MTTS
PB95-201778 Information is ot* butlness
GUIDANCE FOR EVALUATING THE ADVERSE IMPACT
OF COOLING WATER INTAKE STRUCTURES ON THE
AQUATIC ENVIRONMENT: SECTION 316(B)
P.L. 92-500
(U.S.) ENVIRONMENTAL PROTECTION AGENCY, WASHINGTON, DC
1 MAY 77
U.S. DEPARTMENT OF COMMERCE
National Technical Information Service
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bibliographic incokmaiion
. U / J* /. lJ I ' / u
Report Mos
T)t1o Guidance for [va bating the Adverse impact oT¦ Coo 11ng Water intake Strucuires
on the Aquatic environment Section 316(b) I5 L 92-500
Date' 1 May 77
Per f onn i ng Qrga n i za 11 on ¦ [nv i roniiieni.a 1 Protect ion Agency V'a shir iy ton DC Of fire of
Water Let or cement ana Compliance
lypo o!" Report and Period Covered Draft root.
Mi iS ie lei/ Group Cocies. 680 (Water Pollution ?. Control) 9 / i (Clectnc Power
Production). y/fTTFriv i fonniontaStudies). b7Z (Zoology)
Price: PC AO'I/Ml AO I
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VA_/?lT,r""'-
MuihIk.t of Pages Cflp
Keywords 'Cooling water "Intake systems. 'Aquatic environments. Power plant's
¦''•(in,!!, if. ,im nun Is [ nv i romneritr] I impact", !"nt ra inment. Fouling Horl.aliiy Ccreens
I ishes [.nv I roniiierit. i i monitoring, Wafer po I 1111.1 (jr 1 sampling
tract I ho guidance manual describes i ho studios needed i.u evaluate the impdct of
cooling water intake structures or i iho aquatic environment and ¦iMow for do term i ria i. i or i
of the best technology nvailablo for minimizing adverse env i roirnonta I uiiuaci
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REPORT DOCUMENTATION PAGE
Form Approved
OMB No 0704-0188 t
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2 REPORT DATE 3 REPORT TYPE AND DATES C0VERED
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1J ABSTRACT (\1ri'inujrn ?00 words)
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iJSN /5'10 0 i 'HO SSOO St.md.ird Fcm 9H (Rev ,>-89)
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GUIDANCE
FOR EVALUATING THE
AO VERSE IMPACT OF COOLING WATER
32TTAKLE STRUCTURES OH THE AQUATIC- ENVIRONMENT:
SECTION- 316(b) P.L. 92-500
U.S. Environmental Protection Agancy
Office of Water Enforcement
Permits Division
Industrial Permits Branch
Washington,. D.C.
May 1. 1977
RCRODUCtD RY MTB
U ft 0*piftm»rU ol Comrn^rci ~ "
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TABLE OF CONTENTS
Page
r-
Statement of Problea
L
n-
Introduction
4.
hi.
Information. Flow Chart.
6.
IV.
Decision Criteria
LL
V.
Definition* and. Concepts
L5
71.
3tod7 Format
22
VII.
D«tai_Led Study Reference*
25
vrir.
Site Description
1. Sit* location and layout
2. Meteorology
3. Additional, •tresaoft era. vacar body oegmanc
4. Cooling- water intake etructurc.-
26
u.
Sourca Water Iovolveaent
1. Hydraulic faaturoa
2. Probability of entralnaant
29
i.
Biological Surrey laquiraaant* - HEW INTAKES
1. Saapling dao Ign
2. Saapling nathodology
3. Follow-up studiee
33
IT.
Monitoring Program - EXIST ISC IBTAJ2S
I. Saapling prograa — Entrapaent-Iapingement
Zm- Saapling prograa — Entrainaant
. Follow—op studies
39
nr.
Iapoct Asaoaonont
45
I- Bioatat-Jtical analyses
Z. Predictive biological nodal©
3. Coeaaunity reaponaa paraaatars
4. Biologic*-! raloa concept
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-L-
LIST OF FIGimZS
Mo. figure
Paste
L 3L60>) no* Chart 7
Existing Incaltcg
2 116 0>) Flow- Chart 8
Source- Intak.es
J 316(b) Flow Chart 9-
Htw Tncakag (Not Mev Source)
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-ii-
LIST OF TABLES
Tabla
Exaapl* Data Matrix
(Sp«ci«s I) Data. She«c
(Spetial Cowpartaeut [A])
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1-
I. STATEMENT 0? THE PROBLEM
The Federal Water Pollution Concrol Act Aaendaents of 1972
(Public Law 92-500) require cooling water Intake structures to
reflect the- best technology available Cor ainiaizing adverse
environmental, iapact.
Cooling water Intakes can adversely Iapact aquatic organisms
basically In two ways.. The first Is entralnaent, which Is the caking
Irr of organlsas with the cooling water* The organisms involved are
generally of mall six** dependent on the screen afcsh size, and.
include, phyto— and* zooplankton » fish eggs and Larvae, shellfish
larvae, and aany other forme- of aquatic life- As these entrained
organlaaa pes* through the plant they are subjected to numerous
source* of daaage. These Include eechanlcal daaage due to physically
coocacting internal surfaces of puape, pipes and condensers;, pressure
dasiage due to passage through puapa; shear daaage due to complex
wecer flows; thermal daaage due to elevated teaperaturbs in condenser
pasoago; and toxicity damage caused by the addition of biocldes to
prevent condenser foaling and other corrosives. Those organisms
which survive plane passage potentially could experience delayed
mortality when returned to th« receiving, water*
The second way in which intakes adversely lapacc aquatic life
Is through en trapaent-laplngeaent. This is the blocking of Larjrar
entrained organises that enter the cooling water intake by soara
type of physical barrier- Most electric generating plants have
screening equipaent (usually 3/8** eesh) installed in the cooling
water flow to protect dovnstreaa equipaent such as pumps and
condensars froa daaage or clogging. Larger orgaalsas, such as
fish which enter Che systas and cspnot pass through the screens,
are trapped ahead of thea. Eventually^ if a fish cannot escape
or Is not reaoved, it will tire and becooe laplnged on the screens.
If laplngeaent continues for a long tlae period the fish may
suffocate because the water current prevents gill covers froo
opening. If the fish is laplnged for a short period and removed,
1c aay survive; however,, it aay lose its protective sliae and/or
scales through contact with screen surfaces or froa the high
preasuro- tester Jets designed to remove debris froo the screens.
Delayed aortality to aany species of fish following laplngeaent
say approach 100 percent* For soae species of fish, the intake
represents, a doable- joopsrdy situation where the saae population
will b« cnbject to increased acrtality through encrainment of eggs
and. larva* and additional arctality to Juveniles and adults through
laplngeaent.
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The data presently available on Che aagnltude of encrainaent
losses. at existing electric generating' stations, although Just beginning
to aceuaulstc, reveals very large numbers of fish passing through some
facilities* Results of one of these studies, conducted at the Detroit
Edison plane, on Ijke Erie- near Monroe, Michigan, Indicate that 400-800
ailllon fish |^rva« may have passed through that plane during April—
August 19 74-. The face of these larvae has not yet been determined,,
but the daca froa previous years Indicate that some may have disinte-
grated during passage through the plant.
Other studies have shown that mortality nag t^g hlgn among fish
larvae that pass through plant cooling^s^stems * due aainly to
aechanical damage or shearing forces. ' The circulating pump^h^s
bean identified a^the aoac likely site for mechanical damage. '
Coutant and KedL in a simulation study have demonstrated that the
condenser tubes are- an unlikely site for mechanical damage to occur.
k large mount of data are available on the magnitude of
entrapaent-impingement losses at cooling water Intakes. The data
available on fish losses at^jreat Lakes cooling water Intakes have
been euaaarlxed by Edsail. He reported the following losses:
Abouc 92,000 pounds of gizzard shad at the
Ontario Hydro Lsabton plant on the St. Clair
River in 6 weeks during December 1971 -
January 1972; 82,187 pounds (nearly 1.1 million
individuals) at the Detroit Ediaon Company's
plant on Lake Erie near Monroe, Michigan between
April 1972 and March 1973, when the plant was
operating at lass than maximum capacity; 36,631
pounds (384,687 fish) at the Consumers Power
Company'® Palisades plant on Lake Michigan
between July 1972 and June 1973,. when the plant
mis operating at about 68 percent of its total
capacity (the plant is nc«# closed cycle); an
estimated 1.2 ailllon fish (no weight data given)
at. Commonwealth Edison's Waukagen (Illinois)
plant on Lake Michigan between Jure 1972 and
June 1973; 150,000 pounds of fish at the Ontario
Hydro Pickering plant on Lake Ontario in April-
June 1973; 659,000 fish (weight unavailable} it
the Mine Mile Point plant generating unit .Tutiber
one on Lake Ontario during intermittjnt sampling
fro* January-December 1973, representing an
estimated total of about 5 million fish at unit
one for thsC period; and about 67,950 pounds
(929,000 fish) at Cooaonwealth Edison's Zion
plant near Zion, Illinois, on Lake Michigan.
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during September-December 1973 and March-June 197*,
when the monthly cooling water flow averaged only
about 45 percent of the maximum capacity.
Approxiaataly 14,000 fish of 44 species vere impinged in 1974.
at the- Northern States Power Prairie Island Plant on the Mississippi
River. The Commonwealth Edison Company's Quad Cities Plant,
aLao on rhe Miaaiasippi Silver, impinged an estimated 1.8 million
fish during 1974.
The extent of flak losses- of any given quantity n^'-^a to be
considered, on a plant-by-plant basis, in that cha- language of section
316(b) of P.L. 92-500 requires cooLing water intakes to "minimize
adverse environmental impact." Regulatory agencies should clearly
recognize that some level of intalca damage can be acceptable If chac
damage represents a minimization of environmental impact.
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II. INTRODUCTION
This guidance manual describes the studies needed co evaluate the
Impact. of cooling water intake structures on the aquatic environment
and. allow for determination of the best technology available for
minimizing adverse envirotnaental impact. The 1972 amendments to the
Federal Water Pollution ControL Act (P.L. 92-500) require in section
316(b) that:
Any standard established pursuant to section 301
or ••ction 306 of this Act and applicable to a
point source shall require that the location, design,
construction and capacity of cooling water intake
structures reflect the best technology available
for: minimizing adverse environmental impact.
Sections 301 and 306 of the Act refer to the development of effluent
limitation!! and dates for achievement of various standards of performance
for existing and nev sources of waste discharges. The steam-electric
generating point source category is che largest user of cooliag vacer
in the United States and this guidance manual La direcced primarily- at
this category. Other categories of point source dischargers such as- Iron
and oteel and petrochemicals for which intakes withdraw a major portion for
cooling water would also require such a determination. This document 1.3
intended foe use by the U".S. Environmental Protection Agency (EPA), Scace
water pollution control agencies, industry, and nembers of the public who
may wish to participate In such determinations_
The overall goal of conducting intake 9tudies should be to obtain
sufficient information on environmental impact to aid in determining
whether the technology selected by the company is the best available co
minimize adverse environmental impact. In the case of existing planes,
thirf goal will be accomplished by providing, reliable quantitative estimates
of the damage that is or «ay be- occurring and projecting che long-range
effect of such damage to the extent reasonably possible. In the case of
proposed intakes, reliable estimates of any future damage are to be
obtained through Che use of historical data, pre-operaclonal models, and
the operating experience of other plants.
General. guidance is provided for the development, conduct, and review
of surveys designed to determine and evaluate that portion of aquatic
biota potentially Involved with and subject to adverse environmental
impact froa cooling water Intake structures. Guidance is also
supplied for the analytical methodology needed to determine the extent
and importance of aquatic- environmental impacts. The «nvlronment-intake
Interaction*- in question are highly site- specific and the decision as
to beet technology available for intake design, location, construction,
and capacity must be nade on a case-by-caae basla.
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Information is not provided on available intake technology. Such
iafonaacion is contained la the "Development Document for 3est Technology
Available for the location, Denign, Construction and Capacity of Cooling
U«t«r Intake Structures fur Minimizing Adverse Enviromnencal Impact
which also contains additional references on Intake . impacts , Information
la. also qoc provided on aoo-squedc impacts of cooling water intake
atruc turce.
Thi» dociaaent will be eosc useful in situations where 3iting and
Intekst design !-»: aot been flaellxed; however, procedures to determine
and evalustt the environmental iapacr. of existing cooling water intakes
are incladed .
Seeders are cautioned not to depend coo heavily on chir aanual.
Hore specific advice as regards procedures and individual sice evaluation
will be available from the agency ataff responsible for decision asking
and cha biologists who boat underacand the are*. In question.
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III. INFORMATION FLOW CHAAT
The development of 316(b) programs i» a new procedure foe many regu—
la Cory agencies and. user groups. To assist In an orderly processing of
data requirements for both existing and new cooling water intakes. flow
charts have been developed (Figures lr 2, and 3) .
Tfce- procesa for evaluating existing. Intakes (Figure 1) is Intended,
to be flexible so that the data requirements can be revised based on an
agency determination of the potential for adverse Impact and the availa-
bility of data on the plant's intake. It la expected that for some
existing plants* sufficient data may already exist to make further studies
unnecessary for a decision regarding best technology available. The
process for nev intakes (Figures 2 and 3) is more extensive because of
requirements for data acquisition and models prior to 9ite review and
approval by the appropriate regulatory agency. Proper Intake siting, in
many cases, is the only way of minimizing adverse environmental Impact.
To obtain the neceiaary pre-siting perspective, the utilization of valid
historical data and local knowledge is essential. A one- to three-year
biological survey Is required, to obtain, in a preliminary fashion, the
necessary data, for assessment of environmental impact. A one-year survey
is generally of limited, value. However, la circumstances where substan-
tial valid historical data can be presented and. the intake can be
represented as having lov potential impact, a one—year survey may be
acceptable. A decision as to the appropriate number of years of pre-
operational data that are necessary will be made by the agency upon Che
submission of proposed study plans and their juatification (see flow
charts,. "Figures 2. and 3).
The type and. extent of biological data appropriate in each ca3e
will be determined by the actual or anticipated severity or adverse
environmental impact. Since the expected impact will vary, it Is not
expected that each case will require the same level of study.
A. decision will be made at the outset by the agency a3 to whether
the intake has high or low potential impact. Low potential Impact
Intakes are generally those in which the volume of water withdrawn
comprlaes a snail percentage of Che source vacer body segment and
are located in biologically unproductive areas, or that have historical
data shoving no effect, or which have other considerations Indicating
reduced impact.. High potential impact intakes will generally require
extensive field surveys or tnodela to elucidate potential total water
body effects. New intakes will provisionally ba considered high
impact until data la presented in support of an alternate finding.
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Figure 1. 316(b) FLOW CHART
EXISTING INTAKES
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Pigure 2. 316(b) FLOW CHART
NEW SOURCE INTAKES
Sew Source Intake Prior to Construction "j
Submit pre—construction study plana and juatificacicrn for
agency review and recognition
Dociaioa rade or Appropriate number of years of pre—conatruction
baaaline data (1—3) and whether intake is high or lov potential
impact
Hi$h Iapace
Low Impact
Submit
model
study plan
or alternate
strategy
Model
activity
Pre-conatruction data collection
and status reports
Pre-cana truetion report ^
Agency renders preliminary Best
Technology Decision, approving
aito and plana
Approval
I
Not
Approved
Begin conntraction
Problem solution
> Report prc-operatlon
I
Program modification
z
Tea
No
—i
Best Technology approval, begin
operation under NPDES permit and
follow-up studies including
verification of models used
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Figure 3. 316(b) FLOW CHART
NEW ".NTAXES (Noc New Source)
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Th* inclusion of several poind in the flov chart for agency review
and approval will ansure chac all parties are in agreement aa co Che
scope: and specific details at vork plaan« This unifor* data base vlll allow for easier evaluation of any
subooquant emulative effect fron all intakes operating on a water body.
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IV. DECISION CRITERIA
Adverse aquatic environmental impacts occur whenever there will be
entrainment or impingement damage as a result of the operation of a
specific cooling vacer intake structure. The critical question ls-the
magnitude of any adverse impact, The exact point at which adverse aquatic
impact occura at any given plant site or water bddy segment is highly
speculative and can only be estimated on a. caae-by-case basis by considering
the apeclea involved, magnitude of the losses, years of intake operation
remaining, ability to reduce Losses, etc. Yhe best guidance that can be
provided to agencies in thia regard would be to involve professional
resource people in the decision—making process- and tc obtain the best
possible quantitative data, base and assessment tools for evaluation of such
impacts. The- Development Document for 316(b)^ la an essential reference
for guidance in these evaluations-
Some general guidance concerning the extent of adverse impacts can
be obtained by aasesaing the relative biological value of the source
water body zone of influence for selected species and determining the
potential for damage by the intake structure. For a given species, the
value of an area la baaed, on the following considerations;
1. principal spawning (breeding) ground;
2. migratory pathways;
3. nursery or feeding areas;
4. ambers of Individuals present; and
5. other functions critical during the life history.
A. once-through system for a power plant utilizes substantially more
water frora the source water body than a closed recirculating system for
a similar plant and thus would tend to have a higher potential impact.
A, biologies 1 value-potential impact decision natrlx for best intake
technology available could be:
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| qOOLINC WATER FLOW
I (Relative to Source Water Body Segment)
1
BIOLOGICAL
VALtn:
1 I
I HIGH. |
1 1
LOW
1
I
I
ttigfc
L " 1
I So [
1 1
Questionable
1
1
r
Low
1 1
1 Questionable |
1 1
Tea
(L) An open ayet a* large volua* Intake In an area of high biological
value does not rapraaant beat technology available to minimize
advarae anyironmcntal lnpact and will generally result In
disapproval.
Exceptions to this nay be deaonstrated on a caae-by-case baaia
where* despite high biological value and high cooling water
Clow* involvement of the- blocs 1s low or survival at thoaa
Involved, is high, end subsequent reduction of populations is
¦lalMl.
(Z) Generally,, tho combination- of low value and Lov flov most
likely la « reflection of best technology available- in location,
design, and operation of the intake structure. Exceptions to
this could Involve significantly affected rare and endangered
species.
(3) Other coeiblnatloas of relative vslua—lopact present the moat
difficult problems. In such clrcunstances, the biological
survey and data analysis requires the greatest care and
lnalghc in accoapliahlng the ixpact evaluation upon which Che
i^t-«ant of beat technology available la baaed. K caae-by-
case- s^udy la required and local knowledge and informed
Judgment are essential.
It iff accepted that cloead cycle cooling is not necessarily the best
technology available, despite the draaatlc reduction in rates of water
used. The spproprlate technology is best determined after a careful
evaluation of the specific sspecta at each site. A detailed discussion
of available intake technology la contained in tha 316(b) Development
Docuaant. '
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Biological survey requirements suggested in this manual should
provide a sufficient data. base to provide insight as to the best
location, design, construction, and capacity characteristics appro-
priate for achieving minimal Local impact-
47
A stepwis* thought process is recommended for cases- where
adverse environmental lapact from entrapment/impingement is occurring
and must be minimized by application of best, technology availabLe:
The first step should be to consider whether the adverse
impact will be minimized by the modification of the existing
screening ay a tea*.
The second step should be to consider whether the adverse
impacc will be minimized by increasing the size of the Intake to
decrease high approach velocities.
The third step should be to consider whether to abandon the
existing intake and to replace it with a new intake at a different
location and to incorporate an appropriate design in order to
minimize adverse environmental impact.
Finally, if the above technologies would not minimize adverse
environmental impact, consideration should be given to the
reduction of intake capacity which may necessitate instal-
lation of a closed cycle cooling system with appropriate design
modifications as necessary.
Where environmental impact froor entrainment oujt be minimizec,
reliance must be placed primarily on flow reduction and intake
relocation as remedial measures:
Reducing cooling water flow is generally an effective means
for minimizing potential entrainment impact. la fact, this may be
the only feasible means to reduce impact of entrainment where po-
tentially involved organisms are in relatively large concentration
and uniformly distributed in the water column. Entrapment and
impingement may elso be lessened with lover flow as proportionally
fewar animals will be subject to contact with the Intake structure;
water velocities associated with the structure can be reduced,
enhancing probability of survival if impinged or of escape if
trapped- Reduction of flow is accomplished primarily by an
increase in condenser temperature rise or through recirculating
cooling systems. When cooling water flow is reduced, however,
elevated temperature or the effects of an auxiliary cooling system
can increase the mortality rate of the organisms that are entrained.
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Slte location measures may prove effective In areas of
discontinuous, temporal or spatial occurrence (patchiness)
of those- species, subject to entralnaent (or entrapment/
laplngeoent).
Enhancing survival of organlsns once- entrained In the cooling
water system generally appears to b«~the least effective means for
avoiding advars* impact; however, operational regime* have been
developed, to decraaae mortality of entrained species where heat,
chlorine or both exert the predominant impact. Realistic Laboratory
studies can lead to optlsLsl tine-temperature regimes for survival.
The effects of blocldea can b« reduced by intermittent and "split: —
str»4a" chlorination procedures. Mechanical methods for cleaning
cooling systen component:* whore feasible can eliminate or reduce
th» need for blocides. The mechanical stresa of entrainment La, in
many cases, the critical factor in organism survival with the pump
tha alee of major damage. At present, little can be done to
ninimiro ©ochtnlcal impact although potentially harmful effaces
may possibly ba reduced by punp redesign which incorporates lov
RPM, lov pressure and vide clearance characteristics. Reducing
velocity changes, pressure, and turbulence in the piping system
should prove helpful. Encrainaent screening techniques auch as
leaky da»» may have application In soma clrcumstanceo. Regardless
of beneficial measures taken, many fragile forma will not survive
entrainment.
In ounraary, tha location of a powor plane, or ocher cooling vscer
use, coupled with the associated intake structure design, construction,
and capacity results in a unique situation. While generalities nay be
useful, the opciaal combination of measures effectively Minimizing
adverse impact oa th» biota is site and plant specific. The best
technology available should b« established on a case-by-case basis
naklag full use of the kinds of information suggested for acquisition
in this manual.
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V. DEFINITIONS AND CONCEPTS
Adverse Environmental Impact
Adverse aquatic environmental iapacta occur whenever there will be
entrainmant or impingement damage as- a result o£ the operation of a
specific cooling water intake structure. The critical question is the
magnitude o£ any adverse impact.
The magnitude of in adverse impact should be estimated both in terms
of abort term and long term iapact with reference to the following factors:
(1) Absoluts damage (# of fish impinged or percentage of
larvae entrained on a monthly or yearly basis);
(2) Percentage damage (I of fish or larvae in existing
populations which will be impinged or entrained,
respectively) ;
(3) Absolute snd percentage damage to any endangered species;
(4) Absolute and percentage damage to any critical aquatic
organism;
(5) Absolute and percentage damage to commercially valuable
ard/or sport fisheries yield; or
(6) Whether the iapact would endanger (Jeopardize) the
protection and propagation of a balanced population of
shellfish and fish in and on lua body of water from which
the cooling water is withdrawn (long term iapact) .
Agency
This term refers to the Regional Administrator of the U.S.
Environmental Protection Agency or the Directors of those State
agencies authorized to issue NPDES permits.
CoBwunitr
A. coasaunity in general is any assemblage of populations living l.i a
prescribed area or physlcsL habitat; it is an organized unit to the extent
that it has rharacteristics in addition to its individual and population
components and functions as a unit through interacting metabolic trans-
formations.
Critical Aquatic Organisms
Adverse environmental impact may be felt by many species in all trophic
levels. A species need not be directly affected but nevertheless harmed
due to loss of food organisms 0/ other associated organisms In some way
necessary for the well-being and continued survival of the population.
It is not practicable to study all species that may be directly or
indirectly harmed by intake structure operations.
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The critical aquatic organisms concept is defined in the 316(b)
Development Document.4^ Cmerally, 5 to 15 critical aquatic organisms
will be selected for consideration on a case-by-case hasis. Relative
to envirrnmental impact associated with intake structures, effects
o-.t tea roplaaktotr organiams , nacroinvertebratea, and Juvenile and adult
fishes appear to be the first order problem. Accordingly, the selections
of species should include a relatively large proportion of organisms in
these categories that are directly impacted. Generally, because of
short life spaa and population regeneration capacity, the adverse Lmpac.
on phytoplankton and zooplankton species is less severe. It is suggesced
that* in addition to study of the selected, species, the total phytoplankton
and znoplanktoa communities be assessed to determine if the area under
stiviy la unique and important qualitatively or quantitatively. If
preliminary sampling or prior data does not support special or unique
-»aluo of these organisms at the site, phytoplankton and zooplankton
species trill generally not be selected.
The following guidelines are presented for selection of critical
aquatic orgauiams for consideration in Intake studies:
A, Critical aquatic organisms to be selected are chose species
which would be involved with the intake structure and are:
1. representative, in tarns of chelr biological
requirements, of a balanced, Indigenous community
of fish,, shellfish, and wildlife;
2. commercially or recreatlonally valuable (e.g.,
among the top ten species landed — by dollar
~slue)i
3. threatened or endangered;
4. critical to the structure and function of the
ecolojglcal system (e.g., habitat formers);
3» potentially capable of becoming localized
"noissnce species;
fr. necessary, in the food chain, for the well-being
of species determined in 1-4;
7. one of 1-6 and have high potential susceptibility
to entrapment-impingement and/or entralnment; and
8-' critical aquatic organisms baaed on 1-7, are
suggested by the applicant, and are approved by
the appropriate regulatory agencies.
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Ajsauoptiona in the selection o£ critical aquatic organisms:
L,. iiac* til species which are critical~ representa-
civ»r etc.* cannot. be studied, in detail,- some
aaaller nuaber (e.g., 5 to L5) may have to be
••lacted,
£» The species of concern are- those aoat lllcely to
b« affected, by lncaite structure, deaign,. con-
st ruction r and operation„
3. Som species vlll be economically important in
their own right,, e.g.* cooaerclal and sports
fishes.
4. Some of the species selected vlll be particularly
vulnerable or sensitive to intake structure impacts
or hove sensitivities of aott other species and,
if protected,. vlll reasonably aaaure protection
of other species at the site.
5. Often* but not alvays, the aoet useful list would
Include eostly sensitive fish* shellfish, or other
species of direct use to nan, or to the structure or
functioning of the ecosystea..
6- Officially listed "threatened or endangered
species'* are autooatically considered "critical."
7". The species chooen nay or nay not be the sase as
those appropriate for a 316(a) determination
dependent cm the relative effects of the theraal
discharge-or the Intake in question.
Cooling Water Intake Structure
The- cooling vater Intake structure is the total structure used to
direct utter into the coaponents of the cooling systems wherein the
cooling function is designated to take place, provided that the intended
uba of the aajor portion of the water so directed la to absorb waste
heat rejected. fro« the process or processes eaployed or froo auxiliary
operations on the prealses, including air conditioning.
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-18-
Entrainmant
The- incorporation of organisms into the cooling water flow ia
entrainswnt ~ There are two generally recognized types' of entrairunent:
pumped entralnmeot referring to those organisms that enter the Intake
and are piaped through the condenser,. and plume entrainnent — referring
to organisms that are incorporated into the discharge plume by the
dilation water- Plume entrainment is not covered by section 316(b) but
1* pert at the thermal discharge effect to be considered in conjunction
vlch- thermal effects demonstrations under section 316(a) .
Entrapment-Impingement
The physical blocking of larger organisms by a barrier, generally
sostk type of screen syi '.em in tha cooling water intake. Entrapment
emphasizes the prevention of eecspe of organisms and impingement
emphasizes Che collision of sn organism with a portion of the
structure.
gstuarr
An estuary La defined se a semi-enclosed coastal body of water which
tiaa a free connection with tho open son; it Is thus strongly affected by
tidal action and within ic see water is nixed (and ususlly measurably
diluted) with fresh water from land drainage. It «ay be difficult to
precisely delineate the boundary of estuarlne and river habitats in che
upper reaches of a fresh wmter river discharging into aarlne waters.
The interface is generally a dynamic entity varying dally and seasonally
in geographical location. In ouch cases, determination of habitat
boundaries ahould be established by autual agroement on a case-by-caae
basis. Uhare boundary determination, is not clearly established, both
estuary and river habitat biological survey requirements should be
satisfied In a combined determination for environmental effects and best
available technology for minimizing adverse impact.
Habitat Formers
Habitat formers are plants and/or animals characterized by a
relatively sessile life state with aggregated distribution and functioning
as:
1. & live snd/or lormeriy living substrate for the attach-
ment. of epibiota;
2. either e direct or indirect food source for the production
of shellfish, fish, and wildlife;
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3. a biological mechanism for the stabilization and modifi-
cation of sediments and contributing to processes of
soil buildings;
a nutrient cycling path or trap; or
5. specific sites for spawning, and providing nursery,
feeding, and cover areas for fish and shellfish.
High Potential Impact Intakes
High potential iapact intakes are those located in 'biologically
productive ar*as or where the vo.luae of water withdrawn comprises a
large proportion of the source wacer body segment or for which histor-
ical data or other considerations indicate a broad impact.
Imp ingenent
See Entrapment-lapingement.
Lake
Any naturally occurring large volume of standing water occupying a
distinct basin ard, for purposes of this document, reservoirs ana
impoundments.
Low Potential Iapact Intakes
Low potential iapact intakes are those located in biologically
unproductive areas and having lov flow or having historical data showing
no effect or for which other considerations indicate low impact. Plants
with low capacity factors or with few remaining years o* lifetime slight
be considered "low iapact" despite their historical impact.
Macroinvertebrates
. For the purposes of this docuaent, the tera aacroinvertebrates
may be considered synonyvoua with "aquatic aacroirrvertebrates" and
are those invertebrates that are large enough to be seen by the
unaided eye and can be retained by a U.S. Standard No, 30 sieve
(0.595 am. nash opening).
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-20-
Meroplankton
Foe the purposes oi this document, meroplankton are defined as
planktonic life atagea (often e?".gs or Larvae) of fish or invertebrates.
Oceana
The ocean habitat,, for the purposes of this annual, is considered
mariae watera other Chan those water bodies claaaified aa estuaries. This
include® open coastal areas, eabayments, fjords,. and ocher semi-enclosed
bodies of water open to the aea and not taeasurably diluted with fresh
water from land drainage.
Two principal zones within the oceanic habitat potentially impacted
are: (1) littoral tone — from high tide level lo lov tide Level, and
(2) oaritic zona (near shore) — low tide level to the edge of the
continental eheli.
Phytoplankton
Phytoplankton are the free-floating plants, usually microscopic
algae- that photoaynthetically fix inorganic carbon and are, therefore,
primary producers in iom aquatic environments.
Plankton
Plankton are essentially Microscopic organisms, plant or animal,
suspended in uater which exhibit near neutral buoyancy. Because of
their physical characteristics or size, most plankton organisms are
incapable of suotainad. nobility in directions against rater flow. Con-
sequently, plankton drift mora or less passively in prevailing currents.
Population
A papulaeion is generally considered to be cooprissd of individuals
of the sow species in a geographic area. Populations exhibit parameters
such as mortality, natality, fecundity, intrinsic rata of increase,
density, etc.
Primary Study Area
Thi« Includes the segment of the water body determined to be the area
of potential damage. This concept is most pertinent to organisaa subject
to inner-plant passage, normally weakly aotlle or planktonic, and spatially
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-21-
subjecc co vacer body currents rather than possessing the ability co
change location independent of water mass movements. Animals capable of
Large scale movements, i.e.,. Migrant fishes, will move into this area
periodically.
Rivers and Streama
A river or stream is a naturally occurring body of running (surface)
water, with an unbroken, unidirectional flov, contained within a discrete
channel. Reservoirs and/or impoundments, for the purposes of chls document,
will generally be viewed as lakes.
Secondary Study Ax a a
The area within the vacer body segment outside the primary study
area. Biota in this area directly affected by the intake structure stay
or aay not be a significant coaponenc of the total population of indigenous
species. For many species, particularly pelagic fishes, th* total popula-
tion may be spread over a vide geographical area. This area could be
considered the secondary study area. However, other intake structures
associated with cooling vater uses, e.g., power plants, nay also be
impacting the population in th'.ae other areas. This iaay be considered
in two ways:
1. consider the total population throughout the geographical
range, estimate existing impacts, and determine to vhac
extent the specific intaka structure adversely impacts
that portion of the population not already adversely
stressed by sources outside the primary study area; or
2. consider only the. population in the area of potential
involvement and adjacent areas of occurreuce not
already impacted by an existing source of stress.
for example, vhan a number of intake structures are located within
a. water body such as the Hudson River, Ohio River, Long Island Sound,
Western. Bssin of Lake Erie, Ifarragansett Bay, San Francisco Bay, etc.,
either of the two approaches may be taken to assess the impact of the
structure under consideration. The total impact of all existing stresses
may be weighed against the toesl population of biota studies and th.e
adverse effects of the new stress added to existing stresses and assessed
against impact to the total system. The alternative is to assign a section
of the water body not already impacted by other intake structures and
compare th# segment of the conunlty in the sssigned area to the effect
of the single structure concerned.
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Thrtatdnsd or Endangered Species
A threatened or endangered species La any pLanc or animal chat has
been determined by Che Secretary of Commerce or the Secretary of the
Interior Co be a threatened or endangered species pursuant to the
Endangered Species Act of 1973,. as amended.
Water Body Segment
A Mater body segment la * port Ion of a basin, the surface waters of
which have coaon hydraulic characteristics (or flow regulation patterns)
caonoa natural physical, chemical, and biological processes, and which
have coaon reactions to external stress, e.g., discharge of pollutants.
Uhere they have been defined, the Meter body segments determined by che
State Continuing Planning Process under section 303(e) of P.L. 92-500
apply.
lone of Pocencial Involvement
The son* of potential involvement la considered the wacer mass
surrounding the Intake structure and likely to be drawn into the structure
itself or into che associated cooling water system. This varies with cine
and is dependent on ambient water movements In the affected body of source
wacer as modified by Che Influx of coolins water *c che Intake structure.
It will be difficult to preclaely define Che limits of this zone of
influence because of temporal and spatial variables. The zone of potential
Involvement always includes the primary study area and nay Include the
secondary study area.
2vx>plankton
True, zooplankton ara free-floating animals which have little or no
ability for horizontal movement. They ara thua carried passively along
with natural currents In the water body.
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-24-
Ic is the incencion of che F.PA to make Che cechnical information
suboicced by induscrles In accordance wich 316(b) available for use
by ocher induscrles, scienciscs, and members of che public. This viL L
be done Initially by placing copies in che responsible F.PA Regional
Office library. A similar approach is also suggested for Scace agencies.
In cases where demand for che demonstradon macerials exceeds che capa-
bility of an EPA or State agency library, Che EPA Regional Adm Inistracor
may also submit the materials to Che NTIS so that che reports are
available to the public In microfiche or hard copy form ac che price of
duplication. In che meantime, EPA is developing lists of pLants wich
completed 316(b) demonstrations and will submit che plane name and an
abscract of each scudy Co NTIS.
Ic is also noted chac che Atonic Industrial Forum has developed
1KF0RUW, a data system which will extract and index information f ron
reports submitted by utilities in accordance wich seccions 315(a) and
(b). Questions should be referred to INFORUM at 1747 Pennsylvania
Avenue, Washington, D.C. 20006, telephone 202-833-9234.
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VII. DETAILED STUDY REFERENCES
This document, of necessity. Is generalized to provide an overall
framework of guidance and conceptual approach. Six references are
recommended which treat various aspects of the study requirenents in .uore
specific detail:
1. U.S. Environmental Protection Agency, Office of Water
& Hazardous Materials, Water Planning Division,
September 30, 1974, Draft, 316(a) Technical Guidance
on Thermal Discharges. (Revised draft to be published
In 1976.)
2. U.S. Environmental Protection Agency, Office of Uater
& Hazardous Materials, Effluent Guidelines Division,
April 1976, Development Document for Beat Technology
available for the Location, Design, Construction ana
Capacity of Cooling Water Intake Structures tor Minimising
Adverse Environmental impact.
3. Batelle Laboratories, Inc., Environmental Impact Monitoring
of Nuclear Power Plants - Source Book. Atomic Indu3triaL
For\», Inc. August 1974. 810 p.
4. Aquatic Ecological Surveys. American Nuclear Society,
F.W. Hinsdale, Illinois, Drsft, October 1974.
5. Entralnment: Culde to steam electric pover plant cooling
system siting, design and operation for controlling damage
to aquatic organisms. Amer. Nuc. Std. Publ. N1H. - 19 74.
Draft, July 1» 1974, 44 p. and appendices.
6. Entrapment/Impingement: Culde to steam electric power
plant cooling system siting, design and operation for
controlling damage to aquatic organisms at water intake
structures. Amer. Nuc. Std. Publ. N18 - 1974. Draft,
September, 1974. 24 p. and appendix.
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-26-
VIII. SITE DESCRIPTION
The following Information is generally needed to fuliv describe :ne
potential experiences of organisms which may be encrapped within intake
structures, impinged on parts of the structure and/or entrained in the
water mass taken in and circulated through the associated cooling vater
system. It 1s necessary to describe the full range of resultant physical,
chemical, and biological parameters of these experiences which could be
encountered throughout the annual operation cycle. , Information on daily
and seasonal fluctuations is of special importance in those waters
subject to wide variation in water quality at the speciiic site. Other
data pertinent to the evaluation of environmental impact of the Location
or intake structure in question should be included even though not
specifically listed.
The following data are required for adequate description oi sites
located on either fresh or marine water bodies:
1. Site location and layout
A. Location of additional intake structures - Smaller scale,
map showing locations of intake structures, associated
cooling water systems, and other pertinent discharges
related to surrounding short and water features in a
50-alle radius.
B. Site Plan - Larger scale map with topographic and
hydrographic data depicting specific location of
structure in the water body. Data required Includes:
- Topographic details
- Hydrological features (sea U.S. Department of
Commerce, National Ocean Survey Charts, --tiere
available), Including depth contours
- Water body boundaries
-• Affected water body segment
- Location and description of other cooling water
intakes in water body segment
- Existing site with topographic and hydrological
features as changed by proposed intake structure
construction and operation (where applicable)
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2. letoroLofcy (when hydrodynamic modeling is performed)
Air cemperacure, maximum, ulnimun, n-mon t n 1 y
Rainfall, monthly
Solar radiation kcal/ra ^ /day (average/.nontn :or
the annual cycle)
Wind speed and direction, prevailing winds identi-
fied as co seasonal patterns
Other relevant site specific daca
3. Additional stresses on water body segment
Location of existing or planned poinc sources of
potential adverse environmental impact
Summary of Impacts associated with existing or
future stresses (and citations to more extensive
analyses, such as 316(a) demonstrations, impact
statements, NPDES permits, etc.)
4. Cooling water Intake structure
A. Structure
- Location with respect to cooling water system
Location In water body, horizoncaL and vertical
(Including sklnnaer vails)
Configuration, Including c;inals and channels;
detailed drawings
- Capacity
Screening devices (behavioral and physical)
Fish by-pass and handling facilities
Average and maximum approach and thru-screen
water velocities, by depth
Flow rates and frequency o: occurrence correlated
with load characterlscics
Location, amount, and duration of recirculation
water for deicing or tempering
- Other relevant system-specific daca
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-23-
3. Pumps
- Design details (location in structure, c on; ra c :cr.
of blades, and housing)
Revolutions per oinuce
Number, capacities, and planned operating schedule
Pressure regimes in water subjected to pumping
- Velocity shear stresses in pumping
Sites of potential turbulence and physical Impacts
C. Biocides
Location of introduction in system
Description and toxicity of biocide used
- rising and duration of use
Concentrations of biocide in various pares of
cooling water aysten and receiving waters
D. Thermal experience
- Tabulation of annual ambient temperatures,
thermal addition to cooling water of various
operating capacities, and resultant tlme-
teaperature experience of organisms subjecced
to entrainaent in cooling water system
E. Other relevant data on cooling water circulation system
- Dissolved gases
- Suspended solids and turbidity
- Other wastes and chemicals added
- Size of condenser Cubes, heat exchanger com-
pound, water piping, siphon pits, etc.
- Maintenance procedures, use of heat treatment
or delclng procedures
5. Plant Data
- Age and expected lifecine
- Capacity factor and percent of time a: fractional loads
- History of Intake model
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-29-
IX. SOURCE WATER INVOLVEMENT
The physical Interaction of the Intake and the adjacent water body
forms a base for assessment of bloLogical Impact by reLacing the behavior
and notion of local organisms with the flow of water around the sice and
into the Intake structure. To determine this involvement with the intake,
it is desirable to identify the type or types of circulation which will
be dominant in the water body, am. to esc.ablish a program of monitoring
currents and other relevant hydrological and physical parameters of the
system. Predictive tools, such ad computer models, are useful in
assessment of impact, and for delineation of the area of potential damage.
The approach outlined here is sug^jsted for new plants having high poten-
tial impact when sufficient model accuracy is obtainable. The approach
may be useful for other pLanta as well, as discussed in the irr.pacc assess-
ment section below. The modeling program should be discussed with the
agency in advance of application and should Include sensitivity analyses.
1. Hydraulic Features
The dominant modes of circulation in Che water body are
frequently identified in the literature and include channel
flow, tidal and wind-driven currents, estuary or gravitattonal
circulation, littoral drift, and others. The local currents
(or velocity structure) -in be modified by bathymetry and
transient atmospheric co .ditlons, and contain local features
such as eddies; their Importance can be modified by their
effect on biological pro:essea. tt is also useful to identify
Interface zones if several current regimes or physical pro-
cesses are evident. Larga water withdrawals and discharges
can be sufficient to modify exls-ting hydraulic patterns enough
to create new biological habitats.
A program of monitoring r'.e currents and other relevant
physical parameters Is desirable for the study of source
water involvement. Whenever possible, historical data should
be used to Identify the expected circulations and guide in
the selection of Instrument stations, although as data comes
la, a re-evaluation of t' • monitoring program is useful.
The relevant parameters are water current, speed and direction,
wind speed and direction, tides or local water levels, tem-
perature, and water dens.ty. Salinity data are important in
an estuarlne environment.
The spatial distribution of instrument stations is usually
indicated by the circulation regime and local bathymetry,
but la best organized to provide input to an<« verification
data suitable for a predictive hydraulic model of the
currents. Vertical spacing of instruments should be
sufficient to identify any important depth variation in
the circulation.
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-30-
The use of a hydraulic aodel requires several other specific
inputs to provide realistic prediction of currents Ln che
area. Typical parameters Include:
1.
boundary geometry;
2.
bottom topography;
3.
bottom friction coefficients;
4.
latitude of the area;
5.
tides or water levels at open boundaries;
6.
river flows;
7.
temperature and salinity;
8.
wind stress;
9.
power plant cooling water flow rates; and
10.
other point source flow races.
A significant period of time (two weeks) night be chosen for
a continuous (burst sampling) monitoring sequence to sense
periodic variations in the circulation, and another program
to sample changes on an annual (or longer) cycle. Careful
recording of placement and start tines is recommended.
The Instruments chosen should be durable and resistant to
fouling. The accuracy may be Influenced by the scale of che
parameters but for inter level should generally be at least
+ 0.01 ft. and, for current speed and direction, + .15 knots
and + 3.0 0 respectively. For temperature and sallnicy
+ 0.1 ° C 4n<* i ° /oo respectively can be expected.
Special lnstrinentation for water current sensing may be
necessary at threshold speeds.
An instrument calibration program is necessary to Insure
accuracy. Redundant marking of station locations and
provision for recovery of unmarked lnstnnents should be
nade.
Computer models as predictive tools represent the best
available predictive tools and are useful in assessing
water use and biological Impact. Mathematical models
solve the equations of water flow and are used to.
predict currents In the water body. Anncher model (of
water quality) can be developed ln tandem to solve the
equation of mass flow and used to predict mass or concen-
trations of organisms under Influence of che currents.
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-31-
The selection of Che appropriate model is guided by the circ-ia: -.on
regime and the geomorphology ot the water body. A nuciDer of
mathematical models of tidal flow are- available, and these can be
extended to include channel flow. For example, the Leendertse 3,
9_type square-grid models for tidal cujgents and larvae Transport
have been used. Finite-element models are being developed for
"tidal-circulation, and may have advantages in certaiy^areas.
For river-bay situations, the channel-junction model may have
special advantages. Three-dimensional models such as those
described in references 12,13, and 14 may be appropriate. A.
comprehensive summary of^vailable models has been compiled
by Cordon and Spaulding. The rationale for selection of the
particular set of models should be Justified by either emphasizing
their suitability or by demonstrating a lack of other sufficient
models.
Verification of model output should be made for both current
and organism concentrations. Data from the monitoring survey
are useful for verifying the current model while the biological
sampling program may be used to verify the motion of organisms.
Dye studies may alao be useful in model verification.
Means for delineating study area and source water involvement may
vary from intuitive Judgments to highly sophisticated prediccive
models. The most logical measures, consistent with the local
conditions should be determined.
2. Probability of Entralnaent
The zone of potential Involvement of the cooling water Intake
varies with species of organisms and time but the core concept
is the determination of probability of entralnaent. The
predictive models are useful for mapping probability isoplechs.
This could be done by the simulation of drifters with the hydraulic
model, or the spread of mass from point sources into the intakes
with the concentration model. Drogue or dye studies could be
used for verification. Drifters, drogues, or dye may, however,
b« poor analogs for the organisms in question. As a consequence,
any study of this nature must be accompanied by justification
that adequate adjustment is being made for differences in
behavior between the organisms and their mechanical analogs.
-------
A Mp of probability of entrainraent would be useful In delineating
the outline of the area of potential involvement by a rational,
analytical method. For example, the computer hydraulic model for
currents could be used to simulate the flow of drogues in the
region. A simulated release of drogues (several per hour) would
be carried out until all drogues have either been entrained or
have crossed the model boundaries and left the area. The rat lor
of entrained drogues to the total gives the probability of
entrainment. A repetition of this procedure for other release
points gives a field distribution of probability.
An alternate method is to simulate mass transport from a field of
points, wherein the ratio of mass entrained to the total released
gives the probability. This method could be verified by the use
of dye studies.
In environments likely to exhibit density stratlf icatior., or in
which the organisms stratify, It may be necessary to use multi-
level sampling for all parameters, and consider stratification in
the modela chosen. Wind effects are more likely to be important
in shallow water. The spatial changes in parameters in stratified
systems are likely to be larger, so this must also be incorporated
in a sampling program.
Obviously, models are highly desirable and the probability isopleth
cortcept Is a powerful analytical tool. However, the time arid costs
Involved will not be Justifiable In many situations.
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X. BIOLOGICAL SURVEY REQUIREMENTS (NEW INTAKES)
The purpose of the biological survey is to provide a sufficient ar.a
valid data base for rational assessment of environmental impact reiaced
to the location, design, construction, and capacity of a cooling water
intake structure, prior to a final siting decision.
Due to the possibility of extreme fluctuations In overall abundance
of the species from year to year and shifts within a study area of its
centers of abundance, several years' study nay be« required. A term of
three years is suggested as permitting an "exceptional" year co be
detected and criticized on the grounds that events in so short a scan
cannot be understood in the context of long tern trends. A period of
L5 to 25 years is one in which many cyclic biological phenomena become
evident, but a preliminary study of this length will be out of the
question excepc as it can be gleaned from historical data. A one-vear
pre-operat ional study is generally of limited value but may be acce:>C3D!.*
for preliminary agency determinations in situations where substantial
historical data can be presented and the intake can be represented as
having low potential impact.
Data collected must be sufficient to permit analysis and reduce ion
to assessment criteria which will be useful In reaching a judgment on the
existence and extent of an adverse Impact. Suggested measures for data
reduction and analysis, which are Included in this manual, should
be reviewed prior to developing a survey program.
Designation of species of the critical aquatic organisms to be
studied is the first step in a sequence of operations for the
subsequent biological survey. The species selected may or may not be
the same as the Representativ-e Important Species designated in connec-
tion with demonstrations under section 316(a) of the Act. Differences
uould depend on the greater or lesser effect on such species of
chenaal discharges or Intakes. Once species and source water invol/e-
aenc are known, the sampling methodology, survey study areas, and
temporal characteristics of the survey can be determined to suit che
organism f*ljc;ed, location, and characteristics of the Intake
structure. Each survey should be designed on a case-by-case basis
recognizing the uniqueness of biota-site-structure interrelationships.
Biological surveys should be designed and implemented to deter-
mine the spatial and temporal variability of each of the Important
components of the biota that may be damaged by the Intake. These
surveys could include studies of meroplankton, benthic fish, pelagic
fish, beothlc oacrolnvetebratea, phytoplankton, rooplankton, benthic
infauna and boring and fouling communities where appropriate.
Generally, the majority of critical aquatic organisms will oe fish
or macrolnvertebrates.
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-1L-
Once the occurrence and relative abundance of critical aquatic organises
at various Life stages has been estimated, it is necessary to determine tlie
potential for actual involvement with che intake scructure. An organism nay
¦pend only a portion oI its life in the pelagic phase and be susceptible to
ent rainaent. Migratory species may be in the vicinity of the intake for a
short segnent of the annual cycle. Some species are subjected to intake
structure effects during life history stages. For example, winter flounder
larvae ate found In che ichthyoplankton during their pelagic larval phase,
and are susceptible to being entrained. During later life stages, as
Juveniles and adults, they are vulnerable to impingement. Both entrainment
and impingement must be considered in subsequent Impact assessment. Know-
ledge of the organism's life cycle and determination of local water circula-
tion patterns related to the structure are essential to estimating an
Individual specie's potential for involvement.
Once involvement is determined, actual effeccs on those organisms nusc
be estlaaccd. As a first order approximation, 100 percenc loss of Individuals
Impinged, entrapped, or entrained could be assumed unless valid field or
laboratory data are available to support a Lower loss estimate.
The final step la to relate lo*a of 1 idlv ldu jIs to effects on che
local popuiatlon as Impacted by Intake structure location, design,
construction, and capacity. It Is Imports-: to consider che means for
data reduction and analysis in the early sages oc survey design. Data
¦ust be amenable to bloetatlstiral analyses, as utilized in arriving ac
the Judgment for best available technology to minimize adverse environmental
impact.
1. Sampling Design
It It necessary at th« outset to clearly define the objectives
of the sampling program and th« area to be sampled. Quantitative
sampling studies are designed to estimate niaabers per unit and/or
volume. The major considerations in these studies are:
- The dimension of th<* sampling unit. In general
the smallest practical sampling unit should be
used.
• The nunber of sapl'ng units in each sample.
The size of samples for a specified degree of pre-
cision can often be calculated tf there is some
preliminary sampling Information. If not, preli-
minary sampling should be executed before exten-
sive programs are developed.
- The location of sampling units in the sampling
areas. Stratified random sampling is often
preferable to slmp:e random sampling. Strata
can b« unequal In area or volume, with sampling
units allocated In proportion to the area or
volume.
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-35-
The survey effort should be intensive for at lease the first
year after which, based on first year result" and historical
data, lower effort progams could be justified. Survey data
are usually of a time-series nature and, therefore, averages
over time Intervals within the series cannot be assumed inde-
; tine
Reference 19 is a recent example of the difficulties encoun-
tered when attempting to determine differences in portions of
a time-series. The development of more powerful statistical
methods for application to this type of data is necessary.
It appears that only catastrophic impacts will be revealed co
temporal comparisons of monitoring program data. Plant
impact may be better revealed by spatial comparisons.
The discriminating power of surveys should be estimated prior
to implementation.
This can be done by design based on previously collected data
at the site, or by assuming the variability of the system based
on previous studies at similar sites. The expected discrimina-
ting power of the survey should be adequate for the purposes
for which the data are intended.
2. Sampling Methodology
Recommendations on specific sampling protocol and methodology
are beyond the scope of this document. The optimal methodology
is highly dependent on the individual species studied coupled
with site and structure characteristics. Some general guidelines
are provided here,. More specific details are provided in
reference 20.
Sampling gear used should have known performance characteristics
under the conditions in which it is to be used, or it will be tested
in comparison with a standard gear (such as the 60 cm. "bongo" net
developed for purposes of ichthyoplanktun sampling by the
National Marine Fisheries Service MARMAP program).
When a new gear is introduced, data should be included on its
efficiency relative to a standard gear. Gear shouTd~hot be
changed in the course of long-term investigations unless the
comparative efficiencies of the old gear and the new can be
satisfactorily demonstrated.
It is recognized that no sampling gear is, in practice,
strictly quantitative and equally efficient in retaining
different sizes of organisms.
A rationale for the choice of gear, raesii size, etc., should be
developed for each sampling program. In most cases, lacking
strong reasons to the contrary, adoption of a standard gear to
permit comparisons with other investigations is recommended.
Ichthyoplankton-Meroplankton Samp 1 ing
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-36-
In general, replicate tows Indicate that horizontal distribution
of fish eggs and Larvae and other planktonic organisms is uneven
or patchy in character, and that vertical distribution not only
of actively swimming forms but of eggs commonly shows sorce
stratification. This typicaLly varies over 1U hours due to
the Influence of water movement and changes in light intensity.
Depth distribution of individual species of fish eggs may change
during the course of developaenc, and buoyancy may differ at
different periods of the spawning season.
Night tows frequently produce larger catches and may show less
variability than day cows for fish larvae in the sane area.
Both phenomena are related In part to differences in net
avoidance under conditions of light and darkness. However,
certain larvae may be altogether unavailable co the usual
plankton sampling gear at some time of a diel cycle; for example,
they may lie on or near the bottom by day, md migrate upwards
at night.
Night sampling must be considered in survey design as essential
for an accurate picture of the numbers of lchthyoplankton
actually present at a station, especially with regard co post-
larvae and young Juveniles. Sampling over the entire dlcl
cycle should be conducted.
Characterization of the lchthyoplankton in a study area made
exclusively from single tow* at a series of stations is
Inadequate. Replication sufficient co show the typical vari-
ation between tows will be necessary, and it must be borne In
mind that this may differ widely for different species, and
may change over the course of a season. In reasonably
homogeneous study areas, replicates can be taken at a subset
of stations and the results applied co the rest. In certain
circumstances, close co shore, or in the vicinity of the
proposed intake, more rigorous error analysis is advisable,
and this may require replication at each station. Determina-
tion of a suitable nwber of replicates will depend on
characteristics at each sice, and muse b« based on field
studies. The mosc variable (pacchy) of the critical species
of lchchyoplankcon under acudy at a given season will
determine the number of replicates that are desirable.
Confidence limits for esclm~4Ces~ of abundance must be based
not only upon variation between tows a given station,
but muat incorporate other sources of error, which include
subaaapllng error (when allquots of large samples are taken
for lab analysis) and counting errors.
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-3 7
The lchthyoplankton-meroplankton sampling will generally be
re laced co che impact of passing Che organisms through che
intake structure and associated cooling water system, i.e.,
encrainmeac.
Fishes and Macrolnvertebrates
Sampling of fish and macrolnvertebrates will be generally
conducted in relation to the potential impact of entrapment
and impingement. An exception would be juvenile and small
fish of a size that would pass through intake screening
rather than be caught upon such screens.
As previouj^y noted, specific sampling methodology is detailed
elsewhere.
Some specimens taken from che screens may appear healthy;
however, species-specific experiments with controls to assess
Che delayed morcalicy co ehese fish are required if less than
100 percent mortality is to be assumed.
Potential affects at proposed Intake structures should make
maximum use of existing data ac operating structures co
extrapolate involvement and mortality estimates to a new
intake. Attention should be given to experiments which have
statistically evaluated the effect of intake modifications
on impingements-entrapment losses.
In cases where preliminary surveys indicate thac the entrap-
ment and entrapment-impingement losses may be high, ic will be
necessary to estimate the lapact of these losses on che
populations that will be involved. For each life stage
susceptible to entrainment and/or entrapment-impingemenc,
parameters necessary to adequately predict losses caused by
power plant withdrawal include life stage duration, fecundity,
growth and mortality rates, distribution, dispersal patcems,
and Intake vulnerability. These parameters can be either
measured In the field or obtained from available literature.
Estimates of equivalent adult stock loss on the basis of
entralnaent losses of immature foras requires a measure of
natural mortality from Immature to adult. For many if not
aose critlcal.species, the natural mortality may be impossi-
ble to determine and the impact may have to be based on a
reasonable Judgment. Other data are required to project che
long-term impact of the intake on the population and co Include
che population size, its age structure, and fecundity and mortal-
ity rates. These data can best be synthesized using
mathematical aodels as discussed in section XII of this manual.
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-38-
Zooplankton
Zooplankton sampling will generally be directed towards
determination of entrainment impact. Zooplankton are
essentially microscopic animals suspended in water wich
near neutral buoyancy. Because of their physical
characteristics, most are incapable of sustained
nubility in directions against water flow and drift
passively in the currents.
In most cases, intake effects are of relatively short
duration and confined to a relatively small portion of the
water body segment because of short life span and regenera-
tive capacity. Zooplankton, however, should not be dismissed
from consideration vichout a preliminary assessment of the
Importance or uniqueness of. the species' assemblage at the
site.
Phytoplankton
Phytoplankton are free-floating green plants, usually
microscopic in size, and are generally the main primary
producers in the aquatic food web.. Again, the potential
cooling water intake structure impact on phytoplankton
would be through entrainment. The short life-cycle and
high reproductive capability of pl.ytoplankters generally
providas a high degree of regenerative capacity. In most
cases, incake structure effects are of short duration
and confined to a relatively small portion of the water
body segment. Phytoplankton, however, should not be
dismissed from consideration vichout a preliminary assess-
ment of uniqueness or special importance of the species'
assemblage at any particular site.
3. Follow-up Studies
Post-operational studies at nev intakes will also be
ottcessary in order to determine if the design, location,
and operation, in fact, minimize adverse environmental
Impact and whether the model predictions utilized were
realistic. Some suggestions for follow-up studies are
available in section XI. However, the appropriate program
at a new plant site should be determined in large part by
the need for consistency with pre-operational study results.
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XI. MONITORING PROCRAM (EXISTING INTAKES)
The study requirements necessary to evaluate losses of aquacic
life at existing cooling water intakes can be considered in two separate
steps. The first is assessment of the magnitude of the problem at each
site through direct determination of the diel and seasonal variation La
numbers, sizes and weights of organisms involved with operation of the
intake. Wht- losses appear to be serious, as a second step it may be
necessary to conduct studies in the source water body if there is a need
to evaluate such losses on a water-body-vide or local population basis.
However, before requiring auch studies it should be realized thac the
natural variability of biological systems, the difficulty of separating
other stresses on population size, and difficulties in obtaining accurate
and precise samples of the biota may mask the environmental impact from
cooling water system operation. The magnitude of sampling variati^g is
high and may range from 20 to 300 percent of the probable numbers.
Thus, effects of the intake structure often cannot be identified above
this "background noise" unless they are considerably greater. For
many species, adverse environmental impact may be occurring at levels
below that which can be "seen" with the standard survey and analytical
techniques. Such field studies therefore will be extensive and difficult
to conduct, and will generally require several years of data collection,
all without certainty of results. Such studies should not be required
unless abac'utely necessary for the best technology available decision
and then 01 ly to address specific questions. Because of the above
difficultikj, it say be necessary to base a determination of adverse
impact on rofesslonal Judgment by experienced aquatic scientists.
In evaluating data froa the following studies, it is often desirable
to assume "worst case" conditions where all organisms which pass through
the intake suffer 100 percent mortality. If the magnitude of the numbers
precludes such an analysis, specific mortality estimates may be necessary
«
The following study requirements are based in part on the
recommendations confined in the reports of the Lake Michigan Cooling
Water Studies Panel and Lake Michigan Cooling Water Intake Committee:
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-40-
L. Stapling Prot,rvi - Entrapment-lapIngement
The objective of this sampling program is to document the
magnitude of loi.ies of fiah life at operating cooling water
Intakes. Since Lt is possible to obtain a complete daily
count of fish which are impinged by collecting the intake
screen backwash material, this intensity of collection
should be considered for application through one calendar
year. The data wtiicii result will most accurately reflect
the total annual loss by species. This approach does ignore
possible delayed mortality to organisms involved with the
intake structure but not impinged on the .screens long enough
to be killed. If total entrapment-impingement mortality Ls
estimated by sampling from the screens, the sampling scheme
must consider day-night and seasonal differences.
If a less than complete daily count over a year is utilized,
daily sampling once every four days for one year is suggested
as the lowest effort which will be acceptable from the stand-
point of allowing for reliable loss projections reflective of
the plant's operation. Both more and less intensive sampling
approaches may also be justifiable based on apparent impact,
intake data, spawning periods, and other site specific and
seasonal considerations. The 4-day interval for sampling Ls
based on observed variability in dally impingement losses.
For example, in a study of the Central Illinois Light Company's
E.D. Edwards Plant oa the Illinois River, numbers of fish
impinged varied from 7,000 on July 18 to 500 on July 19. On
Aug^t 23, 1,500 fiah v«re impinged versus 30,000 fish on August
26. Not all plants exhibit such wide variations in numbers
of fish impinged; however, until intensive sampling is completed
at a site, total loss figures will be subject to question.
Collection of the samples can usually be accomplished by
inserting collection baskets in the screen backwash sluiceway.
These baskets should have a mesh size equal to or smaller than
the intake screen mesh.
Th« following data should be collected during the sampling
period:
A. Plane operating data required:
1. Flow rate;
2. Temperature (intake and discharge);
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3. Time started, duration, and amount of warm vac<;r recircu-
lated for intake deicing and thermal defouling;
4. Total residual chlorine contained in recirculated water
during condenser chlorinatlon;
5. Current velocity at intake(s) over the range of water
volumes used in plane operation (representative aeasure-
oents or calculated values nay suffice);
6. Number of times screens are operated between sampling
intervals;
7. Tidal stage (where appropriate) and flow;
8. Salinity (where appropriate); and
9. Dissolved oxygen if intake withdraws water from an
area (or strata) of potentially low oxygen content;
B. Data required from biological collections:
1. Species, number, length, weight, and age group (young of
the year, yearlings, or adults) collected from the
screens or representative subsamples when numbers of
individual species collected are very large. Subsampling
approaches should be approved In advance by the Agency;
2. Representative samples of each species for determination
of sex and breeding condition;
3. Numbers of naturally occurring dead fish in the area
ahead of the intake screening system should be estimated;
and
4. Periodically conduct a teat to determine the recovery
rata of fish impinged on the screen. This can be done
by spiking the screen with tagged dead fish and deter-
mining the proportion that are recovered in the screen
backwash sluiceway.
Sampling Program - Entralnment
The following section describes investigations necessary co
determine effects of entralnment of phytoplankton, zooplankton.
benthos, fish , and shellfish at existing cooling water intakes.
Such studies should generally concentrate on fish and shellfish
unless the phytoplankton, rooplankton, or benthos are uniquely
important at the site la question.
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-4 2-
Flsh and Meroplankton
The potential for damage to fish or shellfish populations by
entrainaent depends on the number of organisms that pass through
the coadenser system and on conditions experienced during passage.
Overall objectives of the study are to determine the species
and numbers of fish and shellfish eggs and larvae drawn into
and discharged from the cooling systems and, if necessary,
determine the immediate and delayed effects of cooling system
passage on these organis-is.
A pump system is acceptable as the primary sampling method,
provided it does not damage fragile organisms, and pumps are
easier to automate and quantify than systems in which sampling
is done with nets suspended in the cooling vater flow.
Dial sampling is recommended because the numbers of organisms,
even in areas known to be good spawning and nursery areas,
typically have low concentrations, and their distribution in time
and space is usually either changing rapidly or patchy as a result
of natural conditions. Therefore, adequate representation of these
organisms can usually only be obtained vlth continuous sampling
throughout a dlel cycle.
The actual volume of water to be pumped to provide an adequate
saaple is dependent on the densities of fish eggs and larvae in
the water surrounding the cooling system Intake structure. The
saaple volume should therefore be determined baaed on the least
dense species of concern. If no a" priori'source water density
data exists, then as large a saaple voluae as can be handled will
be necessary. Once Information la developed on the least
detactlble density for species of concern, saaple volumes may be
adjusted accordingly. This point Is extremely critical to
acceptance of the resulting dees. If the saaple volume is too
small the study wlli be biased and show fairer organisms involved
vlth the structure than actually exist.
Saaple lpcatlons in the intake system should be located immediately
ahead of che Intake screens and, wbenless than 100 percent mortality
is usuaed, at a suitable point In the discharge system. When
less than 100 percent is assuaed, saaples at lfitake and discharge
should be from the sane water mass. At each Location one sampling
point should be located near the surface, one near the bottom, and
one at aid-depth. If uniform organism distribution can be demonstra-
ted, one sampling depth, may suffice.
Saapling should normally be conducted continuously at a frequency
(e.g., every fourth day of plant operation) allowing the estimation
of annual nuabers of organisms vlth a 95 percent confidence inter/aL
which Is + 50Z. More frequent sampling may be desirable during
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-4 3-
peak spawning seasons. Sampling shouid continue over ac least
one year. Sampling in subsequent years nay be deemed necessary
based on the results of the first year of study.
MacroInvertebraces
The primary concern regarding the effects of entrainment on macro-
invertebratea Ls-does entrainment affect the rates of mortality,
growth or reproduction? Specific objectives are to determine the
kinds and numbers of organisms entrained, to assess the effect of
encrainaent on their survival and reproduotlon, and to describe the
seasonal and diurnal patterns of entrainaent. Pumped samples are
acceptable provided the pump does noc damage fragile organisms. A
pump which will transfer small fish without harm is often satis-
factory for zooplaakton and benthos. Son-toxic material should be
used throughout the sampling syscem.
Sets used to concentrate zooplankcon and benthos from the pumped
sample should be metered, or Che pumping rate should be timed to
provide an accurate determination of the volume filtered. Samples
should be taken in duplicate. If no vertical stratiflcacIon of
organisms is documented, duplicate mid-depth or duplicate Integrated
samples may be taken.
Sampling sites should be established in Che forebay, Immediately
ahead of the traveling screens, and as close as possible to the
poinc of discharge.
Samples should be carefully coocencraced in non-toxic containers
and Inspected microscopically for mortality and damage as soon as
possible afcer collection.
Samples should be collected in the forebay and at the discharge
during a 24-hour period ac lease monthly. Duplicate samples should
b« taken every 3 to 4 hours during Che 24 hour survey.
Phytoplankton
Phytoplankton are susceptible to encralnment and possible damage
in cooling water systens such thac races of morcality, growth,
reproduction, and primary production are affecced. Studies to
determine those effects should involve microscopic examination,
measurement of chlorophyll concentrations, measurement of
races of primary producdon, and observations of cell growth
and division. In mosc cases, effeccs are of short duration
and confined co a relatively saall portion of the water body
segment. Phytoplankton, however, should noc be dismissed
from conslderacion without a preliminary assessmen: of
uniqueness ot special importance of the species' assemblage at
any particular site. Special sampling methodology can be
found In reference 20.
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—a4 —
Zooplankton
Zooplankcon sampling will generally be direcced cowards decer-
ainaclon of encrairunenc Impact by an intake scruccure. Zoo-
plankcon are essentially microscopic animals suspended in water
wich near-neutral buoyancy. Because of cheir physical charac-
ceriadcs, most are Incapable of suscained nobillcy in directions
against water flow and drifc passively in che currents.
In most cases, lncake effeces are of relatively shore duracion
and confined to a relatively snail portion of the water body
segment because of short life span and regenerative capacity.
Zooplankton, however, should not be dismissed from consideration
without a preliminary assessment of the importance or uniqueness
of che species' assemblage at the site.
3. Pollov-up Studies
K follow-up monitoring program is also necessary at existing
plants to determine whether the approved lncake la fact
minimizes environmental impact. In cases where an existing
lntaka has been approved, lc would be expected chat che raonicor-
ing program could be on a reduced level from chac noted above.
Howwer, where algniflcanc changes In intake location, design,
construction, capacity, or operation have taken place, a program
comparable to che pre-operational one should be followed.
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-45-
XII. IMPACT ASSESSMENT
The goal of impact assessment is to anaLvze and reduce biological
survey data to a form easily conceptualized and understood in the con-
text of best available technology to minimize adverse environmental
'.mpact of intake structure location, design, construction, and capacity
The following approaches are suggested for use, although their applica-
cion will not be appropriate in each case:
1. Bloatatlatleal Analyses
In general, the minimum raduced raw sample data should include
the arithmetic mean, the standard error (or the standard
deviation), and the sample size from which these calculations
were made.
IC a large nuaber of measurements or counts of a variable
(e.g., species) are made, the data may be summarized as a
frequency distribution. The form or pattern of a frequency
distribution is given by the distribution in numerical
form (as In a frequency table). However, the data ls more
clearly evident In .a diagram such as a histogram (I.e., a
graph in wnich the frequency in each class ls represented
by a vertical bar). The shape of a histogram describes the
underlying sampling distribution. Known mathematical fre-
quency distributions may be used as models for the populations
sampled in the study, and the frequency distributions froa
samples may be compared with expected frequencies from known
models.
The spatial distribution of individuals in a population
can be described in quantitative terma. In general, three
basic types of spatial distribution have been described.
They are: a random distribution, a regular or uniform
distribution, and a contiguous or aggregated distribution.
The spatial dispersion of a population may be determined
by the relationship between the variance and the mean, as
well as by other methods. In a random distribution, the
variance is equal to the mean. The variance is less than
the mean in a uniform distribution, and it ls greater than
the Man in a contiguous distribution. In general, a
Polsson distribution is a suitable model for a random
distribution, a ?osltive binomial ls an approximate
model for a uniform distribution, and a negative binomial
is probably the most often used, among possible models, for
a contiguous distribution.
Temporal and spatial changes in density can be compared
statistically. Significance tests for comparisons of
groups of data may be parametric when the distributions of
the parent populations are known to be normal, or nearly
normal, from previous experience or by deduction from the
samples. Often, non-normal data may be transformed into
data suitable for such testing. Otherwise, nonparametric
tests for significance should be applied.
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Predictive Biological Models
Models used to simulate currents (circulation taodels) and the
dispersion of constituents (concentration models) are becoming
aar« available for use in assessing impact. These models,
when soundly-baaed conceptually, can usually be verified against
hydrographic data and, therefore, represent an important tool for
considering the Influence of a power plane on its surroundings.
Diverse population and community models can be developed, but
the assumptions on which they are baaed are difficult to test
and the parameters difficult to estimate. Some Important
parameters depend on long time series of data (tens of years)
and no level of effort can offset the requirement of time.
These problems with biological models can sometimes be overcome
by asking "worse case" assumptions and estimates, but this
course nay tend to produce a plethora of models indicating
potential disaster. Nevertheless, models are a means of
Integrating the available information and the subjective
underlying assumptions about a problem in order to produce
the moet rational answer based on the inputs. In this regard,
sone models may serve an important role in assessing impact.
As previously noted, hydrodynamlc models in theory can be used
to predict the source of water drawn through a power plant
Intake structure. This is does by simulating the movement of
drifters or the dispersion of a constituent originating at a
particular point in the area modeled. The slaalatlon is carried
out for sufficient time for most of the raaeerial to be transported
to the point of the assumed intake structure .where it is con-
sidered entrained, or for the material to be transported suffi-
ciently far away from the intake structure so that it ha* little
chance of future entrairaent. This procedure must be repeated
(or performed simultaneously) for numerous constituent origins
and for numerous initial flow or tidal conditions. These
results will provide isoplaths of entralnmmnt probabilities
surrounding a proposed intake structure. The lsopleths can
be eiwpered with the biological value zone to assure that the
plant will not draw a high percentage of entralnable organisms
fro« highly productive areas. Various Intake locations may be
considered to minimize impact. In practice, it might be very
expensive to calculate the probability of antrairtment isopleths
(source area) of an intake atructure because a large area may
have to be modeled and consldersble computer time expended.
-------
For a giv^n critical aquatic organism, it may be possible co use
hydrodynanic models co estimate the percent reduction in annual
recruitment resulting from entraimcent of pelagic earLy life
stages. When the source of pelagic eggs and/or larvae is '
-------
'-(hen che reduccion in recruirment because of ent r a intnen c
and cne umingemenc nor:a!i:y races have been estimacec for
a critical acuacic organism, it is useful co assess che
long-Cera Lipacc on cne Local populacion. The dynamic- ::
che populacion can be sunulaced by a coraparcraenc acdel ^icn
organisms discribuced inco compartments according to age.
Each coraparcraenc is assumed co suffer non-power plane related
mortality. Aging is simulaced by advancing organisms co che
next older compartmenc. Agfr-specific fecundity races are
used co determine che total biotic potential- of che
populacion. The recruicmenc co che youngest compa.:cmenc
is a function of cocal egg production. The effect of
encrainnenc, entrapment, and impingement are incorporated
by reducing che predicced recruicmenc by che appropriate
prooorcion and adding .-ge-(or size-) specific encrapmenc-
impingeaenc norcalicy co che age compartments. Conpucer
simulations of chp future i/namics of che populacion based nr.
che coraparcacnc model wich and wichout che plant can be
compared .
Such simulacions require knowledge of che Life cable for che
species being considered. Life cable information for some
species may be based on che literature. It may be possible
co supplement chis informacion with knowledge gained from
field scudies. The age-(or length-) '-cundlty function
and che «gt? production-recruitraenc relationship must also
be 'ww. The latter may be of thtee forma: (1) recruicmenc
as a linear funccton of egg production, (2) recruicmenc as
a densicy dependenc funccion of egg production, * or (3)
recruitment independent of egg production. The choice of cne
appropriate egg production-recruitment relationship and
estimation of parameters oust be based on che available -
historical informacion on che species. At lease cvency years
of daca is probably required co make such a decision. In che
absence of enough daca, che assumption o£ a linear egg pro-
duction-recruitmenc relationship is appropriate. Mote chac fo
a linear egg produccion-re-cruitraent sodel, there is only a
single equilibrium condition, and any plane related .nortal-
icy 1j Likely to disturb this equilibrium.
II Che population is noc isolated, exchange with other
populations aay be modeled. The results o£ mark and recapcure
experimencs may be useful for estimating exchange rates.
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-49-
The methods for assessing Impact described in this section
are useful but of unknown validity. Moat assessments based
on biological models have yet to be field verified, develop-
ment of predictive models for assessing impact should be
encouraged but only after full consideration of the diffi-
culties involved, the expense compared to the reliability of
results, and the dangers of a "worst case" analysis.
3. Community Response Parameters
The populations of all species in a given area or volume
are defined as a community. Although the term "community"
is considered a useful concept in delineating the group of
interacting species in an area, it Is believed to be a
subjective entity. Thus, for specific studies and tests
of hypothesis, the composition of the community must be
strictly defined.
Community response parameters, such as changes in structure,
have sometimes been studied and estimated by certain multi-
variate classification techniques. Various measures of
species diversity or association coefficients have also
been employed to measure cocnunity response to perturbations.
In estimating community diversity, the most widely used
indices are those baaed on information theory. When the
sample of species' abundances may be considered randomly taken
from an ecological community or subcommunlty, the Shannon
index (also referred to as the Shannon-Ulener or Shannon
Weaver Index) may be used. If the sample may not be
considered a random set of species' abundances taken from a
larger species' aggregation of Interest, then the Brlllouln
Index should be used. Cither index may be computed with
computational ease and, in either case, the logarithmic
baae used must be stated.
The shortcomings of all existing indices of species' diver-
sity and the biological phenomena which may influence
these values should be recognized. References 28, 29, and
30 should be consulted for further explanation of diver-
sity indices and their utility.
For the purposes at hand, the phrase "classification of
communities" is utilized for processes that sort species
into groups, and it includes both discrimination and
clustering. In general, discrimination techniques
begin with a priori conceptual distinctions or with data
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divided into a priori groups. Then one should proceed to
develop rules which separate data into chese a priori categories.
Clustering techniques, on the other hand, use a priori selection
of a measure of similarity, a criterion, and a class description
to find inherent empirical structure in data, i.e., clusters.
Clustering does not use an externally supplied label and Involves
finding derived data groups which are internally similar, A.
good review and summary of various discrimination and clustering
procedures is provided in reference 31.
The aquatic environment can often be stratified in some way,
such as by depth, substrate composition, etc. It is suggested
that such stratification be done and that tables showing the
frequency, or density, of each species at each environmental
stratum be compiled. These tables are ana^gous to the distri-
bution curves made in a gradient analysis, and are consi-
dered a natural and useful description for species association
data. It la suggested that chese tables be the basis for
certain multivariate methods of data analysis for spatial
and temporal variability, such aa cononical variate analysis
described in reference 33. In addition, for these data which
now contain a priori groupings, the linear discriminant function
may also be successfully utilized for testing the differences
among environmental strata using multiple measurement or counting
data.
Biological Value Concept
The concept of establishing relative biological value zones
in the water body segment impacted by a cooling water Intake
structure could be a useful approach in determining best
technology available for intake design, location, and operation
to minimize adverse environmental impact. The principal use
of this concept is in delineating the optimal location within
the vater body for minimum impact on the biota potentially
involved with the specific intake structure.
The essence of this concept is in establishing biological value
of various zones for the water body segment (or other defined
area) within which the intake structure is to be located. A.
judgment of value is made for the representative important
species considering type of involvement with the intake (entrap-
ment, impingement, entrainment) and the numbers of each which
are adversely impacted. Results are summed up by species,
seasonally or annually, and represented by graphical means to
depict areas of the water body highly important to the species
and, conversely, areas of low relative value, thus potentially
favorable intake structures.
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Methodologv. The following methodology for using Che biological
value concepc la based on methods developed and utilized in
community planning studies as described in reference 3&.
Use of the biological value concept would require acceptance of
the reasonableness of several basic premises:
1. There are areas of different concentrations of representative
important species within the water body segment comprising
potential sites for an Intake structure.
2. Areas of biological concentrations can be expressed in cerms
of relative value to perpetuation of representative Important
species populations in the water body segment.
3. The area of zone of least biological value, expressed in
relative terms of population densities, would be the optimal
location for an intake structure in order to reduce adverse
environmental impact.
This la not a precise method because of inexactness of differen-
tiating relative value between species and difficulties in
comparing Importance of ioss between eggs, larvae, and adults.
Also, it la assumed that the adverse impact on the populations
of critical aquatic organisms is significant to some degree and
therefore, it is desirable to minimize this impact, thus giving
importance, to best available Intake locations.
If one can determine chat one species is more important Chan
another, one can weigh it. in some way. If not, least concentra-
tions of critical aquatic organisms in any one location indicate
its intrinsic suitability for Intake structure location.
A step-by-step procedure could include:
1. Select critical aquatic organisms; and
2. Divide water body segment into spatial compartments (use
hydrologlcaJ model) .
For each species and spatial compartment:
1. Determine life stages potentially Involved with Intake
and type of Involvement (entrapment. Impingement, entrap-
ment);
2. Estimate numbers of organisms involved at represencacive
times during the annual operation cycle;
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3. F.acimace numbers of those Involved that are Lose (determine
percent survival or aortality of chose entrained or Lmpiagea)
on an annual basis;
k. Estimate conversion ratios to express eggs and Larvae Lost
in terns o£ nunber of adults (this is a value Judgment and
assumes the loss of one egg is not as important to survival
of the species as the loss of an adult).;
5. Develop the data matrix for construction of the biological
value level overlay charts (Table 1);
6. Construct transparent overlays for each species on chart of
water body segment. Areas of different impact in terras of
organisms lost due to involvement with the intake structure
could be color-coded; e.^., areas of mosc value could be dark
gray; areas of Least value, clear. Generally, three levels
of value wiL1 suffice;
7. Superimpose overlays for all representative important species
on chart to obtain compositive value, indicated by relative
color, for all spatial compartments in the water body
segment; and
8. Analyze graphic display of relative value and identify
lighc-toned areas as most favorable intake sites, heavy
areas as least favorable.
The methodology is Intended to be flexible. Various shades
of different colors could indicate comparative value between
selected species or variations in density with depth. The
value grades could be expressed in terns of their relation
to populations of critical aquatic organisms in the overall water
body to provide insight on importance of the specific segment
studies to the whole system.
The biological value concept lor analyzing survey data in the
determination of best technology available, to minimize adverse
environmental Impact appears to have the principal application in
selection of the minimal imact zones for locating the Intake
structure. The usability of the concept is, of course, data-
dependent. Aa noted, it is not precise, but at least integrates
multiple factors and presents a defined indication of suitability
for location of an incake structure in the affected water body
segment.
Three-dimensional computer graphic techniques can also be
applied to.portray spatial and teaporal distribution of biological
data. 10,35
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Time-aeries graphs can be useful In depicting the dynamic
nature of occurrence and abundance of a designated species
during the annual operacing cycle of Che incake scruccure.
The principal application would appear to be in the deter-
mination of the optimal location of the intake structure.
Also, graphic representations of the biologically predicted
mathematical model output could assist in more clearly
depicting intake structure impact on populations of Repre-
sentative Important Species (R1S).
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TABLE 1
EXAMPLE DATA MATRIX
(SPECIES 1)
DATA SHEET
(SPATIAL COHPARTMENT [A)>
TYPE
OF
INVOLVEMENT
Organlsa Involved
X Lost
(If aaauaed other
than 100 2)
Nuabera
Lost
Calculated
lent Adult
1 1
Equiva- | Value |
Loaa | Grade |
1 1
£88*
Larvae | Adult
1
Eggs
Larvae
Adul t
E.| L.| A
1 I
E. | L.
1
A.
Total |1. II, HI 1
1 1
Kntrapaent
InplngemenC
Kntrulament
1
1
1
1
1
1
1
1 1
1 1
1 1
1 1
1 1
1 1
1
1
1
1
1
1
1
1
1
1
Total Effect
1
1
1
1 1
1 1
1
1
1
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XIII. ACKNOWLEDGEMENTS
The concept of a 316(b) Technical Guidance Manual was inidated
by an interagency working group composed of James Truchan, Michigan
Department of Natural Resources; Howard McCormick and Alan Beck, U.S.
F,nvironmental Protection Agency; and Phillip Cota, U.S. Nuclear
Regulatory Commission. The first draft of the Manual was completed
in December 1975, followed by a revised version in April 1976.
The Manual in its present form is the product of' the following
individuals who provided comments and assistance: James Truchan and
Robert Courchaine, Michigan Department of Natural Resources;
U. Lawrence Ramsey, Nary land Department of Natural Resources; Allan.
Beck, Alan Beers, William Brungs, Stephen Bugbee, William Jordan,
Torn Larsen, Harvey Lunenfeld. Howard McCormick, Cary Milburn, F.ric
Schneider, and Lee Tebo, U.S. Environmental Protection Agency;
Thomas Cain, Phillip Cota, Bennett Harless, and Michael Masnik,
U.S. Nuclear Regulatory Agency; Phillip Goodyear, Mark Maher,
and Roy Irwin, U.S. Flsh,and Wildlife Service; William Anderson II,
Hunton, Williams, Cay & Gibson; J.Roy Spradley, Jr., National
Association of Electric Companies , Charles Coutant; Oak Ridge National
Laboratories; Lajendra Sharsa, Argonne Laboratories, Saul Sella,
University of Rhode Island., George Mathiessen, Marine Research Inc.;
and Gerald Zar, Northern Illinois University.
Special acknowledgment goes to Howard Zar, U.S. Environmental
Procecrion Agency, who was responsible for reviewing and incorporating
comtnencs received into this Manual.
Overall coordination and preparation of this Manual was done
by the Industrial Permits Branch, Permits Division, Office of
Fin forcement, U.S. EPA, Washington, D.C.
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-56-
XIV. LITERATURE CITED
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-59-
39. Coutant, C.C. and R.J. Kadi. 1975. Survival of Larval
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40. Edsall, T.A. Electric Power Generation and Its Influence an
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