liberty Lake, 1n Spokane County, has a surface
area of 316 ha.The lake has a mean depth of 7.0 m, and a maximum depth of
9.1 m. A combination of septic tank drainage, urban runoff, and poor solid
waste disposal practices caused excessive nutrient levels and heavy blooms
of blue-green algae 1n the lake.
In 1974, Liberty Lake was treated with aluminum sulfate to precipitate and
Inactivate phosphorus. Jar tests and In situ tests were made to determine
dosage. The alum slurry was applied to the surface. After application of
aluminum sulfate, total phosphorus was reduced from 0.026 mg/1 to less than
0.015 mg/1. Water clarity Increased following the treatment. Although
alkalinity and pH dropped, the effect was short lived and these parameters
returned to pretreatment levels within 24 to 48 hours (Funk and Gibbons,
1979).
The treatment effectively controlled algal blooms from 1974 to 1977. Heavy
blooms equivalent to those prior to treatment did occur 1n the fall of
1977.
Dollar Lake and West Twin Lake, Ohio. Dollar Lake has a surface area of
Z.ZZ ha, a mean depth of 3.89 m and a maximum depth of 7.5 m. West Twin
Lake, which Is adjacent to Dollar Lake, Is larger, with a surface area of
34.02 ha, a mean depth of 4.34 m and a maximum depth of 7.50 m. Septic
tank drainage was largely responsible for eutrophlc conditions. Although
septic effluent was diverted In 1971-72, algal blooms continued, partly
because of Internal cycling of phosphorus.
Aluminum sulfate was applied to the hypollmnlon of the lakes to Inactivate
and precipitate phosphorus. Following the alum application, both lakes
showed decreased phosphorus content In the water column and Improved water
transparency. Blue-green algae dominance 1n West Twin Lake was reduced by
80 percent (Funk and Gibbons, 1979; Cooke and Kennedy, 1981). Zooplankton
populations were affected, and the dominant species shifted from Cladocera
to Copepoda. Hypol1mnet1c phosphorus concentration 1n Dollar and West Twin
Lakes remained low for four years after treatment.
Aeratlon/C1rculatlon
Introduction
Aeration/circulation 1s a potentially useful technique for treating
symptoms of eutrcphlcation. The range of aeration/circulation techniques
can be divided Into two major groups: artificial circulation and hypo-
Hmnetlc aeration. Both of these techniques Increase the dissolved oxygen
IV-22
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concentration or hypolimnetic waters. The two techniques differ 1n that
hypollmnetlc aeration aerates hypollmnetlc waters without mixing the* with
surface waters while artificial circulation breaks down stratification by
•1x1ng the upper and lower strata of the water column. These techniques
can be used to enhance the habitat of aquatic biota and Improve water
quality by alleviating problems created by stratification and deoxygenatlon
of the hypollmnlon.
Both techniques restore oxygen to anaerobic bottom waters. These res-
toration procedures lead to habitat expansion for zooplankton, benthos and
fish. Destratlflcatlon Is usually beneflcal for wartnwater fish, promoting
an Increase In the depth distribution. However, complete mixing may
eliminate coldwater habitats and fish such as salmonlds may disappear fro*
the lake.
Lakes Best Suited for Aeration/Circulation. Anaerobic bottom waters of a
stratified lakecan5eoxygenated byaeration/circulation techniques.
Either method may be Implemented when the primary purpose of treatment Is
to alleviate "taste and odor" problems resulting from high concentrations
of Fe, Hn, H«S and other chemicals In an anoxlc hypollmnlon. Both methods
expand or Improve habitat for zooplankton, benthos, and warmwater fish.
However, artificial circulation and hypollmnetlc aeration do not produce
the same effects In lakes.
Artificial aeration may cause the replacement of blue-green algae com-
munities by more desirable communities of green algae, while hypollmnetlc
aeration generally does not have an effect on phytoplankton. Since
hypollmnetlc aeration does not effect mixing of surface and hypollmnetlc
waters, nutrient concentrations In the euphotlc zone are basically
unaffected when this technique Is employed. Consequently, hypollmnetlc
aeration generally does not affect the phytoplankton community. In
contrast, artificial circulation vertically mixes the water column and can
Increase nutrient concentrations In the euphotlc zone. In a series of
experiments, Shapiro (1973) showed that natural populations of blue-green
algae were replaced by green algae after enrichment with phosphorus and
nitrogen when carbon dioxide was added or pH was lowered. These results
Indicate that green algae can outcowpete blue-green algae under enriched
nutrient conditions as long as C02 Is abundantly available.
When control of algal blooms Is.not a prime consideration and a coldwater
supply 1s necessary, the preferred method Is hypollmnetlc aeration. A cold
hypollmnlon Is needed for survival of coldwater fish, and thus hypollmnetlc
aeration 1s recommended when Improvement of fisheries 1s the only con-
sideration. In southern lakes, high water temperatures In the epH1mn1on
and metallmnlon often preclude survival of coldwater fish; therefore, It 1s
necessary to preserve the Integrity of the water layers, Including the
colder hypollmnlon, and artificial destratlflcatlon would not be appro-
priate.
Artificial circulation Is preferred when limitation of algal blomass 1s
desired, oxygenatlon of the metalImnlon Is needed, or a completely mixed
water column Is acceptable. Artificial circulation 1s also suitable for
northern lakes where the tempe-ature of surface waters does not exceed 22°C
during the summer (Pastorak, et al., 1981).
IY-23
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Purpose
Artificial Circulation. Anaerobic conditions In the hypo11mn1on of a
stratified lake restrict the vertical distribution of fish, eliminate
certain benthlc organises, and may cause the release of nutrients and toxic
substances to the overlying water. Artificial circulation alleviates these
problem by destratlfylng and oxygenating bottom waters of the lake. The
water becomes oxygenated primarily through atmospheric exchange at the
water surface. Except In very deep lakes, the transfer of oxygen from air
bubbles of diffused air systems Is relatively small.
By aerating and destratlfylng lakes, artificial circulation Improves water
quality, decreases algal growth, and Improves fish habitat. These effects
are described below.
Elimination of Taste and Odor Problems. Generally, artificial destratl-
f1cation oxygenates anaerobic hypollmnetlc waters. Anaerobic conditions
near the lake bottom cause the release of reduced chemical species from
sediments to the water column. Water supply utilities experience water
quality control problems resulting from the accumulation of Iron (Fe),
manganese (Mn), carbon dioxide (C02), hydrogen sulflde (H2S), ammonium Ions
(NH.+) and other chemicals 1n the Tiypollmnlon. As hypollmnetlc waters are
brought to the lake surface during artificial circulation, gases such as
CO*. H~S and NH* are released to the atmosphere. Artificial circulation
Increases hypollmnetlc oxygen, and raises the redox potential near the lake
bottom. The result Is decreased concentrations of reduced chemical
species, thereby eliminating taste and odor problems.
Decreased Algal Growth. In some cases, algal production 1s reduced through
artificial circulation. Pastorak, et al. (1981) cited Fast (1975) for
several mechanisms that cause reduced algal growth. Internal nutrient
loading may be reduced through the elimination of anaerobic conditions that
cause nutrient regeneration. Artificial circulation also Increases the
mixed depth of the algae, thereby reducing algal growth through light
limitation. When mixing Is Induced during an algal bloom, the algae are
distributed through a greater water volume, and lake water transparency
will Increase Immediately. In addition, as water Is pumped to destratlfy
the lake, rapid changes In hydrostatic pressure and turbulence serve to
destroy phytopiankton.
Artificial circulation does not consistently decrease algal populations,
and may cause Increased algal blomass In some Instances. Pastorak, et al.
(1981) surveyed the literature covering 40 experiments In which destratlfl-
catlon was relatively complete. Only 26 experiments exhibited significant
changes 1n phytoplankton blomass, and of these, about 30 percent exhibited
Increases In algae.
Forsberg and Shapiro (1981) found that changes 1n algal species composition
during artificial aeration depend primarily on the mixing rate. With slow
mixing rates, surface levels of total phosphorus and pH generally In-
creased, and the relative abundance of blue-green species such as Anabaena
drcullnus and M1crocyst1s aureglnosls Increased.
IV-24
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The abundance of green algae and diatoms Increased when faster nixing rates
were used. Complete chemical destratlflcatfon caused by high mixing rates
was accompanied by large Increases In surface total phosphorus and CO-
concentration. The green algae Sphaerocystls schroederl, Anklstrodesmus
falcatus and Scenedesaus spp., and the diatoms Hltzchla spp., Synedra spp.,
and Meloslra spp. grew particularly well under these conditions (Forsberg.
and Shapiro, 1981).
Benefits to F1sh Populations. Artificial circulation may enhance fish
habitat and food supply, thereby potentially Improving growth of fish,
environmental carrying capacity, and overall yield.
Low oxygen levels In the hypo11mn1on say prevent fish from using the entire
potential habitat. Destratlflcation and aeration of bottom waters may
allow fish to Inhabit a greater portion of the water column, expanding the
vertical distribution of warmwater fish.
Salmonlds In particular may be restricted to a layer of metalImnetlc
habitat, with warm water above and anaerobic conditions below. If surface
water temperatures remain below 22*C throughout the summer, as In northern
lakes, artificial circulation should Increase habitat for cold-water fish.
In addition, summer-kill of fish due to anoxlc conditions and toxic gases
may be prevented by art1flc1al circulation.
Artificial circulation has also proved to be an effective method of
preventing over-winter mortality of salmonlds. Whereas natural oxygen
concentrations may be depleted during the winter, aeration prior to Ice
formation can provide sufficient oxygen for fish survival. Winter mor-
talities of fish In Corbett Lake, British Columbia, were prevented In this
way (Pastorak, et al., 1981).
Hypo!Imnetlc Aeration and Oxygenatlon. HypolImnetlc aeration and oxygen-
atlon add dissolved oxygen to the bottom waters without destratlfylng the
lake. Aeration of the hypo!Irani on occurs through oxygen transfer between
air bubbles and water, and oxygenatlon occurs more slowly than with
artificial circulation.
Major goals of programs employing hypolImnetlc aeration and oxygenatlon are
to Improve water quality and provide habitat for coldwater fish. Unlike
artificial circulation, there Is no evidence that hypollmnetlc aeration
will control algal blooms.
Improvement of Water Quality. Hypollmnetlc aeration minimizes taste, odor
and corrosion problems by oxygenating bottom waters, which raises the pK
and lowers concentrations of reduced compounds. Although artificial
circulation aerates the water column more rapidly, hypollmnetlc aeration
maintains stratification, thereby retaining a coldwater resource.
Improvement of Fisheries. Hypollmnetlc aeration creates habitat for cold-
water fish by oxygenating the cold bottom layers of a lake. Because the
lake does not become completely mixed as a result of hypollmnetlc aeration,
a two-story fishery can develop. Aeration clso enhances fish food supply,
since the distribution and abundance of macrolrvertebrates Increases.
IV-25
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Planktlvorous fish may also find an Increased food supply following hypo-
llmnetlc aeration. While phytoplankton abundance 1s generally unaffected,
zooplankton populations way expand their vertical range after treatment.
Fast (1971) found a significant Increase In the population of Daphnla pulex
following aeration of Keylock Lake. Michigan. He attributed the population
change to an expanded habitat, which allowed Daphnla to Inhabit dimly lit
depths of the lake and avoid predatlon by troufT
Environmental Concerns of Aeration/Circulation
Most of the environmental concerns are associated with the use of arti-
ficial destrat1f1cat1on systems, whereas very few adverse Impacts of
hypollmnetlc aeration are known. HypoHmnetlc aeration has very little
Influence on depth of mixing, pH of the water, sediment resuspenslon, «R^
algal densities. Adverse Impacts of aeration/circulation, Including
effects on water quality, nuisance algae, macrophytes and fisheries, are
described In the following sections. Examples of Impacts of aeration/
circulation on lakes are presented later 1n a section on Case Histories.
The purpose of the present discussion of environmental concerns 1s to point
out adverse consequences that might occur as a result of artificial
destrat1f1cat1on. Although these effects will not necessarily be seen, 1t
Is Instructive to recognize the potential problems that could arise, on a
site-specific basis.
Mater Quality. Artificial circulation may cause several chemical and
physical changes that adversely affect water quality. The mixing of
nutrient rich hypollmnetlc water could Increase the concentrations of
nutrients In the upper water layers. Heightened concentrations of the
gases NHj and HgS may also occur 1n surface water.
Turbulence due to mixing and aeration systems may further affect water
quality by resuspendlng silt, thereby Increasing turbidity. Decreases 1n
water transparency after mixing may also be associated with surface algal
blooms (Pastorak, et al., 1980).
Nuisance Algae. Artificial c1rculat1on/destrat1f1cat1on may produce un-
deslrable changes 1n phytoplankton communities. For example, temporary
algal blooms may occur because of recycling of hypollmnetlc nutrients and
elevation of total phosphorus. Such a rise In algal blomass may favor
blue-green algae by depleting COg and keeping pH levels high.
Macrophytes. Improved water transparency following artificial circulation
may allow Increased macrophyte growth. Rooted aquatic plants could expand
to nuisance levels, especially 1n lakes with shallow littoral shelves.
Fisheries. Where coldwater fish exist 1n the metal1mnet1c region, artlfl-
clal circulation and the subsequent warming of bottom waters may eliminate
habitat for certain species. The surface temperatures of northern lakes
generally remain below 22*C, and thus the bottom waters will not be warmed
(as might occur In southern lakes), and habitat for coldwater fish will be
enhanced during circulation. Destratlflcatlon and nixing can also lead to
dissolved oxygen decreases In the whole lake. In this Instance, resus-
penslon of bottom detritus Increases the biochemical oxygen demand (BOD)
beyond the rate of reaeratlon (Pastorak, et al., 1981).* Extensive
IV-26
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depletion of dissolved oxygen may be responsible for fish mortalities.
Aeration of Stewart Lake Initially caused a decline In blueglll population,
presumably because of reduced dissolved oxygen (Pastorale, et al., 1981).
F1sh kills may also be caused by supersaturated concentrations of nitrogen,
which may result from circulation or hypollmnetlc aeration. In spring, N2
levels generally equilibrate at 100 percent saturation with respect to
surface temperature and pressure. Warming of the hypo Hani on during the
summer results 1n supersaturatlon of N2 relative to surface temperature and
ambient temperature at depth. This fupersaturation of N? may Induce gas
bubble disease 1n fish, causing stress or mortality (Pa'storak, et al.,
1981). Although this has not been documented 1n lakes, dissolved nitrogen
concentrations of 115-120 percent saturation Induced salmonld mortalities
1n rivers (Rucker, 1972).
Implementation of Aeration/Circulation Projects
Aeration/circulation 1s a relatively Inexpensive and efficient restoration
technique. The following sections briefly describe methods and equipment
used 1n restoration projects employing artificial circulation or hypo-
limnetic aeration.
Artificial Circulation. Lake circulation techniques can be broadly classl-
fled In the categories of diffused air systems or mechanical mixing systems
(Lorenzen and Fast, 1977). Diffused air systems employ the "air-lift"
principle, as water Is upwelled by a plume of rising air bubbles. Mechan-
ical systems move water by using diaphragm pumps, fan blades, or water
jets. Lorenzen and Fast (1977) reviewed the design and field performance
of various circulation techniques, and concluded that diffused air systems
are less expensive and easier to operate than mechanical mixing systems.
Diffused Air Systems. Diffused air systems Inject compressed air Into the
lake through a perforated pipe or other simple dlffusers. Johnson and
Davis (1980) reviewed submerged jetted Inlets and perforated pipe air-
mixing systems used In reservoirs. Hypollmnetlc water Is upwelled by the
rising air bubbles. Upon reaching the surface, this water flows out
horizontally and sinks, mixing with the warm surface water In the process.
The amount of water flow Induced by the rising bubbles 1s a function of air
release depth and air flow rate. Artificial circulation 1s generally most
effective If air Is Injected at the maximum depth possible (Pastorak, et
al., 1981). In a thermally stratified lake, mixing will normally be In-
duced only above the air release depth. However, while an aerator located
near the surface of the lake may be unsuitable for destratlfylng a lake, It
may effectively prevent the onset of stratification (Pastorak, et al.,
1981).
Mechanical Mixing. Mechanical mixing devices such as pumps, fans and water
Jets are employed less frequently than diffused air systems. Pastorak, et
al. (1981) notes several Instances In which mechanical mixing devices have
been successfully employed:
IV-27
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(1) Stewart Hollow Jteservolr and Vesuvius Reservoir, Oh1o--a pumping
rate of 10.9 m /mln was sufficient to destratlfy the reservoirs
within 8 days (Irwln, et al., 1966);
(2) Kan's Lake. Oklahoma—an axial-flow pump with a capacity of 102
mvmln completely destratified the lake, which has a mean depth of
2.9 m, after 3 days of operation (Toetz, 1977).
On the other hand, mechanical mixing may not always be successful:
(1) West Lost Lake—a pumping capacity of 1.3 m3/m1n over a period of
10.1 days was not sufficient to completely mix the lake (Hooper,
et al., 1953);
(2) Arbuckle. Lake, Oklahoma—an array of 16 pumps (total capacity
1,600 m /m1n) did not completely mix the lake, which has a mean
depth of 9.5 m (Toetz. 1979).
Artificial circulation techniques should be started before full development
of thermal stratification, because nutrients that become trapped In the
hypoHmnlon and then are recycled may cause. Increased algal growth.
Lorenzen and Fast (1977) recommend about 9.2 m /m1n of air per 10 m of
lake surface (• 30 SCFM per 10° ft ) to adequately mix and aerate the water
column.
Hypollmnetlc Aeration. Fast and Lorenzen (1976) reviewed designs of hypo-
llmnetlc aerators, and proposed the following divisions: mechanical agi-
tation systems, pure oxygen Injection, and air Injection systems (which
Include full a1r-Hft designs, partial a1r-Hft designs, and downflow air
Injection systems). Hypollmnetlc aeration systems generally remove water
from the hypol1mn1on, aerate and oxygenate 1t, and then return the water to
the hypollmnlon.
Mechanical Agitation. Mechanical agitation systems generally draw hypo-
limnetic water up a tube and aerate It at the surface through mechanical
agitation. Fast and Lorenzen (1976) noted that a surface agitator design
1s most efficient for hypollmnetlc aeration of shallow lakes where water
depth 1s Insufficient to provide a large driving force for gas dissolution.
Oxygen Injection Systems. As 1n other hypollmnetlc aeration systems, water
1s removed from and returned to the hypoHmnlon. In oxygen Injection
systems, nearly pure oxygen becomes almost completely dissolved when 1t 1s
returned to the hypoHmnlon (Fast and Lorenzen, 1976).
Air Injection Systems. The full air lift design Is the least costly system
to construct, Install and operate (Fast and Lorenzen, 1976; Fast, et al.,
1976; Pastorak, et al., 1981). In these systems, compressed air Is In-
jected near the bottom of the aerator, and the air/water mixture rises. At
the water surface, air separates from the mixture and water Is returned to
the hypoHmnlon.
Partial air 11ft designs are less efficient than full air lift designs.
Partial air 11ft systems aerate and circulate hypollmnetlc water by an air
Injection system, but the air/water mixture does not upwell to toe surface.
IV-28
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Air and Mater separate below the lake's surface and afr rises to the
atmosphere while water returns to the hypo11mn1on (Fast and Lorenzen,
1976).
Aeration/Circulation Case Studies
Three case studies are presented In this section to summarize the effects
of artificial circulation on lakes.
Parvln Lake. Colorado. Parvln Lake Is a 19 ha mesotrophlc reservoir, with
a maximum depth of lu m and a mean depth of 4.4 i. Summer surface tempera-
tures remain less than 21*C year-round.
The effects of artificial circulation on Parvln Lake were studied for two
years (Lackey, 1973). November 1968 to October 1969 was the control period
during which phytoplankton were sampled to provide baseline Information.
The treatment year, when the destratlflcatlon system operated continuously,
extended from November 1969 to October 1970.
Phytoplankton In Parvln Lake were affected In the following ways (Lackey,
1973):
o Abundance of green algae significantly decreased during treatment;
o Anabaena, a nuisance blue-green algae, followed a similar pattern
of abundance during both control and treatment years;
o Planktonlc diatoms decreased In abundance during the treatment
winter.
Ham's Lake, Ok 1ahoma. Pastorak, et al. (1981) summarized the effects of
artificial destratlflcatlon on Ham's Lake, Oklahoma. The lake, which has a
maximum depth of 10 m, and a mean depth of 2.9 m, covers an area of 40 ha.
Following destratlflcatlon, the lake showed an Increase 1n Secchl disc
depth, dissolved oxygen concentration, and phosphate concentration. Both
the density and the diversity of benthlc organisms Increased. Decreases 1n
concentrations of ammonium, nitrate, Iron and manganese In the water column
were noted. No changes 1n algal density, chlorophyll-^, green algae,
blue-green algae, or the ratio of green algae/blue-green algae was
observed.
Kezar Lake, New Hampshire. Kezar Lake has an area of 73 ha, a maximum
depth of 8.4 m, and a mean depth of 2.8 m. Artificial circulation was
Imposed from July 16 to September 12, 1968, and became completely de-
stratified (Haynes, 1973). The responses of the lake to artificial
circulation were:
o Increases 1n Secchl disc depth, pH, dissolved oxygen concentra-
tion, phosphate, and total phosphorus;
o Decreases 1n ammonium, Iron and manganese concentrations;
o Reductions 1n algal density, algal standing blomass, and blue-
green algae;
IV-29
-------
o Increases In green algae, ui.u the ratio of green algae/blue-green
algae; and
o No change 1n Man chlorophyll-^ concentration.
OttovUle Quarry, Ohio. Ottovllle Quarry Is a small (0.73 ha) water-filled
quarry, with a maximum depth of 18 m. Prior to treatment, rainbow trout
(Salmo gal rdnerl) were unable to survive the summer because of high water
temperature and oxygen depletion. A program employing hypol1mnet1c oxy-
genatlon was Implemented 1n 1973 (from July to September), and Increased
summer dissolved oxygen concentrations from nearly zero to 8 mg/1 (Over-
hoi tz, et al., 1977). Aeration from May to October, 1974, caused dissolved
oxygen concentrations In the hypollmnlcn to exceed 20 mg/1 by September.
Overholtz, et al. (1977) found that hypol1mnet1c aeration created an
environment suitable for rainbow trout survival while maintaining thermal
stratification 1n the quarry.
Lake Drawdown
Introduction
The primary purpose In restoration programs employing lake drawdown 1s to
control the growth of nuisance aquatic macrophytes. In general, the water
level 1n a lake 1s lowered sufficiently to expose the nuisance plants while
retaining an adequate amount of water 1n the lake to protect desirable fish
populations. This technique 1s effective for short-term control (1-2
years) of susceptible aquatic macrophytes. Secondary objectives Include
turbidity control by sediment consolidation, reduction of nutrient release
from sediments (through sediment consolidation or removal), management of
fish populations and waterfowl habitats, repair of shoreline structures and
simultaneous use of other restoration methods such as covering sediment
with new clean material (Cooke, 1980a, 1980b). Sediment consolidation may
also cause a slight Increase In lake"depth." The following sections expand
upon the technique of lake drawdown, Including methods and case studies.
Lake Conditions Host Suitable for Lake Drawdown. Drawdown and sediment
consolidation may be feasible for the restoration of shallow lakes If two
conditions are met. The lake basin should have a shallow slope, so that a
small vertical decline In water level exposes a large part of lake bottom,
and the source of water must be controlled (Doorls, et al., 1982).
The nature of the lake sediment Is particularly Important to the success of
drawdown projects. The sediment that will be exposed must be able to dry
and consolidate quickly so that a prolonged dewaterlng period 1s not re-
quired, and the dried and compacted sediment should not rehydrate signifi-
cantly after the refilling of the lake basin. However, the sediment should
be of a consistency which would allow colonization by desirable plants and
bentMc organisms (Doorls, et al., 1982).
Purpose
The main objective of lake level drawdown Is to marage nuisance macrophytes
by destroying seeds and vegetative reproductive structures through exposure
IV-30
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to drying and/or freezing conditions. In addition, dewaterlng and consoli-
dation of sediments alters the substrate, thereby eliminating conditions
required for the growth of certain aquatic plants. Sediment consolidation
also helps control turbidity, reduces nutrient release from sediments and
causes a slight deepening of the lake.
Lake drawdown can be used to enhance fisheries and waterfowl habitats. The
simultaneous use of other restoration techniques, such as sediment covering
or removal, will be even more effective for control of vegetation. The
period of dewaterlng may also be used to repair shoreline structures, such
as dams, docks and swimming beaches.
Environmental Concerns of Lake Drawdown
There may be negative Impacts of lake drawdown as well as desirable
effects. Negative environmental changes that may occur following drawdown
Include establishment of resistant nacrophytes, algal blooms, fish kills,
changes In littoral fauna, failure to refill, and decline 1n attractiveness
to waterfowl.
Algal blooms that occur after refloodlng may be one of the undesirable
effects of drawdown. Gelger (1983) observed Increases In total nitrogen,
total phosphorus, and chlorophyll-^ following drawdown of Blue Lake,
Oregon. The cause of such Increases Is unclear although It Is postulated
that drawdown and exposure of sediments, and the subsequent aeration and
oxidation bring about nutrient release when the basin Is reflooded. The
released nutrients are then available for algal growth.
Fish kills may be caused by drawdown, especially 1f the water level 1s
lowered during the summer. The wanner temperatures cause Increased rates
of metabolism and heighten the sediment oxygen demand. However, Cooke
(1980aO noted that a 2 m summer drawdown of Long Lake, Washington (maximum
depth 3.5 m) did not cause fish kills, and the dissolved oxygen remained
above 5 mg/1.
Drawdown and refloodlng may cause changes 1n the diversity and density of
benthlc fauna. Increases In Invertebrate density, but decreases In species
diversity, have been observed following drawdown and refloodlng (Cooke,
198(ta). Summer drawdown and subsequent hardening of littoral soils may
reduce repopulatlon by Insects. These changes may be detrimental to fish
and waterfowl.
The basin may not refill because of an Insufficient watershed drainage
area, unexpected drought and, In the case of reservoirs, failure to close
the dam at the proper time. Failure to refill may have a great Impact on
the aquatic biota, Interrupting the life cycles of those species dependent
at some time upon littoral areas.
While drawdown brings about short-term control of most rooted species, some
species are strongly resistant to exposure and may even be stimulated by
It. Those species that are strongly resistant to drawdown and exposure
Include Myrlophyllum spleaturn. Ceratophyllum demersum, Lemna minor, Najas
flexllls, and Potamogeton pecllnatus. Cooke (198(ta) compiled the following
list of responses of some common nuisance aquatic macrophytes to drawdown:
IV-31
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o Increased: A"! tcrnanthera philoxeroIdes (alUgatorweed)
Hajas fiexfRs (naiad)
PotaaogeTon spp. (pondweed)
o Decreased: Chara vulgarls (muskgrass)
Etchornia crasslpes (water hyacinth)
Nuphar spp. (water 11 ly)
o No clear response or change: Cabomba carolInlana (fanwort)
Elodea can*dens1s (elodea)
MyrlophyTTua spp. (milfoil)
UtrlcularTT"vu1gar1s (bladderwort)
Information on the responses of 63 aquatic plants to drawdown 1s available
1n Cooke (1980a).
Additional negative effects of drawdown may Include lowered levels 1n
potable water wells, and the loss of open water or access to open water for
recreation.
Implementation of Drawdown Projects
Lake drawdown should not be considered without first conducting a number of
laboratory and other Investigations to determine the feasibility of the
technique. These Investigations should Include simulations of lake draw-
down, and laboratory studies of nutrient solub1l1zat1on. Lake drawdown 1s
applicable only to lakes 1n which water Input and output may be controlled.
The extent of macrophyte growth Is Important In specifying the depth to
which the lake level will be lowered.
Laboratory Experiments. Drawdown simulations are performed to determine
the extent to which sediments will dry and consolidate. Containers that
have been used 1n lake simulations range 1n size from Plexiglass tubes that
are 4.45 cm (ID) and 0.3 m high (Doorls, et al., 1982), to columns 0.3 m
(ID) and 1.2 m high (Fox. et al., 1977). Fox, et al. (1977) also used
plastic swlmlng pools (2.4 m In diameter, 45 cm deep) In lake simulation
experiments. The containers of sediment are exposed to air and light for a
period of time, during which sediment shrinkage and water loss are meas-
ured. The drying rate of the sediment can then be determined.
The container of dried sediment should be refilled, and the orthophosphate,
total phosphorus and total nitrogen levels measured. Ideally, only small
amounts of nitrogen and phosphorus compounds should be released from the
consolidated sediment. Large releases of nutrients may presage algal
blooms that may occur when the lake basin 1s refilled following drawdown.
Drawdown. The level of the lake should be lowered sufficiently to expose
most of the nuisance macrophytes, but to allow enough water for fish sur-
vival (If desired). It may be advantageous to combine drawdown with other
restoration techniques such as sediment removal and sediment covering.
Certain species of aquatic maci^phytes may be more susceptible to drawdown
during one season than another. The decision to employ summer or winter
drawdown should be based upon tho severity of the climate 1n a particular
IY-32
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area, and upon consideration of lake uses and secondary management objec-
tives. For example, winter drawdown is advantageous because there will be
no invasion by terrestrial plants nor development of aquatic emergents, and
little interference with lake recreational uses. In addition, water bodies
drawn down in winter can usually be refilled in spring. In contrast, re-
filling in the autumn after a summer drawdown way not be possible.
Complete dewatering of sediment is problematic during the winter, espe-
cially in regions of heavy snow or frequent winter rain. Winter drawdown
•Ay also defeat other objectives such as the establishment of emergent
vegetation for waterfowl habitat, since these species may be susceptible to
the cold.
Lake Drawdown Case Studies
Lake level drawdown is a multipurpose improvement technique. The major
objective 1s generally to control the growth of rooted aquatic vegetation,
with secondary objectives of fish management, sediment consolidation, and
turbidity control. The following case histories exemplify the effects of
drawdown on lake biota.
Murphy Flowage. Wisconsin. Murphy Flowage (303 ha) was drawn down for two
consecutive winters TrT" an effort to control the macrophyte species
Potamogeton robbinsii (Robbln's pondweed), Ceratophyllum demersum
(coon tall), Nuphar sp. (water lily), Potamogeton natans (floating-leaf
pondweed}, and Myrlophyllum sp. (water mil foil). In 1967 and 1968, the
water level of the Flowage was lowered 1.5 m from November to March, and
restored In April. There was an 89 percent reduction In area covered by
macrophytes following the first drawdown, and an additional 3 percent
reduction occurred following the second drawdown. The species that had
been dominant were controlled or nearly eliminated. No fish kills occurred
during drawdown. Following the second drawdown, resistant species such as
Megalondonta beckii (bur marigold), Najas flexilis (naiad), and Potamogeton
divers ffoTTuis (pondweed) began to spread. The extent to which resistant
species may have spread Is unknown, because a flood destroyed the Flowage
in 1970 and evaluations were ended (Cooke, 1980aj.
Blue Lake. Oregon. Blue Lake is an oxbow lake with a surface area of 26.3
ha, a maximum depth of 7.3 m, and a mean depth of 3.4 M. Prior to draw-
down, Eurasian water «1lfo1l, Myriophyl 1 urn spicatum, dominated the littoral
areas of the lake. During the winter of 1981-1982, the lake level was
dropped 2.7 m to the base of most of the milfoil beds.
Drawdown reduced the standing crop biomass by 47 percent at depths less
than 1.2 m, and 'by 57 percent at depths from 2.4-3.7 m. The death of
shoots by drying and freezing during drawdown served to reduce milfoil
biomass. However, drawdown alone did not eliminate the milfoil, and re-
growth from surviving rooter owns was widespread. The herbicide 2,4-D was
applied in 1982 to reduce milfoil growth.
quality effects that may be seen following refl coding include a
dec-ease In Seech i disc transparency and an Increase in total suspended
solids, turbidity, chlorophyll-^ and total nitrogen and total phosphorus
concentrations (Geiger, 1983).
IV -33
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In-Lake Treatment Techniques
Several additional Mthods of lake restoration are available, but have not
been applied as widely as the techniques noted 1n the previous sections.
The techniques that will be discussed In this section Include dilution/
flushing, techniques to control nuisance aquatic vegetation (chemical
applications, harvesting, habitat Manipulation and biological controls),
and lining of acidified water bodies.
Dilution/Flushing
Dilution/flushing Improves lake water quality by reducing the concentration
of the Uniting nutrient and Increasing the water exchange rate 1n the
lake. Th: result Is a reduction In the bloMss of plank tonic algae because
the loss rate exceeds algal growth rate. The technique 1s Implemented by
adding low-nutrient water to the lake 1n order to reduce the concentration
of the limiting nutrient and thereby reduce algal growth. In addition,
nutrients and algal blomass are washed from the lake because the water
exchange rate Is Increased (Welch, 1979, 1981a_. 1981^).
The purpose of dilution, as suggested earlier, 1s to deter blue-green algal
blooms by decreasing total phosphorus and total nitrogen, and by elimi-
nating blomass at a greater rate than the growth rate can supply new cells.
Ihe reduction of allelopathlc substances excreted by blue-green algae may
also contribute to the Increased abundance of diatoms and green algae
(Welch and Tomasek, 1980).
Use of the dilution/flushing method 1s most feasible when large quantities
of low-nutrient water are available for transport to the lake that Is to be
restored. This condition was met In the instances of Moses and Green Lakes
1n Washington State. Case histories of these two lakes are discussed
below.
Moses Lake, Washington. Moses Lake has an area of 2,753 ha and a mean
depth of 5.6 m. Prior to restoration by dilution/flushing, the lake was
eutrophlc and experienced blue-green algal blooms because of high nutrient
concentrations. Inflowing water (Crab Creek, [P]»92 ug/1) was diluted with
low nutrient water from the Columbia River ([P]-30 ug/1) with about a 3:1
dilution of Crab Creek. Following dilution/flushing, Seech1 disc depth In
the lake Increased from 0.5 m to 1.1 m (April-July values). Total phos-
phorus, which had a mean value of 142 ug/1 prior to dilution, was reduced
to 53 ug/1. Chlorophyll-a also decreased from 55 ug/1 (mean values for
April-July) to 9 ug/1 (Aprfl-July mean).
Green Lake, Washington. Green Lake, which Is located 1n King County,
Washington State, has a surface area of 104 ha, a mean depth of 3.8 m, and
a maximum depth of 8.8 m. Prior to dilution, Green Lake had a high level
of blue-green algal production, and high nutrient levels caused by sub-
surface seepage (U.S. EPA, 1982).
Dilution began 1n 1962 with the Seattle city water supply as the source of
low nutrient v.:ter. The technique applied to Green Lake was one of long-
term dilution at a relatively low rate. Post-dilution monitoring did not
begin until thre* years after dilution was begun, and only one pre-dllutlon
IV-34
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Habitat Manipulation. Dredging May be used to mechanically remove the
whole plant from shallow waters, or It may be used to Increase the depth to
a point below which plants are unable to grow. Dredging may also remove
sediment nutrient sources for aquatic plant growth.
Shades, dyes, bottom coverings and drawdown are also Included In habitat
manipulation techniques to control aquatic weeds. Black plastic sheeting
that floats on the water surface has reportedly controlled growth of
Myr1ophyl1 urn splcatum (Nichols and Shaw, 1983). Following four weeks of
rnadlng, the plants were brown and dead, and there was little or no re-
growth during the rest of the summer. Cooke (1980b) reviewed the various
methods that are encompassed by the general category of covering bottom
sediments. Included within these techniques are sheeting and screening,
and smothering with sand or fly ash. Cooke (1980b) concluded:
o Plastic sheeting appears to be effective In retarding macrophyte
growth, but there are problems with application methods and 1n
anchoring the material;
o Fiberglass screens hold promise as effective means of controlling
macrophytes, but further evaluation 1s recommended;
o Sand Is apparently not effective 1f enriched sediment 1s not first
removed because the sand particles sink Into flocculent sediments;
and
o Fly ash was not recommended because of the negative water quality
effects (elevated pH, low dissolved oxygen, high concentrations of
heavy metals) and subsequent effects on the biota.
The aniline dye nlgroslne has been used In attempts to control macrophytes.
Although the toxldty of aniline dyes to other organisms Is not known, they
are very toxic to humans. Other considerations associated with the use of
dyes Include aesthetics, loss of effect through dilution, loss of dye
through plant uptake and loss by sorptlon to suspended sol Ids and sediment.
Biological Controls. Biological controls Include the use of fish, shell-
fish, insects, and disease. Some fish that have been suggested for control
of aquatic weeds are the common carp (Cyprlnus carplo), roach (RutHus
rutllus), rudd (Scardlnus erythopthalmus), some species of tllapla (Tllapla
211111, T. mossambica), silver dollar fish (Metynnls rooseveltl, Mylossoma
argenteum). white amur (Ctenopharyngodon 1 dell a) and hybrids of the white
amur (Mulligan, 1969; Nichols and Shaw, 19HTTIt should be noted that the
Introduction of exotic species Is strictly regulated 1n many states.
Carp are not primarily herbivores, but they serve to decrease plant growth
by uprooting plants when searching for benthlc organisms or when spawning,
and by Increasing turbidity 1n the water. Although carp have been shown to
effectively control el odea and curly-leaved pondweed, they cause water
quaTUy problems (suspended sediment, turbidity) which can lead to the
demise of sportflsh populations (Nichols and Shaw, 1983).
Herbivorous fish can be used to control certain species of aquatic weeds.
For example, roach and rudd prefer el odea over milfoil. Milfoil Is also
IV-36
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the least preferred food of T1 lap-la spp. The Introduction of grass carp at
Red Haw Lake, Iowa, resulted In control of El odea, Pptamogeton. Cerate-
phyllum and Najas. The blomass of aquatic, macrophytes in the lake
decreased from27?38 g/ir in 1973 to 211 g/«r in 1976 (Mltzner, 1978).
Since milfoil Is not the preferred food of herbivorous fish, there Is a
possibility that persistent monocultures of Myrlophyllum splcatum will
develop.
Herbivorous snails have been suggested as potential controls for macro-
phytes. Although native snail species In temperate regions do not eat
wacrophytes, two South American species (Marlsa cornuarlellsl L. and
Pomacea australlal 1s) are macrophyte herbivores that may potentially be
used to control pelt soedes. The crayfish Orcqnectes causey 1. which
consumes both El odea canadersts and Myr1ophy 11 urn exalbescens, has also been
suggested as a means of biological control of macrophytes (Nichols and
Shaw, 1983).
Several Insects have also been Investigated as predators on Eurasian water
•11 foil. Some of the promising species noted are Parapoynx stratiota, P.
alllonealls, Acentrla n1 vea. Lltodactylus leucogaster andTTI aquatic
moths.Rowever, most of these Insects are not specific to milfoil. Dis-
eases that may cause declines In milfoil populations Include "Lake Venice"
disease and "Northeast" disease. The causes of these two diseases are not
known nor are the long-term consequences of artificial Introduction of
disease. Thus, the use of pathogens to control milfoil Is not recommended
(Nichols and Shaw, 1983).
Neutralization of Acidified Lakes
Causes of Acidity and Problem Definition. Acidity of surface waters Is
largely caused by two nonpolnt sources: add mine drainage and add
precipitation. Add mine drainage results when mine water comes In contact
wltn sulfur-containing minerals. Acid precipitation Is caused by atmos-
pheric sulfur that Is released by electric utilities and urban and In-
dustrial operations'that use sulfur-containing fuel. Oxidation of sulfuric
compounds produces sulfuric acid, which dissociates to form H and SO.
Ions In surface or atmospheric water (Novotny and Chesters, 1981).
Add mine drainage and acid precipitation cause undesirable "ollgo-
trophlcatlon" (a severe loss of productivity caused by the low pH condi-
tions), Including loss of natural fish populations. Salmonld fisheries,
particularly lake trout, are susceptible to acidification (Goodchlld and
Hamilton, 1983).
The ability of surface waters to neutralize acidic Inputs 1s largely a
function of the chemical composition and solubility of the surrounding
soils and underlying rocks. For example, limestones (CaCO,) and dolomites
(CaMg(CO,)2) yield Infinite acid neutralizing capacity, whereas hard rocks
such as°gran1tes (I.e., quartz - S102, feldspar - KA1S1308) and related
Igneous rocks, crystalline metamorph1
-------
and 01 em, 1983). Areas of the United States where lakes are highly sensi-
tive to acidification are 1n New England, the Adirondack Mountains of New
York, the Appalachians, and the Rockies.
Neutralization. Several materials have been considered for use In neu-
tralizing acid lakes. These Include 11me (CaO, Ca(OH)2), limestone
(CaCOJ, dolomite, line slags, basic flyash, soda ash, and pfiosphorus. Of
these; 11me and limestone are the most widely employed to neutralize sur-
face waters (OHscoll, et al., 1982). Dolomite, dolomltlc hydrated lime,
and dolomite quicklime (each exceeding a 35 percent magnesium content) may
also be used. However, limestones containing more than 10 percent mag-
nesium carbonate dissolve slowly and are not practical for use In neutral-
izing surface waters. Agricultural limestone, while not as effective as
quicklime or hydrated lime, has several advantages: 1t 1s noncaustlc,
relatively Inexpensive, relatively free of harmful contaminants, and does
not produce harmful alkaline conditions (Brltt and Fraser, 1983).
Application. Techniques for 11me application In lakes Include using trucks
(blowers), boats (blowers, slurries, bags), aircraft, and sediment Injec-
tion systems. The proper time and place to apply neutralizing agents
depends upon two main factors: the time and location of addle episodic
events (e.g., snowmelt, autumnal rains); and relationships between such
events and the critical life stages of aquatic biota. For example, 1n
d1m1ct1c lakes, mixing and distribution of lime 1s enhanced when It Is
applied during the spring overturn. However, spring acidic snowmelt
creates two problems. First, neutralization may occur too late to prevent
fish embryo and fry mortality that Is caused by acidic snowmelt. Second,
the colder snowmelt water may be less dense than deeper lake water, and
mixing with neutralized water may be Inhibited (Brltt and Fraser. 1983).
Liming the entire lake area 1s desirable, but may not be feasible because
of time and other resource constraints. Alternatively, application of 11me
over the deepest part of the lake allows the particles of CaC03 more time
to react within the water column. Another alternative may be to distribute
limestone 1n shallow littoral zones where wave action enhances dissolution
(Brltt and Fraser, 1983). An alternative Hmlng strategy Involves
chemically treating watersheds, thereby neutralizing the associated aquatic
ecosystem. Methods to estimate lime requirements are found In Boyd (1982)
and Or 1 scoH, et al. (1982).
Liming Effects. The biological consequences of Hmlng have been summarized
by Hultberg and Andersson (1982) and Brltt and Fraser (1983). Case histo-
ries of limed lakes show the following changes 1n lake biota:
o Decreases 1n addophlllc algae and mosses, with concurrent In-
creases 1n diversity of planktonlc algae;
o Predominance of cladocerans shifts to a predominance of copepods
after neutralization;
o Reduction 1n benthlc blomass after Hmlng, but eventual recovery
with repopulatlon of less add tolerant species;
IV-38
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o Most fish species respond positively, with enhanced survival due
to successful spawning and hatching.
Some chemical changes caused by neutralization may be of concern. Toxldty
changes of aetals, especially aluminum, nay have serious environmental con-
sequences. Aluminum toxlclty varies with pK changes; gill damage to fish
My be caused when aluminum reacts with hydroxides from pH 4.4 to 5.2,
while other studies Indicate that aluminum Is most toxic to fish from pH
5.2 to 5.4 (Brltt and Fraser, 1983). The sediments of a Hmed lake may
become sinks for aluminum and other toxic metals as pH Is raised and the
metals are removed from the water column. If the lake Is allowed to re-
acidify after several years of treatment, the remobHlzatlon of metals may
cause serious biological problems.
Watershed Management
The quality of a lake's water Is often a direct manifestation of the number
and types of pollution sources In the surrounding watershed. Agricultural
practices such as tillage, the use of fertilizers, and operations of con-
fined animal feedlots may potentially Increase the loss of sediments and
nutrients from the land and accelerate the natural process of lake
eutrophlcation. In urban areas, many pollutants are carried to lakes In
stormwater runoff, via combined sewers, storm sewers and direct surface
runoff.
The effectiveness of 1n-lake restoration techniques would be short-lived If
the cause of eutrophlcatlon (high nutrient Input) was not corrected.
Watershed pollution control techniques are Important corrective and often
preventive measures. The following sections highlight watershed management
techniques that help control nonpolnt sources of pollution from agricul-
tural and urban areas.
Agricultural Pollution Control
Control of Sediment Input and Associated Nutrients. One of the most Impor-
tant water pollutants that results from agricultural activities 1s the
sediment Input from eroding croplands. Sediment Itself 1s a physical pol-
lutant, and In addition serves as a vehicle to transport nutrients,
pesticides, toxic chemicals, organic matter, and Inorganic matter to water
bodies. Techniques to reduce soil loss from agricultural lands have been
discussed In the U.S. Environmental Protection Agency publication entitled
Effectiveness of Soil and Mater Conservation Practices for Pollution
Control (1979b) and in a publication by Stewart, et al. (1975).Several
Soil and Water Conservation Practices (SWCP). will be discussed In the
following paragraphs.
No-Till Planting. Planting Is accomplished by placing seeds In the soil
without tillage, using a fluted coulter that leaves the vegetative cover
virtually undisturbed. Chemical herbicides are used to control weeds and
previously planted crops. No-till planting can reduce soil loss to less
than 5 percent as compared to conventional plowing and planting practices
(Novotny and Chester*, 1981). However, this metncd requires a greater use
of herbicides, and lower yields may be expected on some soils. Because
vegetative cover Is left to decompose on the surface, the loss of soluble
IV-39
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plant nutrients 1$ greater 1n runoff from no-till than from conventionally-
tilled plots (U.S. EPA, 1982).
In summary, no-till farming reduces runoff and erosion losses. Therefore,
losses of strongly adsorbed and solid phase pollutants (total phosphorus
and organic nitrogen) are decreased. Losses of weakly adsorbed pesticides
and plant nutrients (dissolved phosphorus) may Increase; but overall the
no-till technique 1s effective 1n reducing losses of both phosphorus and
nitrogen.
Conservation Tillage. This technique replaces conventional plowing with a
form of nonlnverslon tillage that retains some of the plant residue on the
surface. A chisel, field cultivator, or disk can be used for tilling. The
organic residue cover protects the soil surface from erosion and decreases
the volume and velocity of runoff (U.S. EPA, 1979J>). Because runoff volume
and soil loss are reduced, losses of strongly adsorbed organic phosphorus,
organic nitrogen and Insecticides are decreased.
Sod-Based Rotations. This system Involves the periodic rotation of row
crops and a sod crop such as alfalfa, other legumes, or grasses. Plowing
the sod Improves filtration and reduces credibility. Increased soil
porosity helps decrease surface runoff, and the reduction 1n runoff can
continue for several years of continuous row crops after t'te ;e
-------
(Novotny and Chesters, 1981). Ridge planting Involves planting crops on
preformed ridges that follow the natural contours of the field. Crop
residues are pushed Into the furrows between rows, further deterring runoff
and erosion (U.S. EPA, 1982).
A special plow (lister) Is required to form alternating ridges and furrows
for contour listing. Row crops are then planted either In the bottom
furrows or the ridge tops. Contour strip cropping Is accomplished by
alternating the cultivated crops with strips of grass or close growing
crops.
The principal erosion control practices for use on croplands are summarized
In Table IV-4.
Waste Management Planning. The planning of a waste management system helps
prevent the owner from Investing In unnecessary components. Evaluations
Include estimations of liquid and solid waste sources on a farm and devel-
opment of a complete system to manage them without degrading air, soil or
water resources. An operation plan, which provides specific details for
operation of the system, should Include:
1. Timing, rates, volumes, and locations for applications of waste
and, If appropriate, approximate nucber of trips for hauling
equipment and an estimate of the time required.
2. Minimum and maximum operation levels for storage and treatment
practices and other operations specific to the practice, such as
estimated frequency of solids removal.
3. Safety warnings, particularly where there 1s danger of drowning or
exposure to poisonous or explosive gases.
4. Maintenance requirements for each of the practices.
Waste Storage Ponds. The purpose of waste storage ponds Is to temporarily
store liquid and solid wastes, wastewater, and polluted runoff until It can
be applied to land without polluting surface or ground water. Common uses
of waste storage ponds are storage of n1Ikhouse wastes and manure and
storage of polluted runoff from feedlots and barnyards.
Diversions or dikes are usually combined with systems employing waste
storage ponds. Clear water diversion systems direct water from upland
watersheds away from feedlots or barnyards. Polluted runoff may be
collected and directed to storage ponds by constructing, a system of curbs,
gutters or terraces. Design of waste storage ponds should consider the
maximum period of time between emptying, which varies according to
precipitation, runoff, and waste volume.
Waste Storage Structures. Waste storage structures such as storage tanks
and manure stacking facilities serve the same purposes as waste storage
ponds, and while storage structures are more expensive they o*fer several
advantages. Advantages Include preservation of nutrient content of stored
wastes, minimization of odors, management flexibility and improved
aesthetics.
IV-41
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TABLE IV-4
PRINCIPAL TYPES OF CROPLAND EROSION CONTROL PRACTICES AND THEIR HIGHLIGHTS (Continued)
E9
£10 Grated row*
C»m reduce average ***• *°" ** *** «• moderate dope*, bwf late «• Ueep riope*;
U rows break over; MMI be Mpportad by terrace* o« loaf *mpe»; Mi. ctfmaik. Md lopopapMc
kmiuiio**; M>I compatible wttb MM of tiff* iarmiac •qiMpMMU oMic ytacltot by Mdudm «ffocth» ttop« battli mt ntaoff co»c«Hf«-
; i«duc« Motto* Md coMtn* MM Motaim; fadHUU
p»die*l tMrmcc* oftta Uompatiblt with mmoftugt t*tuif**M. but MW dniyii IMM alkvfaud tWt
ptoblMi; tMteUMW Mttol COM »ad
FtciHuu dniMtc of padMl tow* Md Unac* doMdi whfc •iaiaiil «orio>;
i aad Buy feMtfm witk MM of bigi MptMwao.
£14
Earbci wuMioc »«d dryi*c of fow low; rad«CM MotiM by coMMtnltef iMMff ftow ta Miittdi-
coveted furrow*; MM •ffectiM wbJ« row* Ml i
£15 CONUMM HUM*
Minimixet row bieakom; CM ndM« MMU> r jit km by 50»; ION* «ff*
corn ctiltivttioH; dita4vMta«H IMM M E9.
£16 ChMfle fa bMt u*e
Sometime* tbc orfy anfatiaa. We* m*aa»id i«rma»e»t gram or woodlaad effective wbere otbar
coatrol practices are iaudaqwale. loat acnaf* «M be compeMaMd for by more mtMtrve me of lea*
crodibktMd.
EI7 Otber practice*
Conioor furrow*. dtenkMU. MbMufaca dnoMft; iMd formmc. doMt row «P«C»T. «tc.
SOURCE: Stewart, et al., 1975
IV-42
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TABLE IV-*
PRINCIPAL TYPES OF CROPLAND EROSION CONTROL PRACTICES AND THEIR HIGHLIGHTS
Erosion Control rracik*
•eneAss and Impact
11 No-lUI plant in prior-crop residues
E2 Conservation tillage
E3 Sod-based rotations
E8
Ptow-pla*t systems
Moil effective m dormant KMU or MuM grain; highly effective m crap residues; minimises spring
sediment surges »Mt provides year-round control; leduccs Man, machine, and fuel requirements;
delays toil warming «»d drying; requites MMC petlickkt and nilrafca; HmiU ferlttiei- a*d peslicU*-
pbccmenl option*: WMM dimalk and toil reiUiclioM.
Indvdet a variety of no-plow sytieiM thai relate MMNC of Ike residues on the surface; ntort widely
adaptable but somewhat lest effective than El; advanlafcs and dbadvanla«e* generally saaM as El
out la tenet deftec.
Good meadows UMC virtually no soi and reduce erosion from succccdini crops; total soil lost pnitv
reduced but losses unequally diitribuMd over rotation cycle; aid in control of some diseases and
pests; MOTC ferisMxer-placeMienl options; less realiicd income fiom nay veais;(ieatcr potential Uans-
port of water-soluble P; some climatic restrictions.
E4
EJ
E6
E7
Meadowtess rotations
Winter cover crops
Improved toil fertility
Timinc of field operation!
Aid in disease and pcsl control; may provide more continuous soil protection than one-crop system*;
muck test effective than £3 .
Reduce winter erosion where com stover ha* been removed and after low- residue crops; provide good
base for (lot-phmiitc. next crop; usuaHy no advantage over heavy cover of chopped slafts or straw;
may reduce leaching of nitrate; water use by winter cover may reduce yield of cash crop.
Cm substantially reduce erosion hazards as well as increase crop yields.
Fall plowing facilitates more timely planting in wet springs, but it greatly increases winter and early
spring erosion hazards; optimum liming of spring operation! can reduce erosion and increase yield*.
Rough, cloddy surface increases infiltration and reduces erosion: much less effective than El and E2
when long rain periods occur; seedling stands may be poor when moisture conditions arc less than
optimum. Mulch effect ia lost by plowifig.
IV-43
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Waste Treatsent Lagoons. Treatment iagoons may be designed as anaerobic,
aerobic, or aerated lagoons. They are used principally to treat liquid
wastes.
Anaerobic lagoons are the most commonly used. They require less area than
aerobic lagoons, and do not need require electricity for operation, as do
aerated systems. Treated wastes may be lower 1n nitrogen due to ammonia
volatilization; therefore, the waste Bay be applied over a smaller land
area.
Aerobic lagoons are used for weak agricultural wastes, such as those
originating from milk centers. They require large surface areas, and the
effluent 1s rarely suitable for discharge to surface water.
Filter Strips. In this Method, runoff from feedlots and barnyards flows
over grassy strips. The strips help reduce the volume and pollution
content by soil percolation, the filtration capability of the grass, and
volatilization.
Waste Utilization. Waste utilization refers to where and when manure
should be applied to land. Its purpose Is to use the wastes as fertilizer
for crops, forage and fiber production, to prevent erosion, to Improve or
maintain soil structure, to produce energy, and to safeguard water
resources.
Factors to be considered Include the land areas available, and the crops
that will be grown. Other factors that should be considered are the timing
of application, nutrient release rates, soil types, and climate.
Urban Runoff Pollution Control
Lakes In urban areas are subject to pollution from stormwater runoff which
enters lakes via combined sewers, storm sewers, and direct surface runoff.
The runoff contains high concentrations of sediment, nutrients, heavy
metals and toxic chemicals.
During storm events, the capacity of combined sewer lines may be exceeded,
and overflow structures at sewage treatment plants or 1n the sewerage
system are designed to discharge the excess Into surface water bodies. The
"first flush effect" refers to the phenomenon 1n combined sewer overflow
samples whereby the highest concentrations of BOD5, suspended solids,
grease and other pollutants are found during the earliest part of a storm
event. Accumulated solid deposits that contain organic matter undergoing
decay 1n combined, sanitary and storm sewers may Increase B005 concen-
trations to levels greater than those of normal untreated dry-weather
wastewater (Lager and Smith, 1974). Long periods between rainfall, low
sewer slopes, Infrequent cleaning, and failure to block off or clean catch
basins magnify pollutant concentrations 1n combined sewer overflows, and
(to a lesser extent) storm sewer discharges.
Several management alternatives are available to alleviate problems caused
by urban stormwater. Techniques may be grouped Into three categories:
land management, collection system modifications, and storage. While
detailed descriptions of urban runoff control measures are beyond the scope
IV-44
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of this manual, several components of each category will be briefly sum-
marized In the following paragraphs.
Land Management. Land management practices Include those measures designed
to reduce urban and construction site stormwater runoff at the source, by
employing Best Management Practices (BMPs). On-s1te measures can be
further divided Into low structural or non-structural controls.
Low structural control measures require physical modifications In a
construction or urbanizing area. The most common on-slte control Is
storage. Storage attenuates peak runoff flows, treats runoff (detention/
sedimentation), or contains the flow In combination with another treatment
process such as retention/percolation (Lynard, et al., 1980).
Non-structural control measures Include surface sanitation, chemical use
control, use of natural drainage, and certain erosion/sedimentation control
practices (Field, et al.. 1977). Surface sanitation (street sweeping
operations) may have a significant Impact on the quantity of pollutants
washed off by stormwater. Certain street cleaning techniques are able to
remove 93 percent of the dry weight solids, which make up a significant
portion of the overall pollution potential (Field, et al., 1977; Lager and
Smith, 1974). A frequently overlooked measure for reducing the pollution
potential from urban areas Is reduction In the use of fertilizers, pesti-
cides and delclng materials. Suggestions for methods to reduce such Inputs
can be found In Lager and Smith (1974) and Field, et al. (1977).
Construction In urbanized areas replaces areas of natural Infiltration and
drainage wfth Impervious areas. The result 1s Increased runoff and
flowrates, and decreased Infiltration to the groundwater. Use of natural
drainage helps reduce drainage costs and pollution, while It enhances
groundwater supplies and flood protection (Field, et al., 1977).
Non-structural erosion/sedimentation controls Include cropping (seeding and
sodding), use of mulch blankets, nettings, chemical soil stabilizers and
earthen berms. These measures are described 1n Lager and Smith (1974),
Field, et al. (1977), and Lynard, et al. (1980).
Col 1ectlon System Controls. Collection system controls Include sewer
separation,inflow control, flushing and polymer Injections, regulators,
and remote flow monitoring and control. Several of these alternatives are
briefly described below.
Sewer Separation. Sewer separation refers to the conversion of a combined
sewer system Into separate sanitary and storm sewer systems. The practice
of sewer separation has been used for many years, but Lager and Smith
(1974) note two main reasons for Devaluating sewer separation. The first
reason stems from changes 1n physical conditions and quality standards from
the past, which Include: (1) Increases In urban Impervious areas and
municipal water usage, causing overflows of Increased duration and quan-
tity; (2) rapid Industrial expansion, causing Increased quantities of
Industrial wastewaters In the overflows; (3) Increasing environmental
concern for better water quality; and (4) the realization that the total
amount of available fresh water Is limited and that complete reclamation of
substantial portions of the flow may be necessary In the future. The
IY-45
-------
second reason Includes: (i) separated stom sewer discharges contain pol-
lutants that affect the rece1v1r-j water and create new problems; and (2)
stom sewer discharges occur more frequently and last longer than combined
sewer overflows because combined sewer regulators prevent overflows during
•Inor events.
Lager and Smith (1974) concluded that In many cases the separation of
existing combined sewer systems Is not practically or economically feasible
to resolve combined sewer problems. A feasibility study Including the cost
of alternative methods would Indicate the practicality of each option.
Infiltration/Inflow Control. Problems result from Infiltration Into sewers
from groundwater sources, anH high Inflow rates through direct connections
from sources other than those which the sewers are Intended to serve.
Examples of Infiltration are the volumes of water that enter the sewer
system through manhole walls, cracks, defective joints, and Illegal
connections.
Remote Flow Monitoring and Control. Computerized collection system control
can be applied to upgrade combined sewer systems. Control systems are
Intended to assist In routing and storing combined sewer flows to
effectively use Interceptor and line capacities (Lager and Smith, 1974).
The control cystew Is able to sense and report minute-to-minute system
status, Including flow levels, quantities, treatment rates, pumping rates,
gate (regulator) positions, and characteristics at significant locations 1n
the system. Such observations may assist In determining where necessary
overflows can be discharged with the least Impact. The control system also
provides a means for manipulating the system to maximum advantage.
Storage. Storage of runoff effectively prevents or reduces stormwater
runoff from entry Into combined sewers and surface water bodies. Storage
facilities can provide complete or short-term retention of stormwater
flows. Retention facilities may Incorporate Infiltration systems such as
gravel bottoms or tile drains.
Detention basins are capable of reducing peak flow volumes from storms, and
providing a sediment trap for suspended sol Ids. The gradual release of
stormwater lessens Impacts caused by flooding, erosion, and disruption of
aquatic habitats (U.S. EPA, 1982).
Stormwater flows to treatment plants, and subsequent overflows, may be
controlled by 1n-l1ne or off-line storage facilities. Storage facilities
have several advantages: they are basically simple In design and opera-
tion, they respond without difficulty to Intermittent and random storm
behavior, they are relatively unaffected by flow and quality changes, and
they are capable of providing flow equalization (Lager and Smith, 1974).
Drawbacks of storage basins Include their large size (real estate require-
ments and therefore cost), visual Impact and the need to provide for solids
dewaterlng and disposal.
Storage facilities may be 1n-l1n», 1n which regulators and pumping stations
are used to store stormwater runoff 1n areas of the sewer system with extra
capacity, or off-line,'which may be concrete vaults, or storage basins such
IV-46
-------
as described earlier. Detailed Information concerning storage facilities
1s available In Lager and Smith (1974), Field (1977), and Lynard, et al.
(1980).
IY-47
-------
CHAPTER V
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V-9
-------
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V-12
-------
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V-13
-------
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Y-14
-------
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V-15
-------
APPENDIX A
PALMER'S LISTS OF POLLUTION TOLERANT ALGAE
Source: Palaer, 1969
A-l
-------
APPENDIX A
PALMER'S LISTS OF POLLUTION TOLERANT ALGAE
TABLE A-l
POLLUTION-TOLERANT GENERA OF ALGAE
LIST OF THE 60 MOST TOLERANT GENERA,
IN ORDER OF DECREASING EMPHASIS BY 165 AUTHORITIES
No.
1
2
3
4
5
6
7
3
9
10
11
12
13
14
IS
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
Genus
Euglena
OsclllatoMa
Chi aaydooonas
Scenedesaus
Chi ore! la
NUzchla
Navlcula
Stlgeoclonlu*
Snynedra
Ankl strode sows
Phacus
Phor»1 d1 UNI
Meloslra
Goaphoneoa
Cyclotella
Clost«Hu«
M1cract1n1u»
PandoMna
Anacystl s
L«poc1nc11s
Splrogyra
Anabaena
Cryptoaonas
PedlastruM
Arthrosplra
Trachelooonas
Carterla
Chlorogonlu*
Frag11ar1a
Ulothrlx
Surlrella
Stephanodlscus
Eudortna
Lyngbya
Oocystis
Agmen^'luw
SplruHna
Pyrobotrys
Group*
F
B
F
G
G
D
D
G
D
G
F
8
D
0
0
G
G
F
B
F
G
B
F
G
8
F
F
F
D
G
0
0
F
B
G
B
B
F
No.
authors
97
93
68
70
60
58
61
50
44
36
39
37
37
35
35
34
27
32
28
25
26
27
27
28
18
26
21
23
24
25
27
22
23
17
20
19
17
16
Total
Points
172
161
115
112
103
98
92
69
58
57
57
52
51
48
47
45
44
42
39
38
37
36
36
35
34
34
33
33
33
33
33
32
30
28
28
27
25
24
A-2
-------
TABLE A-l (CONTINUED)
No.
39
40
41
42
43
44
45
46
47
46
49
50
51
52
53
54
55
56
57
58
59
60
Genus
Cyabella
Actlnastrua
Cotlastrua
Cladophora
Hantzschla
Ofatoeu
Spondyl omorua
Golenklnla
Achnanthes
Synura
Plnnularla
Chlorococcuoi
Asterlonella
Cocconels
Cos«ar1u«
Gon1u»
Trlbonena
Stauronels
Selenastrua
Dlctyosphaerlm
Cynatopleura
Crudgenla
Group*
D
G
G
G
D
0
F
G
D
F
0
G
D
0
G
F
G
D
G
G
D
G
NO.
authors
19
20
21
22
18
19
16
14
16
14
15
13
14
14
14
15
10
14
13
11
13
13
Total
Points
24
24
24
24
23
22
21
19
19
18
18
17
17
17
17
17
16
16
15
14
14
14
'Groups: B, blue-green; D, dlaton; F, flagellate; G, green.
SOURCE: Palmer, 1969.
A-3
-------
TABLE A-2
POLLUTION-TOLERANT GENERA OF ALGAE
LIST OF THE 80 HOST TOLERANT SPECIES,
IN ORDER OF DECREASING EMPHASIS BY 165 AUTHORITIES
NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Genus
Euglena v1r1d1s
Nltzschla palea
Oscillator! a 11«osa
Scenedesaus quadrlcauda
OscWatorla tenuls
St1geoc1on1u« tenue
Synedra ulna
Ankl strode sous falcatus
Pandorlna norua
Oscillator la chlorlna
Chi orel la vulgarls
Arthrosplra Jennerl
Meloslra varlans
Cyclotella neneghlnlana
Euglena grac111s
Nltischla aclcularls
Navlcula cryptocephala
Osclllatorla prlnceps
Osclllatorla putrlda
Go«phonema parvulua
HantzscMa amphloxys
Osclllatorla chalybea
Stephanodl scus hantzsch11
Euglena oxyurls
Closterlua acerosun
Scenedesmus obllquus
Chi orel la pyrenoldosa
Cryptooonas erosa
Eudorlna elegans
Euglena acus
SuHrella ovata
Lepoc1nc11s OVUM
Osclllatorla fornosa
Osclllatorla splendlda
Phacus pyruH
Mlcractlnlum puslllufli
Agmenellm quadr1dup11catu»
Meloslra granulata
Pedlastrum boryanu*
Dlatoma vulgare
Lepodnclls texta
Euglena deses
Group*
F
0
B
G
B
G
D
G
F
B
G
B
D
0
F
0
0
B
B
0
D
B
D
F
G
G
G
F
F
F
0
F
B
B
F
G
B
0
G
0
F
F
No.
authors
50
45
29
26
26
25
25
21
23
17
19
15
22
20
18
18
19
16
13
14
18
14
16
15
16
16
11
15
16
16
16
14
14
14
11
12
13
14
15
17
12
13
Total
Points
93
69
42
41
40
34
33
32
30
29
29
28
28
27
26
26
25
24
23
23
23
22
22
21
21
21
20
20
20
20
20
19
19
19
18
18
18
18
18
18
17
17
A-4
-------
TABLE A-2 (CONTINUED)
No.
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
Genus
Spondylooorua quaternarlun
Pnoraldluii unclnatua
Chlanydomonas re1nhard11
Chlorogonlum euchlorim
Euglena polynorpha
Pnacus pleuronectes
Navlcula vlrldula
Phor»1d1um autumnal e
Oscillator! a 1auterborn11
Anabaena constrfcta
Euglena pi self orals
Actlnastrun hantzschll
Synedra acus
Chlorogonlum elongatun
Synura uvella
Cocconels placentula
NUzschla slgaoldea
Coelastrun «1croporu«
Acnnanthes n1nut1sst«a
Cyitatopleura so lea
Scenedesnus dtaorphus
Frag11ar1a crotonensls
Anacystls cyanea
Navlcula cuspldata
Scenedesmus acumlnatus
Euglena Intermedia
Pedlastru* duplex
Closterlum lelblelnll
Osclllatorla brevls
Trachelomonas volvoclna
D1ctyosphaer1u« pulchellum
Fragllarla capuclna
Cladophora glomerata
Cryptomnas ovata
Gonluffl pectorale
Euglena proxlma
pyrobotrys grac111s
Tetraedron mutlcun
Group*
F
B
F
F
F
F
0
B
B
B
F
G
D
F
F
0
D
G
0
0
G
0
B
0
G
F
G
G
B
F
G
0
G
F
F
F
F
G
NO.
authors
13
15
10
10
11
11
13
13
8
9
11
13
9
10
11
12
12
13
10
12
a
9
10
10
10
11
11
a
8
8
9
9
10
10
10
7
7
7
Total
Points
17
17
16
16
16
16
16
16
15
15
15
IS
14
14
14
14
14
14
13
13
12
12
12
12
12
12
12
11
11
11
11
11
11
11
11
10
10
10
*Groups: B, blue-green; D, diatom; F, flagellate; G, green,
SOURCE: Palmer, 1969.
A-5
-------
APPENDIX B
U.S. ENVIRONMENTAL PROTECTION AGENCY'S PHYTOPLANKTON TROPIC INDICES
Source: U.S. EPA, 1979*
B-i
-------
All genus-trophlc-values used in formulating the phytoplankton trophic
Indices are presented 1n Table B-l. The genus-trophic-values, total
phosphorus (TOTALP), chlorophyll-* (CHLA), and total Kjeldahl nitrogen
(KJEL) in Table 8-1 are simply mean photic zone values associated with
the dominant occurrences of each genus. TOTALP/CONC, CHLA/CONC, and
KJEL/CONC were calculated by dividing the TOTALP, CHLA, and KJEL values
by the corresponding mean cell count. Also given in Table B-l is a
genus-trophic-multlvarlate-value (MV) calculated for each genus using
the following formula:
MV » Log TOTALP + Log CHLA + Log KJEL - Log SECCHI
B-2
-------
TABLE B-l
TROPHIC VALUES OF SELECTED GENERA BASED UPON MEAN PARAMETER VALUES ASSOCIATED WITH THEIR OCCURRENCES
AS DOMINANTS.
GENUS
Aohnanthee
Aotinattnan
Anabaena
Anabaenoptie
Ankistrodtatnus
Anomoeoneif
Aphanixamenon
Aphanooapsa
Aphanotheoe
Arthroepira
Aeterionella
Attheya
Binualearia
Botryooooaug
Carteria
Ceratium
Ch lamydcmonae
Chlorella
Chramulina
Ckroooooaue
Chroomonae
Chryeocapea
Chryeooocaua
Cloeterium
Coelaatnan
Coolortphaeriun
CotoinoditauB
Cotmarium
Cruoigenia
DOMINANT
OCCURRENCES
6
2
33
7
9
3
41
4
3
2
36
1
1
2
2
2
4
3
1
19
1
1
2
4
6
6
3
3
2
TOTALP
29
56
183
70
75
10
147
242
65
51
36
70
42
56
509
140
847
70
8
163
116
10
1580
20
60
44
138
14
361
CHLA
11.5
3.5
19.7
32.9
17.9
5.4
37.6
21.1
32.4
21.0
9.6
1.4
6.7
10.3
44.5
5.2
55.1
53.1
VO.O
46.6
32.9
7.9
75.0
19.8
13.4
11.7
62.7
9.9
11.8
KJEL
734
594
1015
1393
573
364
1437
1427
1493
1227
491
473
425
1049
1513
1046
3143
991
348
1630
1421
261
4631
698
1208
868
1267
586
1048
TOTALP
CONC
.027
.142
.098
.008
.082
.005
.058
.034
.009
.022
.023
1.892
.038
.013
.176
3.784
.162
.015
.008
.028
.084
.015
.197
.007
.077
.097
.053
.003
.696
CHLA
CONC"
.001
.009
.011
.004
.020
.002
.015
.003
.004
.009
.006
.038
.006
.002
.015
.141
.011
.012
.010
.008
.024
.012
.009
.007
.017
.026
.024
.002
.023
KJEL
cW
.689
1.506
.545
.165
.626
.166
.569
.200
.203
.519
.310
12.784
.384
.250
.523
28.270
.601
.215
.336
.283
1.032
.380
.576
.249
1.549
1.965
.488
.115
2.019
MV
3.53
3.62
4.82
5.01
4.25
2.32
5.18
5.04
4.98
4.37
3.87
3.23
3.37
4.20
6.04
3.84
6.75
5.13
2.46
5.37
5.50
2.16
7.32
3.60
4.36
3.8?
5.25
3.27
4.67
Continued
B-3
-------
TABLE B-l
TROPHIC VALUES OF SELECTED GENERA BASED UPON MEAN PARAMETER VALUES ASSOCIATED WITH THEIR OCCURRFNfFS
AS DOMINANTS (Continued)
GENUS
Cryptomonai
Cyolottlla
Daotyloooooopti*
Diotyoiphasrium
Dinobryon
Eugltna
Eunotia
Fragilaria
Gltnodinium
Glo0oey*ti»
Glo*oth*o»
Golcnkinia
Gomphonma
Gaiiphotphacria
Gymnodinitan
Kirohntritlla
Lyngbya
Hallcmonat
Hclotira
Meri*mop»dia
Mtsoftigma
Hioraotinitm
Miarooyttif
Hougfotia
Navieula
Hit **ahia.
Ocoyttie
Otoillatoria
Petridiniun
Phaout
DOMINANT
OCCURRENCES
72
83
58
1
31
8
1
45
4
6
2
Z
1
4
2
8
99
6
255
22
1
1
53
2
6
29
5
105
6
2
TOTALP
115
185
178
18
27
318
178
64
8
35
9
615
10
25
9
139
99
87
94
183
57
101
148
76
74
92
38
125
16
2523
CHLA
16.5
29.9
25.0
10.8
8.1
24.5
8.6
17.5
6.4
10.9
4.0
26.9
7.4
8.3
2.8
7.6
29.5
6.0
18.1
33.6
12.8
52.8
37.5
29.2
8.2
26.5
14.0
39.2
8.4
22.8
KJEL
798
1053
1041
949
594
1481
1199
843
403
639
412
1040
782
1270
256
755
1448
642
774
1387
571
1098
1457
990
490
883
1098
1356
595
4049
TOTALP
CONC
.102
.073
.026
.050
.043
.190
3.296
.019
.020
.057
.069
.195
.019
.123
.053
.123
.008
.798
.034
.059
.131
.041
.056
.058
.127
.042
.005
.014
.054
3.955
CHLA
CONC
.015
.012
.004
.030
.013
.015
.159
.005
.016
.018
.031
.009
.014
.041
.016
.007
.002
.055
.006
.011
.029
.021
.014
.322
.C'14
.012
.002
.004
.029
.036
KJEL
cW
.711
.418
.153
2.658
.938
.884
22.204
.247
1.025
1.034
3.169
.330
1.507
6.225
1.506
.669
.115
5.890
.277
.444
1.310
.446
.547
.757
.838
.402
.157
.150
2.024
6.346
MV
4.53
4.10
5.05
3.45
3.16
5.70
4.88
4.13
2.34
3.50
2.23
5.60
—
3.65
1.68
4.15
4.98
3.62
4.49
5.34
4.04
5.22
5.27
5.09
3.93
4.78
3.97
5.27
3.01
7.59
Continued
B-4
-------
TABLE
TROPHIC VALUES OF SELECTED GENERA BASED UPON MEAN PnKAMETER VALUES ASSOCIATED WITH THEIR OCCURRENCES
AS DOMINANTS (Continued)
DOMINANT
GENUS OCCURRENCES
Fhmmidiun
Pinnularia
Raphidiopai*
RhiMOBolenia
Roya
Soenedetmua
Sohroederia
Selenaatrum
Sperma toioopai*
Sphaere 1 lop»i»
Sphaerocyatit
Sphaerotoma
Spondyloaium
Stauraetnm
Stauroneia
StephanoditouB
Synadra
Synura
Itibellaria
TetraHdron
Tetraetnon
Troche lanonae
GENERAL CATEGORIES
centric diatoms
pennate diatoms
flagellate
flagellates
chrysophytan
3
1
45
1
1
50
2
1
2
1
2
1
1
1
1
73
48
1
20
5
1
4
32
17
108
199
5
TOTALP
172
4
106
31
7
351
17
99
65
57
46
13
21
13
79
166
82
131
22
18
28
97
142
254
154
99
54
CHLA
113.2
0.5
30.5
15.9
2.4
60.4
4.1
9.3
8.8
6.4
11.3
16.6
6.4
16.6
1.9
37.0
19.0
8.9
7.7
5.2
6.9
6.0
24.9
46.8
13.7
14.6
10.5
WEL
1955
264
1073
1161
332
1826
552
465
1631
532
1274
750
599
750
557
1112
797
1449
455
384
625
867
1000
1615
882
749
635
TOTALP
CONC
.102
.400
.010
.014
.030
.058
.063
.116
.085
.594
.032
.002
.058
.004
9.875
.045
.027
1.056
.015
.040
.043
.292
.033
.036
.075
.054
.010
CHLA
cW
.067
.050
.003
.007
.010
.010
.015
.011
.012
.067
.008
.003
.018
.006
.238
.010
.006
.072
.005
.012
.011
.018
.006
.007
.007
.008
.002
KJEL
cW
1.164
26.400
.097
.519
1.437
.303
2.060
.546
2.132
5.542
.897
.128
1.659
.251
69.625
.304
.261
11.685
.307
.859
.963
2.611
.234
.227
.427
.411
.118
HV
5.77
0.78
4.88
4.19
1.68
6.01
2.54
4.13
4.13
3.56
4.23
3.61
3.61
3.62
5.27
4.42
5.11
2.86
2.66
3.53
4.38
4.97
5.81
4.55
4.30
3.73
-------
TABLE B-2
PROCEDURE FOR CALCULATING THE TOTALP(PD) PHYTOPLANKTON TSI USING
FOX LAKE, ILLINOIS, AS AN EXAMPLE
Dominant Genera
1n Fox Lake
(STORET No. 1755)
Aptanisoownon
tolotira,
Sttphanoditeu*
Percent
Occurrence
41.2
15.9
15.5
V
(TOTALP, from Table
147
94
166
8]
SUM Total • 406
TOTALPCPO) phytoplankton TSI • ^S6- • 135.6
B-6
-------
TABLE B-3
PROCEDURE FOR CALCULATING THE TOTALP/CONC(P) PHYTOPLANKTON TSI
USING FOX LAKE, ILLINOIS, AS AN EXAMPLE
Genera Counted In
Fox Lake. Illinois
(STORET No. 1755)
Anabatna
Aphatn*onicnon
Clotttriun
Cmeigtnia,
Cyalottlla
Flagellates
Glcnodiniwi
Goraphotphatria
tolofira
Nicrocyiti*
Ooaytti*
Oicillatcria
PhoTni&iun
Scfntdeamus
Sphacrocyiti*
Stiphanoditauf
Syntdra
Percent of
Count
3.7
41.2
0.3
0.3
1.0
0.3
1.7
1.7
15.9
5.1
4.1
4.1
0.3
3.7
0.7
15.5
0.3
C
(Algal Units
per ml )
237
2631
22
22
65
22
108
108
1014
324
259
259
22
237
43
992
22
V
(TOTALP/CONC,
Table 8)
.098
.058
.007
.696
.073
.054
.020
.123
.034
.056
.005
.014
.102
.058
.032
.045
.027
V x C
23
153
0
15
5
1
2
13
34
18
1
4
2
14
1
45
1
SUM TOTAL • 332
TOTALP/CONC(P) phytoplankton TSI » 332
B-7
-------
TABLE B-4
PROCEDURE FOR CALCULATING THE TOTALP/CONC(PD) PHYTOPLANICTON TSI
USING FOX LAKE, ILLINOIS, AS AN EXAMPLE
Dominant Genera 1n
Fox Lakt, Illinois
CSTORET NO. uss)
Aphani.Mcmencn
Htlctirc
Stcphanoditau*
Percent of
Count
41.2
15.9
15.5
C
(Algal Units
Per ml )
2631
1041
992
V
(TOTAL?/ CONC
Table 8)
.058
.034
.045
V x C
153
34
45
SUM TOTAL • 232
TOTALP/CONCCPD) phytoplankton TSI « 232
B-8
-------
APPENDIX C
CLASSIFICATION, BY VARIOUS AUTHORS, OF THE TOLERANCE
OF VARIOUS MACROINVERTEBRATE TAXA TO DECOMPOSABLE WASTES:
TOLERANT (T), FACULTATIVE (F), AND INTOLERANT (I)
Source: Weber, 1973
C-l
-------
CLASSIFICATION, BY VARIOUS AUTHORS, OF THE TOLERANCE OF
VARIOUS MACROINVERTEBRATE TAXA TO DECOMPOSABLE ORGANIC WASTES;
TOLERANT (T)t FACULTATIVE (F), AND INTOLERANT (I)
Macroinvertebrate T J F
Ponfera
Demospongiae
Monaxonida
Spongillidae
Spongilla fragile
Bryozoa
Ectoprocta
Phylactolaemata
Plumatellidae
Plumatella repens
P. princeps var. mucosa 1 1
P. p. var. mucosa spongiosa
P. p. var. fruticosa 1 1
P. polymorpha var. repens
Cristatellidae
Cristatella mucedo
Lophopodidae
Lophopodella carter!
Pectinatella magnifica
Endoprocta
Urnatellidae
Urnatella gracilis
Gymnalaemata
Cienostomata
Paludicellidae
Paludicella chrenbergi
Coclenterata
Hydrozoa
Hydroida
Hydridae
Hydra
Clavidae
Cordylophora lacustris
Platyhelminthes
Turbellaria
Tricladida
Planariidae
Planaria
Nematoda
Nematomorpha
Gordioida
Gordiidae
Annelida
Oligochaeta 4 , 3
Plesiopora
Naididae
Nais
Dero
Ophidonais 1 4
Stylaria
Tubificidae
Tubifex tubifex 11,9
Tubifex 11,6,1^
Limnodrilus hoffmeisteri 11,2,9
L. claparedianus 11
Limnodrilus 11,6,1^
Branchiura sowerbyi 9
1 1
1 3
1 1
13
111,9
1 1
9
9
9
11
9
11
11
11
9
11
9
I I Macroinvertebrate T
'"] "PTosopora
1 Lumbriculidae 1 4
9 *
1 1
9
111,9
Hirudmea
Rhynchobdelida
Glossiphoniidae
Glossiphonia complanata 1 1
Helobdella stagnalis 11,9
H. nepheloidea 1 1
Placobdella montifera 1 4
P. rugosa
Placobdella
Piscicolidae
Piscicola punctata
Gnathobdellida
Hirudidae
Macrobdella 8
Pharyngobdellida
Erpobdellidae
Erpobdella punctata 1 1
Dina parva 1 1
D. microstoma 1 1
Dina
Mooreobdella microstoma 9
Hydracarina
Arthropoda
Crustacea
Isopoda
Asellidae
Asellus intermedius
Asellus 1 4
Lirceus
Amphipoda
Talitridae
Hyallela azteca
H. knickerbockeri 1 1
Gammaridai
Gammarus
Crangonyx pseudogracilis
Decapoda
Palaemonidae
Palaemonetes paludosus
P. exilipes 1 1
Astacidae
Cambarus striatus 7
C. fodiens 1
C. bartoni bartoni
C. b. cavatus
C. conasaugeansis
C. asperimanus
C. latimanus
C. acuminatus
C. hiwassensis
C. extra ne us
C. diogenes diogenes 1
C. cryptodytes f
F I |
'
11
9
14
9
4
1 1
9
9
3
4,2
3,9
9
9
4,2
3
1
1
1
4,3
1
1
1
1
1
1
1
* Numbers refer to references enumerated in the "Literature"
section immediately following this table.
f Albinistic
C-2
-------
(Continued)
MUOUW MM IN 1
Cflortdumt
CtwoJtaut I
C tnnfitui kiiiftiMtPii
Pnctmbuna rmtyi
f. mnaiama I
f. pMfttaWtVMI
f. tftatHftr
P. nrmtv*
f. ptfAratrK
f. JbMTcnuOT
/. atoftoaunufm
r tiynHfui
f. mninotu
f. tnmamnul I
*«*•»!•* l
f. 0XfWMmf$ 1
f. pmbuefttltt
f t^jt^fm
ft 0Vr MflW
f. troftodyta \
f. tfteyrtui
f. ftUtt 1
r.d*cti
f.kuui
O.nutic**
O.fWMtttUt
0.
-------
(Continued)
Ma
ratnu
1
Maaottvwttbratt
I
C,
C,
C ip. R (Jofc.)
C. frfcriw
C.{
C.attt
S
XfMOCHVOfWMItt JtffftOVOtf
jr!
«torrfrni group
MitnttHdtpn
T futcicontto
Htntitekm coUnor
//. rewicnidtM
Dfcrofwidfprt modttrut
D.
D.
D fiim&a
Clypnundtptt ttmlit
C.ftrifM
C. toM/«vt
G. tarty**
G.<
f.fttox
A *ofb
-------
(Continued)
Macrowvtrttbraia T
H. bifid* povp
H. dimawf
H.fnunti
H. iiteommod*
Hydroftyet*
Ok*da«
Snetiyctntna
Molannida*
Ephcmaroptara
Htpuicniidaa
SttnoHtmt uiitgmm
S. mtnimatlttum
ifutatm
S. pulchtUum
S.trti
S. tamlum
S. ftmontvm
S. ttrmumtum
S. mnrpwtetamm
iioMomm
5. i. CWMrffflM
S. L ttttfourutt
S. txtguum
S. tmithtt
S. projcimum
S. tripuHctinim
Sitnontnit
Haxafamidaa
Htxtgtntt UmbtU
H. biUrttttt
PotUftrnf vittftn
Baatidat
BftOt MlfilU
Ctltibtttts /lohdtnut '•*
CalUbtttit
F
9
11
4, 14
2.3
9
9
9
9
4.3
4,3
15.9
15
15
9
6.9
15
14
6
1
9
9
4.2.3
4.3
4.2.3
g
•J
9
9
4.11
3
4.3
11
9
4.2.3
9
9
11
9
9
2.3
4.3
3
11
IS
15
15
9
15.9
15
15
4,2.3
4.2.3
2
15
15
9
11
9
9
Macroinratabraia T
Caaaidaa
CMNO dimtmit 3
Cwaai
Tncoryttuda*
Siphlomiridaa
Itomychm
Ftacopiara
Parlidaa
ftritat ptoctfi
A.thtlt
Namouridai
r«wtta»pnryjr ittttHt
Attottpmm iniptn*
Partodidaa
/vpwai MbiMM
Nttiropttra
Siiyndaa
Cimao* tnoitrit
Maialopiara
Corydalidaa
CorydtUr corrtumt
Sialtdaa
yiffff
Odonaia
Catoptarypdaa
Ht ManiM rttit
Afnoiudaa
A. rrmtitt*
Arp*
ltduiifi rtrtictMt 1 1
CM/lafiN* «n/«wMium
C. tigmntm
Aaihnidaa
Anvttwttut
CompMdaa
Gomptuu ptUUia
G. pltftttut
G. txttmttt
G. spottetpt
G. Mina
Gompbut
Profompkut
Dwnofomptnu
Erpttogomphut
(JbaUuUdat
LitoOutt lydlt
NtuncorduUt motstt
ftotumti
Mtcromm
Hcmiplara 3
CotixidM
Corixt 6
Htiptrocorixi 6
Carridaa
Gtrrit 6
Balotlomatidaf
Sthaoim 6.2
Hydro maffidaa
Hydfomtai mtrhitl 2
F
9
9
6
6
9
9
9
9
9
9
9
4.2.3
9
9
4.3
9
9
6
9
9
4.9
9
1
1 1
9
4,3
2
9
9
9
9
4,2.3
11
3
4.3
1 1
1 1
1 1
1 1
4.3
3
C-5
-------
(Continued)
iwoma
ThM*
VatortdM
v.
VMpvidM
P
Ctmpthim
•CUM
*JnwiiMi
A. Hum*
9
6
2
2
6
6.8
8
9.12
9.12
12
12
8
8
8
B
8
8
11.8
14
11,8
8
8
8
11.8
8
8
8
8
6.12
6
12
12
12
12
II
11,8
11
) J
11
11
11
4.3
11
1 1
11
L
L
L
L
Lotnam
L
L
L
Li
EnlaaMttbrwcWa
UaioaktM
V.ftetomm
Lamp*!*
Qutdmli ptatuhm
8
8
8
2
4.3
8
8
8
8
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C-6
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(Continued)
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C-7
-------
REFERENCES
1. Allen, K.R. The Horok1w1 Stream—a Study of a Trout Population. New
Zealand Marine Oept. Fish Bull. No. 10, 1951.
2. Beck, W.M., Jr. Biological Parameters 1n Streams. Florida State Board
of Health, Gainesville. (Unpublished).
3. Beck. W.M., Jr. Indicator Organism Classification. Florida State
Board of Health. Gainesville. H1meo. Rept. (Unpublished).
4. Beck, U.M., Jr. Studies 1n Stream Pollution Biology: I. A Simplified
Ecological Classification of Organisms. J. Fla. Acad. Sciences,
17:211-227, 1954.
5. Curry, 1.1. A Survey of Environmental Requirements for the Midge
(Dlptera: Tend1ped1dae). In: Biological Problems 1n Water Pollution.
Transactions of Third Seminar, C.M. Tarzwell, ed., USOHEW. PHS, Robert
A. Taft Sanitary Engineering Center, Cincinnati, 1962.
6. Gaufln, A.R. and C.M. Tarzwell. Aquatic Macrolnvertebrate Communities
as Indicators of Organic Pollution In Lytle Creek. Sewage and Ind.
Wastes. 28:906-924, 1956.
7. Hubbs. H.H., Jr. List of Georgia Crayfishes with their Probable
Reactions to Wastes (Lethal Chemicals not taken Into Consideration).
M1meo. Rept. (Unpublished), 1965.
8. Ingram, W.M. Use and Value of Biological Indicators of Pollution:
Fresh Water Clams and Snails. In: Biological Problems 1n Water Pollu-
tion. C.M. Tarzwell, ed. USOHEW, PHS, R.A. Taft Sanitary Engineering
Center, Cincinnati, 1957.
9. Mason, W.T., Jr., P.A. Lewis, and J.B. Anderson. Macrolnvertebrate
Collections and Water Quality Monitoring 1n the Ohio River Basin,
1963-1967. Cooperative Report, Office Tech. Programs. Ohio Basin
Region and Analytical Quality Control Laboratory, WQO, USEDA, NERC-
C1nc1nnat1, 1971.
10. Paine, G.H., Jr. and A.R. Gaufln. Aquatic Dlptera as Indicators of
Pollution 1n a Midwestern Stream. Ohio J. Sc1. 56:291, 1956.
11. Richardson, R.E. The Bottom Fauna of the Middle Illinois River,
1913-1925: Its Distribution, Abundance, Valuation and Index Value 1n
the Study of Stream Pollution. Bull. 111. Nat. Hist. Surv. XVII
(XII):387-475, 1928.
12. Sinclair, R.M. Water Quality Requirements of the Fam1l1y Elmldae
(Coleoptera). Tenn. Stream Poll. Cont. Bd., Dept. Public Health,
Nashville, 1964.
13. Tebo, L.B., Jr. Bottom Fauna of a Shallow Eutrophlc Lake, Lizard Lake,
Pocahontas County, Iowa. Aroer. Midi. Nat., 54:89-103, 1955.
C-8
-------
14. U1n«er, G.R. and E.W. Surfaer. Bottoa Fauna Studies In Pollution
Surveys and Interpretation of the Data. Presented at: Fourteenth Mid.
Hlldl. Conf., Des Molnes, Iowa, 1952.
15. Lewis, P.A. Mayflies of the Genus Stenonema as Indicators of Water
Quality. Presented at: Seventeenth Annual Meeting of the Mid. Benthlc
Soc., Kentucky Oaa Village State Park, Gllbertsvllle, Kentucky, 1969.
C-9
-------
APPENDIX 0
KEY TO CHIROHOMID ASSOCIATIONS OF THE PROFUNDAL ZONES OF
PALEARCTIC AND NEARARCTIC LAKES
Source: Seather, 1979
D-l
-------
APPENDIX 0
Key to chlronomld associations of the p refund*! zones of PaTaearctlc and
Nearctlc lakes
In the key "absent" Mans less than 11 as accidental occurrence My take
place, "present" Mans wore than II. The Halt of 21 Is regarded as the
level above which the species can be regarded as a perslstant non-
accidental member of the community, while the 5% limit Is a level above
which the species can be said to be a common member of the community.
These If alts should of course not be regarded rigidly if the samples are
few.
1. PseudodlaMsa and/or Ollverla trlcornls present ...... u -oil gotrophlc
The above absent ......................... 2
2. Hetcrotrlssocladlus. Protanypus. Mlcropscctra or ParacladopelM
present and making up at least 2% of the profundal chlronomlds .....
oil go- Msotrophlc lakes ................. 3
The above absent or making up less than 2% of the profundal chlrono-
•Ids ....... eu trophic lakes ...... 10
3. Heterotrlssocladlus subpllosus - group present, tribe Chlronomlnl
absent from the true profundal zone - ............. ..*..£ -ol 1 gotrophlc
H. subpllosus group present or absent,
Tribe Chlronomlnl present ................ 4
4. Heterotrlssocladlus subpllosus group, Protanypus caudatus group,
Mlcropsectra groe'nTandlca or Paracladlus spp. present and making up
•ore than 5% of the profundal chlronomlds 5
The above absent or Mklng up less than 51
of the profundal chlronomlds ............. 7
5. Protanypus caudatus group or Paracladlus usually present, Chlronomus
absent. Phaenopsectra (Including Screen t1 a) and St1ctoch1ronomus at
most present In very low numbers (<2I) ... ...... ..... y -oil gotrophlc
When Protanypus caudatus group or Paracladlus present, Chlronomus.
Phaenopsectra or"Stlctoch1ronomus present in 1 ow numbers
. ...... ............................. 6
6. Heterotrl ssocl adlus subpllosus group plus H. maeaerl group more common
than H. Mrcldus group; Chlronomus ~~
making up less than 21 ............................... a -oil gotrophlc
Heterotrl ssocladlus subpllosus group plus H_. maeaerl gnoup absent or
less common than H. Mrc1dus""group; Chlronomus usually makes up more
than 2% .............................................. « -ollgotrophlc
7. Heterotrlssocladlus, Paracladopelma nlgrltula. P. galaptera. Mlcro-
psectra notescens group. MonodlamesaTube;:cuTatT. Macropelopla
fehimannt and/or TanytarsUTTiathophllus common (>5D {• -ollgotroph
The above at most present In
very 1 ow numbers ......................... 8
0-2
-------
8. Mlcropstctra and/or Monodlaaesa comaon, wore or about as coaaon as
Stlctochlronoaus and phaenopsectra. or Chlronoaus except saHnarlus or
sealreductus types ir -aesotrophlc
Hkropsectra and/or Monodlaaesa less coaaon than StlctocMronoaus and
Phaenopsectra or SDP. of Chlronomus except sallnarlus or senlreHuctus
types .. "9
9. Monodlaaesa, Protanypus. Htterotrlssoclad1 us. StlctocMronoaus.
pTTenopsectra or Chiro"no«us sallnarlus and seaTreductus types aore
cooMon tharTother Chironomus spp 9 -aesotropMc
The above less common than other Chlronoous <• -«esotrophic
10. Heterotrlssocladlus. Protanypus. Mlcrppsectra, Paracladopelaa
nlgrltula or P. gaTaptera present In low nmabers *-eutroph1c
The above abs?nt 11
11. No ch1rono«1ds present »-eutroph1c
Ch1rono«1ds present 12
12. Only Chlronoaus pluaosus type and Tanypodlnae present £ -eutrophic
Other chlronomlds also present TJ
13. Only Chlronoaus and subfaa. Tanypodlnae present *-«utroph1c
Other groups also present 14
14. Oflly.tribe Chlronoalnl, Tanytarsus spp. and subfaa. Tanypodlnae
present M -eutrophic
Other groups also present X-eutroph1c.
0-3
-------
TABLE D-l
rwftflACTERISTIC PRtF'^l CHIRONIMIDS IN NEARARCTIC(-—^.
S?KARCTicl ) LAKES. FULLY DRAWN LINES AND FILLED CIRCLES:
DISTRIBUTION UNDER GOOD TO EXCELLENT CONDITIONS. BROKEN LINES AND
MT? !£xiMUM RANGEOR SINGLE FINDINGS. A: IN EUROPE, ALPINE.
B: IN EUROPE, BOREAL.
SPECIES
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Joh
(Subl )
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tafuHchicola tip.
ttnvittylvl Br«nd.
Salh.
0-4
-------
TABLE D-2
CHARACTERISTIC SUBLITTORAL AND LITTORAL CHIRQNOMID HABITATS IN
NEARACRTIC AND PALEARCTIC tttES,
ff
OV.IOOWUWIC
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11
1
D-5
-------
TABLE D-2
CHARACTERISTIC SUBLITTORAL AND LITTORAL CHIRONOMIDS OF HABITATS IN
NEARACRTIC AND PALEARCTIC LAKES (Continued)
SPECIES
XlOONUMIC
(Wf«
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(Joh)
Cr>C9t90
------- |