vvEPA
United States
Environmental Protection
Agency
Environmental Research
Laboratory
Corvallis, OR 97333
EPA 600/3-B9/038b
October 1989
Research and Development
Wetland Creation and Restoration:
The Status of the Science Vol. II
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EPA/600/3-89/038
October, 1989
WETLAND CREATION AND RESTORATION:
THE STATUS OF THE SCIENCE
Volume II: Perspectives
•V
•05 Edited by:
vV
Jon A. Kusler
Association of State Wetland Managers
Box 2463
Berne, New York 12023
- V
J and
) Mary E. Kentula
NSI Technology Services, Corporation
200 S.W. 35th Street
Corvallis, Oregon 97333
U.S. Environmental Protection Agency
Region 5, Library (P1-12J)
77 West Jackson Boulevard 1 ?th ci
Chicago, IL 60604-3590 loor
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DISCLAIMER/CREDITS ON CONTRACTS
This project has been funded by the United States Environmental Protection Agency (EPA) and conducted
at EPA's Research Laboratory in Corvallis, Oregon, through Contract 68-C8-0006 to NSI Technology
Services, Corp. and Contract CR-814298-01-0 to the Association of State Wetland Managers. It has been
subjected to the Agency's peer review and approved for publication.
This document reflects the diverse points of view and writing styles of the authors. The opinions
expressed herein are those of the authors and do not necessarily reflect those of the EPA. The official
endorsement of the Agency should not be inferred.
Mention of trade names of commercial products does not constitute endorsement or recommendation for
use.
Cover by Kathryn Torvik
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CONTENTS
VOLUME I: REGIONAL REVIEWS
Foreword v
Office of Wetlands Protection
Introduction vii
Mary E. Kentula and Jon A. Kusler
Executive Summary xi
Jon A. Kusler and Mary E. Kentula
Wetland Mitigation Along the Pacific Coast of the United States 1
Michael Josselyn, Joy Zedler, and Theodore Griswold
Creation and Restoration of Tidal Wetlands of the Southeastern United States 37
Stephen W. Broome
Creation and Restoration of Coastal Plain Wetlands in Florida 73
Roy R. Lewis, III
Creation and Restoration of Coastal Wetlands in Puerto Rico and the U.S. Virgin Islands 103
Roy R. Lewis, III
Creation, Restoration, and Enhancement of Marshes of the Northcentral Gulf Coast 127
Robert H. Chabreck
Creation and Restoration of the Coastal Wetlands of the Northeastern United States 145
Joseph K. Shisler
Regional Analysis of the Creation and Restoration of Seagrass Systems 175
Mark S. Fonseca
Creation and Restoration of Forested Wetland Vegetation in the Southeastern United States. 199
Andre F. Clewell and Russ Lea
Freshwater Marsh Creation and Restoration in the Southeast 239
Kevin L. Erwin
Restoration and Creation of Palustrine Wetlands Associated with Riverine Systems of the Glaciated
Northeast 273
Dennis J. Lowry
Regional Analysis of the Creation and Restoration of Kettle and Pothole Wetlands 287
Garrett G. Hollands
Regional Analysis of Fringe Wetlands in the Midwest: Creation and Restoration 305
Daniel A. Levine and Daniel E. Willard
Creation and Restoration of Riparian Wetlands in the Agricultural Midwest 333
Daniel E. Willard, Vicki M. Finn, Daniel A. Levine, and John E. Klarquist
The Creation and Restoration of Riparian Habitat in Southwestern Arid and Semi-Arid Regions. . . . 359
Steven W. Carothers, G. Scott Mills, and R, Roy Johnson
Restoration of Degraded Riverine/Riparian Habitat in the Great Basin and Snake River Regions. . . . 377
Sherman E. Jensen and William S. Platts
Riparian Wetland Creation and Restoration in the Far West: A Compilation of Information 417
John T. Stanley
Overview and Future Directions 465
Joy B. Zedler and Milton W. Weller
111
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VOLUME II: PERSPECTIVES
Wetland Restoration/Creation/Enhancement Terminology: Suggestions for Standardization 1
Roy R. Lewis, III
Information Needs in the Planning Process for Wetland Creation and Restoration 9
Edgar W. Garbisch
Wetland Evaluation for Restoration and Creation 15
Kevin L. Erwin
Wetland Dynamics: Considerations for Restored and Created Wetlands 47
Daniel E. Willard and Amanda K. Hiller
Restoration of the Pulse Control Function of Wetlands and Its Relationship to Water Quality
Objectives 55
Orie L. Loucks
Vegetation Dynamics in Relation to Wetland Creation 67
William A, Niering
Long-term Evaluation of Wetland Creation Projects 75
Charlene D'Avanzo
Regional Aspects of Wetlands Restoration and Enhancement in the Urban Waterfront Environment. . 85
John R. Clark
Waterfowl Management Techniques for Wetland Enhancement, Restoration and Creation
Useful in Mitigation Procedures 105
Milton W.Weller
Wetland and Waterbody Restoration and Creation Associated with Mining 117
Robert P. Brooks
Mitigation and The Section 404 Program: A Perspective 137
William L. Kruczynski
Options to be Considered in Preparation and Evaluation of Mitigation Plans, 143
William L. Kruczynski
Contributors 159
IV
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WETLANDS RESTORATION/CREATION/ENHANCEMENT
TERMINOLOGY: SUGGESTIONS FOR STANDARDIZATION
Roy R, Lewis m
Lewis Environmental Services, Inc.
INTRODUCTION
This document includes a glossary that was
prepared after review by all the authors. Four
versions of the manuscript have been circulated
for reviewers' comments, and each version was
an improvement on the previous one. The
specific definitions in the glossary represent an
attempt to bring some order to the terminology
applied to the topic of wetland creation and
restoration. It has been our collective experience
that much confusion exists about specific terms,
and they are used in different ways by different
authors in different parts of the country.
Unfortunately, much of the existing confusion is
becoming formalized as states, counties, and
municipalities develop their own regulations
related to wetland creation and restoration. This
discussion of terminology is meant to highlight
the major problem areas.
HISTORICAL CONTEXT
In looking for a starting point we were able
to find only three existing glossaries applicable
to the topic. These were contained in the U.S.
Army Corps of Engineers Wetlands Delineation
Manual prepared by the Environmental
Laboratory Waterways Experiment Station,
Vicksburg (Environmental Laboratory 1987), the
U.S. Fish and Wildlife Service's classification
of wetlands and deepwater habitats of the United
States (Cowardin et al. 1979), and the proceedings
of a conference titled Wetland Functions,
Rehabilitation and Creation in the Pacific
Northwest: The State of Our Understanding,
prepared by the Washington State Department of
Ecology (Strickland 1986). Three additional
glossaries (Helm 1985, Rawlins 1986, and Soil
Survey Staff 1975) were recommended by
reviewers and have been used to improve this
section. To these combined glossaries were added
definitions from individual authors of published
papers or proceedings, for example Zedler (1984)
and Schaller and Sutton (1978), and regulatory or
review agency rule promulgation, such as U.S.
Fish and Wildlife Service (1981). Where the
existing definitions were checked against
dictionary definitions, Websters Unabridged
Dictionary, Second Edition (McKechnie 1983)
was used as the reference dictionary. Some
geological terms were taken from Bates and
Jackson (1984) and Gary et al. (1972) as
recommended by reviewers.
DISCUSSION
The five key definitions are: mitigation,
restoration, creation, enhancement, and success.
Briefly, McKechnie (1983) defines these terms as
follows:
MITIGATION alleviation; abatement or
diminution, as of anything
painful, harsh, severe,
afflictive, or calamitous (p.
1152);
RESTORATION a putting or bringing back into
a former, normal, or
unimpaired state or condition
(p-1544);
CREATION
the act of bringing
existence (p. 427);
into
ENHANCEMENT the state or quality of being
enhanced; rise, increase,
augmentation (p. 603);
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SUCCESS favorable or satisfactory
come or result (p. 1819).
out-
For the purposes of this document, we are
defining these terms so that there is as little
ambiguity and overlap as possible. The glossary
definition and an explanation of each of the key
terms is provided below.
MITIGATION - For the purposes of this
document, the actual restoration, creation, or
enhancement of wetlands to compensate for
permitted wetland losses. The use of the word
mitigation here is limited to the above cases and
is not used in the general manner as outlined in
the President's Council on Environmental
Quality National Environmental Policy Act
regulations (40 CFR 1508.20).
MITIGATION BANKING - Wetland restoration,
creation, or enhancement undertaken expressly
for the purpose of providing compensation for
wetland losses from future development
activities. It includes only actual wetland
restoration, creation, or enhancement occurring
prior to elimination of another wetland as part of
a credit program. Credits may then be withdrawn
from the bank to compensate for an individual
wetland destruction. Each bank will probably
have its own unique credit system based upon the
functional values of the wetlands unique to the
area. As defined here, mitigation banking does
not involve any exchange of money for permits.
However, some mitigation programs, such as
those in California, do accept money in lieu of
actual wetland restoration, creation or
enhancement.
RESTORATION - Returned from a disturbed or
totally altered condition to a previously existing
natural, or altered condition by some action of
man. Restoration refers to the return to a pre-
existing condition. It is not necessary to have
complete knowledge of what those pre-existing
conditions were; it is enough to know a wetland
of whatever type was there and have as a goal the
return to that same wetland type. Restoration
also occurs if an altered wetland is further
damaged and is then returned to its previous,
though altered condition. That is, for restoration
to occur it is not necessary that a system be
returned to a pristine condition. It is, therefore,
important to define the goals of a restoration
project in order to properly measure the success.
In contrast with restoration, creation
(defined below) involves the conversion of a non-
wetland habitat type into wetlands where
wetlands never existed (at least within the recent
past, 100-200 years). The term re-creation is not
recommended here due to confusion over its
meanings. Schaller and Sutton (1978) define
restoration as a return to the exact pre-existing
conditions, as does Zedler (1984). Both believe
restoration is therefore seldom, if ever, possible.
Schaller and Sutton (1978) use the term
rehabilitation equivalent to our restoration. For
our purposes, "rehabilitation" refers to the
conversion of uplands to wetlands where
wetlands previously existed. It differs from
restoration in that the goal is not a return to
previously existing conditions but conversion to
a new or altered wetland that has been
determined to be "better" for the system as a
whole. Reclamation is also used to mean the
same thing by some, but "wetland reclamation"
often means filling and conversion to uplands,
therefore its use is not recommended.
CREATION - The conversion of a persistent non-
wetland area into a wetland through some
activity of man. This definition presumes the
site has not been a wetland within recent times
(100-200 years) and thus restoration is not
occurring. Created wetlands are subdivided into
two types: artificial and man-induced. An
artificial created wetland exists only as long as
some continuous or persistent activity of man
(i.e., irrigation, weeding) continues. Without
attention from man, artificial wetlands revert to
their original habitat type. Man-induced created
wetlands generally result from a one-time action
of man and persist on their own. The one-time
action might be intentional (i.e., earthmoving to
lower elevations) or unintentional (i.e., dam
building). Wetlands created as a result of
dredged material deposition may have
subsequent periods during which additional
deposits occur. Man-initiated is an acceptable
synonym.
ENHANCEMENT - The increase in one or more
values of all or a portion of an existing wetland
by man's activities, often with the accompanying
decline in other wetland values. Enhancement
and restoration are often confused. For our
purposes, the intentional alteration of an existing
wetland to provide conditions which previously
did not exist and which by consensus increase
one or more values is enhancement. The diking
of emergent wetlands to create persistent open-
water duck habitat is an example; the creation of
a littoral shelf from open water habitat is another
example. Some of the value of the emergent
marsh may be lost as a result (i.e., brown shrimp
nursery habitat).
SUCCESS - Achieving established goals. Unlike
the dictionary definition, success in wetlands
restoration, creation, and enhancement ideally
requires that criteria, preferably measurable as
quantitative values, be established prior to
commencement of these activities. However, it is
important to note that a project may not succeed
in achieving its goals yet provide some other
values deemed acceptable when evaluated. In
other words, the project failed but the wetland was
a "success". This may result in changing the
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success criteria for future projects. It is
important, however, to acknowledge the non-
attainment of previously established goals (the
unsuccessful project) in order to improve goal
setting. In situations where poor or nonexistent
goal setting occurred, functional equivalency
may be determined by comparison with a
reference wetland, and success defined by this
comparison. In reality, this is easier said than
done.
LITERATURE CITED
Bates, R.L. and J.A. Jackson (Eds.). 1984. Dictionary of
Geologic Terms. American Geological Institute.
Anchor Books, Garden City, New York.
Cowardin, L.M., V. Carter, F.G. Golet, and E.T. LaRoe.
1979. Classification of Wetlands and Deepwater
Habitats of the United States. U.S. Fish & Wildlife
Service. FWS/OBS-79/31.
Environmental Laboratory. 1987. Corps of Engineers.
Wetlands Delineation Manual, Technical Report
Y-87-1. U.S. Army Engineer Waterways Experiment
Station, Vicksburg, Mississippi.
Gary, M., R. McAfee, Jr., and C.L. Wolf (Eds.). 1972.
Glossary of Geology. American Geological Institute,
Washington, D.C.
Helm, W.T. (Ed.). 1985. Aquatic Habitat Inventory:
Glossary and Standard Methods. Western Division,
American Fisheries Society, Utah State University,
Logan, Utah.
McKechnie, J.L. (Ed.). 1983. Websters New Universal
Unabridged Dictionary. Simon and Schuster,
Cleveland, Ohio.
Rawlins, C.L. 1986. Glossary. In S. Jensen, An
Approach to Classification of Riparian Ecosystems.
White Horse Associates, Smithfield, Utah.
[mimeo]
Schaller, F.W. and P. Sutton. 1978. Reclamation of
Drastically Disturbed Lands. American Society of
Agronomy, Madison, Wisconsin.
Soil Survey Staff. 1975. Soil Taxonomy, A Basic System
of Soil Classification for Making and Interpreting
Soil Surveys. Agriculture Handbook No. 436. U.S.
Dept. of Agriculture, Soil Conservation Service.
U.S. Government Printing Office, Washington,
D.C.
Strickland, R. (Ed.). 1986. Wetland Functions,
Rehabilitation, and Creation in the Pacific
Northwest. Washington State Department of
Ecology, Olympia, Washington.
U.S. Fish and Wildlife Service. 1981. U.S. Fish and
Wildlife Service Mitigation Policy. Federal
Register 46(15):7644-7663.
Zedler, J.B. 1984. Salt Marsh Restoration-A Guidebook
for Southern California. California Sea Grant
Report No. T-CSGC P-009.
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GLOSSARY
AREAL COVER - A measure of dominance that
defines the degree to which above-ground portions of
plants (not limited to those rooted in a sample plot)
cover the ground surface. It is possible for the total
areal cover in a community to exceed 100% because (a)
many plant communities consist of two or more
vegetative strata (overstory, understory, ground cover,
undergrowth); (b) areal cover is estimated by
vegetative layer; and (c) foliage within a single layer
may overlap.
ARTIFICIAL WETLAND - A created wetland
requiring constant application of water or
maintenance to provide wetland values.
BASAL AREA - The cross-sectional area of a tree
trunk measured in square inches, square centimeters,
etc. Basal area is normally measured at 4.5 feet (1.4
m) above ground level or just above the buttress if the
buttress exceeds that height and is used as a measure of
dominance. The most easily used tool for measuring
basal area is a tape marked in units of area (i.e.,
square inches). When plotless methods are used, an
angle gauge or prism will provide a means of rapidly
determining basal area. This term is also applicable to
the cross-sectional area of a clumped herbaceous plant,
measured at 1.0 inch (2.54 cm) above the soil surface.
BASELINE STUDY - An inventory of a natural
community or environment that may serve as a model
for planning or establishing goals for success criteria.
Synonym: reference study.
BENCH MARK - A fixed, more or less permanent
reference point or object, the elevation and horizontal
location of which is known. The U.S. Geological
Survey [USGS] installs brass caps in bridge abutments
or otherwise permanently sets bench marks at
convenient locations nationwide. The elevations on
these marks are referenced to the National Geodetic
Vertical Datum [NGVD], also commonly known as
Mean Sea Level [MSL] although they may not be
exactly the same. For most purposes of wetland
mitigation, they can be assumed to be equivalent
although a local surveyor should be consulted for final
determination. Locations of these bench marks on
USGS quadrangle maps are shown as small triangles.
The existence of any bench mark should be field
verified before planning work that relies on a
particular reference point. The USGS, local state
surveyor's office, or city or town engineer can provide
information on the existence, exact location and exact
elevation of bench marks, and the equivalency of
NGVD and MSL.
CANOPY LAYER - The uppermost layer of vegetation
in a plant community. In forested areas, mature trees
comprise the canopy layer, while the tallest herbaceous
species constitute the canopy layer in a marsh.
CONTROL PLOT - An area of land used for
measuring or observing existing undisturbed
conditions.
CONTOUR - An imaginary line of constant elevation
on the ground surface. The corresponding line on a
map is called a "contour line".
CREATED WETLAND - The conversion of a
persistent upland or shallow water area into a wetland
through some activity of man.
DEGRADED WETLAND - A wetland altered by man
through impairment of some physical or chemical
property which results in a reduction of habitat value or
other reduction of functions (i.e., flood storage).
DENSITY - The number of individuals per unit area.
DIAMETER AT BREAST HEIGHT [DBH] - The width
of a plant stem as measured at 4.5 feet (1.4 m) above the
ground surface or just above the buttress if over 4.5 feet
(1.4 m).
DISTURBED WETLAND - A wetland directly or
indirectly altered from a natural condition, yet
retaining some natural characteristics; includes
natural perturbations.
DOMINANCE - As used herein, a descriptor of
vegetation that is related to the standing crop of a
species in an area, usually measured by height, areal
cover, density, or basal area (for trees), or a
combination of parameters.
DOMINANT PLANT SPECIES - A plant species that
exerts a controlling influence on or defines the
character of a community.
DRAINED - A condition in which the level or volume
of ground or surface water has been reduced or
eliminated from an area by artificial means.
DRD7T LINE - An accumulation of debris along a
contour (parallel to the water flow) that represents the
height of an inundation event.
EMERGENT PLANT - A rooted plant that has parts
extending above a water surface, at least during
portions of the year but does not tolerate prolonged
inundation.
ENHANCED WETLAND - An existing wetland where
some activity of man increases one or more values,
often with the accompanying decline in other wetland
values.
EXOTIC - Not indigenous to a region; intentionally or
accidentally introduced and often persisting.
EXPERIMENTAL PLOT - An area of land used for
measuring or observing conditions resulting from a
treatment (i.e., an installation of particular plants).
FILL MATERIAL - Any material placed in an area to
increase surface elevation.
FREQUENCY (vegetation) - The distribution of
individuals of a species in an area. It is quantitatively
expressed as:
Number of samples containing species A
Total number of samples
X100
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FUNCTIONAL VALUES - Values determined by
abiotic and biotic interactions as opposed to static
measurements (e.g., biomass).
HABITAT - The environment occupied by individuals
of a particular species, population, or community.
HABITAT VALUE - The suitability of an area to
support a given evaluation species.
HEADWATER FLOODING - A situation in which an
area becomes inundated primarily by surface runoff
from upland areas.
HERB - A nonwoody individual of a macrophytic
species.
HERBACEOUS LAYER - Any vegetative stratum of a
plant community that is composed predominantly of
herbs.
HYDRIC SOIL - A soil that is saturated, flooded, or
ponded long enough during the growing season to
develop anaerobic conditions that favor the growth and
regeneration of hydrophytic vegetation. Hydric soils
that occur in areas having positive indicators of
hydrophytic vegetation and wetland hydrology are
wetland soils.
HYDROLOGIC REGIME - The distribution and
circulation of water in an area on average during a
given period including normal fluctuations and
periodicity.
HYDROLOGY - The science dealing with the
properties, distribution, and circulation of water both
on the surface and under the earth.
HYDROPHYTE - Any macrophyte that grows in water
or on a substrate that is at least periodically deficient
in oxygen as a result of excessive water content; plants
typically found in wet habitats. Obligate hydrophytes
require water and cannot survive in dry areas.
Facultative hydrophytes may invade upland areas.
HYDROPHYTIC VEGETATION - The sum total of
macrophytic plant life growing in water or on a
substrate that is at least periodically deficient in
oxygen as a result of excessive water content. When
hydrophytic vegetation comprises a community where
indicators of hydric soils and wetland hydrology also
occur, the area has wetland vegetation.
IMPORTANCE VALUE - A quantitative term
describing the relative influence of a plant species in a
plant community, obtained by summing any
combination of relative frequency, relative density,
and relative dominance.
INDIGENOUS SPECH5S - Native to a region.
IN-KIND REPLACEMENT - Providing or managing
substitute resources to replace the functional values of
the resources lost, where such substitute resources are
also physically and biologically the same or closely
approximate those lost.
INUNDATION - A condition in which water from any
source temporarily or permanently covers a land
surface.
MACROPHYTE - Any plant species that can be readily
observed without the aid of optical magnification. This
includes all vascular plant species and mosses (e.g.,
Sphagnum spp.), as well as large algae (e.g., Chara
spp., kelp).
MAINTENANCE - Any activities required to assure
successful restoration after a project has begun (i.e.,
erosion control, water level manipulations).
MAN-INDUCED WETLAND - Any area of created
wetlands that develops wetland characteristics due to
some discrete non-continuous activity of man.
MEAN SEA LEVEL - A datum, or "plane of zero
elevation", established by averaging hourly tidal
elevations over a 19-year tidal cycle or "epoch". This
plane is corrected for curvature of the earth and is the
standard reference for elevations on the earth's
surface. The National Geodetic Vertical Datum
[NGVD] is a fixed reference relative to Mean Sea Level
in 1929. The relationship between MSL and NGVD is
site-specific.
MESOPHYTIC - Any plant species growing where soil
moisture and aeration conditions lie between extremes.
These species are typically found in habitats with
average moisture conditions, neither very dry nor very
wet.
MITIGATION - The President's Council on
Environmental Quality defined the term "mitigation"
in the National Environmental Policy Act regulations
to include "(a) avoiding the impact altogether by not
taking a certain action or parts of an action; (b)
minimizing impacts by limiting the degree or
magnitude of the action and its implementation; (c)
rectifying the impact by repairing, rehabilitating, or
restoring the affected environment; (d) reducing or
eliminating the impact over time by preservation and
maintenance operations during the life of the action;
and (e) compensating for the impact by replacing or
providing substitute resources or environments" (40
CFR Part 1508.20(a-e)). For the purposes of this
document, mitigation refers only to restoration,
creation, or enhancement of wetlands to compensate
for permitted wetland losses.
MITIGATION BANKING - Wetland restoration,
creation or enhancement undertaken expressly for the
purpose of providing compensation credits for wetland
losses from future development activities.
MONITORING - Periodic evaluation of a mitigation
site to determine success in attaining goals. Typical
monitoring periods for wetland mitigation sites are
three to five years.
NATURAL - Dominated by native biota and occurring
within a physical system which has developed through
natural processes (without human intervention), in
which natural processes continue to take place.
NUISANCE SPECIES - Species of plants that detract
from or interfere with a mitigation project, such as
most exotic species and those indigenous species whose
populations proliferate to abnormal proportions.
Nuisance species may require removal through
maintenance programs.
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OUT-OF-KIND REPLACEMENT - Providing or
managing substitute resources to replace the functional
values of the resources lost, where such substitute
resources are physically or biologically different from
those lost.
PHYSIOGNOMY - A term used to describe a plant
community based on community stratification and
growth habit (e.g., trees, herbs, lianas) of the dominant
species.
PLANT COMMUNITY - All of the plant populations
occurring in a shared habitat or environment.
PLANT COVER - see AREAL COVER.
PONDED - A condition in which water stands in a
closed depression. Water may be naturally removed
only by percolation, evaporation, and/or transpiration.
POORLY DRAINED - Soils that are commonly wet at
or near the surface during a sufficient part of the year
that field crops cannot be grown under natural
conditions. Poorly drained conditions are caused by a
saturated zone, a layer with low hydraulic
conductivity, seepage, or a combination of these
conditions.
PRODUCTIVITY - Net annual primary productivity;
the amount of plant biomass that is generated per unit
area per year.
QUANTITATIVE - A precise measurement or
determination expressed numerically.
RECLAIMED WETLANDS - Same as restored
wetland, but often used in other parts of the world to
refer to wetland destruction due to filling or draining.
REHABILITATION - Conversion of an upland area
that was previously a wetland into another wetland
type deemed to be better for the overall ecology of the
system.
RELATIVE DENSITY - A quantitative descriptor,
expressed as a percent, of the relative number of
individuals in an area; it is calculated by:
Number of individuals of species A
Total number of individuals of all species
-X100
RELATIVE DOMINANCE - A quantitative descriptor,
expressed as a percent, of the relative amount of
individuals of a species in an area; it is calculated by:
Amount of species A
X100
Total amount of all species
The amount of a species may be based on percent areal
cover, basal area, or height.
RELATIVE FREQUENCY - A quantitative descriptor,
expressed as a percent, of the relative distribution of
individuals in an area; it is calculated by:
Frequency of species A
-X100
RELIEF - The change in elevation of a land surface
between two points; collectively, the configuration of the
earth's surface, including such features as hills and
valleys. See also TOPOGRAPHY.
RESTORED WETLAND - A wetland returned from a
disturbed or altered condition to a previously existing
natural or altered condition by some action of man
(i.e., fill removal).
SAMPLE PLOT - An area of land used for measuring
or observing existing conditions.
SOIL - The collection of natural bodies on the earth's
surface containing living matter and supporting or
capable of supporting plants out-of-doors. Places
modified or even made by man of earthy materials are
included. The upper limit of soil is air or shallow
water and at its margins it grades to deep water or to
barren areas of rock or ice. Soil includes the horizons
that differ from the parent material as a result of
interaction through time of climate, living organisms,
parent materials and relief.
SLOPE - A piece of ground that is not flat or level.
SUBSTRATE - The base or substance on which an
attached species is growing.
TIDAL - A situation in which the water level
periodically fluctuates due to the action of lunar and
solar forces upon the rotating earth.
TOPOGRAPHY - The configuration of a surface,
including its relief and the position of its natural and
man-made features.
TRANSECT - As used here, a line on the ground along
which observations are made at some interval.
TRANSITION ZONE - The area in which a change
from wetlands to nonwetlands occurs. The transition
zone may be narrow or broad.
TREE - A woody plant >3.0 inches in diameter at
breast height, regardless of height (exclusive of woody
vines).
UPLAND - As used herein, any area that does not
qualify as a wetland because the associated hydrologic
regime is not sufficiently wet to elicit development of
vegetation, soils, and/or hydrologic characteristics
associated with wetlands. Such areas occurring within
floodplains are more appropriately termed non
wetlands.
WATER TABLE - The upper surface of groundwater or
that level below which the soil is saturated with water.
The saturated zone must be at least 6 inches thick and
persist in the soil for more than a few weeks.
WETLANDS - Those areas that are inundated or
saturated by surface or groundwater at a frequency
and duration sufficient to support, and that under
normal circumstances do support, a prevalence of
vegetation typically adapted for life in saturated soil
conditions. Wetlands generally include swamps,
marshes, bogs, and similar areas.
Total frequency of all species
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INFORMATION NEEDS IN THE PLANNING PROCESS
FOR WETLAND CREATION AND RESTORATION
Edgar W. Garbisch
Environmental Concern Inc.
ABSTRACT. This chapter addresses both the factors which should be considered at various
stages of the permitting process and those which should be contained in plans to create or
restore wetlands. The information wetland regulatory agencies need to critically evaluate
proposed mitigation projects in terms of acceptability, feasibility, and soundness is presented.
If the process suggested is followed, the permit conditions should contain (1) details of
construction and landscape plans, (2) specifications to facilitate verification by the regulatory
agencies that the wetland creation/restoration project has been constructed according to the
plans, and (3) the criteria by which to determine if the project has been maintained and
monitored during the life of the permit.
INTRODUCTION
State wetland regulations and policies vary
widely and many are still under development.
Marked variances also occur in the
administration of federal regulations in the east
and probably nationwide. Consequently, it is not
possible to recommend a planning process for
wetland creation and restoration that will be
uniformly acceptable. This chapter reflects the
opinions of the author whose experiences have
been limited largely to the eastern United States.
Hopefully, the recommendations provided here
will prove useful and applicable to some regions
of the United States.
Much of the wetland creation and restoration
work conducted throughout the United States
results from regulatory requirements that
compensation (mitigation) take place for
permitted wetland impacts and losses. Prior to
issuing permits, regulatory agencies review the
applicants' mitigation plans to ensure that
disturbed wetlands are restored or appropriate
compensation is provided through compensation.
If proposed mitigation plans are found
acceptable, they generally become part of the
permits together with stipulations or conditions
relating to criteria for success and acceptability,
timetables for wetland creation/restoration,
monitoring, and reporting-especially when these
stipulations or conditions have not been
specifically addressed in the mitigation plans.
Most of the wetland creation/restoration
plans published in the Corps of Engineers Public
Notices lack the details necessary to evaluate
their potential for successful execution. Such
plans are often the only ones available for
review by interested members of the general
public and by the state and federal regulatory
agencies. Moreover, they are often of insufficient
detail for the agencies to verify that the "as built"
project will compare acceptably to the one
conceptually proposed. Without such details, the
regulatory agencies must place full
responsibility on the applicant, and indirectly on
the applicant's mitigation consultant, to design
and acceptably construct the wetland
creation/restoration as called for in the permits.
If a regulatory agency is charged with the
preservation of wetlands by legislation and
policy, and if the agency permits a given
wetland to be destroyed provided there is
adequate compensation, then the regulatory
agency's responsibility is to (1) engage in all
aspects of review and evaluation of the wetland
construction details, as well as other matters of
planning, and (2) help ensure that such
compensation is constructed successfully. Re-
quiring "successful compensation" as a permit
condition does not, in itself, ensure success. The
compensation site and/or the plans and
specifications may be inappropriate and success
may not be possible. The regulatory agencies
should have complete confidence in the
compensation site and in the plans and
specifications before making success a permit
condition.
The objectives of this chapter are to define the
information needed by the regulatory agencies at
pre-permit application, at permit application, and
during the life of the permit in order for proposed
wetland creation/restoration mitigation projects
to be fully and critically evaluated in terms of
(1) acceptability, feasibility, and soundness of the
proposed plan, (2) the construction performance
as related to the project being constructed in
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accordance with the plans and specifications,
and (3) the post construction performance as
related to maintenance of hydrological
requirements and vegetation establishment. All
of the above combine to provide the regulatory
agencies' planning process for wetland creation
and restoration.
If a regulatory agency feels that it does not
have in-house the qualified staff to conduct the
necessary critical review and evaluation of
detailed mitigation plans involving wetland
creation/restoration, a qualified consultant
might be retained to perform this service.
PRE-PERMIT APPLICATION
The development of detailed construction
plans and specifications for wetland
creation/restoration mitigations is usually time
consuming and expensive. Their submittal
should not be required until such time that (1) the
regulatory agencies have agreed that the proposed
project will be permitted pending review and
acceptance of a final mitigation plan or (2) it is
determined to be in the best public interest that
they be submitted (e.g., for complicated or
controversial projects).
Generally, the regulatory agencies will not
discuss wetland creation/restoration as a
compensatory measure for proposed wetland
losses and impacts at early stages of pre-permit
application meetings. They must be assured first
that all other measures to mitigate such losses
and impacts have been explored. However, after
this is done, the applicant should be prepared to
discuss wetland creation/restoration when
certain wetland losses and impacts are
unavoidable. In this event, the applicant should
have available for distribution and discussion a
preliminary mitigation plan that contains the
basic information provided below.
PRELIMINARY MITIGATION PLAN
The Preliminary Mitigation Plan should
contain the following:
1. Text, 8.5" X 11" plans, and photographs
describing the existing conditions at the
project site and particularly the wetlands on
site and the portion(s) of these wetlands
where disturbance and/or loss is
unavoidable. Accurate areas of all wetlands
to be disturbed and/or lost should be provided
according to wetland type, if more than one
type is involved.
2. An evaluation of all wetlands that are
proposed to be disturbed and/or lost including
their apparent stabilities, their dominant
vegetative compositions, and their prevailing
functions. An objective evaluation such as
provided by WET (Wetland Evaluation
Technique) to level-1 is suggested.
3. Text, 8.5" X 11" plans, and photographs
briefly describing the existing conditions at
the wetland creation site.
4 Text and 8.5" X 11" plans that describe
conceptually the proposed •wetland creation
together with arguments, data, and
calculations that demonstrate that the
necessary hydrological requirements will be
realized. Accurate areas of all wetlands to be
created should be provided according to
wetland type, if more than one type is
proposed to be created.
5. An evaluation of the proposed created
wetland(s), as in Section 2, with an emphasis
on functional replacement and enhancement
relative to those functions provided by the
existing wetland(s) to be lost.
6. Text providing methods of any wetland
restoration that is proposed together with
discussion of any possible enhancement of
functional values that may be provided as
part of the restoration. Issues related to the
impact of soils compaction and other wetland
disturbances on the success of the restoration
should be addressed. If such impact(s) may
limit the success of the restoration,
approaches to circumvent the problem(s)
should be discussed.
The Preliminary Mitigation Plan should not
be a voluminous submittal. It should be brief and
to the point. It is intended to be the precursor to
the Draft Mitigation Plan which should be
submitted later with the permit application,
following reviews and comments by the
regulatory agencies.
If the necessary hydrological requirements
for the created wetland cannot be verified,
monitoring of stream flows, ground water levels,
etc. will be necessary for up to one year before the
Draft Mitigation Plan can be prepared. Detailed
soil borings throughout the proposed wetland
creation site should be completed prior to
preparing the Draft Mitigation Plan to verify that
the soil characteristics will support the desired
hydrology and functions of the created wetland.
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PERMIT APPLICATION
DRAFT MITIGATION PLAN
Following any necessary monitoring and
testing, and receipt and consideration of
comments by the reviewing agencies, the Draft
Mitigation Plan can be prepared. The Draft
Mitigation Plan is a revised Preliminary
Mitigation Plan and will include changes
primarily in Sections 4-6.
The 8.5" X 11" plans provided in the Draft
Mitigation Plan should be sufficient to be
included in the Corps of Engineers Public Notice.
Larger plans that are reduced to 8.5" X 11" are
not recommended, as details and letterings may
be reduced beyond recognition. After receipt of
the comments on the Public Notice and review of
comments derived from any public meetings, the
regulatory agencies will come to a decision
regarding issuance of permits. If the decision is
to issue such permits pending receipt and
acceptance of the construction and landscape
plans and specifications for any created and
restored wetlands, these materials must be
provided. These plans and specifications together
with the Draft Mitigation Plan constitutes the
Final Mitigation Plan. The Final Mitigation
Plan may have been requested by the regulatory
agencies at an earlier time or it may have been
provided voluntarily by the applicant.
FINAL MITIGATION PLAN
Draft Mitigation Plan + Construction and
Landscape Plans and Specifications
The construction and landscape plans and
specifications should be sufficiently detailed for
bidding purposes, engineering and biological
review, and verification of the "as built"
condition. All monitoring, inspections,
reporting, and maintenance during the life of the
permit or during the required period of time
should be detailed on the plans and
specifications. The extent and duration of all
landscape guarantees should be specified. It is
recommended that the plans and specifications
submitted as part of the Final Mitigation Plan
include but not necessarily be limited to the
following items:
1. All plans should be scaled at 1" = 100' or
larger i.e., 1" = 50') and show 1.0' contours
or less, if important.
2. All slopes should be designed to be stable in
the absence of vegetation.
3. Sufficient cross-sections of land and
structures should be provided so as to clarify
all typical and atypical conditions.
4. In addition to wetlands, all land (e.g.,
transition and buffer zones and upland)
included in the proposed mitigation should be
shown.
5. A summary of the sizes and types of
wetlands lost and created should be given.
6. A summary of the sizes and types of non-
wetland habitats created as enhancement
features should be given.
7. The site hydrology should be clearly shown.
For example:
Pool Elevation: if water level is static and
non-fluctuating.
Seasonal Pool Elevations: spring, summer,
fall/winter if water level fluctuates.
Tidal Elevations: when flooding water is
tidal. Mean high water (MHW), and mean
low water (MLW) should be indicated.
Corrections to National Geodetic Vertical
Datum (NGVD) or other local datum should
be provided in the NOTES.
Ground Water Levels: when flooding is
temporary during times of storms and
spring thaws. The expected seasonal ground
water levels should be provided in the
NOTES.
8. Verification of hydrology should be detailed
in the NOTES: e.g., stream flow year-round
and weir controls pool level; groundwater
given in soil boring logs; stream/river water
level data and analyses; calculations if
stormwater is the only source of water;
vegetation zonation of existing nearby
wetlands sharing the same hydrology as the
proposed vegetated wetlands; etc.
9. The construction timetable should be
provided together with notations of any
elements whose timing may be critical to
biological success; e.g., coordination of
completion of earthwork with the installation
of certain species of plants to minimize the
impact of salt buildup in soils; timing of
plant installation to minimize the impact of
waterfowl and drought; specify time windows
for seeding to ensure vegetation
establishment.
10. The locations and elevations of all bench
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marks on site should be shown on the plans.
11. A Summary of the volume of earthwork and
total tonnage of stonework should be given.
12. The proposed disposition of any excavated
materials should be given.
13. The elevations and elevation ranges for the
planting and seeding of all plant species
should be shown. Plant spacings and seeding
rates should be given.
14. Landscape lists, notes, and specifications
should include the following:
a. Plant lists for seeding and planting that
provide total quantities, plant sizes, and
plant conditions (e.g., bare root, can, peat
pot, etc.). Acceptable substitutes should be
indicated if the availability of some
species might be limited.
b. Because of the variable quality of
nursery-produced wetland plant mater-
ials, acceptable plant conditions should
be clearly specified. Some examples
follow: Container grown nursery stock
shall have been grown in a container
long enough for the root system to have
developed sufficiently to hold its soil
together. Peat-potted nursery stock shall
have been grown in 1.50" to 1.75" square
peat pots long enough and under proper
conditions for the root systems to be
sufficiently well-developed through the
sides and bottoms of the pots to prevent
easy removal of the plants from the pots.
Each pot shall contain a minimum of
(specify) steins. Container grown
nursery stock to be transplanted to wet
areas year-round shall have been grown
under hydric soil conditions for at least
one growing season. The nursery pro-
viding these materials must certify that
these growing conditions were met.
c. Fertilization requirements that include
rates and fertilizer formulations.
d. Any special conditioning of the plant
materials that may be required. For
example, conditioning plant materials to
specified water salinities or condition-
ing facultative/facultative wet species to
hydric soil cultivation.
e. Any geographical constraints regarding
the origin of the plant materials.
f. The names and addresses of all
acceptable commercial sources of plant
materials.
g. A requirement that the supplier of seeds
specified provide the purity and the
current germination percentages of the
seeds.
h. What plant materials, if any, may be
field collected and from where they will
be taken.
i. Construction details and timetable for
any required controls against wildlife
depredation.
j. Details and definitions of any landscape
guarantees, including the guarantee
periods.
15. Maintenance program during the guarantee
period, the life of the permit, or other
required period should be detailed. Such
maintenance may include invasive weed
control of algae, common reed, purple
loosestrife, etc.; removal of deposited litter
and debris; watering; replanting; repair of
water control structures; clearing of culverts;
etc.
16. Any critical elements and possible problems
(with solutions) that may influence the
success of the project should be described,
even if these items have been addressed in
other sections; i.e., 9, 14i, 15. For example, a
watering program for vegetation establish-
ment in a floodplain wetland construction
may be critical for success and should be
restated, even though such a program was
included in Section 15. In many instances,
wildlife management will be critical for
success and should be restated, even though
Section 14i describes the item.
17. Reporting timetable during the life of the
permit or until final approval should be
included. The regulatory agencies will want
to be informed periodically regarding the
wetland construction progress. For example,
is construction on schedule and, if not, why
and what is being done to get it back on
schedule. Are the criteria for success being
realized (i.e., has the project been constructed
according to the plans and specifications)
and if not what corrective action is being
taken. Reporting of the results of monitoring
should be included in the reporting timetable.
Generally, it would seem appropriate to
report quarterly during the construction
phase of the wetland and annually thereafter
during the life of the permit or until final
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18.
inspection and approval. Photographs that
are keyed on the site plan and that show the
existing conditions should be included with
all reports to facilitate verifications by the
regulatory agencies.
The monitoring program for the life of the
permit should be provided in the
specifications or on the plans.
It is the author's opinion that if the wetland
is constructed or restored according to the
detailed construction and landscape plans and
specifications that are part of the Final
Mitigation Plan, the project must be considered
successful. If the "as built" project is according
to plans and specifications, then the wetland
functional replacement and enhancement, as
determined in Section 5 of the Draft Mitigation
Plan, have been realized. Consequently, the
monitoring program should be one of inspection
and verification of the "as built" project
according to hydrological performance, veg-
etation establishment, and other key elements in
the plans and specifications. Scientific studies
should not be part of a monitoring program
sanctioned by the regulatory agencies. While
such studies often will be important and should
be encouraged, they should not be part of the
required mitigation process.
CONCLUSION: NEED FOR CERTIFICATION
OF MITIGATION CONSULTANTS
To a very large degree, the success of
wetland creation/restoration projects will depend
on the correctness of the plans and specifications
and the execution of the construction according to
these plans and specifications. Consequently, it
is important that people with a background in
both wetland creation/restoration design and the
practicalities of construction become associated
with such projects. To ensure that future wetland
creation/restoration projects are planned and
directed by qualified people, it is suggested that
the Preliminary, Draft, and Final Mitigation
Plans be signed and stamped by an individual
who has been certified as a qualified wetland
creation/restoration scientist. It is further
suggested that such a certification program be
undertaken by an organization such as The
Society of Wetland Scientists.
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WETLAND EVALUATION FOR RESTORATION AND CREATION
Kevin L. Erwin
Kevin L. Erwin Consulting Ecologist, Inc.
ABSTRACT. One of the principal questions that must be addressed when evaluating the
success of a created, restored, or enhanced wetland is, to what extent does the wetland provide
biological and hydrological functions similar to those of the original or desired "reference"
wetland. Wetland evaluation methods are widely discussed throughout the literature.
However, many would not be appropriate to evaluate a created or restored wetland,
particularly given the time and financial limitations often placed upon the investigator and
reviewer. The selected method must adequately characterize and evaluate the functions of the
created and reference wetlands given the limitations of time, budget, type of wetland, size of
wetland, context, degree of alteration from original wetland, location, and expertise of
investigator. A qualitative wetland evaluation plan should include: a baseline vegetation
survey, annual reporting of post construction monitoring conducted for a minimum of five
years, fixed point panoramic photographs, rainfall and water level data, a plan view showing
all sampling and recording station locations, wildlife utilization observations, fish and
macroinvertebrate data, a maintenance plan, and a qualified individual to conduct
monitoring. Quantitative evaluation is recommended when the proposed construction
technique is unproven, where the ability to successfully create or restore the habitat is
unproven, or when success criteria are related to obtaining specific thresholds of plant cover,
diversity, and wildlife utilization. Quantitative evaluation should include: surface and
groundwater hydrological monitoring, and vegetation analysis. The methods will often
require some site specific fine tuning to prevent the over simplification of the wetlands
complexity.
A rapidly accessible, easily understood, and cost effective database on wetland creation
and restoration projects is needed to support environmental regulatory agency review,
decision making, and action on specific projects. Any comprehensive wetland evaluation
effort must be proceeded by the establishment of criteria which the investigator and regulator
believe to be fundamental to the existence, functions, and contributions of the wetland system
and its surrounding landscape. Failure to address the wetlands system's surrounding
landscape leads to an inaccurate characterization of the wetland. Additional research is
needed to establish the inter-relationships between wetlands, transitional areas, and adjacent
uplands.
INTRODUCTION
Wetland evaluation is needed prior to a
project to set goals and develop a plan, as a
component of the monitoring program, and as a
means for ultimately determining compliance.
Although the timing differs for each of these
evaluations, the factors to be considered and the
general needs and approaches are much the
same.
The following chapter has been prepared to
assist consultants, client/permit applicants, and
regulatory personnel in evaluating restored and
created wetlands. It does not exhaustively review
potential evaluation approaches, but presents a
general framework and discusses selected topics.
The chapter draws heavily upon the author's own
experience and his many discussions with
colleagues. An extensive bibliography of
publications dealing with wetland evaluation is
provided to assist the reader. As can be seen
from the bibliography, a number of efforts have
developed and assessed methods for evaluating
wetlands. The author draws your attention to:
Golet 1973, Winchester and Harris 1979, Reppert
et al. 1979, U.S. Army Engineer Division 1980,
U.S. Fish and Wildlife Service 1980, Lonard et
al. 1981, Adamus and Stockwell 1983, Adamus
1983, Euler et al. 1983, Lonard et al. 1984, and
Marble and Gross 1984.
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EVALUATION NEEDS IN RESTORATION/CREATION
Evaluation may be needed for any or all of
the following purposes:
1. Assessing the Original Wetland. The
investigation must obtain, if possible,
baseline data which evaluates the reference
wetland's form and functions. The reference
wetland may be the wetland to be impacted or
another wetland chosen as a model for the
mitigation project. This baseline data should
be used to aid in the establishment of selected
success criteria and the design of the
wetland project.
2. Setting goals for the enhancement,
restoration or creation of a wetland required
as mitigation. Prior to designing the
wetland required as mitigation, if possible,
the wetland to be restored or enhanced, or an
acceptable reference wetland should be
evaluated. This information should be used
to set goals for the mitigation project. It also
should be used as a baseline from which to
design the mitigation project and measure
its success. In the case of wetland
enhancement, the pre-enhancement baseline
evaluation date will be compared with post-
enhancement data.
3. Assessing Project During Maturation.
Monitoring a project periodically during
maturation will determine the need for
corrections in design or maintenance to get
the project back on course.
4 Determining Post-Project Compliance. At this
stage the evaluation is used to establish
compliance with goals or success criteria and
to obtain the regulatory agencies' approval.
5. Describing the Long Term Status. Informa-
tion about the wetland's responses to changes
in site conditions (i.e., increased water
levels, decreased hydroperiod, or colonization
by problematic exotic vegetation) is obtained.
This will indicate the ability of the system to
persist.
The following is a general discussion of
factors and considerations in wetland
evaluation. It is intended as an overview of the
choices available and not as an instructional
guide to performing detailed data collection and
analysis. These methods, when used individ-
ually or in some combination, will provide a
varied database: qualitative or quantitative,
inexpensive or costly, and relatively quick or
lengthy.
PRACTICAL CONSIDERATIONS
What is the practical approach to wetland
evaluation in a particular restoration/creation
context or at a specific stage of a project? The
answer depends upon a variety of factors.
Economic and spacial constraints must be
considered for each project evaluation. The
investigator should evaluate the available
methods and select or develop the method best
suited to the situation given its limitations. In
many instances the limitations placed upon the
investigator have a greater influence on the
methods finally selected than the objectives of the
study.
TIME
Time may be a factor when conducting
baseline monitoring of a wetland area because of
the constraints of the permit application review
procedure. In most cases, the regulatory agency
should require baseline monitoring to be
presented with the permit application to aid in the
evaluation of existing conditions and in the
establishment of success criteria.
In many instances the investigator may not
have the time necessary to conduct a thorough
study over the desired number of wet/dry or
growing seasons. In such cases, the investigator
should choose a time which will provide the
greatest amount of information about the site.
This information should be easily gathered over
time. The most satisfactory time for a limited
event evaluation is during the late phase of the
growing season and, if possible, when the site is
inundated to allow for the collection of fish and
macroinvertebrate samples.
BUDGET
In some instances (i.e., where the project is
small or where a public agency is involved) only
limited funds will be available for evaluation.
In cases where budget constraints exist, some
compromises will inevitably be necessary. The
investigator must choose an evaluation method
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and monitoring plan which is the most efficient
and provides the greatest amount of desired
information at the least cost ("the most bang for
the buck").
TYPE OF WETLAND
Certain methods are more appropriate for
one type of wetland than another (i.e., line
intercept for nonforested wetlands and line strip
or belt transects for forested wetlands). In
addition, the fact that certain wetland habitats
have proven to be less difficult than others to
restore or create should have a bearing on the
evaluation method used, and the scope of the
baseline monitoring of the reference wetland
and the post-construction monitoring.
hardwoods), therefore, the monitoring of a marsh
restoration project may need to be intensive for a
shorter period of time. Many marsh restoration
projects can be successfully completed and
agency approval received within three growing
seasons following construction, whereas a
forested wetland project may take one to three
decades.
DEGREE OF ALTERATION FROM
ORIGINAL WETLAND
The greater the deviation of the proposed
restoration or enhancement project from the
original wetland, the more comprehensive the
baseline and post wetland construction
evaluation methods should be.
SIZE OF WETLAND
The size of the wetland, the number and
types of habitats to be evaluated, and the
parameters to be examined will place constraints
on the method selected.
CONTEXT
The selection of an evaluation method
should depend upon whether single or multiple
parameters are chosen as success criteria for the
enhanced, created, or restored wetland. If
wildlife utilization is the major goal, then a
detailed vegetative analysis could be replaced by
a more simple floral characterization with
greater emphasis on monitoring for wildlife
utilization. The science of creating certain
marsh habitats is more advanced than for most
forested wetland habitats (e.g., bottomland
LOCATION
Wetlands are "open" systems with strong
links to their adjacent ecosystems. A major
factor determining the ecological value of the
wetland is its relationship with other ecosystems.
These relationships make the wetland an
integral part of the landscape of a region or
watershed.
EXPERTISE
The biases, objectives, and the expertise of an
investigator will influence the choice of a
method, therefore care must be taken to
objectively select a method of evaluation that can
successfully be used. This caution also holds true
for the reviewer who must have an adequate
understanding of the method and presentation of
data.
WETLAND FUNCTIONS NEEDING ASSESSMENT
At each stage, the wetland evaluation should
be geared toward evaluating particular functions
of the created or reference wetland. Excellent
references on wetland functions are in the
proceedings of a national symposium on
wetlands held in 1978 (Greeson, Clark and
Clark, 1979), in Reppert et al. (1979), Larson
(1982), Adamus (1983), Sather and Smith (1984),
Gosselink (1984), Mitsch and Gosselink (1986),
and Kusler and Riexinger (1985).
The Federal Highway Administration's
Wetland Functional Assessment Method
recognizes eleven functions (Adamus 1983)
which form a good checklist. These functions
are:
GROUNDWATER RECHARGE
Groundwater recharge by wetlands is
generally poorly understood. The majority of
hydrologists believe that while some wetlands do
recharge ground water systems, most wetlands do
not (Sather and Smith 1984). The soils
underlying most wetlands are impermeable
which is why there is standing water during the
annual cycle (Larson 1982). In the few studies
available, recharge was related to the
edge:volume ratio of the wetland. Recharge
appears to be relatively more important in small
wetlands such as prairie potholes than in large
wetlands (Mitsch and Gosselink 1986). These
small wetlands can contribute significantly to
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recharge of regional groundwater (Weller 1981).
Heimberg (1984) found significant radial
infiltration from cypress domes in Florida, with
the rate of infiltration relative to the area of the
wetland and the depth of the surficial water table.
If groundwater recharge is a goal of the
restoration or creation project, the design should
emphasize the wetland edge to maximize
potential for groundwater recharge.
GROUNDWATER DISCHARGE
Wetlands are generally considered by
hydrologists to be a discharge area in terms of
total water budget, however, recharge and
discharge may be occurring at the same time in
some wetlands. The recharge/discharge
relationship of a wetland is a function of
groundwater piezometric surface ("head")
relationships and antecedent conditions
(Hollands 1985). Water may be recharging an
aquifer and/or discharging to a down gradient
wetland, attenuating flows, and possibly
providing baseline water flows to the down
gradient wetland.
FLOOD STORAGE
Wetlands may intercept and store
stormwater runoff, and hence change sharp
runoff peaks to slower discharges of longer
duration. Since it is usually the peak flows that
produce flood damage, wetlands can reduce the
danger of flooding (Novitzki 1979, Verry and
Boelter 1979). A study undertaken by Ogawa and
Male (1983) found that for floods with a 100-year
recurrence, interval or greater, the increase in
peak stream flow was very significant for all
sizes of streams when the wetlands within the
watershed were removed.
Ogawa and Male (1983) summarized that the
usefulness of wetlands in reducing downstream
flooding increases with: (a) an increase in
wetland area, (b) the seriousness of the flooding
downstream of the wetland, (c) the size of the
flood, (d) the closeness to the upstream wetland,
and (e) the lack of other storage areas such as
reservoirs. These factors should be considered if
the proposed restoration or creation project is
within a flood prone area where some
improvement to these conditions is desirable.
SHORELINE ANCHORING
Wetlands such as tropical mangrove forests
and temperate Spartina- Juncus saltmarshes,
bind shoreline sediments with their root systems,
thus anchoring the substrate. The aboveground
biomass provides friction to overland sheetflow,
wave energy, and storm surges, providing a
degree of stabilization to the shoreline under
natural conditions.
SEDIMENT TRAPPING
Wetlands can serve as sinks for particular
inorganic nutrients. Many marshes are nutrient
traps that purify the water flooding them.
Wetlands have several attributes that cause them
to have major influences on chemical materials
that flow through them (Sather and Smith 1984).
Mitsch and Gosselink (1986) describe these
attributes in the following manner:
A. A reduction and velocity of streams entering
wetlands, causes sediments and chemicals to
drop into the wetland.
R A variety of anaerobic and aerobic processes
such as denitrification and chemical
precipitation remove certain kinds of chem-
icals from the water.
G The high rate of productivity of many
wetlands can lead to high rates of mineral
uptake by vegetation and subsequent burial
in sediments when the plants die.
D. A diversity of decomposers and decomposi-
tion processes occur in wetland sediments.
E. A high amount of contact of water with
sediments, because of the shallow depths, lead
to significant sediment-water exchange.
F. The accumulation of organic peat in many
wetlands causes the permanent burial of
chemicals.
FOOD CHAIN SUPPORT
Wetlands possess an inherent ability to trap
nutrients. They often store nutrients when there
is an abundance, then frequently release them
when they are most needed (Niering 1985). In
mature wetlands, food chains are elaborate,
species diversity is high, the space is well-
organized into many different niches, organ-
isms are larger than in immature systems, and
life cycles tend to be long and complex.
Approximately 60% of the fish and shellfish
species that are harvested commercially are
associated with wetlands. For example, many
fish species utilize wetlands as spawning and/or
nursery areas. Some important species are
permanent residents and others are transients
that periodically feed in the wetlands. Virtually
all freshwater species are somewhat dependent
upon wetlands, often spawning in marshes
bordering lakes or in riparian forests during
spring flooding. Saltwater species tend to spawn
offshore, moving into the coastal marshes during
18
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their juvenile stages, then migrating offshore as
they mature. The importance of wetlands to the
sport and commercial fishery harvest is well
documented in the literature (Peters et al. 1979).
WILDLIFE HABITAT
It has been estimated that within North
America 150 kinds of birds and some 200 kinds
of animals are wetland-dependent. Other
animals including deer, bear, and racoon also
use wetlands (Niering 1985). In addition,
wetland habitats are necessary for the survival
of a disproportionately high percentage of
endangered and threatened species.
ACTIVE RECREATION, PASSIVE
RECREATION, HERITAGE, AND
EDUCATION
Wetlands are living museums, where the
dynamics of ecological systems can be taught.
The high productivity of wetlands is related to the
efficient functioning of both the grazing and
detritus food chains. In many wetlands there are
two major energy flow patterns: (1) the grazing
food chain, which involves the direct
consumption of green plants, and (2) the detrital
food chain, composed of those organisms that
depend primarily on detritus or organic debris
as their food source. Often the two patterns are
interrelated. In lake and pond ecosystems,
submerged aquatic plants and floating algae
serve as the basis of the food chain. Zooplankton
feed on the algae and aquatic insects eat the
zooplankton. These are eaten by small fish,
which in turn are consumed by larger fish,
which in turn may end up on a fisherman's
dinner table. In streams, the main sources of
organic input, or food for stream organisms,
include partly decomposed leaves or other
organic material flowing down stream. This
debris, or detritus, may be caught in nets set by
the larvae of caddis flies. Stone flies also glean
the rocks for algae. These insects are in turn
consumed by fish, many of which are
commercially important.
Activities such as sport fishing along a
wetland edge of a lake and canoeing through a
hardwood swamp are pursued by thousands of
people on a regular basis. Wetlands are an
important national heritage providing the sites
and experiences many of us attribute to our
country's heritage.
FISHERY HABITAT
Wetlands have been documented as
important sources of food and habitat for sport
and commercial fisheries. These outdoor
laboratories can demonstrate such basic
ecological principles as energy flow, recycling,
and limiting carrying capacity (Niering 1985).
The Federal Highway Administration
(PHWA) assessment procedures are among
several which can by used for wetland
evaluation for restoration/creation purposes.
There are limitations, however, with this
approach. Manual implementation of the FHWA
assessment procedure (Adamus 1983) is
cumbersome and time consuming. The U.S.
Army Corps of Engineers Waterways
Experiment Station (WES) developed a wetland
evaluation technique (WET) that can reliably
assess and partially quantify wetland functions
and values for Corps of Engineers use. The main
structural reorganization of the FHWA
technique was to computerize the analytical
portion. A discussion of WET is provided in
Clarian (1985) and more detailed information on
WET is contained in Winchester (1981a and
1981b).
LEVEL OF DETAIL-DEGREE OF QUANTIFICATION
Having determined the stages in a
restoration/creation project at which evaluation
should take place and the functions that need
assessment, the next major decision relates to the
level xif detail needed. In general, quantitative
evaluation is much more expensive and time-
consuming than qualitative approaches. How-
ever, quantitative approaches are essential in
some instances.
To determine whether qualitative or
quantitative evaluation methods are appropriate,
the investigator should consider the established
history of success in creating the type of wetland
proposed for mitigation. In general, much more
quantitative and detailed analyses are needed
for wetlands with no history of success in
creation or restoration.
Choosing the appropriate level and detail
ofevaluation and the factors to be evaluated in a
particular instance is a process that must be
thoroughly considered by each party involved in
the evaluation process including the investigator,
the reviewer, and the client/applicant. Each
should consider the appropriateness of the
selected method to provide an adequate character-
ization of the wetland and the ability to produce
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the required data and analysis within a realistic
time frame. The client or project manager must
also assess his/her ability to provide the required
budget for the expected duration of monitoring
and reporting.
Assuming appropriate funding, enough time,
and an attempt to create a wetland with no or
little history of success, what should the propon-
ent of a wetland restoration/creation project
evaluate? The author suggests the "quantitative"
evaluation described in the following section.
QUANTITATIVE EVALUATION
When the investigator requires quantitative
data, both detailed field studies and office
evaluation are required. A detailed evaluation
often involves hydrologic analysis, studies on
plant and animal population dynamics, water
quality sampling, soils analysis, topographic
mapping, wildlife counts, and a regional
watershed analysis. These studies are time
consuming, labor intensive, costly, and subject to
producing biased results when not properly
conducted.
Quantitative evaluation is particularly
needed when (1) the proposed construction
technique is unproven, (2) where the ability to
successfully create or restore the habitat has not
been established, or (3) when success criteria are
related to attaining specific thresholds of plant
cover, diversity, wildlife utilization, etc. Prop-
erly applied quantitative evaluation may often be
replaced by less intensive evaluation methods
after a sufficient period of study (i.e., the latter
stages of a restoration/creation project).
Investigators need rapidly accessible, easily
understandable, and cost effective data in support
of environmental regulatory agency review,
decision making, and action on specific projects
pursuant to local, state, and federal policies and
regulations. A variety of systematic and
quantified approaches for evaluating either
individual or the full range of wetland functions
have been developed by agencies and researchers
(see Appendix I). These assessment models vary
from very simple to quite sophisticated in the
types of factors considered. Their outputs range
from a qualitative to a quantitative evaluation of
a particular wetland's ability to provide a
particular service or function. Some models
produce a single numerical rating for the
wetlands, while others provide a rating for each
function.
HYDROLOGY
Hydrology is the single most important
factor to consider in designing and
implementing restoration/creation projects for
specific types of wetland systems and their
related functions.
GROUNDWATER
Gathering actual wetland groundwater data
is time consuming and expensive; extrapolating
data from one wetland to another can be
problematic. No quick, accurate, and inexpen-
sive groundwater function predictors are
available. Even hydrogeologists experienced in
wetland hydrology cannot consistently predict
the hydrogeologic functions of specific wetlands
(Hollands 1985). Data requirements for
understanding the groundwater function of a
specific wetland include:
1) Geologic history, including an
understanding of the current theories
relative to the geologic processes that created
the topographic and hydrologic setting in
which the wetland is located, (e.g., bedrock
and surficial geology).
2) Stratigraphy of the geologic units underlying
the wetland and their physical properties,
such as permeability.
3) History, stratigraphy, and physical properties
of the wetland's organic or mineral soils.
4) Description of the wetland vegetative
community.
5) Groundwater and surface water hydrology,
including a water budget for the wetland
based on items 1 through 4 above.
The recharge/discharge relationship of a
wetland is a function of groundwater (head)
relationships and antecedent conditions. To
determine head relationships, nested water table
observation wells (piezometers) are required.
These permit simultaneous measurements of
head at various levels within the aquifer.
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Measurements for at least one year should be
required to establish a complete record of
recharge/discharge functions. This is normally
a costly process.
Perched wetlands, water table wetlands, and
other hydrogeologic classifications such as
artisan and water table/artisan wetlands (Motts
and O'Brien 1980) also require nested wells for
identification. Hydrogeologic classifications of
wetlands are important in understanding a
wetland's water balance and the effect of
hydrology on other wetland functions (Hollands
1985). The wetland hydrogeologic classification
that appears to be most used by non-
hydrogeologist wetland regulators is that of
Novitziky (1978). Novitziky classified wetlands
in Wisconsin as "surface water depression",
"groundwater depression", "surface water slope"
or "groundwater slope". This classification
combines topography, surface water, and
groundwater parameters. However, without
wetland specific hydrogeologic data, it is doubtful
if this method can be accurately applied by non-
hydrogeologists (Hollands 1985).
SURFACE WATER
A hydrological model should be developed to
determine the watershed dynamics which affect
the subject wetland system. Usually a very
simple model can at least establish the extent of
the watershed, timing and volume of input to the
wetland, depth and duration of flooding, and
discharge from the wetland. Post-construction
monitoring of the created wetland should
establish where fine tuning is required in order
to provide the desired levels of inundation and
hydroperiod. As noted above, the wetland's
relationship to the surrounding 'groundwater
system should be identified when constructing
the hydrological model. Water quality analysis
is also recommended at upstream and
downstream locations as well as within the
wetland itself to determine inputs to the wetland
and its present ability to handle pojlutants.
Riparian wetland systems will' require
evaluation of stream flow and the sedimentation
process.
Ideally, monitoring of ground and surface
water quantity and quality should be done in the
reference wetland area for at least one annual
cycle, and if possible, including two wet seasons
and one dry season. Similar monitoring for the
created wetland should be done until the project
goals are met and possibly longer where this
information is of value to the long term
management of the system. Factors critical to the
maintenance of the wetlands's hydrology and
that of surrounding lands should be used to assist
in future land use decisions and to prevent
adverse impacts from taking place.
VEGETATION
Analysis of the vegetation in a wetland
system is usually second only to understanding
the hydrology of the area when characterizing the
wetland and evaluating its functions. The
method of monitoring/evaluation will depend on
the type and size of the wetland. The methods
discussed below are "goal oriented", that is, they
will provide sufficient data to adequately
characterize the reference and created wetland
systems for quantitative measurement of success
criteria.
In order to adequately characterize reference
wetland vegetation within the scope of most
mitigation related evaluations, three methods are
recommended and described below: (1) belt
transects for forested wetlands, (2) replicate
quadrats for herbaceous wetlands, and (3)
multiple quadrats for shrub wetlands.
BELT TRANSECT
This method, also called the modified line
intercept method (Bauer 1943), consists of
observation of plant species occurring along a
belt transect extending through the study area. A
single belt transect 6.10 meters in width divided
into 15.25 meter intervals is established through
each forested wetland. The belt transect is
positioned so that each vegetation zone of the
wetland is sampled. Belt transects should extend
into adjacent upland in order to characterize the
wetland-upland ecotone as well as the upland
habitat. Each interval of the belt transect
(quadrat) covers 93.025 square meters. Within
each quadrat canopy, rnidstory, and groundcover
taxa are recorded. The diameter at breast height
(DBH) of all canopy trees (DBH > 25.4
millimeters) are measured to the nearest 30.48
millimeters. Trees with multiple stems
originating from a common trunk are recorded
as individual trees. The percent cover of
midstory taxa (DBH < 25.4 millimeters and 457.2
millimeters or greater in height) should be
estimated for the entire quadrat. Percent cover of
ground cover taxa (less than 0.91 meters in
height) is estimated for the entire quadrat.
Water depth and percent cover of bare ground
should also recorded.
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REPLICATE QUADRATS
The vegetation within individual reference
or created herbaceous wetlands should be
delineated into major macrophyte zones. Seven 1
m2 quadrats are established in each zone. The
vegetation within the quadrat is divided into as
many as three strata based on relative height.
The percent cover of each taxa within each strata
is estimated and the average height recorded.
Water depth and percent cover of non-vegetated
areas should also be recorded.
MULTIPLE QUADRATS
The ground cover in a shrub dominated
wetland is recorded for seven replicate 1 m2 quad-
rats as described above. Two 3.0 meter x 3.0
meter quadrats should be established to describe
the shrub strata. Within both quadrats the
number and average height of individuals from
all non-herbaceous taxa is recorded and the DBH
of the five largest individual's of each taxa is
recorded.
These sampling methods were developed and
used for several reasons. First and most
important, these methods have been modified and
refined to develop a standardized method for
establishing an absolute measure of species
occurrence by using defined frequency intervals
and cover estimates. Use of small continuous
frequency intervals allows increases or
decreases of colonizing vegetation to be
accurately mapped and subsequent changes
easily followed with time. In addition, since
frequency data is based on species presence or
absence it is absolute. Therefore, no error is
introduced as is the possibility when using
ocular estimates. Frequency is needed in
determining cover percentages. Although cover
estimates are not absolute (and may be somewhat
variable when performed by different people),
they serve as comparative indices for evaluating
cover between different treatments and/or
wetlands.
Occurrence of non-vegetated areas (bare
ground) throughout the transects were given the
same consideration as plant species cover. Bare
ground or non-vegetated surfaces are present in
all systems and as such are not necessarily a
definitive characteristic of newly created
wetland areas. Bare ground is defined as all
ground area not covered by some form of
vegetative structure as viewed from above.
Analyses of bare ground allows for determining
vegetation stratification. With bare ground
considered, vegetation coverage of an area will
seldom be greater than 100% cover. Analyses
may indicate that a great degree of plant
stratification occurs; however, areas are most
often not 100% covered by vegetation. The bare
ground method is recommended because
coverages based totally upon species occurrence
(which often total much greater than 100%) may
no longer be an acceptable method of reclamation
success determination.
The methods recommended to characterize
the plant community within created or restored
wetlands overlap in scope with the reference
wetland evaluation methods. The differences are
those modifications required to monitor survival
and growth of planted woody species in a created
or restored wetland. The line-strip (elongated
quadrat) technique (Lindsey 1955, Woodin and
Lindsey 1954) has been used to facilitate an
intensive, accurate, and repeatable sampling
program. Permanent quadrats are established at
a constant width to allow for a maximum
sampling of trees concomitant with planting
density such that generally four to five parallel
planting rows (average 1.525-3.05 meter centers)
can be monitored within each quadrat. Elong-
ated quadrats can be extended parallel to the
slope of the wetland to allow for survival and
growth comparisons to be made on a gradient
from flooded through moist to dry conditions.
Best and Erwin (1984) and Erwin (1987) used this
method to evaluate the effects of hydroperiod on
survival and growth of tree seedlings in a
phosphate surface-mined reclaimed wetland.
MEASUREMENT PARAMETERS
AND CRITERIA FOR PLANT
CONDITION ASSESSMENT
All trees occurring within the sample
quadrat should be measured during the growing
season for height. Water depth in the quadrat
should also be measured. Qualitative
observations should be made concerning the
individuals' overall appearance. Generally
seven different categories are suggested for
condition assessment. Categories and descriptive
criteria are:
Live
Tree appears in apparently good condition--
leaves green, no symptoms of wilting, die back,
or chlorotic appearance of leaves.
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Stressed
BIOMASS
Tree appears to be in a generally poor
condition-chlorotic leaves, wilting, and leaf
drop.
Tip Die Back
The main stem is in good condition, but the
most apical portions are in very poor condition
exhibiting wilting and die back symptoms.
Basal Sprouts
The main stem is dead but new growth is
initiated from the stem base or the root stock.
Not Found
In some cases seedlings are not found
during a particular sampling period. If a
seedling is not found on two successive sampling
periods, the seedling is counted as dead.
Apparently Dead
The general appearance of the stem is dry
and brittle with no live wood observed and there
is no observable green foliage growth.
Dead
A decision as to whether a tree is dead is
generally made only following a sampling
period in which the tree was classified as
"apparently dead". Only if initial observation
indicated that the stem was in such poor
condition that survival was unlikely should a
tree be listed as dead.
To completely evaluate the potential for
"forest" development in a created or restored
wetland, crown cover should be recorded for
species above the herbaceous stratum. In
addition, trees producing seed should be noted.
Table 1 is a summary of planted tree survival
(total of all species), change in height and crown
size from a created wetland in central Florida
(Erwin 1987).
These methods for evaluating a created
forested wetland have provided data which
established trends of survival and growth for
certain tree species after four years of
monitoring (Erwin 1987). Forested wetland
creation projects should be monitored using this
method for a minimum of five years. The
established trends will dictate whether further
intensive monitoring is required or if a reduced
periodic evaluation is appropriate to maintain
conditions required for maturation of the system.
Biomass of vegetation per unit area may be
an important parameter to be measured in a
restored wetland when standing crop of the
restored wetland is a criteria for its success. For
small quadrats and herbaceous vegetation, the
biomass can be measured by cutting all above
ground matter, drying it in an oven, and
weighing it. Ideally roots are also excavated, but
they are often ignored and consequently most of
the biomass data represents only the above
ground plant matter. Quadrat size and shape are
important. The significantly limiting factor is
generally man-hours and the cost to perform the
analysis.
Productivity can be determined from these
measures as the rate change and biomass per
unit area over the course of a growing season, or
a year or several years during the maturation of
a restored or created wetland. This process is
described below.
PRODUCTIVITY
Productivity may be a criteria for evaluating
the success of wetland to be created or
restored.
The most accurate means of measuring
primary productivity is to measure the net
photosynthetic rates of photosynthetic tissues, and
extrapolate to the community level, using the net
production per gram of biomass of each species
in a community. Obviously, this assessment of
net primary productivity is not possible under the
circumstances associated with the typical
wetland creation or restoration project. Conse-
quently, the most practical measurement of net
primary productivity (NPP) in frequently
conducted by calculating the change in biomass
through time where NPP = (Wt + 1 - Wt) + D + H
where Wt + l - W t is the difference in standing
crop biomass between two harvest times, D is the
biomass lost to decomposition and H is the
biomass consumed by herbivores during the
period between harvests.
Above ground biomass may be measured with
little error in herbaceous vegetation by replicate
samples harvested randomly from a grid. This
technique is most effective with annual
vegetation, where little biomass is lost to
decomposition during the growing season. If
herbivore activity is significant, comparisons
between replicate samples taken inside and
outside herbivore enclosures are often employed
(Barbour et al. 1987).
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Table 1. Summary of planted tree survival, change in height and crown size during 1987 growing
season.
SURVIVAL
SPRING SUMMER FALL
Number/Acre %
Live 757 71
Dead 315 29
Number/Acre %
696 65
382 35
Number/Acre %
679 63
406 37
SPRING
Height
123
SPRING
Height
38
GROWTH (HEIGHT cm)
PALL
Height Change in Crown
151 +28
CROWN (DIAMETER «n)
PALL
Height Change, in Crown
46 +8
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MACROINVERTEBRATE
MONITORING
One of the least known facets of freshwater
wetland systems is the role of the
macroinvertebrate fauna. These communities
are very important, forming an intermediate
level in the wetland's food chain, providing a
primary food source for higher organisms such
as fish and wading birds. Certain
macroinvertebrate species are excellent
indicators of water quality.
Comparisons from one marsh to the next,
even when they may closely resemble one
another with regard to hydrology and
physiognomy, may yield different species
composition and diversity. Species composition,
richness, and diversity will depend on the
season in which the monitoring was conducted,
the macrophyte community from which the
samples were taken and the method of collection.
The lack of baseline data for wetland
habitats makes it impossible to detail the exact
degree of macroinvertebrate utilization in a
wetland creation project. However, monitoring
should be required to determine whether, in fact,
a project is being utilized by at least some of the
desired species. The Macroinvertebrate monitor-
ing program should be designed to complement
the wetland community and water quality
monitoring of the project. The objective is to
develop a predictive model of success for the long
term trends in biological community
development in a created wetland. In riparian
systems where flowing water is present, the use
of Hester-Dendy multi-plate artificial substrate
samplers seasonally, in combination with some
of the methods described below, may be
appropriate. A number of monitoring plans
included in recently issued permits have
required the use of Hester-Dendy plate samplers
in freshwater marsh systems where no flowing
water is present. The author's research indicates
that the use of Hester-Dendy plate samplers in
static water situations provides unrepresentative
data when compared with other methods. Thus,
they should not be used in these situations.
Substrate coring and leaf and/or stem
scraping are usually satisfactory methods for
obtaining quantitative data as long as the
substrate areas are measured and computed for
each sample. This method has not been widely
used in many wetland systems, probably due to
the great expense in time and labor. It is often
common to find stem samples harboring few
organisms. The author has used the method on
many reference and created wetlands and has
observed that, proper qualitative sampling,
usually consisting of dipnet samples, can
provide a more accurate characterization of the
wetland. Sample size should be as large as
possible with collections made within each niche
of each macrophyte community.
Seasonal data collection for at least one
annual cycle is recommended for the natural
wetland to be altered. Monitoring of the created
wetland should be continued until the vegetation-
related goals are met. Freshwater marsh and
some salt water marsh creation projects
generally will require less intensive monitoring
over a shorter period of time (two to five years)
than forested wetland projects.
WILDLIFE UTILIZATION
The most widely used generally successful
method of evaluating wildlife utilization of a
natural or created site is reliable observation.
The observations are made during the correct
season, time of day, and over a satisfactory
number of events for the type of wildlife
anticipated by qualified personnel. Once again,
where more specific goals have been established
with regard to particular species utilization,
more intense monitoring may be required which
may involve quantitative surveys to determine,
for example, the number of nests per acre or
breeding pairs per season. Wildlife utilization
of a wetland creation project is almost always
one of the specified or inferred goals, but actual
monitoring or observation of wildlife utilization
is often lacking in the permit conditions.
Special consideration should be given to
endangered, threatened, or listed species (of
special concern). The reference wetland should
always be evaluated with respect to current or
possible future utilization by and suitability for
listed species. Habitat characteristics that are
necessary for use by listed species should be
thoroughly documented. In addition, the
wetland's proximity to other wetlands or specific
types of upland habitat may dictate its degree of
utilization by particular wildlife species. Thus,
it is important to describe the location and type of
connecting corridors.
There are cases when the proposed biological
structure of a created wetland focuses on preserv-
ing those species threatened with extinction.
Managing a created habitat to favor these en-
dangered species will inevitably hamper the
growth of some more abundant species. This
approach is appropriate if the criterion is to pre-
serve a full diversity of species regardless of
relative abundance. However, management is
often intensive.
RARITY
An often overlooked aspect of wetland
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evaluation is the rarity or uniqueness of one or
more components of the habitats within a region.
While fish, wildlife, and vegetation are usually
evaluated, other aspects are often overlooked.
Items of importance include the rarity of the
specific habitat in that particular stage of
succession; geomorphology; water quality; and
other characteristics such as stream flow and
cultural criteria such as archaeological,
scientific, and public/recreation significance.
SOCIAL ECONOMIC VALUES
Sather and Smith (1984) state that
nonconsumptive values up to this time have been
given secondary status to other wetland values
for which scientific criteria can be developed or
direct economic gain can be realized (Sather and
Smith 1984, Gosselink et al. 1974, and Niering
1985). This is partly related to the fact that
aesthetic or cultural values are more difficult to
measure since they involve a more personal
approach as well as value judgments (Niering
1985). There is a need to further develop a method
for assessing nonconsumptive values of
wetlands (Niering and Palmisano 1979).
ECOLOGICAL WATERSHED CONTEXT
The author believes that wherever possible,
wetland evaluation should be broadened to assess
original or restored/created wetlands in their
broader ecological and hydrologic context,
including regional wetland functions. Any
comprehensive wetland evaluation effort should
be preceded by the establishment of certain
criteria or goals which the investigator believes
to be fundamental to the existence, functions, and
contributions of the wetland system to its
surrounding landscape and vice versa. Failure
to address the wetland system's surrounding
landscape leads to inaccurate characterization of
the wetland. Additional work is needed to
develop definitive techniques and models for
better assessing the importance of individual
wetlands in a broader watershed context for flood
control, flood conveyance, pollution control, food
chain support, habitat, and other purposes.
However, approximations can be made with
existing approaches. Inter-relationships between
wetlands, transitional areas, and immediate
uplands need to be studied to determine the
importance, not only of adjacent lands, but of the
functioning of wetlands in adjacent areas as
total systems.
QUALITATIVE EVALUATION
As discussed above, quantitative and
detailed evaluations are rarely possible for all
wetland functions and all aspects of a wetland at
any stage in a wetland restoration/creation
project due to cost or time limitations. In some
instances, they are simply not needed, as, for
example, with proven designs or in the later
stages of a restoration/creation project where the
goal is to determine compliance rather than to
design a system.
The author's experience with wetland
reclamation in Florida suggests that successful
freshwater marsh creation (see Erwin this
volume), and mangrove and saltmarsh creation,
can take place with more generalized qualitative
evaluations. Proper planning, design, and
management can result in the creation of a
functioning freshwater marsh within three full
growing seasons (Erwin 1986). In this case,
qualitative baseline monitoring of the reference
wetland and post-construction monitoring of the
created wetland for a minimum of three or four
years is usually adequate.
The topics needing attention in a quantitative
evaluation remain much the same in a
qualitative evaluation, but the approaches differ.
The author offers several suggestions with
regard to specific aspects of qualitative
approaches in the following sections.
VEGETATION MAPPING
Vegetation mapping of wetlands can provide
both physiognomic and floristic information,
and may be useful in several different ways. If
the wetland area to be evaluated is too large to
evaluate by the methods previously described due
to short time allotted for analysis and/or a
restricted budget, vegetation mapping on an
aerial photograph verified by groundtruthing
may be the answer. The investigator should try
to distinguish as many different communities or
vegetation types as possible and outline the
boundaries of each on the aerial photograph.
Species richness and assorted observations on
topography, water depth, and wildlife utilization
should be recorded for each vegetative type.
Acreages for each type can then be computed
26
-------
from the vegetation map.
Vegetation mapping may also be used in a
final, but long term phase, following short term
intensive data collection using the previously
described methods. A vegetation map could be
prepared on a currently studied wetland and
correlated with data for each mapped vegetation
type (Figure 1). The author has satisfactorily
used this method for evaluating large landscapes
with wetlands. Vegetation mapping on high
quality aerial photographs (black and white,
color, and infrared sensitive film) taken on an
annual cycle can confirm the continuity of
trends or changes in habitat types and vegetative
cover. Figure 2 is a vegetation map of a portion
of a wetland reclamation study site where the
quantitative data collected will be correlated with
the detailed mapping (Erwin 1987 and Erwin this
volume). While this method does not produce the
detailed data previously produced by belt
transects, it will provide a relatively inexpensive
and reliable confirmation and description of the
habitat. Maps should be regularly groundtruthed
to confirm the reliability of the habitat types and
boundary definitions. Recently developed
computer aided drawing (CAD) allows for great
flexibility in generating scaled vegetative maps
and habitat acreage figures.
In addition to generalized vegetation maps,
a more specific qualitative baseline vegetation
survey should be performed in most cases.
Transects should be established through wetlands
to be preserved, impacted, and created so that
each major vegetation zone, including adjacent
upland habitat, will be represented. Each major
vegetation zone should be identified and a
sampling station (3.0 meter x 3.0 meter quadrat)
located within each zone. All plant species should
be recorded. Relative abundance and percent
cover of species should be noted. The same
transects and stations should be used for all
future post-construction monitoring.
An example of the results obtained using this
method is shown in Table 2, which represents
baseline vegetation monitoring data collected in
four quadrats from one of several transects
(Transect D, shown in Figure 3) established in
selected preserved and constructed wetlands of a
proposed surface water management system.
Each major vegetation zone is represented.
Transect D (Figure 3) was aligned to
intersect each major vegetation zone in which a
3.0 meter x 3.0 meter quadrat (sampling station)
was established. All plant species were recorded.
Percent cover was estimated for each species.
The results are presented in Figure 4. Figure 4
also illustrates the basic structural differences in
major species composition and cover between the
three macrophyte zones of this marsh and the
adjacent uplands. In some of the quadrats the
vegetated areas were structurally complex and
the stratified vegetation layers yielded cover
values greater than 100% (Table 2). The same
transects and quadrats will be used for all future
monitoring.
In some cases where multiple wetlands are
present (i.e., Cladium. Pontederia, and Spartina
marshes), it may be possible to group wetlands of
similar physiognomy and monitor a subset of
each group using this method as a minimum
requirement. This will still provide the required
data as long as the investigator selects a
representative wetland from each group and all
vegetation zones are monitored. If there are
adjacent upland habitats that are recognized as
an important component of the wetland system,
the transects and quadrats should extend into the
adjacent upland habitat.
POST CONSTRUCTION MONITORING
Project evaluation is essential both during
and after construction to determine compliance
with project goals and permit mid-course
corrections. Certain aspects of such evaluation
may need to be quantitative (depending upon the
project goals and measures of success), but much
of it can be qualitative. Based upon the author's
experience, the following are suggested as key
components of a monitoring plan for post project
evaluation.
MAINTENANCE PLAN
The methods to be used for maintaining the
wetland after construction should be submitted
with the original baseline survey. The plan
should address removal of nuisance species, i.e.,
Melaleuca. Brazilian pepper, purple loosestrife,
and cattails, and assure an 80% survival rate for
planted or recruited species. An evaluation of the
success of the maintenance effort should be
discussed in annual reports.
ANNUAL REPORTS
Post-construction monitoring should be
conducted annually for five years (minimum
three years) at the end of the wet season (October-
27
-------
AGRICQ SVAMP WEST-MARSH COMMUNITY (September 1986-1987)*
HYDRDCOTYLE
MIXED BRDAD-LEAF MARSH SSP.
MIXED BREAD-LEAF MARSH/
TYPHA
I PANICUM/JUNCUS/SPARTINA
A UU-llll PDNTEDERIA
4 B (VT^I PONTEDERIA
nriifi /Panlcuh hemrtomon/NaJas
C §SSS PDNTEDERIA/TYPHA/GAGITARIA
SALIX/BACCHARIS/LUDVIGIA
SCIRPUS
SCIRPUS/TYPHA
t j TRANSITIONAL-UPLAND
* t H GRASSES
DW ESSSj! CPEN WATER
A |*«!*!*| TYPHA
B
TYPHA/HYDRDCDTYLE
or HYDRILLA
SAGITTARIA/KYDRCCDTYLE
N
Prellrilnary napping based on September 1986 non-rectified CIR aertal photo with ground verification
in 1989 by Kevin L. Erwln, Consulting Ecologlst, Inc.
Figure 1. Vegetation map of plant communities, acreages, and percent cover on a 106.94 acre parcel in
southwest Florida produced by Computer Aided Drawing (CAD).
28
-------
ACRICO SWAMP WKST-IUHSH COKUDMTr (September 19M-1M7)*
HTOtOCOTTLI
uin/unnnau POL
/Vyrio,
runiuniu/yAiaam Hnanucan
-------
Table 2. Baseline vegetation data (%-Cover, Ht.-Water Depth) from four 3 m x 3 m quadrats along a
wetland/upland transect (Transect D) in a surface water management system. M: Species
present within Macrophyte community, but outside of sample quadrat.
SPECIES
QUAD D1
% Ht (cm)
QUAD D2
% Ht (cm)
QUAD D3
% Ht (cm)
QUAD D4
% Ht (cm)
Background
Water depth
Beak rush
Rhvnchospora spp.
Broom sedge
Andropogon spp.
Cyperus sedge
Cyperus spp.
Floating orchid
Habenaria repens
Floating heart
Nvmphoides cordata
Gallberry
Ilex qlabra
Green algae
Joint grass
Manisuris spp.
Ludwigia
Ludwigia repens
Marsh aster
Aster spp.
Maiden cane
Panicum hemitomon
Marsh fleabane
Pluchea rosea
15
dry
10 122-183
moist
70 30-60
65
7-8
1 30-60
<1 30
30 30-60
1 30
25
Pickerel weed
Pontederia lanceolate
Plume grass
Erianthus spp.
Red root
Lachnathes caroliniana
Rusty lyonia
Lvonia ferruoinea
San Palmetto
Serenoa repens
St. Johns wort
Hypericum spp. A
St. Peter's wort
Hypericum stans
Sundew
Drosera spp.
Hire grass
Arlstida stricta
Yellow eyed grass
Xyris app.
80
30
90-120
15-30
25 60-90
0.25
90 30-75
15 60-90
1 30-90
30
-------
PROPOSED DIKE
BOUNDARY-
LEGEND
• PHOTO STATION
X STAFF GAUGE
1 QUADRAT NUMBER
A-E TRANSECTS
( ) ACREAGE
641 FLOW WAY
(2.59)
641
(4.22)
COVERTYPE
SUMMARY
COVER
TYPE
AREA
(ACRES)
411 Pine Flatwoods 125.44
641 Fresh Water Marsh 118.08
*** Total ***
243.52
**p.
*— cs
cs
,
1-16-89
r=660*
Wttl
«*• BMttfM IMaW
«- +-T-M
•f
"JMH "~
mmcTto rftwm
"•
Reservoir South
Wetland Monitoring Plan
Kevin L. Erwin
Consulting Ecologist, Inc.
8077 Bajride Parlmy
Fort HJOT. FL 33601
(813)337-1600
Figure 3. Locations of transects, quadrats, water level recording stations, and photo location stations
in preserved and created marshes within a surface water management-reservoir system.
31
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November). Reports should be submitted within
90 days following sampling, and should
document any vegetation changes including
percent survival and cover of planted and/or
recruited species (trees and herbs). Issues related
to water levels, water quality, sedimentation,
etc., should be addressed and recommendations
or changes for improving the degree of success
discussed.
FIXED POINT PANORAMIC
PHOTOGRAPHS
Establish locations for fixed point photos in
each wetland area to be monitored by providing a
range pole in each section of photo panorama for
scaling purposes. Photos should provide physical
documentation of the condition of the wetland
and any changes taking place within it. They
should accompany the baseline vegetation survey
and each annual report. Photo points and range
pole locations are to remain the same throughout
the duration of the monitoring program.
wetland area to be monitored. Staff gauges
should be located in the deepest portion of the
wetland and set to National Geodetic Vertical
Datum (NGVD) elevation. Water levels should
be recorded monthly and summarized with
annual reports.
PLAN VIEW
A plan view showing locations of transects
through wetland areas with rain gauge, staff
gauge(s), and photo points should be provided
with the baseline vegetation survey.
OBSERVED WILDLIFE UTILIZATION
Qualitative observations of wildlife
utilization of the created/restored wetland should
be recorded during all visits and annual
surveys. If wildlife utilization is a major success
criteria, extensive observations should be taken
at least monthly.
RAIN GAUGE
A rain gauge in a conveniently located area
of the project site should, in general, be provided.
It is unnecessary for some projects. Rainfall
should be recorded daily. A summary of rainfall
should accompany annual reports.
STAFF GAUGE
Staff gauges should be provided in each
FISH AND MACROINVERTEBRATES
Qualitative macroinvertebrate and fish
should in many instances, be collected within
each macrophyte zone containing standing
water. Samples should be collected utilizing a D-
frame dip net for a period of at least 20 minutes
per station. All samples should be field sorted,
preserved in 70% ethanol, and identified to the
lowest possible taxon. A checklist of species
collected should be compiled for submittal with
annual reports.
CONCLUDING REMARKS
Wetland evaluation approaches including
post project monitoring must, of course, be
tailored to the specifics of the site and project
goals. This requires expertise and creativity on
the parts of the project designers and reviewers.
Without such expertise and creativity, huge
amounts of money may be spent on gathering
useless data while no attempt is made to gather
essential data. Qualified wetland scientists with
knowledge of wetland ecology, hydrology,
wildlife, and an appreciation of practical
considerations in restoration or creation must be
involved in the design and execution of
evaluation efforts.
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35
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APPENDIX I: A SELECTED BIBLIOGRAPHY
ON WETLAND EVALUATION
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37
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Strategies for Protection and Management of
Floodplain Wetlands and Other Riparian
Ecosystems. General Technical Report WO-12, U.S.
Dept. of Agric., Forest Service, Washington, D.C.
Calkins, H.W., and R. F. Tomlinson. 1977. Geographic
Information Systems: Methods and Equipment for
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WETLAND DYNAMICS: CONSIDERATIONS FOR
RESTORED AND CREATED WETLANDS
Daniel E. Willard and Amanda K. Killer
School of Public and Environmental Affairs
Indiana University
"Who can explain why one species ranges widely and is very numerous, and why
another allied species has a narrow range and is rare? Yet these relations are of the
highest importance, or they determine the present welfare, and, as I believe, the future
success and modifications of every inhabitant of this world." (Darwin, 1859).
ABSTRACT. Wetlands are affected by intrinsic and extrinsic forces. Managers cannot
always predict or control the extrinsic forces leading to wetland changes, nor can they predict
the range of species adaptations to those changes. Managers should plan for extreme
circumstances by including mechanisms for wetland adjustment and persistence and by
maintaining multiple sites as refugia to spread the risk of catastrophe. Our recommendations
include:
- creating buffer zones and corridors
- recreating spatial and temporal habitat variability
- maintaining marginal wetlands as reserve sites
- planning for worst case scenarios (cumulative impacts)
- suggestions for managing for uncertainty and risk in wetland restoration and creation.
INTRODUCTION
For the purpose of this chapter, we consider
wetlands as ecosystems with water. As such they
respond to biological, chemical and physical
change and they demonstrate properties more or
less common to other ecosystems. Many of these
properties have been discussed at length in many
textbooks of ecology. Here we will review
several concepts that seem to have applicability to
restoration and creation of wetlands.
This discussion focuses on the methods by
which wetland ecosystems change and the
methods by which plant and animal species
adapt to those changes. To introduce the
discussion we will briefly review succession,
which we call "change by intrinsic elements"
and perturbations, which we call "change by
extrinsic forces". Because many wetlands are
open ecosystems, these kinds of changes often
operate together in ways that make them difficult
to distinguish. For restoration and creation
purposes, this separation helps managers
understand what parts of the ecosystem they can
manipulate, what parts change in fairly
predictable ways and what parts remain
uncertain.
Planning and regulation must consider
landscape consequences. Often when we cannot
understand the consequences of change at the
local level, we can gain insight by looking at the
change regionally, or vice versa. The role of a
wetland in the landscape depends on its change
pattern, its proximity to other habitat and its
persistence. These considerations become
particularly important as wetlands become
stressed. That a wetland has become entangled
in the permit process may provide sufficient
evidence for stress.
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EQUILIBRIUM, INTRINSIC ELEMENTS AND EXTRINSIC FORCES
Wetlands are dynamic systems. While some
wetlands appear constant on a human-relevant
time scale (e.g., bogs and fens), others change
much more frequently. Generally, newly
restored or created wetlands are not in
equilibrium and may undergo a period of
adjustment before functioning in socially and
ecologically desirable ways. Some ecologists
consider internal vegetation readjustments not
as change, but rather as the maintenance of
ecosystem equilibrium through homeostatic
balancing. Urban et al. (1987) show that our
perception of the significance of wetland
responses changes as the scale from which we
view changes. For them equilibrium is a
function of geographic scale and may emerge if
that scale is large enough. DeAngelis and
Waterhouse (1987) state that wetland changes
may occur regularly or irregularly and may
result from internal or external causes. Each of
these views attempts to understand the relation
between the internal dynamics of ecosystems
and external events that affect ecosystems.
Managers, restorers, and creators of
wetlands act through extrinsic forces on
wetlands. These extrinsic forces can cause
modifications in the intrinsic elements so that
the wetland provides functions which society
values. Unfortunately the application of manage-
ment to wetlands is not yet an absolute science,
so outcomes vary. Unpredictable natural ex-
trinsic forces such as drought, fire, or insect
infestation further complicate the wetland
manager's ability to predict the outcome of his or
her project with confidence. Those who work in
environments affected by anthropogenic sources
of extrinsic forces, such as cities or heavily
farmed land, should consider the sorts of wet-
land ecosystems which can tolerate these forces.
HIERARCHICAL SYSTEMS APPROACH
We discuss wetland creation and restoration
considerations from the perspective of wetland
dynamics. We take a hierarchical systems
approach (which looks at a hierarchy of
individualistic events) with particular emphasis
on the landscape ramifications of wetland
dynamics and management activities. Urban et
al. (1987) defines "landscape as a mosaic of
patches, each a component of a pattern".
Landscape ecology focuses "on the wide range of
natural phenomena by considering the apparent
complexity of landscape dynamics and
illustrating how a hierarchical paradigm lends
itself to simplifying such complexity".
Random stochastic events play an extremely
important role in the creation and development
of wetlands. Habitat can only change in certain
ways at certain rates. The dominant variables
controlling a wetland frame the possibilities for
wetland response to a stochastic event.
Community responses to intrinsic elements limit
the possible responses to extrinsic forces. In
other words, if the wetland is in state X then a, b,
and c are possible responses, but if it is Y then d,
e, and f are possible. This ecological "roulette"
confuses the outcome of any wetland change
sequence. Managers are stuck with statements
like, "If x doesn't happen and y happens the way
it usually does, this wetland will look like this
in 10 years." Annoyingly, x and y are
uncontrollable.
LOCAL WETLAND CHANGE IN A REGIONAL CONTEXT
Andrewartha and Birch (1984) describe the
differential effects of local and regional
extrinsic events on populations and species.
Local populations of plants and animals prosper
and wane in response to the interaction between
their population dynamics and the local
environmental conditions. In wetlands subject
to change, local populations may vary
considerably from season to season and year to
year. Contrarily, regional populations may
remain relatively constant. This regional
constancy results from the asynchrony of the
separate local populations: when some have low
levels, others are high.
Bertness and Ellison (1987) studied change
patterns in New England salt marshes. Local
small scale extrinsic events caused differential
plant mortality. These short term disturbances
changed the relationship between species,
allowing those with greater colonizing ability to
recolonize disturbances. This scrambled the
areal distribution of the species and provided
new patterns.
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Most plants and animals which have evolved
to exploit wetlands have adapted to the change
patterns of wetlands. Plants and animals have
considerable physiological and genetic
adaptability. Clausen et al. (1940) showed with
altitudinally separate populations of Phlox along
an environmental gradient that ecotypic
variability allows many plant species to use a
variety of habitats. McNaughton (1966) showed
that Tvpha latifolia varies somewhat within
populations and broadly across its range. Tvpha
can adjust its position along a gradient quickly
through vegetative growth.
Animals adapt to changing wetland
conditions through a variety of behavioral
strategies in addition to the genetic and
physiological mechanisms suggested above.
These strategies include movement, dispersal,
environmental change, or no action. Weller
(1981) describes a variety of behavioral
adaptations for freshwater species (e.g.,
muskrats, Ondatra: black terns, Chlidonias
niger). Many species have adapted to wetland
environments which combine both spatial and
temporal heterogeneity. This heterogeneity
allows internal adaptation.
Most species do not occupy all of their
environment at any given time. Skeate (1987)
demonstrated regular periodic movement by 22
bird species to exploit ripening fruit in northern
Florida hammocks. These birds oppor-
tunistically actively foraged on only a small
segment of their habitat at any one time. The
portion of the habitat which the birds were not
using at any time was relieved of predation until
it had replenished the supply of fruit. Wiens
(1985) shows the effect of local rainfall on
establishing varied patches in the desert. Areas
that receive rain at a particular time "reset"
themselves and begin new intrinsic change
sequences. In a single square kilometer several
different sequences operate simultaneously.
Switching from patch to patch allows more
species of animal to exploit these local areas.
This opportunistic habitat switching is a
behavioral adaptation to changing conditions in
the landscape. The survival of the animals
depends to some extent on the continuing pattern
of changes in the various patches included in
their range.
Opportunistic habitat switching may lead to
fluctuating population levels on a given wetland.
Willard (1980) describes the resetting of small
ephemeral farm ponds in Wisconsin and their
subsequent use by migratory shorebirds. Gen-
erally, farmers drained the ponds on their farms
every four or five years, but patterns varied. The
shorebirds preferred ponds on the first and
second wet year because the opportunistic
invertebrates on which the birds prey had higher
population densities during those years. The
shorebirds exploited fairly specific environments
by finding which pond provided that
environment at a given time. Myers et al. (1987)
discusses the importance of these changing
patches of foraging habitats to transcontinental
migratory shorebirds. They argue that even
though the ruddy turnstones (Arenaria interpres)
and red knots (Calidris canutus) used the
wetlands of Delaware Bay only as stopover sites,
these sites were essential to their survival. "On
these stopovers they [the birds] doubled their
weight in preparation for the last stage of their
migration from South America to the Arctic."
For many of the species we have just
discussed, the various patches of habitat are
isolated from one another. Each small bit of
habitat may be of essential importance to a
species which uses it only irregularly, yet short-
term observation of these wetland habitats may
reveal little habitat value. The loss of these
apparently low-value isolated sites may appear
as a small loss of acreage but may instead
constitute a large loss for the survival potential
of some desirable species. This critical, but
ephemeral habitat contributes to the difficulty of
measuring the cumulative impacts of threats to
these otherwise unimportant appearing wetlands.
When Gosselink and Lee (1987) analyzed
cumulative impacts in bottomland hardwoods,
they expressed these impacts as a special case of
hierarchical organization of the landscape. They
considered that an area contains a pattern of
optional patches that a population can use. The
areas they described often contained watersheds.
By analogy they described the collection of
disjunct sites used by a duck as a "duckshed".
This analogy helps understand the movement
and flow of the population as it exploits available
habitat within an area.
Lewin (1986) describes the necessary
movement of African elephants (Loxodonta
africana) within their large home range.
Elephant foraging behavior destroys trees so that
elephants must move continually. However, as
they eat the canopy trees they open up the forest
for the rapidly increased growth of new forage
plants. The "elephantshed" must be big enough
to allow this cycle to take place before the
elephants revisit. The foraging activity of the
elephants causes faster regrowth. In the absence
of elephants, the forage plants become replaced by
non-elephant food plants. The interaction of the
elephant and its food plants maintains a
persistent community which is composed of a
fairly rapidly changing array of habitat patches.
In this case the animal itself causes the local
inconstancy of habitat, but is adapted to achieve a
balanced ecosystem which allows both the
animal and its food to survive. From this Lewin
suggests that change can provide persistence for
organisms and that if we attempt to manage for
constancy we may ultimately fail to conserve the
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very resources we intended to save. He
summarizes by urging that we manage for
persistence, not constancy.
All change may not necessarily help
wetland species. Many impacts, both natural
and human-induced, are environmental changes
of great magnitude and size. These extrinsic
forces sometimes cause environmental change
beyond adaptability of the species. Andrewartha
and Birch (1984) explain the effect of local and
regional environmental events on the range and
success of species. They suggest that populations
succeed best when local habitat patches change
asynchronously. By the same reasoning, not all
of the habitat patches change in a manner, or at a
rate, beyond the ability of the species to adapt at
the same time. In essence, each population
distributes risk by using independently varying
habitats, so that as some of these habitats become
depleted others will improve. Plants and
animals maintain themselves by using each site
to its limit. Some regional extrinsic forces can
affect all of the habitat sites of a species, but most
affect only a portion of the species range. Those
sites which remain habitable act as reserves to
"spread the risk". As human activities remove
portions of habitat, even though these parts seem
marginal at the time, we may have critically
reduced the species' ability to react to other
perturbations, by removing these "reserve" or
"emergency" habitats, and increasing the risk
of population extinction.
An example may help tie these ideas
together. The Kesterson (California), Stillwater
(Nevada), and Malheur (Oregon) National
Wildlife Refuges all provide wetland habitat for
a variety of water birds. All occur in essentially
desert habitats where they experience irregular
cycles of drought and flood. Each refuge cycles
differently. A population of White Pelicans
(Pelecanus ervthrorhvnchos) uses several of
these refuges alternatively. The number of
individuals on each refuge varies from year to
year as the population tries to exploit the best
conditions. All these refuges (and probably the
Great Salt Lake) constitute the "pelicanshed".
All the refuges act to allow pelicans to "spread
the risk".
In contrast the sandhill crane (Gru s
canadensis) populations, which winter on the
gulf coast and nest in eastern Canada, all
concentrate on the Jasper-Pulaski Wildlife
Refuge in northern Indiana during spring and
fall migration. Because wetland habitat in the
midwest is so reduced, the cranes have few other
choices. For several weeks each year the entire
population is at risk on the same site. If that
small refuge fails to provide resting and forage
for the cranes because of drought, fire, or
contamination the crane population will suffer
severely. Wildlife managers have attempted to
adapt other sites with some success, but have
difficulty convincing politicians that it is wise to
conserve habitat on the speculation that a species
might need it briefly sometime.
The sandhill crane population during
migration has only a single locality which all of
the subpopulations use. An impact to this site
affects the entire crane population. Since the
pelican population is comprised of several
scattered subpopulations, there is a greater
likelihood that the population as a whole will
survive environmental changes at a particular
refuge. These wetlands taken together comprise
a single pelican habitat unit. Should one of the
several refuges suffer an impact which reduces
its habitat value, the other refuges will still
support viable populations. The removal of any
one option lowers the survival ability of the
pelicans by reducing their ability to distribute
risk, but they will survive. However, for the
cranes the Jasper-Pulaski Refuge and
surrounding fields constitute the only option for
migratory stopover. The loss of this site would
cause the crane population considerable distress.
The problem is real because currently each
refuge has a water quality problem induced by
agriculture, with the problems differing in kind
and severity.
RESTORATION AND CREATION CONSIDERATIONS AND
RECOMMENDATIONS
PERSISTENCE VS. CONSTANCY
In some cases the wetland complex survives
because various portions of the system
continually change from one type to another, but
the sum of each habitat type more or less
balances. This dynamic balancing, which may
destroy a particular type of a subunit, also creates
that type elsewhere in the wetland system. This
principle of dynamic balancing is not new, but
merely adds a temporal dimension to the concept
of spatial heterogeneity. Simply stated, some wet-
lands persist by balanced change over time and
space.
Resilience is a measure of the ability to per-
sist in the presence of perturbations arising from
weather, physiochemical factors, other organ-
50
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isms, and human activities. (Krebs 1978). Per-
sistence is "continuous existence" (Webster
1970).
A conceptual difficulty arises until we
clarify whether we wish to maintain any
wetland at a specific locality, or whether we wish
to maintain a specific kind of wetland at a
specific locality. In many cases the goal
requires that the site support a persistent bundle
of wetland functions, not necessarily a wetland
that looks a particular way. Because form and
function are related, some wetland types do
perform some functions better than other types.
Operationally, the regulator has to balance form,
function, and persistence.
When planning and managing a wetland
system it is important to examine the goals of the
project. A balance must be found between form,
function, and persistence. For example, wetlands
are often created for stormwater retention. These
need to be persistent functional wetlands. In
other cases maintaining specific habitat
characteristics requires management practices
emphasizing constancy.
Managed habitats can fail by becoming too
constant, changing the wrong way, or changing
too fast. Jacobson and Kushlan (1986) and
Kushlan (1987) illustrate habitat sharing on an
alternate time basis for endangered species in
the Everglades National Park. These species
require quite different seasonal water levels.
Natural flood and drought cycles alternatively
allowed manatees, crocodiles, woodstorks and
other significant species high reproductive
success. Each got a turn often enough to
maintain viable populations. This was at least
the situation before Florida irrigation and
drainage projects limited the upper end of the
gradient. Now animals using it can find no
appropriate sites during high water years.
Current regulated water use must recreate these
variable sequences. Many organisms exist
through their ability to adapt quickly. Habitat
must vary if these species are to survive.
FREEBOARD, BUFFERS,
AND CORRIDORS
Our management practices have hurt the
habitat value of scattered wetlands by limiting
the adaptability of individual wetlands.
Individual wetlands have considerable but
limited powers of recovery. Managers often
place dikes or other structures in the flood plain
so that wetlands cannot expand up gradient
during high water periods, leading to limited
adaptability. Artificial wetland boundaries often
cut off the 100 or 50 year high water level of the
wetland (e.g., Great Salt Lake). Wetland
creation, restoration and other management
plans must contain considerable "freeboard" for
extra protection.
Unconfined wetlands allow vegetation to
grow up and down the bank and adjust itself to
changing hydroregimes. Steep landward banks
may occur as a result of bulkheads on bars or
beaches, levees on stream channels, or seawalls
on lakes. The steep sides of confined systems
remove the potential for adjustment and therefore
force the loss of plant species, animals and
habitat. Buffers are needed to avoid such losses.
Buffers allow for the expansion and contraction
of the plant communities to respond to variations
in hydroperiod, and thus increase the probability
of persistence.
Planning for environmental corridors helps
reduce the isolation of the wetlands in or
adjacent to the corridors, which in turn
facilitates movement and recolonization of these
wetlands. The corridors themselves can provide
a variety of beneficial functions, as well as
acting as buffers.
An increase in the area of a created wetland
may be as simple as adding a modest buffer area
and yet may have a large improvement in
persistence. The buffer will allow the biota in the
wetland to adapt to changing water levels. The
buffer can also become additional refugia for the
resident animals.
Little formal information exists on the
definition and construction of buffer zones. But
the rationale and need for buffers seem clear.
Buffers provide an area of refuge for plants and
animals between their normal or preferred
habitat and human activities.
SPATIAL AND TEMPORAL
HETEROGENEITY AND SIZE
Increased freeboard, corridors, and buffer
areas add internal spatial and temporal
heterogeneity to a wetland construction and
restoration project. Because these forms of
habitat may provide water connections between
potential portions of the wetland, they can become
reserve sites and refugia for aquatic plants and
animals which disperse through water. All of
these techniques increase the "effective" size of
the site.
The effective size of a wetland includes the
area of the wetland available and accessible to
the plant and animal species of concern. In
practice, the effective area for a species is
measured by determining the interconnections
available with the dispersal mechanisms used by
that species. For example, if a manager wished
to use topminnows (Poecilidae) for mosquito
control, he or she should provide water
51
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connections for at least some portion of the year
between the portions of the site that might allow
mosquitos to breed. The best season for dispersal
will vary depending on the climate and the
natural history of the species.
Given the heterogeneity discussed above,
larger wetlands invariably provide greater
habitat value (Andrewartha and Birch, 1984).
This occurs for two reasons. First, greater area
provides additional spatial heterogeneity and
consequent opportunity to spread the risk.
Second, additional spatial heterogeneity over a
larger area creates a more complex pattern. This
pattern complexity allows for an increase in
habitat diversity which supports and encourages
greater species diversity (MacArthur 1972). In
terms of genetic resilience, more species present
on the site help guarantee that some species will
adapt and survive if severe impacts occur. In
this sense, species diversity spreads the risk.
MANAGING UNCERTAINTY
Two kinds of uncertainty simultaneously
plague and bless careful managers. The first of
these includes our inability to predict with
certainty both natural and anthropogenic
extrinsic impacts. The second includes the
unpredictable behavioral adaptations that plants
and animals sometimes make.
The poet Robert Burns once said that the best
laid plans of mice and men oft times go astray.
For those who attempt to manage natural
resources this regularly applies. Things happen.
In the midwest within the last year we have
experienced a 17-year cicada (Magicicada
septendecim) outbreak, record high wind
conditions, and a prolonged summer drought.
All of these have increased the danger from fire.
While scientists predicted the cicada emergence,
the event happens so infrequently that little was
known about the effects of the cicadas on natural
ecosystems. Thus, managed habitats may
combine natural events which occur
simultaneously through chance. This stochastic
summing of independently varying impacts can
over stress the adaptability of the species and the
ecosystem even when the same impacts taken
singly would cause changes well within the
homeostatic limits of the ecosystem.
A third subtle uncertainty frustrates wetland
restoration efforts. Wetlands often act as sinks
for waterborne contaminants. Many accumulate
potential pollutants while they act to clean water.
These contaminants can build up to levels which
harm wetland plants and animals.
Our land use management practices have
hurt the habitat value of many scattered wetlands
by creating habitats which contain threats
animals cannot detect. Animals lack the ability
to detect many fatal pollutants such as DDT,
selenium, mercury, and PCBs. A wetland with
valued habitat characteristics, but accumulated
contaminants may lure animals to their death.
For example, wetlands which receive high
Habitat Evaluation Procedure (HEP) ratings
may have contaminants present. These
contaminants may occur at levels of concern
while the site is otherwise physically and
biologically attractive to the important species.
Our study of the Kesterson National Wildlife
Refuge may help us understand this problem.
Wetland evaluation systems seldom include
detailed chemical analysis and even if
evaluation considers the presence of chemical
contaminants, the data are often not available to
predict impact on particular species. For many
contaminants, we know little about their effect on
plants and animals. Chemical analyses are
also costly (up to $1000/sample) and often raise
questions which defy easy solution.
In some parts of the United States, wetlands
have become so reduced that little habitat
remains and plant and animals quickly
colonize even marginally appropriate sites.
Thus, managers accidentally create or restore
wetlands which can become attractive nuisances.
We know of no easy answer to the
contaminant problem. If the situation indicates
that such a problem might exist (e.g., an
abandoned landfill, an agricultural wastewater
sump, an area which receives stortnwater runoff
from urban or industrial sites, the prudent
manager should get some samples analyzed for
potential pollution problems. Site restoration
may require pollutant removal or abatement.
Unfortunately, this may involve hazardous
waste control agencies and years of cost and
delay. Due to the different responsibilities and
training of agency personnel, habitat assess-
ments rarely consider pollutant hazards and
chemical analyses seldom contain wildlife risk
estimates. Improved agency coordination and
an interdisciplinary approach to wetland evalua-
tion could help identify these problem areas.
To counter the potential for adverse and
unpredictable impacts, wetland restoration and
creation projects could be designed and planned
for a variety of unknown worst cases. No simple
recipe exists to assure the health and survival of
the wetland, but applying a few guidelines taken
from our discussion may help:
1. Understand the natural history of the
individual species of interest.
2. Provide extra space and diverse conditions to
improve the odds for survival of a variety of
species.
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3. Provide spatial heterogeneity which usually
increases with size and gradient.
4. Plan reserve sites as refugia when possible.
Many species of plants and animals require
reserve sites. HEP analysis can often
recognize candidate reserve sites even
though the population levels of the target
species may be low at the time.
5. Imagine the consequences of potential
adverse impacts. Try to design safeguards
against these.
6. When the potential for chemical
contamination exists, attempt to get an
analysis of the risk to the plants and
animals that may use the site.
DISCUSSION OF RECOMMENDATIONS
Assume that all wetlands naturally change
in size, in community structure and in locality.
That is, they get bigger and smaller; they become
different sorts of habitats and, from time to time,
wetlands appear on the landscape and disappear.
Wetlands probably maintain some regional
dynamic balance, but this balance is not precise.
It is difficult to design for precise wetland
types and boundaries. They both change
regularly. Design for a general type which
contains elements for self regulation and
maintenance. Regulators should set standards
for long term monitoring that demand
"persistence" not "constancy" for restored and
created wetlands.
Don't get concerned if the restored or created
wetland does what it will, as long as it does
something (Lewis, pers. comm. 1987). Remember
that the homeostatic strength of any wetland or
habitat cluster causes the system to adjust to some
external perturbations and not others. Most
landscape units develop as a result of
probabilistic external events which no one can
control.
Encourage designs which include room for
change in size and type. Hydraulic gradients
allow greater spatial heterogeneity to develop.
Climatic variation may cause vegetation to
self-adjust higher or lower on the gradient. Rare
species of plants and animals may require more
rigid designs. Species achieve rarity in several
ways. Some exploit specialized local niches
which occur infrequently in the landscape
(Yucca Night Lizards, Xantusia vigilis.
Limpkins, Aramus guarauna: Southern Cougar,
Felis concolor). Occasionally these species
become locally abundant. Other rare species
scatter widely and exploit ephemeral
circumstances that provide food, reduced
competition, or predation (White Pelicans). The
former depend on persistent local conditions
which wetland builders have difficulty
constructing. These local habitats may represent
the species only chance. The latter fall prey to
incremental habitat destruction because each part
of their habitat is scattered over a large region
and is ephemeral.
We recommend that managers plan for the
worst combination of events the wetland they are
restoring or creating may encounter. Natural
causes may force animals into marginal
habitats as refuges. These then become essential.
The current population of animals may be at a
low and will use this habitat later. An animal
population may use a currently marginal or
unused site as a reserve under different
unpredictable circumstances.
All wetlands have some public value, though
sometimes these values are not readily apparent.
Some disturbed wetlands have reduced
functional value. Undisturbed naturally
functioning wetlands are essentially
irreplaceable in the short run.
Expect change in size, wetness and
ecosystem type in created and restored wetlands.
Therefore, they should be designed well
"oversize" compared to the wetlands for which
they compensate.
Unfortunately, the natural variability of
ecosystems, the unpredictability of extrinsic
forces, and the perversity of complex systems
make any absolute guarantee of success
impossible. Therefore, in addition to worst case
and oversize design, most projects should
include a monitoring program geared to some
explicit but flexible and realistic goals. To
protect against the potential (if improbable)
failure of the project, the project sponsors should
be asked to provide, in every permit, some
financial guarantee such as a long term bond.
This bond should cover the cost of trying to repair
the original effort or if necessary, trying again.
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LITERATURE CITED
Andrewartha, H.G. and L.C. Birch. 1984. The Ecological
Web: More on the Distribution and Abundance of
Animals. University of Chicago Press.
Bertness, M.D. and A.M. Ellison. 1987. Determinants of
patterns in a New England salt marsh plant
community. Ecolo(rical Monographs S7C2V.129-147.
Clausen, J., D.D. Deck, and W.M. Heisey. 1940.
Experimental Studies on the Nature of Species. I.
The Effect of Varied Environments on Western North
American Plants. Carnegie Institution of
Washington, Pub. 520, Washington, D.C.
Darwin, C. 1859. On the Origin of Species. Harvard
University Press, Cambridge, Massachusetts (1964
ed.).
DeAngelis, D.L. and J.C. Waterhouse. 1987. Equilibrium
and nonequilibrium concepts in ecological models.
Ecological Monographs 57(1):1-21.
Gosselink, J.G. and L.C. Lee. 1987. Cumulative Impact
Assessment in Bottomland Hardwood Forests. Center
for Wetland Resources, Louisiana State University,
Baton Rouge. LSU GEI-86-09.
Jacobson, T. and J.A. Kushlan. 1986. Alligators in
natural areas: Choosing conservation policies
consistent with local objectives. Biological
Conservation 36:181-196.
Krebs, C.J. 1978. Ecology: The Experimental Analysis
of Distribution and Abundance. Second Edition.
Harper & Row, New York.
Kushlan, J.A. 1987. External threats and internal
management: the hydrologic regulation of the
Everglades, Florida, USA. Environmental
Management 11(1):109-119.
Lewin, R. 1986. In ecology, change brings stability.
Science 2341071-1074.
MacArthur, Rfl. 1972.
& Row, New York.
Geographical Ecology. Harper
McNaughton, S.S. 1966. Ecotype function in the Typha
community type. Ecological Monographs 36:297-325.
Myers, J.P., R.I.G. Morrison, P.Z. Antas, B.A.
Harrington, T.E. Lovejoy, M. Sallaberry, S.E.
Senner, and A. Tarak 1987. Conservation strategy
for migratory species. American Scientist 75:19-26.
Skeate, S.T. 1987. Interactions between birds and fruits
in a northern Florida hammock community.
Ecology 68(2):297-309.
Urban, D.L., R.V. O'Neill, and H.H. Shugart, Jr. 1987.
Landscape ecology. BioScience 37119-127.
Webster, N. 1970. Webster's New Twentieth Century
Dictionary. World Pub. Cleveland.
Weller, M.W. 1981. Freshwater Marshes: Ecology and
Wildlife Management. University of Minnesota
Press.
Wiens, J.A. 1985. Vertebrate responses to
environmental patchiness in arid and semiarid
ecosystems. In S.T.A. Pickett and P.S. White (Eds.),
The Ecology of Natural Disturbance and Patch
Dynamics. Academic Press, New York.
Willard, D.E. 1980. Vertebrate use of wetlands.
Proceedings of Indiana Water Resources
Association Meeting.
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RESTORATION OF THE PULSE CONTROL
FUNCTION OF WETLANDS AND ITS RELATIONSHIP
TO WATER QUALITY OBJECTIVES
Orie L. Loucks
Holcomb Research Institute
Butler University
ABSTRACT. Many wetlands and wetland restoration opportunities occur in the poorly
drained headwaters of streams, along the stream floodplains, and at discharge points to larger
water bodies. All of these are greatly changed by upland development that accelerates flows
and increases the runoff pulse from headwater areas. In turn, the runoff increases scouring
and transport of sediments, and subsequent deposition in or erosion of downstream wetland
types. Successful restoration must consider how the hydrologic pulse may have been changed
and whether pulse control measures can bring stream flows within a range consistent with
historical development of downstream wetlands.
Comparison of spring versus summer loadings pulses indicates major differences in the
seasonality of transport of excess nutrients into wetlands and downstream water bodies. The
annual average loading is misleading, indicating that statements on wetland functions which
ignore their role during pulsed events probably understate their significance in the landscape.
Modelling studies of runoff and sediment transport suggest the combination of reduced soil
exposures and restoration of wetland cover in temporary detention areas can produce major
benefits in stream water quality. With additional parameters, quantitative estimates could be
made of the cumulative impact of wetland restoration toward mitigation of flood peaks and the
transport of sediment and toxic substances into adjacent aquatic systems.
At present, the general physical relationships between land use and hydrology provide
only a guide to the prospective benefits we associate with investment in wetland restoration.
They suggest how to evaluate tradeoffs in benefits and costs between a lower cost investment
higher in the watershed (carried out over large areas), versus investment in a higher risk but
potentially higher quality wetland restoration along the main stem or outlet of a drainage
system. Although limited predictive capabilities exist for assessing the efficacy of restored
wetlands, they have not been subjected to quantitative testing within the environment of
wetland restoration technology. There is a need for more complete treatment-response
modeling and model testing if the predictive capability needed to improve wetland restoration
is to become available.
INTRODUCTION
Many studies have shown that impairment of
rural (and suburban) surface water quality
occurs during infrequent but unusually large
storm events. These events produce pulses in
runoff, leading to flood peaks, unusual levels of
sediment transport or "washouts", and
mobilization of contaminants from agricultural
lands or industrial sites. Studies also have
shown that hydrologic detention in wetlands, or
other means of delaying the peak hydrologic
response, provides important buffering in the
transport of sediment and chemicals by reducing
the size of the pulsed events. This chapter
examines the basic principles of hydrologic
response and material transport, emphasizing
pulsed events, and considers the potential for
improving water quality and aquatic ecosystem
functions through restoration of pulse-control
processes in wetlands.
To meet these objectives the paper reviews the
relevant literature on wetland hydrology,
sediment transport and nutrient detention.
Historical or "reference ranges" in hydrologic
or detention functions are emphasized as well as
modern conditions, as a synthesis of both will
contribute to understanding the potential for
restoration. In landscapes where widespread
alteration of hydrologic and related wetland
functions has occurred, little possibility exists for
consensus on a normal or reference state for
wetland functions, particularly for processes that
ameliorate unusual pulsed events. One important
reference point, however, is the buffering
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associated with the original vegetation and
wetlands of a watershed. In the long-run, the
success of a newly created or restored wetland
needs to be evaluated in relation to the capacity
of even the most natural of remaining wetlands
to function within present-day hydrologically
altered watersheds.
The question of how to further reduce the
effects of unusual hydrologic events, including
the transport of foreign substances, is significant
now because the Agricultural Stabilization Act of
1985 could withdraw up to 50 million acres of
land from agricultural use. Implementation of
this program is already being seen as
significant for further wetland restorations.
Although the set-aside programs (sodbuster and
swampbuster) emphasize highly credible soils,
some of the alternate uses will permit the
restoration of wetlands, or more likely
restoration of the buffering capacity of vegetation
and wetlands in the headwater areas of
watersheds. Indeed, a potential exists to focus
certain of the set-aside programs so that they
greatly enhance the water quality improvement
potential of wetlands in agricultural areas,
thereby enhancing the recovery of wetland
functions and downstream water quality.
PRINCIPLES EVIDENT FROM EXISTING STUDIES
DISTRIBUTION OF WETLANDS
ON A LANDSCAPE
Although wetland types vary widely from
one area to another across the landscapes of the
United States, a very common wetland type,
making up by far the largest part of wetland
acreages in the central regions, are depressions
that provide temporary detention of water. These
wetlands are characterized simply by poorly
drained soils (gleysols) and the presence of a
number of wet-habitat indicator species. This
wetland type is best illustrated by the shallow
basin type described by Novitzki (1979), Figure 1.
Frequently these shallow wetlands are drained
for agriculture, and no longer function as
wetlands. They are not usually protected by state
or federal wetland programs, and most often are
not subject to permitting or mitigation
requirements. Indeed, although the classification
by Cowardin et al. provides for the inclusion of
such temporarily flooded wetland types within
the palustrine wetland systems, and they can be
mapped by following the distribution of gleysol
soils, they are not well illustrated in the cross-
sectional diagrams shown by Cowardin et al.
(1979).
Despite the very large area of temporary
detention in many watersheds, the withdrawal of
shallow basin wetlands through ditching and
drainage has greatly increased the rate at which
water is discharged from the upland landscape
into the remaining wetlands, streams and
floodplains. The importance of this relationship
is shown in Figure 2, where the stream
hydrograph with good retention has a much lower
flood peak and a longer discharge time than the
stream without detention (Reppert et al. 1979).
The presence of the drainage channel system
increases the flood peak and greatly increases
the potential for transport of substances into the
aquatic environment (Carter et al. 1979, Novitzki
1979).
DETENTION IN NATURAL DRAINAGES
Studies in the Lake Wingra Basin around
Madison, Wisconsin from 1969 to 1974 (Loucks
and Watson 1978, Loucks 1981, Loucks 1986) have
illustrated the hydrologic and nutrient detention
potential of wetlands in natural drainage
systems. One part of this study focused on a
comparison of the modern hydrology of the Lake
Wingra basin with the pre-settlement hydrology
reconstructed from measurements on a
subwatershed within the University of
Wisconsin Arboretum. Data summarized by
Prentki et al. (1977) have shown that the natural
subwatershed (Marshland Creek, a large natural
area of forest, prairie and shallow basin
wetlands), yielded much less runoff than that
characterizing watersheds of similar size in the
suburban areas around the Arboretum. Runoff
from the natural watershed occurred only during
snowmelt when the soils were still partially
frozen. Runoff occurred from the other
watersheds during almost every significant rain
event throughout the study period. The hydrology
for the entire Lake Wingra basin, for both
present and presettlement conditions, is
summarized in Table 1. The runoff under
current conditions, where shallow basin
wetlands have been filled or drained, is about
twice that estimated for the presettlement
watershed. A related decrease of almost ten
percent is shown for the inflow from springs and
groundwater to the lake.
Because the concentrations of nitrogen and
phosphorus are higher in runoff waters compared
to groundwater, the hydrologic changes have
resulted in large differences in the nutrient
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SHALLOW BASIN
Dry Much of the Time
MODERATELY DEEP BASIN
Only Occasionally Dry
DEEP BASIN
Permanently Wet
Figure 1. Different plant communities in surface water depression wetlands related to water
permanence and basin depth (Novitzki 1979).
Discharge
Storm profile
Hydrograph w/o storage
Maximum retention
Hydrograph with storage
Rainfall
Time
Figure 2. Flood hydrographs for watersheds with and without wetland storage capacity (from Reppert
et al. 1979).
57
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loadings to this lake, as summarized in Table 2.
Nitrogen input has increased slightly due to the
increased runoff. Phosphorus has much higher
concentrations in runoff, and along with the
increased proportion of surface runoff, yields an
increase of almost two-thirds in the loading of
this key nutrient. This level of increase,
resulting in large part from the loss of
temporary detention, produces what is widely
recognized as a water quality impairment.
A key question then is whether the
restoration of wetlands or other temporary
retention basins at locations between the altered
uplands and the receiving wetland or lake
systems would reduce the effects from pulsed
transport of phosphorus during storm events.
Research reported by Flatness (1980), Huff and
Young (1980), and Perry et al. (1981) provides an
opportunity to answer this question. West Marsh,
a small area remaining at the west end of Lake
Wingra, is the receiving site for storm drainage
from a golf course and urban area on the west
side of the City of Madison, Wisconsin.
Measurements of water inflow, and the net
detention of water and nutrients, were carried
out over a two year period (Flatness 1980). Two
findings are significant: first, the largest part of
the net flow through of water, sediment, and
nutrients across the marsh and into the lake
occurred during the spring runoff when the
marsh was frozen (as was seen in the natural
watershed in the Arboretum). The transport of
water and nutrients is large enough during this
time that the annual average detention achieved
by the wetland, expressed on an annual basis (as
has been done in the past), is a very modest 10
percent.
The second finding, however, is that during
the summer when evaporation from the marsh is
high and the potential for nutrient uptake also is
high, the wetland functioned so as to detain 83
percent of the incoming phosphorus (Table 3).
When this result is considered in the context of
how the lake ecosystem functions through the
seasons, one recognizes that the spring influx of
phosphorus meets a very large percentage of the
lake requirement at that time (as the algae and
zooplankton populations increase in mass by an
order of magnitude). During the summer no
additional input of phosphorus is needed for a
healthy and fully functioning lake ecosystem
(remineralization is quite sufficient). These
relationships indicate a major difference in the
seasonality of pulsed transport of nutrients to the
lake. In this case, focus on the annual average
(Table 3) is misleading, indicating that
statements on wetland functions that pass over
their role during pulsed events will also
understate their significance in the landscape.
MODELING AREAWIDE SEDIMENT
SOURCES AND DETENTION
Consider another study of detention of
sediment and water within the shallow basin
systems of an agricultural landscape: an
analysis of Finley Creek, a small watershed
northwest of Indianapolis, Indiana. This
watershed was studied as a part of the research
on Eagle Creek between 1978 and 1982. The study
was designed to evaluate how much sediment
and nutrient input could be reduced through
changes in tillage practices on this largely
agricultural watershed, chosen as representative
of land use and runoff in central Indiana. The
watershed contributes to the water supply for the
City of Indianapolis.
A capability for evaluating runoff, transport,
and deposition of sediment within a small
watershed was developed by Beasley and others
at Purdue University (Beasley et al. 1985,
Huggins et al. 1982, Lee et al. 1985.) Their work
led to the ANSWRS model (Areal Nonpoint
Source Watershed Response Simulation). The
model is, in effect, a fine grid geo-information
system that allows two-dimensional calculation
of the proportion of runoff from each area in the
watershed. Given the volumes of water from each
area and the rates of flow (from the runoff and
slopes), the amount of sediment mobilized from
the eroding surfaces can be calculated. These
calculations then allow estimation of the
sediment subsequently deposited in the
temporary detention depressions (shallow basin
wetlands) in the watershed (see Figure 3), or
carried on to the stream itself. The model also
calculates the residual transport of sediment to
the stream, thereby allowing estimation of the
potential for water quality improvement through
more environmentally compatible cultivation
measures. The studies have shown reductions of
as much as 36 percent in sediment input as a
result of changes in the tillage practices on the
gentle slopes. These results were obtained without
considering the introduction of natural
vegetation, greenways, or restored wetlands near
the stream itself, steps that would further reduce
sediment transport to the streams.
Given evidence that even the small, shallow
basins in this watershed play a large role in
holding water and sediment (at least during the
growing season), these modeling results suggest
the combination of reduced tillage and
restoration of wetlands could produce major
benefits in stream water quality. Using the
model with additional parameters (for the effects
of increased permanent green cover), an
estimate can be made of the areawide cumulative
impact of wetland restoration toward the
mitigation of flood peaks and transported
sediment and associated chemicals.
58
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Table 1. A comparison of hydrologic inputs for a modern and predisturbance watershed, in volumetric and percent-of-
total forms. (From Loucks and Watson 1978).
Source
Hydrologic Input (10 3 m3/yr)
Present Percent Presettlement
Percent
Rainfall
Runoff
Springs and
Groundwater
TOTALS
920
990
430
6200
15
16
69
100
920
450
4500-4700
5900-6100
15
7
78
100
Table 2. Estimated present and presettlement loadings, Lake Wingra. (From Loucks and Watson 1978).
Source
Nitrogen
Loading (kg yr ~*)
Present Presettlement
Phosphorus
Loading (kg yr ~l)
Present Presettlement
Rainfall
Runoff
Springs and
Groundwater
Dryfall
N Fixation
1200 1200
5200 3000
18000 18000-19000
1900 1800-1900
3800 (assume 3800)
34
710
160
95
34
320
170-180
92-95
TOTALS
30000 28000-29000
1000
620-630
59
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Table 3. Phosphorus mass balance for Wingra runoff water, August 1975-August 1976 (From Livingston
and Loucks 1978).
Dissolved Reactive Phosphorus
Season
Autumn (14 August - 13 December)
Winter (14 December - 10 February)
Spring (11 February - 7 May)
Summer*
Annual*
Input
(kg/day)
0.380
1.232
3.862
0.145
1.282
Output
(kg/day)
0.318
1.231
3.553
0.024
1.155
Retention
(kg/day)
0.061
0.002
0.309
0.120
0.127
Percent
16
1
8
83
10
* Assumes 100 percent infiltration for summer except 15 May and 24 June runoff event.
Research on lake restoration (Cooke et al.
1986), related to the lake/watershed studies cited
previously, also should be considered for its
potential relevance in a synthesis of mitigative
measures for wetlands. The principles of lake
restoration have matured over the past fifteen
years, and are beginning to be viewed as a
predictive science, despite our recognition that
virtually no two lakes are alike or will respond
similarly to the same treatment. The
investigations used to design and evaluate the
prospective response of lakes to restoration
measures show that, before mitigation can be
expected to meet goals set for a given lake, key
characteristics of that system need to be
understood. These include knowing the entire
hydrology of the lake and watershed,
particularly flushing time (i.e., the time required
for the incoming water volume to equal the
volume of water in the lake or wetland), the
annual and seasonal net loading of sediment
and nutrients (expressed in terms of equivalent
weight per unit area of lake), and seasonal
hydrologic fluctuation, shoreline aeration, and
related questions of sediment toxicities. Let us
consider how the lake restoration procedures and
principles would apply to evaluating the potential
for success in wetland restoration.
Prior to restoration, the essential principles
for wetland evaluation need to address the
hydrology of the wetland, just as it would be
addressed in evaluating the restoration of a
small lake. Included are questions of the total
magnitude of the hydrologic inflows and
outflows, from which can be calculated an
apparent flushing time. The flushing-time term
already is recognized as the dominant factor in
coastal wetlands where tidal processes produce
daily flushing (de la Cruz 1978). Freshwater
wetlands, on the other hand, experience flushing
principally during unusual runoff events,
although not all freshwater wetlands experience
flushing. In addition, just as for lakes, the
relative importance of surface water input as
opposed to groundwater input, and how the
balance of these inputs controls the resultant
chemistry of the wetland, are essential to
understanding the biological community that
can be sustained on a restored wetland.
Related to these questions are the seasonal
and longer-period hydroperiods for the sites
being considered for restoration. Although we are
accustomed to dealing with annual averages, the
key characteristics of the wetland and the
associated water courses are often dominated by
pulsed events only partially mediated by the
system as a whole~as the examples cited earlier
in this chapter illustrate.
For the annual hydroperiod of wetlands,
saturation is expected during the winter or
spring, followed by a major drying down in most
parts of the country during the summer. Here, as
we saw earlier, one needs to consider a reference
60
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N
Soil loss > 20 MT/ha
Deposition > 10 MT/ha
FINLEY CREEK
Indiana MIP
Management Strategy
61
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pattern: What was the pre-alteration fluctuation
pattern influencing or controlling a wetland type
for which we may now be setting restoration
goals? An estimate of pre-alteration properties
should be compared with the existing
hydroperiod, so as to evaluate whether the
transition from present conditions to the patterns
associated with the proposed restoration can be
achieved. Illustrative data on the changes
induced in a wetland hydroperiod, and the
associated wetland degradation, are reported by
Bedford and Loucks (1979).
Another important property, the logarithmic
relationship between annual flood peak
(expressed as the ratio to mean annual flood),
and the return interval over which unusual
events are expected to recur in small watersheds
is shown in Figure 4. This relationship is
similar to one used to estimate the hundred-year
flood peak for rivers. In restoring wetlands, the
size and return-period of extreme events must be
considered, whether the event is a 100-year flood,
a 20-year unusual event (at twice the mean
annual flood), or the 5-year pulse (at 30 percent
greater than the annual flood). There is always
some probability, perhaps one in a hundred
(which approaches certainty for 100 or more
wetland or stream systems in any given year),
that extreme events will affect a wetland
restoration. The significance of return-time
considerations lies in the fact that restoration on
a large number of wetlands must be designed
for events that are unusual locally, but fairly
frequent over a large population of wetlands.
Indeed, the threat of serious erosion of wetlands,
or even burial through sediment transport from
the adjacent uplands, must be incorporated into
restoration designs.
Consider also the well-known exponential
rise in sediment load associated with increased
water flow rates. Few studies discuss the
increased transport of toxic substances to the
aquatic environment under peak flow
conditions, but exponential increases in
transport seem to be the best first approximation
for estimating these components as well. When
these two relationships are combined (probability
of extreme events in a large population of
wetlands, and exponential increase in sediment
and toxic substance transport), one begins to
appreciate the potential for relatively simple,
physical predictive tools to aid in understanding
the wetland functions sought in restorations.
Indeed, restoration of sediment and nutrient
detention may be achieved more effectively
through a large number of relatively low-cost
wetlands in the upper reaches of watersheds than
through a similar number of often high-cost (and
high-risk) wetland restorations farther down in
the watershed. These wetlands are more subject
to being overwhelmed by large-volume flows
and transport from the relatively uncontrolled
system above them.
IMPLICATIONS FOR RESTORATION OF THE
PULSE CONTROL FUNCTION
An important part of the design of a
wetland restoration intended to improve pulse
control rests with characterizing the processes
involved. The discussion above has introduced
the concept of small, but large-area influences,
the central principle in "buffering". The
regulatory aspect of this question is evident in
requirements for a "buffer zone" to be
established along the margins of important
wetland habitats. Debate currently focuses on
whether a "buffer" should be 50, 100, or up to 300
feet wide. This concept and terminology is used
despite the fact that a technical definition of
"buffer" emphasizes properties of resilience, i.e.,
the capability to continue to resist an altered state
despite an unusual degree of input or force
toward that alteration. Wetlands distributed in
the shallow basins throughout the headwaters of a
watershed, unrelieved by present-day tile-
drainage and channeling, provide buffering
capability in the original technical sense. On
the other hand, a strip of land retained around
the edge of a wetland provides important habitat
for species that may utilize the wetland border as
shielding from human activity. This strip of
upland cover, however, provides little buffering
capacity for the hydrologic and sediment pulses
from upstream, which represent the greatest
intrusion into the wetland during pulsed events.
These two different functions now being
associated with "buffering" should be made more
explicit during permit review, and
documentation of each aspect should be required
when proposing mitigation. For the present,
provision for the wetland margin buffer zones
exists in some permitting procedures, and
although broad mitigative functions are an
accepted benefit from these reserves, serious
differences of opinion will remain until the
terminology and listing of benefits are more
precise.
Given that unbuffered events impacting
wetlands can be many times larger than average
peak flow conditions, designs for an
optimal buffering capacity to control man-
induced peaks should seek a severalfold
reduction in the size of these fluctuations. A
62
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reduction in the size and frequency of these
events, expressed in clearly measurable
standards (e.g., as in Figure 4), should be
articulated as a performance criterion for
wetland restoration. Such measures should then
be incorporated into design criteria for
restoration projects. In the examples considered
here, one reference point for performance
criteria is the magnitude of the extreme-event
pulses in natural systems, while the magnitude
of the extreme-event pulses characteristic of
urban watersheds is an opposing reference point.
Major pulse reduction can be expected
downstream when restoration is carried out close
to the headwaters of small drainage systems, but
water quality benefits will be expressed locally
as well as downstream. However, as more and
more of the area of a drainage basin loses this
"headwater" buffering capacity, the more
extreme are the pulsed events midway or lower
in the watershed and the more difficult is
restoration or protection of wetland functions in
those areas.
These general physical relationships can
provide only a guide to the expectations likely to
be associated with investment in wetland
restoration. However, they also are a means for
guiding estimates of the long-term survivability
of a restoration project, at least in relation to the
return-time of extreme events that could
negatively impact the restoration. These physical
relationships also suggest how we might evaluate
the tradeoff in benefits and costs. In its simplest
form, the tradeoff is between a lower-cost
investment higher in the watershed (little more
than small area set-asides), versus investment
in a higher risk (but potentially higher quality)
wetland restoration along the main stem or outlet
of a drainage system. Additional research is
needed before fully quantitative expressions of
these tradeoffs can be formulated.
T)
O
O
CO
3
C
C
CO
C
CO
CD
E
CO
DC
1.01 1.1
1.5 2 3 5 10 20 30 50 100
Return period,7J. , (years)
Figure 4. Regional-flood-frequency curve for selected stations in the Youghiogheny and
Kiskiminetas River basins (Pennsylvania and Maryland), showing the return time for
pulsed events expressed as a ratio to mean annual flood. A reduction in the hydrologic
detention of wetlands raises the slope of this curve (U.S. Geological Survey, from Linsley et
al. 1975).
63
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RESEARCH]
While wetlands function in many
important ways, and while technology exists for
proceeding with confidence on a moderate
number of restoration goals, great limitations
exist in our understanding of the variability in
response among sites. These limitations restrict
our ability to predict the outcomes of restoration
measures. Priority research needs for
improving our understanding of risks and
benefits in wetland restoration, particularly
during pulsed events, can be addressed under the
following four headings:
1. A need exists for additional case studies of
hydrologic and water quality responses to the
distribution of wetland buffering capacity
under a wide variety of weather conditions,
soils, and topography. These studies should
include an increased emphasis on the role of
wetlands in intercepting and retaining
nonpoint source pollutants, including toxic
substances mobilized from adjacent uplands.
2. Although some quantitative predictive
capability exists for assessing the efficacy of
restored wetlands, or of specific components
in the restoration processes, these have not
been subjected to significant testing or
validation. There is a need for more
complete treatment-response modeling and
model testing if the predictive capability
required for improved designs and
implementations is to become widely
available.
3. A need has developed for specific case
studies regarding the benefit and cost
relationships from allocating a "buffer
zone" around wetlands where development
is underway. How much benefit is achieved
from a 100-foot or 300-foot strip along the edge
of a wetland receiving the discharge from a
highly developed watershed? What response
can be expected from a restoration
and rehabilitation under such conditions? A
tradeoff may exist between values in the 300-
foot strip, some of which may not be of great
benefit to the wetland, and a comparable
investment at strategic locations in
headwater areas. This research requires
predictive capabilities for both the border or
edge benefits of the buffer zone, as well as the
pulse-control processes.
4. Finally, research should evaluate the
hierarchical relationships among hydrologic
and nutrient pulse control functions, as one
proceeds from the small watersheds that we
are beginning to understand to the larger
watersheds and landscapes where water
quality questions are paramount. Do new
principles come to bear? Can a
geoinformation system such as the ANSWRS
model be extended to adjacent watersheds to
assess cumulative impacts from the
restoration of a pattern of wetlands across the
landscape? The tools appear to be available to
address these questions, and they should be
evaluated as soon as possible.
Some of the above research needs
require a strategy either of establishing new
wetland study sites, or broadening the depth and
perspective of existing wetland research sites
and initiatives. Because so much already is
underway, the research needs described here
need not be thought of as requiring a new
program, but rather a re-articulation of several
existing studies in order to meet additional
needs. Limited work on wetlands already is
underway through the Long-Term Ecological
Research sites sponsored by the National Science
Foundation, and relevant modeling is underway
at several of the EPA research laboratories and
through their supporting institutions. Together,
these initiatives indicate sufficient work-in-
progress to conclude that the above research is a
reasonable target for a five-year program.
LITERATURE CITED
Beasley, D.B., E.J. Monke, E.R. Miller, and L.F.
Huggins. 1985. Using simulation to assess the
impacts of conservation tillage on movement of
sediment and phosphorus into Lake Erie. J. Soil
Water Conserv. 40(2):233-237.
Bedford, B.L. and O.L. Loucks. 1979. Changes in the
Structure, Function, and Stability of a Wetland
Ecosystem Following a Sustained Perturbation.
Progress report on 1978 research. Water Resources
Center, Univ. of Wisconsin-Madison.
Carter, V., M.S. Bedinger, R.P. Novitzki, and W.O.
Wilen. 1979. Water resources and wetlands, p.
344-376. In P.E. Greeson, J.R. Clark, and J.E. Clark
(Eds.), Wetland Functions and Values: The State of
Our Understanding. Proceedings of the National
Symposium on Wetlands, American Water
Resources Association, Minneapolis, Minnesota.
Cooke, G.D., E.B. Welch, S.A. Peterson, and P.R.
Newroth. 1986. Limnology, lake diagnosis, and
selection of restoration methods, p. 9-51. In G.D.
64
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Cooke, E.B. Welch, S.A. Peterson, and P.R. Newroth
(Eds.), Lake and Reservoir Restoration, Butterworth
Publishers, Boston, Massachusetts.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe.
1979. Classification of Wetlands and Deep water
Habitats of the United States. U.S. Department of the
Interior, Fish and Wildlife Service, Washington,
D.C.
de la Cruz, Armando A. 1978. Production and transport
of detritus in wetlands. In PJ5. Greeson, J.R. Clark,
and J.E. Clark (Eds.), Wetland Functions and
Values: The State of our Understanding.
Proceedings of the National Symposium on
Wetlands, American Water Resources Association,
Minneapolis, Minnesota.
Flatness, D.E. 1980. Particulate Phosphorus-Availability
in Tributaries of the Great Lakes and Removal in a
Marsh System. M.S. Thesis, Water Chemistry
Program, University of Wisconsin, Madison,
Wisconsin.
Huff, D.D. and H.L. Young. 1980. The effect of a marsh
on runoff: I. A water budget model. J. Environ. Qual.
9:633-640.
Huggins, L.F., D.B. Beasley, D.W. Nelson, T.A. Dillaha,
III, D.L. Thomas, C. Heatwole, E.J. Monke, R.A.
Dorich, and L.A. Houston. 1982. NFS pollution:
evaluating alternative controls by simulation and
monitoring, p. 5-1 - 5-80. In A.H. Preston (Ed.),
Insights into Water Quality—Final Report. Indiana
Heartland Model Implementation Project.
Lee, J. Gary, S.B. Lovejoy, and D.B. Beasley. 1985. Soil
loss reduction in Finley Creek, Indiana: An
economic analysis of alternative policies. J. Soil
Water Conserv.. January-February 132-135.
Linsley, R.K., M.A. Kohler, and J.L.H. Paulhus. 1975.
Hydrology for Engineers. McGraw-Hill Series in
Water Resources and Environmental Engineering.
McGraw-Hill Book Company.
Livingston, R.J. and O.L. Loucks. 1978. Productivity,
trophic interactions, food-web relationships in
wetlands and associated systems, p. 101-119. In P.E.
Greeson, J.R. Clark, and JJE. Clark (Eds.), Wetland
Functions and Values: The State of Our
Understanding. Proceedings of the National
Symposium on Wetlands, American Water
Resources Association, Minneapolis, Minnesota.
Loucks, O.L. 1981. The littoral zone as a wetland: Its
contribution to water quality, p. 125-138. In B.
Richardson (Ed.), Selected Proceedings of the
Midwest Conference on Wetland Values and
Management, June 17-19,1981.
Loucks, O.L. 1986. Role of basic ecological knowledge
in the mitigation of impacts from complex
technological systems: agriculture, transportation
and urban. In O.L. Loucks (Ed.), Proceedings of a
Conference on Long Term Environmental Research
and Development. Council on Environmental
Quality (CEQ), Washington, D.C.
Loucks, O.L. and V. Watson. 1978. The use of models to
study wetland regulation of nutrient loading to Lake
Mendota, p. 242-252. In C.B. DeWitt and E. Soloway
(Eds.), Wetlands, Ecology, Values, and Impacts.
Proceedings of the Waubesa Conference on
Wetlands. University of Wisconsin-Madison, Inat.
for Env. Studies, Madison, Wisconsin.
Novitzki, R.P. 1979. Hydrologic characteristics of
Wisconsin's wetlands and their influence on floods,
stream flow, and sediment, p. 337-388. In P.E.
Greeson, J.R. Clark, and J.E. Clark (Eds.), Wetland
Functions and Values: The State of Our
Understanding. Proceedings of the National
Symposium on Wetlands, American Water
Resources Association, Minneapolis, Minnesota.
Perry, J.J., D.E. Armstrong, and D.D. Huff. 1981.
Phosphorus fluxes in an urban marsh during runoff,
p. 199-211. In B. Richardson (Ed.), Selected
Proceedings of the Midwest Conference on Wetland
Values and Management, Freshwater Society,
Navarre, Minnesota.
Prentki, R.T., D.S. Rogers, V.J. Watson, P.R. Weiler,
and O.L. Loucks. 1977. Summary tables of Lake
Wingra Basin data, p. 89. In Univ. of Wise.
Institute for Env. Studies, Report 85, December 1977.
Madison, Wisconsin.
Reppert, R.T., W. Sigleo, F. Stakhiv, L. Messuram, and
C. Meyers. 1979. Wetland Values: Concepts and
Methods for Wetlands Evaluation. Institute for
Water Resources, U.S. Army Corps of Engineers, Ft.
Belvoir, Virginia.
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VEGETATION DYNAMICS IN RELATION TO WETLAND
CREATION
William A. Niering
Connecticut College and Connecticut College Arboretum
ABSTRACT. An understanding of the ecological processes involved in wetland vegetation
development is essential to wetland managers concerned with wetland creation. Ascertaining
a sound hydrologic system is basic in any attempt to re-create a wetland system since the
vegetation and associated fauna are dependent upon a consistent but usually fluctuating
hydrologic regime. Any hydrologic manipulations can also greatly modify what species will
become established in a given site or those that may decline in abundance. Traditional
succession-climax dogma has limited usefulness in interpreting vegetation change. Thus an
understanding of the complex of factors involved in the process, including chance and
coincidence, makes the task of the manager even more challenging.
Since vegetation change is not necessarily predictable and orderly, as is sometimes
thought, it is often difficult to predict the ultimate vegetation in a given created site. Some
wetland communities once created may be relatively stable; others may undergo directional or
cyclic change, thus adding to the complexity of the ultimate vegetation.
Therefore, one of the major goals in wetland creation should be the persistence of the
wetland as a self-perpetuating oscillating system. This can be achieved by assuring a sound
hydrologic regime.
INTRODUCTION
In wetland creation it is important to
understand the patterns and processes involved
in vegetation or biotic change. Such ecological
concepts as succession and climax usually come
to mind in this regard. However, depending
upon one's interpretation, they can actually
hamper rather than aid in understanding
wetland dynamics. How do wetlands change? Is
it an orderly, predictable, directional pattern as
suggested by traditional succession? Will a
given wetland reach a so-called climax state?
Does it succeed to upland communities?
Although most ecologists have modified their
views concerning these concepts, there is still
much debate concerning their interpretation as
well as their continued use (Egler 1947;
Heinselman 1970; Drury & Nisbet 1973; Niering
& Goodwin 1974; Pickett 1976; Mclntosh 1980,
1981; MacMahon 1980, 1981; Zedler 1981;
Patterson 1986; Niering 1987).
The purpose of this chapter is to review
wetland vegetation dynamics occurring in
natural systems in order to provide a
background for evaluating wetland change in
created systems.
WETLAND VEGETATION DYNAMICS
The concept of succession has been most
closely associated with vegetation dynamics. As
traditionally conceived by Clements (1916), it set
forth a rather orderly, predictable and
directional process for vegetation change in
which one set of communities replaced another
until a relatively stable system (climax) was
established. It was primarily community
controlled and, in the case of wetlands, the
ultimate vegetation was believed to be an upland
climax.
These traditional concepts have been
considerably modified during the last half
century. Yet, this does not diminish Clements'
contribution to plant ecology since his six basic
processes involved in vegetation change
(nudation, migration, ecesis, competition,
reaction and stabilization) are still relevant.
However, it is now recognized that autogenic
(soil development, competition for light, mineral
depletion or accumulation) as well as allogenic
factors (flooding, drought, fire, wind, and
anthropogenic influences) are important in the
process. In fact, the latter often have an
overriding effect on the former. For example, a
67
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major disturbance that periodically interrupts a
wetland ecosystem can produce changes that may
last for decades or centuries. This introduces
uniformitarian vs. catastrophic ecology (Egler
1977) in which the latter, representing allogenic
change, may be so infrequent that it can be
overlooked by short-term studies or by
researchers who fail to recognize the role of
historical factors. Disturbance is a natural and
normal part of ecosystem dynamics (White 1979;
Pickett & White 1985) to which ecological
systems have become adjusted, especially in
terms of their recovery (Marks 1974; Bormann &
Likens 1979).
Gleason (1926) was one of the first to
challenge Clements, especially his idea of the
plant association and his organismic approach to
vegetation. Instead, Gleason promoted the
Individualistic Concept in which the differential
establishment and survival of the various species
in a given site were critical to the composition of
any resulting unit of vegetation. In essence, the
genetic characteristics of each species limit its
ecological tolerance and every environment has
its own biotic potential. For example, on an
Alaskan floodplain, life history processes or
species longevity, not facilitative interactions,
explained forest development (Walker et al.
1986). This concept has been recently developed
by van der Valk (1981, 1982) and applied to the
prairie pothole wetlands (van der Valk & Davis
1978). He found 12 basic life history types in
which the life forms of the plants, propagule
longevity, and propagule establishment
requirements are critical. Thus the plants which
develop in a given situation will be dictated
primarily by the life history requirements of
each species and its presence or absence in the
seed bank. No two sites, even though similar,
will support exactly the same plant association.
An extension of the Gleasonian approach has
resulted in the continuum concept in which
discrete communities are not thought to exist, but
rather continua, since species tolerances overlap
along environmental gradients. In studying
shoreline vegetation Raup (1975) was unable to
recognize sufficient integration of species
populations to identify community types and thus
proposed the term "assemblages" which is
logical in certain wetlands. It is also important
to recognize that vegetation is highly variable
and that a community is really a relative
continuum between two discontinua (Egler 1977).
Chance and coincidence are especially
relevant in wetland vegetation development
(McCune & Cottam 1985; Egler 1987). The role of
these stochastic factors is often difficult to
measure and quantify and therefore sometimes
overlooked. The three successional models
(Facilitation, Tolerance and Inhibition) proposed
by Connell and Slatyer (1977) are also relevant
in understanding wetland dynamics. The
Facilitation model relates to autogenic processes
resulting in vegetation change in which the
existing biota so influence the environment as to
induce replacement of one set of species by
another. Accumulation of solely organic
sediments may lead to such changes, but
evidence of autogenic development at the
community level is limited. This model is the
traditional concept of vegetation change as
conceived by Clements. It can occur but it is only
one of several possible processes or models that
can be involved in vegetation change. The
Tolerance model implies that various species
may continue to become established over time,
and that differential tolerance to light, and other
limiting factors, will determine those species
which will ultimately dominate. The Inhibition
model suggests that those species which get
established initially following a disturbance
may well inhibit others from taking over. This
may be relevant in wetland situations where
relatively pure stands of cattail (Typha spp.) or
reed grass (Phragmites australis) initially get
established and essentially exclude other species.
This parallels Egler's (1954) Initial Floristic
Composition factor which sets forth the same
idea. For example, in intertidal rocky shore
wetland communities where new sites are
exposed following scouring, those species that get
established first frequently exclude others
(Lubchenco & Menge 1978; Sousa 1979). In fact,
this results in the patch pattern dynamics so
typical in intertidal systems (Paine & Levin
1981; Dethier 1984). The concept of inhibition is
somewhat counter to the concept of succession,
since the vegetation development may be arrested
at a phase that is not considered "climax". The
role of these models, and possibly other factors,
should be carefully evaluated when interpreting
the causal factors contributing to biotic change.
WETLAND ZONATION AND
VEGETATION CHANGE
Wetlands have long been regarded as
transitional communities with a trend toward
terrestrialization or upland communities (Gates
1926). In fact, this general misconception is still
portrayed in certain current biology and
environmental texts using successional
diagrams which show a series of belts from open
water to upland forest and suggesting that one
vegetation belt is replacing another centripetally.
This zonation pattern often represents a set of
species populations that has found its optimum
ecological requirements or tolerance in terms of
water depth and frequency and duration of
flooding. Thus these belts may not be a
successional sequence of one community
replacing another, but may represent relatively
stable vegetation types possibly in a state of flux,
depending upon changing hydrologic conditions
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(Gallagher 1977). Yet, there may be situations
where purely autogenic processes are involved in
this developmental sequence.
In Michigan, Daubenmire (1968) indicates
that upland trees cannot grow on peat soils and
that a transition to upland will not occur. In
Connecticut, Nichols (1915) also indicates that
replacement of forested wetlands, such as red
maple swamps, by upland oak forest is highly
unlikely. More recently Walker (1970) states
that, "Although certain sequences of transition
are 'preferred' in certain site types, variety is the
keynote of the hydroseral succession. In spite of
this the data clearly indicate that bog is the
natural 'climax' of autogenic hydroseres
throughout the British Isles and the transition
from fen to oak wood is unsubstantiated."
Bogs frequently exhibit distinctive belts but
fail to represent a successional sequence. In
Connecticut, Egler (personal communication)
found trees the same age in all belts, indicating
the effect of post-fire or cutting. At Cedar Creek
Bog in Minnesota, Buell et al. (1968) followed
vegetation change over three decades. They
found that the width of the bog mat did not change
in position over this time. However, the width of
the various vegetation belts did change. The
larch-shrub zone expanded outward into the
floating sedge mat, greatly reducing its width.
An earlier droughty period apparently favored
sedge development but as the water level rose
over the 33 years of observation, shrubs and larch
trees expanded outward. Yet Lindeman (1941)
observing this bog over part of the same period
(1937-1947) found that the mat had advanced one
meter, which emphasizes the limitations of short-
term observations. At Bryants Bog in Michigan,
studied since 1917, the bog mat has advanced into
the bog pool in an irregular manner averaging
2.1 cm per year (Schwintzer & Williams 1974).
In 1972 the open water was 76% of its extent in
1926. The mat vegetation has also changed over
more than five decades. The advancing
leatherleaf belt which was dominant in 1917 was
succeeded by a high bog shrub community in the
drier years and eventually by a bog forest by the
late 1960's. Then in the early 1970's the trees
died as the water level rose and leatherleaf was
reestablished. This emphasizes the dynamic non-
predictable cyclic pattern of vegetation change.
In Connecticut, I have observed the mortality of a
mature spruce bog forest due to extreme
prolonged flooding. In fact, beaver activities play
a major role in altering bog vegetation (Rebertus
1986) and vegetation along boreal forest streams
(Naiman et al. 1986). In the Minnesota
peatlands, Heinselman (1970) found no
consistent trend toward mesophytism,
terrestrialization, or uniformity but rather a
swamping of the landscape, rise in water tables,
deterioration of the growth and a diversification
of landscape types. In the northern Canadian
peatlands both water level fluctuations and fire
are primary factors governing vegetation
change. Here long-term records show that the
spatial-temporal approach does not accurately
describe the dynamics of peatlands (Jasieniuk &
Johnson 1982).
In the bottomland hardwood forests six
vegetation zones can often be recognized, based
on soil moisture and hydrology. However, as
Wharton et al. (1982) point out, the term "zone" is
somewhat misleading since many of these plant
communities are arranged in a mosaic pattern,
depending upon the hydrologic conditions.
Along the Northeast riverine systems the
vegetation pattern is also related to the frequency
and duration of flooding (Metzler & Damman
1985).
In the marine environment, mangrove and
salt marshes also exhibit distinct belting
patterns. In south Florida three mangroves - the
red (Rhizophora mangle [most oceanward]),
black (Avicennia germinans), and white
(Laguncularia racemosa [most landward]) -
frequently form a belting pattern which has been
interpreted as a succession oceanward (Davis
1940). Egler (1948) questioned this interpretation
and, more recently, Ball (1980) found that
interspecific competition was an important factor
in controlling the zonation. In Panama,
Rabinowitz (1975) found that reciprocal
transplants can grow well in either zone. She
also found that a primary mechanism
controlling zonation is tidal sorting of
propagules due to their size, rather than habitat
adaptation. It appears that, once a given zone
reaches equilibrium, it is unlikely to change
unless disturbance occurs (Odum et al. 1982). In
fact, major storms such as hurricanes are prime
site builders for the establishment of mangrove
(Craighead & Gilbert 1962; Craighead 1964).
However, in Australia, biotic influences such as
seed predation by crabs can also have a
significant influence on these intertidal
mangrove forests (Smith 1987).
Tidal wetlands of the Northeast offer still
another example of close integration between
vegetation change and hydrology. With coastal
submergence peat cores document a vegetation
development from the intertidal salt water
cordgrass (Spartina alterniflora ) to salt meadow
cordgrass (Spartina patens'). There is also a
tendency for spike grass (Distichlis spicata) and
switch grass (Panicum virgatum) to replace
upland species as the marsh advances landward
with sea level rise. However, once the high
marsh has developed, oscillations in the
vegetation patterns are primarily hydrologically
induced. Waterlogged, poorly drained sites
favor the short form of S. alterniflora. This
condition can be induced by mosquito ditching,
with the levees along the ditches preventing the
69
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flooded high marsh from draining.
Once the high marsh has developed, myriad
vegetation changes can occur as documented by
the hundreds of peat cores taken by Orson (1982)
in tracing the ontogeny of the Pataguanset
marshes in Connecticut, and by the author along
the coastline of Connecticut. For example, a
single core 1 meter in length, representing 500-
1000 years, may show five or six vegetation types
or changes based on the preserved rhizomes in
the core (Niering et al. 1977). There appears to be
no predictable unidirectional pattern.
Hydroperiod, changes in micro-relief, accretion
rates, salinity, redox potential, storms, and other
factors make these systems too complex to be
orderly or predictable (Niering & Warren 1980).
As stated by Miller and Egler (1950), "...the
present mosaic may be thought of as a
momentary expression, different in the past,
destined to be different in the future, and yet as
typical as would be a photograph of moving
clouds."
WETLANDS AS PULSED SYSTEMS
Odum (1971) set forth the concept of pulsed
stability as related to wetland systems. Subjected
to more or less regular but acute physical
disturbance imposed from without, they are often
maintained at an intermediate state in
development. This may further reflect why
traditional successional concepts frequently have
limited application in wetland systems. Tidal
wetlands, for example, may be maintained in a
relatively fertile state by a "tidal energy
subsidy" which provides rapid nutrient cycling
and favors substrate aeration. Among the
freshwater systems the prairie potholes are
pulsed in an even more striking manner, often
completely drying up in droughty periods and
then reappearing with the advent of adequate
precipitation. During droughts, aerobic
breakdown of the organic matter replenishes the
nutrient supply to favor future productivity. In
south Florida, the Everglades is another
fluctuating system. The importance of this
pulsing is dramatically correlated with the
successful breeding of the wood stork (Kahl 1964)
since lower water levels are necessary to
concentrate small fish to feed nestlings. Yet, an
"energy subsidy" from agricultural runoff, with
its nutrient enrichment, can actually be
deleterious to the low nutrient demanding
sawgrass, resulting in its demise and favoring a
dramatic increase in cattail. The sawgrass
(Cladium jamaicensis) can also be destroyed by
peat fires which recently have increased due to
drainage. Under the natural fluctuating water
regime the Glades burned when flooded and
viable sawgrass marsh was maintained (Egler
1952). Other wetlands that are pulsed by drought
and fire are the evergreen shrub pocosins along
the southeast coastal plain (Richardson 1981) and
the Okefenokee Swamp where fire and drought
have set the pattern for vegetation change for
decades (Schlesinger 1978; Hamilton 1984). As
previously mentioned, dry periods favor rapid
decomposition and peat fires can aid in
maintaining more hydric conditions. Some
species like the bald cypress, which normally
grows under flooded conditions, actually require
bare soil conditions for seedling establishment.
The pulsing concept is especially relevant in
wetland creation. Will there be fluctuating
hydrologic conditions in the newly created
wetland? Fixed water levels are not the rule in
nature. Continuous flooding or the absence of
pulsing are deleterious to most trees. Pulsed, not
static water regimes, should be one of the major
objectives in any mitigation project, especially
those in inland waterways and lake systems.
In respect to ecosystem development, Odum
(1969) set forth a series of ecosystem processes--
community structure and energetics—as related
to the stage of maturity in the process. Mitsch and
Gosselink (1986, see Table 7-1, p. 160-1) illustrate
how this scheme relates to some of the major
wetlands in the United States. It is obvious that
wetlands are highly variable with respect to these
criteria, exhibiting aspects of both immature and
mature systems, an attribute to be expected in
pulsed systems. For example, in most wetlands,
except bogs, mineral cycles are open and life
cycles are short, typical of immature systems;
food chains, however, are often complex,
characteristic of mature systems. Figure 1
attempts to more holistically integrate the
multiplicity of factors involved in biotic change
for both terrestrial and wetland ecosystems
without using traditional succession-climax
dogma. Relatively stable states can occur only to
70
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DISTURBANCE
Natural
Man-induced
Fire
Disease
Animals
Drought
Wind
Frost Action
Fire
Disease
Animals
Pollution
Past Land Use
INITIAL FLORISTIC
COMPOSITION
MIGRATION I
Vegetative Reproduction
Seed Bank (residual)
Seed (current)
Mode of Dispersal
Proximity of Propagule Source
FACILITATION
MODEL
TOLERANCE
MODEL
Dependent on life history of
species and local site con-
ditions (i.e.- bare substrate,
windthrows, logs, moss mats, etc.)
INHIBITION
MODEL
Constantly shifting
mosaic of populations
at community or
regional landscape
level.
Nurse Plants
COMPETITION
Plant/Plant Light
Herbivores Nutrients
Allelopathy Moisture
RELATIVELY
STEADY STATE
Mosaic of relatively
stable communities
at regional landscape
level.
Differential species survival
and exclusion.
Figure 1. Holistic view of some of the factors and processes involved in vegetation change.
Following disturbance a given system may eventually reach a relatively stable state or be
in a continuous state of flux (Niering 1987).
71
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be modified by disturbance, often due to
hydrologic changes. As Mitsch and Gosselink
(1986) indicate, the idea of a regional climax is
inappropriate since both allogenic and autogenic
factors are operative in wetland change. They
further point out that changes in wetlands are
often not directional and "...in fact, wetlands in
stable environmental regimes seem to be
extremely stable, contravening the central idea
of succession."
THE CONCEPT OF PERSISTENCE
It is my opinion, and that of a growing
number of other ecologists, that the use of such
terms as "vegetation development" or "biotic
change" is preferred to "succession," and
"relative stability" or "equilibrium state" to
"climax." Some ecologists are now finding the
concept of persistence an even more relevant
paradigm in visualizing ecosystem dynamics
(Lewin 1986). This idea of persistence is
especially relevant in wetland ecology. In
wetland creation the objective is to create a viable
persisting system which will exhibit a variety of
functional roles. Over decades or centuries one
may expect changes in the vegetation structure
and composition of the system. Some will be
small, others catastrophic, but the wetland system
will persist. Therefore, our goal in wetland
creation should not always be to duplicate a
specific vegetation type but to create a wetland
system that is hydrologically sound (Carter 1986)
and incorporates the potential for all those future
biotic variations that might be expressed under
differing hydrologic regimes in that particular
site.
RELEVANCE OF WETLAND DYNAMICS TO WETLAND CREATION
In conclusion, it may be helpful to
summarize how those involved in wetland
mitigation will find an understanding of
wetland dynamics especially relevant.
1. Natural wetlands are characterized by
distinctive, usually fluctuating hydrologic
regimes.
2. As pulsed systems, they are highly dynamic
but can persist as relatively stable entities or
be in a constant state of flux.
3. Biotic change in wetlands is usually not
directional and generally not predictable
since fluctuating water levels, chance, and
catastrophe are constantly interacting.
4. Short-term wetland observations concerning
vegetation change toward wetter or drier
conditions can be misleading, thus dictating
the need for long-term observations.
5. Considering the natural ontogeny of
wetlands over centuries or millennia,
human efforts in the creation of viable,
functional wetland ecosystems should be
approached with trepidation and humility.
6. Any wetland creation effort must be aimed
toward a self-perpetuating system which will
permit the potential for all the future biotic
variations which might occur in a natural
system.
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LONG-TERM EVALUATION OF
WETLAND CREATION PROJECTS
Charlene D'Avanzo
School of Natural Science
Hampshire College
ABSTRACT. Long-term success of wetland restoration and creation projects may be quite
different from short-term success. In this chapter six criteria are used to evaluate the
long-term success of more than 100 artificial wetland projects reported in the literature.
Results from numerous U.S. Army Corps of Engineers' dredged material stabilization
projects demonstrate the importance of long-term monitoring and increasing long-term as
well as short-term success. Several studies reviewing wetland creations are also used to
demonstrate problems with projects in both the short and long-term.
The long-term evaluation of artificial wetlands is very difficult because wetlands are
created for a variety of purposes. We know little about basic aspects of many wetland systems,
"succession" in wetlands is less straightforward than previously assumed, and it is difficult
to generalize from one wetland type to another. There is a striking range of opinions about
the success of wetlands that have been created. On the one hand, the U.S. Army Corps of
Engineers' dredged material stabilization program exemplifies artificial wetland projects
that appear successful over a decade or more. Several types of criteria including vegetation
characteristics, soil chemistry, and animal studies suggest that several dredged material
wetlands are becoming similar to reference wetlands with time. But, some wetlands
characteristics (soil carbon) may require many years to reach natural levels.
In contrast, a great many other artificial wetland projects are problematic or failures.
Reasons for failures include improper hydrology, erosion, herbivory, and invasion by upland
plants. Many projects have never been evaluated so their permanence is not known, and a
disturbing number of required projects have never been created.
In evaluating projects with regard to persistence (long-term success) of the created
wetlands, the following points are especially important: 1) 1-2 years of monitoring is too short;
evaluations over as long a period of time as possible (10-20 years) are desirable; 2) vegetation
characteristics are useful but do not necessarily indicate function; at a minimum, several
parameters should be used (e.g., belowground/aboveground biomass comparisons); 3)
chemical/physical aspects of wetland soils are also useful in evaluating trends in created
sites; 4) local reference wetlands are critical for comparative purposes; and 5) some wetlands
should be created with great caution because they have failed in the past (e.g., high salt marsh
in the northeast) or because we know little about these wetland types (e.g., forested wetlands).
INTRODUCTION: A CHALLENGING TASK
This chapter is a review and evaluation of
changes that have occurred over time in wetland
creation projects. The results of more than 100
artificial wetland studies are discussed; the sites
range from large-acreage federal projects to
small private plantings. The main questions
addressed are: 1) how have artificial wetlands
evolved over time, and 2) what can we learn
from these effects concerning the feasibility of
creating wetlands with long-term functions?
Evaluating the long-term "success" of
artificial wetlands is very difficult for a number
of reasons. First, wetlands are created for a
wide variety of purposes—some are created as
mitigation for destroyed wetlands, some are
experimental plantings, and still others are
aimed at stabilization of dredged material.
Methods of evaluation are also not standardized.
Access to publications of the studies differ as
well; publications in refereed journals are more
accessible while some federal studies, such as
those by the U.S. Army Corps of Engineers
(USAGE), are more difficult to obtain.
A second reason why the long-term
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evaluation of wetland creation projects is
especially challenging was pointed out by Larson
and Loucks (1978) a decade ago. We know little
about many basic aspects of ecosystem-level
processes in wetlands. For example, a
knowledge of wetland seed bank dynamics is
important for creation and evaluation of human-
made wetlands. However, we are particularly
ignorant about this aspect of wetland ecosystems.
The most basic of questions—how water level
influences seedling recruitment (Keddy and
Ellis 1985) and how seed dispersal and on-site
hydrology influences plant community
composition (Schneider and Sharitz 1986)--are
just being addressed for some wetlands. A
wetland-creation evaluator who lacks such
community/ecosystem information will find it
difficult to understand why the outcome of one
project differs from another.
A third reason particularly relevant to
long-term wetland studies is the great difficulty
in predicting vegetation change over time
("succession") in many wetland types. The
classical Clementsian view of wetlands
developing towards an upland climax is not held
today by most wetland ecologists (Niering 1987;
Guntenspergen and Stearns 1985). For example,
bogs can become more hydric with time and
plants typical of low marsh or brackish areas
can grow in the high salt marsh zone (Niering
1987; Odum 1988). The salt marsh example is
particularly important because these are our best
studied wetlands. However, papers are now
being published that discuss factors (e.g.,
flooding, disturbance, and herbivory)
influencing the distribution of plants in the high
marsh of northeast US coastal marshes (Valiela
1984). Once again, without this kind of
information long-term changes in high salt
marsh vegetation will be difficult to predict.
A fourth reason why wetland creation
projects are challenging to evaluate over the long
term, is that wetlands are exceedingly varied,
highly dynamic systems. They are dynamic
because they exist at the interface between
terrestrial and aquatic systems and are
unusually sensitive to variations in hydrologic
regime (Guntenspergen and Stearns 1985). As a
result, it is difficult to generalize from the
response of creation projects in one wetland type
to creations in different locales and habitats.
We do know more about some wetland types
than about others. As an example of this
difference, Mitsch (1988) summarizes the state of
art of wetland modelling; he points out that
freshwater marsh models are "primitive" while
coastal marsh models are "well developed".
Therefore, generalization about saltmarsh
creations may be more accurate than
generalizations about freshwater marsh
creations.
DIVERGENT VIEWS ABOUT THE
LONG-TERM SUCCESS OF WETLAND
CREATIONS
There is a striking range of opinions about
the success of wetland creation projects. The
reported outcomes of USAGE Dredged Material
projects are generally positive (e.g., Newling
and Landin 1985). Other researchers also
conclude from relatively long-term studies that
under proper hydrologic regimes created salt
marshes appear similar to natural ones (e.g.,
Seneca et al. 1976).
On the other hand, the success of many other
wetland creations and mitigations is less
certain. For example, several summaries of
wetland restoration projects in California point
to problems. Josselyn and Buchholz (1984)
concluded from a statewide analysis that most
California sites were not carefully monitored
after project completion; therefore, long-term
success or failure of these creations is not
known. Race (1985) says that "...it is debatable
whether any sites in San Francisco Bay can be
described as completed, active or successful
restoration projects at present". Eliot (1985)
evaluated permits of 58 projects in San Francisco
Bay that required wetland restoration. She states
that "...the 58 projects are diverse, frequently
unsuccessful, and do not adhere to established
mitigation policies. Many projects have not been
completed. Of those that have been, many do not
resemble the existing remnant marshes in San
Francisco Bay".
Difficulties with mitigation projects are not
limited to California. In Washington state Kunz
et al. (1988) reviewed Section 404 projects and
concluded that 1) mitigations resulted in a net
wetland loss of 33% in 6 years (1980-1986), 2)
some wetlands (forested) were not replicated at
all, 3) time lags between project initiation and
mitigation completion resulted in a loss of at
least 1-3 growing seasons per project, 4) there was
no routine procedure for tracking compliance,
and 5) 5 of the 35 projects were never restored or
negotiated.
Why do these conclusions differ so greatly?
The people involved in the USAGE Dredged
Materials Program partially answer this
question. They have a great deal of experience
which they can apply to each project, particularly
with regard to hydrologic design. For example,
Newling (USAGE, pers. comm.) states that
someone familiar with the project design must be
on-site when dredged material is applied to a site
because elevation above water is critical to
project success. Such experience may be lacking
in other creations.
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THE SIX CRITERIA USED FOR WETLAND ASSESSMENT
In this chapter I address wetland creations,
as opposed to restoration or mitigation, unless
these other activities have taken place. I define
wetland creations as artificial wetland habitats
established in new locations. Manipulations of
already existing wetlands—flooding marshes to
enhance wildlife use, for example—are not
described here. Terminology is debatable in
wetland creation studies. For example, Harvey
and Josselyn (1986) criticized Race (1985) for her
use of the term "wetland restoration" in
describing various experimental plantings in
San Francisco Bay.
The projects I discuss differ greatly in 1) age
of the human-made wetland when evaluated (14
months to 40 years); 2) use of natural controls for
comparisons; 3) use of quantitative methods in
contrast to qualitative ones; and 4) reasons for
the creations. Nevertheless, the wetland creation
projects discussed provide considerable in-
formation to address questions concerning
change of these artificial wetlands with time.
Although the focus of this chapter is
permanence of created wetlands and their
evolution with time, most artificial wetlands are
too young to provide information for long-term
studies. Many of the projects described in this
chapter were evaluated 1-2 years after they were
created. Exceptions are USAGE dredged material
projects; some of these have been studied for 14
years.
The criteria used in this chapter to evaluate
success and describe how the human-made
wetlands change with time are:
1. Comparison of vegetation growth char-
acteristics (for example, biomass or density)
in artificial and natural wetlands after two
or more growing seasons;
2. Habitat requirements (for example, upland
vs wetland) of plants invading the created
site;
3. Success of planted species;
4. Comparison of animal species composition
and biomass in human-made and natural
sites;
5. Chemical analyses of artificial wetland
soils compared to natural wetlands; and
6. Evidence of geologic or hydrologic changes
with time.
These criteria are typically used in wetland
ecosystem studies (e.g., Valiela 1984). In
addition, plants are emphasized as wetland
indicators because they reflect the hydrologic
regime and perform numerous important
functions (D'Avanzo 1987).
COMPARISON OF VEGETATION
GROWTH CHARACTERISTICS IN
HUMAN-MADE AND NATURAL
WETLANDS
Using vegetation criteria, USAGE scientists
have generally judged successful marine
wetland creations on dredged materials. But
these studies also note the importance of
long-term monitoring. For example, Hardisky
(1978) found that in Buttermilk Sound, Georgia,
aerial biomass of saltwater cordgrass, Spartina
alterniflora. planted in dredged spoil was 1.3-5.5
times less after four growing seasons than that of
cordgrass in natural sites. Of the 16 comparisons
of aboveground biomass of various plants listed
in this study, in 13 cases the biomass was greater
in natural saltmarshes. Belowground biomass
for Buttermilk Sound S. alterniflora was also
2.1-12.4 times less than that of comparison
marshes. Hardisky expressed concern about
erosion, herbivory, and competition between
saltmarsh and invading plants. By 1982
Newling and Landing (1985) were more positive
about this site because aboveground biomass was
more similar to that in reference marshes.
Belowground biomass still lagged behind.
In contrast, in a different dredged spoil
stabilization project in North Carolina,
aboveground S. alterniflora production measured
in the third through fifth growing seasons was
within the range of that seen in similar natural
marshes; belowground production exceeded
natural controls (Hardisky 1978).
At the Bolivar Peninsula dredged materials
site in Texas the marsh grasses, Spartina
alterniflora and Spartina patens, dominated
plots after 3 years although erosion was noted
there (Webb et al. 1986). Newling and Landin
(1985) concluded from preliminary analysis of
this site after 4 years that stem height and
aboveground biomass equaled or exceeded
reference locales while root biomass was less. In
addition, at the Apalachicola Bay salt marsh site,
Newling et al. (1983) monitored stem density,
height, occurrence and flowering in 8 quadrats 6
years after the site was planted with §L
alterniflora and S. patens: these parameters were
similar to those in reference marshes.
Not all Corps salt marsh projects have been
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entirely successful. Stedman Island in Aransas
Bay, Texas, was almost entirely vegetated after
two years but after 39 months S. alterniflora at
low elevations died (Landin and Webb 1986).
The reason for the die-off is not known, but this
study shows the importance of long term
monitoring.
Some freshwater marshes created within the
Corps dredged materials program are also
judged successful over a relatively short period
of time when vegetation criteria were used.
Windmill Point on the James River, Virginia,
is a freshwater tidal marsh established in 1974-5.
Emergent plants similar to those in comparison
marshes were observed in 1978-82 (Newling and
Landin 1985). Another freshwater intertidal
locale, Miller Sands on the Columbia River in
Oregon, was planted in 1976. Vegetation
development has been slower here than at other
Army Corps sites and some plantings failed.
However, vegetation began to invade bare areas
after several years. Since freshwater tidal
marshes have only been studied in the last
decade or so, experience and information which
could help explain the results here are limited.
Other projects in which vegetation was used
to evaluate the long-term success of created salt
marshes show mixed results. In two artificial
Spartina foliosa marshes in San Francisco Bay,
plant density in experimental plots was less than
a third of that in nearby natural stands, but the
site was only evaluated after two growing
seasons (Morris et al. 1978). Plantings in a salt
marsh mitigation for a marina in Bourne,
Massachusetts failed because the marsh grass
was planted too low in the intertidal zone and
because the grasses were eaten by waterfowl
(Reimold and Cobler 1986). Josselyn and
Buchholz (1984) analyzed 3 wetland restoration
projects in Marin County, California; plantings
failed in 2 sites because proper elevation was
difficult to achieve and contaminated dredged
spoil used to raise elevation may have hindered
plant growth.
Shisler and Charette (1984) compared eight
artificial salt marshes to eight adjacent natural
marshes in New Jersey. Overall live biomass
after 2-6 years was similar in created sites and
natural marshes and, not surprisingly, total
biomass (including dead litter) was
significantly lower in the human-made
marshes. However, density and number of
reproductive grass heads in the artificial
wetlands were also lower than in controls.
These vegetation differences, invasion by plants
not characteristic of salt marshes, and
significantly different soil chemical parameters
(described below) led Shisler and Charette to
recommend no further construction of high
marsh habitat in New Jersey.
Restoration of areas previously vegetated by
marine plants appears less problematic.
Thorhaug (1979) planted the seagrass Thalassia
in Biscayne Bay, Florida in areas that had been
denuded by thermal effluent. After four years,
she measured similar grass densities in planted
areas compared to controls; for these planted
seagrasses, flowering and fruiting compared
well with controls. It is important to note that
these were sites that had previously supported
Thalassia and, therefore, the success of
revegetation after thermal emissions ceased was
promising.
The vegetation characteristics described
above—above and belowground biomass, plant
density, and number of reproductive stalks—are
among the most commonly used quantitative
measures of plant growth. Using these
characteristics as measures of success, it is
difficult to make long-term generalizations about
wetland studies. In New Jersey for example,
only low S. alterniflora has been successfully
established and S. patens exhibited very limited
success; therefore, one cannot predict
replacement of low marsh by high marsh, a
change that can occur in natural marsh
ontogeny. We can say that growth of plants in the
artificial habitats is sometimes different from
that in controls even after 4-6 years. It is
difficult to determine temporal trends, however,
since many sites were not analyzed over time.
In several dredged material sites that have been
evaluated over time, vegetation becomes more
similar to reference sites. This is not so in the
California examples. Therefore, it is impossible
from many existing descriptions to determine
whether these created wetlands are becoming
more like the natural controls as they age.
What generalizations about wetland creation
have been drawn by others from vegetation
studies in artificial wetlands? Again, opinions
greatly differ. On one hand, Zedler et al. (1982)
conclude: "Regardless of the techniques used,
the examples are too few, and their period of
existence too short to provide an instructional
guide for marsh restoration projects in
California. At present restoration must be viewed
as experimental". In contrast, the Corps appears
more confident about the information base.
Landin and Webb (1986) state that: "The Corps
has strived for development of viable wetland
sites and will continue to do so. When problems
have arisen on sites, or failure noted ...lessons
were learned ... and these mistakes were not
repeated on later sites".
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COMPARISON OF ANIMAL SPECIES
COMPOSITION AND BIOMASS IN
ARTIFICIAL AND NATURAL
WETLANDS
While we emphasize vegetation in this
chapter, it is instructive to evaluate animal
responses in created wetlands. One set of studies
again demonstrates the value of long term
analyses. In a North Carolina dredged material
site, Cammen (1976a) found significantly more
macroinvertebrates and 10 fold greater biomass
in natural plots compared to those in the 2 year
old human-made marsh. In addition, in the
natural marsh, isopods, polychaetes, and
mussels were the dominant fauna while
amphipods and flies dominated the artificial
plots. In one sampling location, less than 40%
overall faunal similarity was seen in the
natural/created comparison and in another site
the similarity was less than 10% after three
growing seasons. Sacco et al. (1988) studied the
macrofauna in this marsh 15 years after it was
created. The macrofauna had greatly changed
and was mainly composed oligochaetes (56%)
and polychaetes (36%). Therefore, Sacco et al.
concluded that the macrofauna in the
human-initiated marsh began to resemble
natural marshes within 15 years, although fauna
in reference sites were not listed in this abstract.
In a different comparison of North Carolina
dredged spoil restoration, Cammen (1976b) also
found significantly lower animal density and
biomass as well as different animal populations
in several year old created systems. In this case,
insect larvae dominated the created wetland
while polychaetes accounted for most of the
biomass in the natural marsh. In contrast to
Cammen's findings, in the New Jersey
mitigation sites evaluated by Shisler and
Charette (1984), many species of
macroinvertebrates were common to natural and
artificial marshes and populations were highly
variable in each.
HABITAT REQUIREMENTS OF
INVADING PLANTS
The persistence of obligate wetland plants
with time-either planted or naturally colonizing-
-and their successful dominance over other
vegetation, is one good measure of creation
failure or success. Data on species changes of
wetland versus nonwetland plants over time
indicate mixed success of creation projects.
Kruczynski and Huffman (1978) studied
marsh and dune vegetation on dredged material
in Apalachicola Bay, Florida. One island
supported no plant growth after 17 months
because of erosion. Dikes stabilized another
island where 42 plants-many upland indicators
such as morning glory (Ipomoea sp.) and
cudweed (Gifola germanica)—were already
growing alongside planted Spartina after 14
months. Shisler and Charette (1984) describe
plant species characteristic of upland/marsh
ecotones in numerous artificial marsh projects
in New Jersey. In Creekside Park, a San
Francisco Bay restoration site, upland species
and bare ground occupied as much of the marsh
surface area as marsh vegetation after eight
years. High marsh in particular was not
vegetated due to high salt concentrations
(Josselyn and Buchholz 1984).
On 40 Florida coastal islands of various ages
composed of dredged material studied by Lewis
and Lewis (1978), exotic upland plants were
common invaders, while these plants were
unusual on natural islands; "the predominance
of the exotic Australian pine and Brazilian
pepper in the later serai stages is unique to
dredged material islands in Florida. The
maritime forest climax is rare ..." Birds may
have influenced plant invasion and success on
these islands.
Invasion by upland plants into artificial
wetlands was not seen in many studies.
However, development of non-wetland flora was
not an unusual occurrence and is cause for
concern (Odum 1988). In addition, many
artificial wetlands were observed only after 2 or
3 growing seasons, which may be insufficient
time for establishment and growth of upland
vegetation or to determine if wetland flora will
persist.
SUCCESS OF PLANTED VEGETATION
Particular types of vegetation are planted in
artificial wetlands to temporarily stabilize soil,
provide wildlife habitat, or for aesthetic reasons.
Disappearance of these plants over time is not
unusual (Hardisky 1978; Shisler and Charette
1984; Dial and Deis 1986; Odum 1988). Cer-
tainly, plants in artificial wetlands, as in
natural ones, will likely change with time as,
for example, seeds in the soil or imported seeds
germinate. If these newly observed plants are
obligate wetland plants, we may, by definition,
call the creation site a wetland. However, it is
much more difficult to decide whether the new
wetland is a success if unanticipated plants
invade a project. What if freshwater marsh
plants grow in a saltmarsh project? Is the
creation a failure? The answer to this question
largely depends on the specific functions the
artificial wetland is designed to serve and these
must be outlined in detail in the management
plan. In any case, it is useful to document
unanticipated results.
Examples of unplanned vegetation
communities in artificial wetlands are common.
Hardisky (1978) noted after four growing
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seasons an influx of fresh and brackish water
plants overtopping planted spikegrass (Distichlis
spicata) in a Georgia estuary dredged material
site. Hardisky predicted that the salt tolerant D.
spicata would be outcompeted. The growth of
freshwater plants in this location indicated a
complete inability to predict the hydrology of the
area. Similarly, freshwater wetland plants such
as the royal fern (Osmunda regalis) and a rush
(Juncus sp.) dominated the high marsh in a West
Florida dredged material project where Spartina
patens had originally been planted. In the New
Jersey artificial marshes, Spartina patens was
planted in some locations but Spartina
alterniflora was dominant during subsequent
samplings (Shisler and Charette 1984). Spartina
foliosa was planted in a 95 acre (38.4 ha) dredged
material site in San Francisco Bay; here, as in
other locations in California where S. foliosa has
been planted, Salicornia has invaded the area
(Race 1985). Dial and Deis (1986) reviewed 10
mitigation or restoration projects in Tampa Bay,
Florida. The survival of Spartina alterniflora
ranged from 10-93% and the number of plants per
square meter ranged from 0 to 230. Dial and
Deis (1986) attribute plant deaths to erosion,
competition by upland plants, and poor planting
techniques. Finally, Savage (1978) photographed
the same mangrove plantings in Tampa Bay,
Florida over a six year period; Rhizophora and
Laguncularia did not survive while Avicennia
did.
Odum (1988) points out that invasion by
unwanted plants is common in freshwater
artificial wetlands. Typha spp. often crowd out
more valuable planted species, leading to the
"cattailization of America".
Other factors influencing the success of
plantings of created wetlands include predictions
of hydrologic conditions and proximity to seed
source. High water levels and lack of control of
water level resulted in death of trees planted on
the shore of Missouri River reservoirs (Hoffman
1978). Eastern cottonwood (Populus deltoides)
and green ash (Fraxinus pennsvlvanica) did not
survive inundation, while broadleaf cattail
(Tvpha latifolia) and white willow (Salix alba)
did. Cattle grazing also influenced vegetation
success on the banks of these dams. Reimold
and Cobler (1986) evaluated five mitigation
projects in the northeast U.S.; they rated one
freshwater site after two growing seasons as
"marginally successful" because banks were too
steep and water too deep for emergent vegetation.
Two other freshwater mitigations rated
"ineffective" by Reimold and Cobler were only
seen after one year (D'Avanzo 1987). Gilbert et
al. (1981) studied a 49-acre tract in Florida that
has been mined for phosphate and noted invasion
by 50 wetland plant species after 3 years.
However, plantings had failed because the
hydrology of the site had been incorrectly
predicted. Gilbert et al. (1981) concluded that
species potentially invading the approximately
27,000 acres in Central Florida used for
phosphate mining were site-specific; invading
types depend on source material and type of
habitats close to the restoration. In the case
studied, unmined wetlands supporting a diverse
native flora were adjacent to the mitigation
project.
Race (1985) reviewed 15 experimental
plantings in San Francisco Bay. She concluded
that many problems—high soil salinities,
incorrect slope and tidal elevations, erosion and
sedimentation, and poor water circulation-
-accounted for numerous failures of the
plantings. For example, in the Bay Bridge site,
10% of the Spartina foliosa and 20% of the
Distichlis spicata transplants survived one year;
Salicornia transplanting was more successful.
S. foliosa spread well from plugs at the Marin
County Day School location after two years, but
the stated objective of the project—erosion control--
was not met. All S. foliosa experimental
plantings in the Anza Pacifica lagoon failed
within 2-3 years; the mitigation site was
replanted and, again, after three years only
remnants of the planted plugs remained. In
three USAGE erosion control projects, neither
seedlings, sprigs, nor plugs survived longer than
eight months (Race 1985); survival of marsh
plugs was good only in unexposed areas of
marsh and creeks. Experimental plantings of
cordgrass seedlings in Muzzi Marsh prior to
mitigation were dead after one year. The 125
acre (50.6 ha) Muzzi Marsh project is becoming
naturally colonized by Salicornia and Spartina.
The highly experimental nature of marsh
creation is clear from Race's critical review of
these projects. (See Harvey and Josselyn, 1986
for a critique of this review and Race, 1986 for a
reply). Since saltmarsh restoration is a new
technology and one with a relatively poor science
base, failure of experimental plantings is not
surprising. However, it is disturbing when
projects that are largely unvegetated or that
support exotic vegetation are called successful
restorations (Race 1985).
CHEMICAL ANALYSES OF SOILS IN
CREATED AND NATURAL WETLANDS
Little data exist on sediment characteristics
of human-made wetlands or of comparisons
between these sites and natural controls (Race
and Christie 1982), although this data base is
growing. Several studies do show that nitrogen,
phosphorous, and organic matter increase with
age of the created site (Reimold et al. 1978,
Lindau and Hossner 1981, Craft et al. 1988a).
While organic carbon at various depths was
considerably less in human-made marshes in
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North Carolina, Cammen et al. (1974) estimated
that organic content of soils in these creation
projects would reach reference concentrations in
4-26 years. Studies by Craft et al. (1988b) with
natural isotopes support this trend since marsh
plants were the main source of organic carbon in
both natural and transplanted marshes. After 2
years, organic matter concentrations, total
nitrogen, and ammonium-nitrogen levels in
experimental marsh soils from Texas dredged
spoil projects were on average 2-3 times lower
than those in natural marshes (Lindau and
Hossner 1981). Concentrations of these
parameters increased with time and Lindau and
Hossner concluded that, assuming a linear rate
of increase, concentrations would be equal to
those in surrounding marshes in 2-5 years.
Despite such predictions, Race and Christie
(1982) are cautious in their analysis of these
findings; "no man-made marsh to date has
shown the stabilization of physical and chemical
properties in the range of values for natural
marshes". Their caution is supported in the
findings of Craft et al. (1988a) who compared
natural and planted soil in 5 sites; they
concluded that organic matter pools develop in
15-30 years but development of soil C, N, and P
pools take much longer.
In some cases, the substrate in the created
wetland differs greatly from that in genuine
wetlands. Shisler and Charette (1984) found that
sand was the substrate most often used in eight
artificial marshes studied and this resulted in
distinct edaphic differences. Artificial marsh
sediment was lower in organic matter, nitrogen,
phosphorous and salinity when compared to
nearby reference marshes. Only pH was the
same.
Chemical/physical analyses of artificial
wetland soils are particularly useful indicators
of project progress and success with regard to
changes with time. It is possible to predict trends
(increasing organic carbon concentration, for
example) and to determine rates of change of
these parameters. The few studies in which this
approach was used show that created sites become
more like natural ones with time. An important
question for mitigation projects is: how much
time? The time scale of these projects is several
years and sediment in genuine wetlands has
developed during hundreds and thousands of
years.
EVIDENCE OF GEOLOGIC OR
HYDROLOGIC CHANGES WITH TIME IN
ARTIFICIAL WETLANDS
Much of this information has been described
above but it deserves reemphasis because the
geologic/hydrologic setting is so critical in
wetlands. Clearly, dramatic geologic or
hydrologic changes—including sediment erosion
or deposition, or groundwater seeps—will alter
creation projects as planned.
Some creations, such as the Panacea Island
project in Florida (Kruczynski and Huffman
1978), have entirely eroded away. Waves killed
planted mangroves in a Tampa Bay creation
(Savage 1978). Wave erosion and sediment
inundation was also a problem in some New
Jersey mitigations (Shisler and Charette 1984).
In a freshwater bank stabilization project, high
water killed numerous planted floodplain trees
(Hoffman 1978). Finally, Gilbert et al. (1981)
noted that plantings failed in a phosphate mine
revegetation project because the hydrology of the
site was poorly understood.
Some of these events could have easily been
prevented. Dikes can be better constructed and
creations should be not attempted in areas where
erosive forces may negate the project. However,
storm damage is impossible to predict in many
locations, including the coast and floodplains of
rivers. Therefore, it is not surprising that some
creations fail.
CONCLUSION
What conclusions can be drawn concerning
the long-term evaluation of wetland creation
projects discussed in this chapter? Using six
criteria as measures of success, there is a
striking contrast in the 2-15 year success of
different projects. On one hand, for a decade or
more the U.S. Army Corps of Engineers has
evaluated a large number of wetlands created
with dredged materials. When vegetation
parameters are used, many of these projects
become structurally similar to reference sites
with time. In addition, one 15-year old animal
study showed a similar trend. Several
evaluations of soil chemistry also indicate that
these wetlands become more like natural ones
with time. USACE researchers evaluate their
experiments and use this information in new
projects; a large data base about similar types of
projects is communicated within the program.
It is important to recognize that even the
"old" USAGE artificial wetlands are not
identical to reference wetlands; for example, soil
carbon and belowground plant biomass are
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developing slowly. Therefore, when an artificial
wetland is built as a mitigation for a lost
wetland, decades may pass before the created
project assumes the structure and function of the
lost habitat. During this time, the important
functions that the destroyed wetland may have
served (Larson and Neill 1987) may be lost to
society.
In contrast to these USAGE projects, many
other artificial wetlands—mitigation projects and
experimental plantings—are judged problematic
or partial failures in studies of up to several
years. Reasons for failures include
contamination of soils, herbivory, erosion, and
inappropriate hydrologic regime. In addition,
many created wetlands have never been
evaluated and, therefore, their success in not
known. Studies also indicate that a small but
disturbing number of required projects were
never even initiated.
Many creation projects fail because of
improper hydrology. Basic to the entire concept of
wetland creation is the existence of a functional
hydrologic regime appropriate for the
establishment and development of the specific
wetland species. For example, water level depth,
seed bank potential, and sloping marginal
contours are crucial to the development of
emergent aquatic plants (Niering 1987). Some
types of artificial wetlands do appear stable after
several years; perhaps the hydrology of these
habitats is less challenging to predict than in
other locales. For example, the establishment of
low Spartina alterniflora salt marsh has met
with considerable success while the creation of
high Spartina patens salt marsh has been
problematic (Shisler and Charette 1984). Most
high marsh sites are adjacent to upland and
therefore the hydrology of the high marsh is more
unpredictable than that of the low marsh and
more difficult to reproduce.
Some created wetlands systems will remain
relatively stable over time while others can be
expected to change. Hydrology is an important
factor determining wetland community changes
with time. The basic goal is to create persistent
functional wetland systems. In some situations
this may be more important than creation of
specific wetland types because the present
structure of a wetland may be a momentary
expression of the wetland of the future.
LITERATURE CITED
Cammen, L.M. 1976a. Macroinvertebrate colonization of
Spartina marshes artificially established in dredge
spoil. Est. Coastal Mar. Sci. 4: 357-372.
Cammen, L.M. 1976b. Abundance and production of
macroinvertebrates from natural and artificially
established salt marshes in North Carolina. Amer.
Midi. Nat. 96:487-493.
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REGIONAL ASPECTS OF WETLANDS
RESTORATION AND ENHANCEMENT IN THE
URBAN WATERFRONT ENVIRONMENT
John R. Clark
Rosenstiel School of Marine and Atmospheric Science
University of Miami
ABSTRACT. In urban settings, wetland resources are typically degraded and often seriously
dysfunctional. Loss of wetland function in this manner reduces the productivity of the larger
aquatic ecosystems of which the wetlands are a component. Therefore, in urban settings a
high priority must be given to restoration and enhancement of aquatic ecosystems and to their
component wetlands. Success in system-wide restoration requires formulation of a regional
strategy with goals, objectives, methodologies, and predesignated restoration sites. Such
strategies must be locally generated and cannot be substituted by existing one-agency
programs. All levels of government and private interests must be involved. Moreover, the
existing system of site-by-site permit review must be altered to ensure that permit decisions
are oriented toward the regional restoration strategy. It is particularly important to recognize
that the developers' resources will be the main source of restoration project funds through
voluntary or mitigative restoration and enhancement. Therefore, mitigation has to be given a
role at the front end of the review process and not held until the end as a "last resort".
INTRODUCTION
The urban setting presents distinctive
problems for waterfront development as well as
special opportunities for restoration and
enhancement. For several reasons mitigation
has the potential to become a positive tool for
restoration and enhancement rather than just an
obstacle to developers (Wessel and Hershman, in
press). Currently, the limited waterfront property
that exists in most urban areas is being
aggressively sought for residential and
commercial development. The pressures are
great, front-foot prices are astronomical,
investment funds are abundant, and profits are
assured, providing that permits can be obtained
with reasonable effort. This pressure has resulted
in renewal projects for much of the old,
degraded, urban waterfront area in coastal cities
(Figure 1). For example, the buildout cost of
renewal projects now underway or proposed for
the New Jersey side of the Hudson River opposite
New York City is estimated at $10 to $12 billion.
In urban waterfront settings, there are
virtually no original or unaltered wetlands or
intertidal flats left. Wilderness is not found
here. Most of the urban shoreline edge has been
"hardened" and dredged or otherwise altered,
changing its ecological character to ths
detriment of fish and wildlife. The result is an
overall reduction in biological diversity and
carrying capacity for desirable species within the
adjacent estuary, river, or lake. This habitat
needs to be repaired as much as to be protected.
Much of the urban wetland we try to protect is so
damaged that to be worth saving it should be
repaired. Therefore, in urban settings,
restoration and rehabilitation should be given
maximum attention.
It was predicted in 1980 that restoration
would reach the top of the wetland agenda during
the decade of the 1980's (Clark and McCreary
1980). This has certainly occurred for urban
aquatic ecosystems but in most regions it has
happened de facto , not as the result of policy
decisions or program commitments (one
exception is the California State Coastal
Program). Because funding possibilities are so
limited in the urban setting, rehabilitation
should be primarily focused on biological needs,
such as restoring habitat for endangered or
commercially valuable species or enhancing
critical processes of the wider wetland ecosystem
(Clark 1979). As put by Batha and Pendleton
(1987): "Lack of suitable enhancement sites at
reasonable cost and conflicts among agencies as
to what type of habitats are of greatest importance
to the Bay system greatly concern all people
interested in the future of San Francisco Bay....
Rapid urbanization will make the possibility of
adding wetlands to the Bay increasingly
difficult in the future".
One example of the multiobjective approach
85
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-IT
Figure 1. Typical waterfront scene on the Hudson River in Manhattan. Original wetlands and
tideflats were replaced with piers and channels which are now deteriorated and
dysfunctional. Some interests want to retain these piers, others want them removed, and
still others want ecological rehabilitation in combination with residential development.
that can be used in an urban situation is the Pt.
Liberte canal side residential project in Jersey
City, N.J. (see following section: "Case Study
Port Liberte"). Here the development site itself
was small, but peripheral areas and edges were
used in a voluntary program of multiple
enhancements (Figure 2) to: rehabilitate and
reroute a seriously degraded stream, rehabilitate
a degraded tideflat/ slough system, enhance the
beach-dune system, create a least tern nesting
site, build an artificial reef, enhance a small
peninsula owned by Liberty State Park, and
protect the state-designated Caven Point Natural
Area (tideflats and shallow waters) adjacent to
the site from boater damage.
It is unfortunate that aquatic habitat
restoration has not been given the same priority
as water quality restoration which has received
great attention and lavish budgets in the past 15
years. Direct appropriations for physical habitat
repair and ecosystem restoration by either
Federal or state governments have been
minuscule, regardless of how compelling the
need may have been (Clark 1985). Progress in
habitat restoration has for the most part, been left
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"*» _ WOO JOQO 4000 MM (000 7000 FEET
* 0 I KILOMCTE*
Figure 2. Jersey City, N.J., waterfront now in active redevelopment from industrial to
residential/commercial. Shaded section is the site of the new Port Liberte project which is
occupying an abandoned military site.
87
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to casual and secondary mechanisms. The most
promising of these mechanisms is mitigation in
exchange for development permits, whereby
physical habitat restoration is, in effect, exacted
from developers by regulators as a quid pro quo
for obtaining waterfront development permits.
But this approach has been less than successful
because the mitigation process under most permit
programs has been poorly organized and ad hoc.
Since long term future goals have not been
established for particular ecosystems or regions,
nor guidelines formulated for developers,
mitigation has been a case-by-case, un-
coordinated activity. Often this seems to have
been deliberate, because regulatory agencies may
want to relegate mitigation to a "last resort"
basis. This may be commendable in rural areas
where more natural conditions exist, but in
urban settings mitigation may often have to be
the "first resort" where no other mechanisms are
available for repair of damaged aquatic habitats.
A mitigation goal of "no net loss of habitat
value", often advocated for rural settings is not
sufficient for highly damaged urban aquatic
ecosystems. Here the goal should be "a net gain
in habitat value" if we are to regain the losses of
the past, reach higher levels of biological
productivity, and accomplish recovery of depleted
populations of economically valuable or
endangered species. This goal could be stated in
another way, specifically as a policy "to achieve
net positive cumulative impacts". This approach
to ecosystem recovery through strategic, rather
than reactive mitigation has promise for certain
urban aquatic ecosystems where a basis for
cooperation among regulators, developers,
scientists, and environmentalists can be found
(Clark 1985).
It is far too easy to drift into an attitude, or
approach, where only potential negative impacts
are addressed. I believe we should try hard to
prevent future losses of wetland, but we also
should Work to regain lost functions. To be
workable, the restoration approach must address
the total individual wetlands ecosystem (lake,
river, estuary, marsh, etc.); that is, the whole
aquatic system of which the wetland is a part.
We should recognize that certain functions are
being lost in an aquatic system, see which are
dependent upon wetlands, establish priorities for
the functions of greatest value (e.g., bird habitat,
flood storage, productivity) and enhance these
functions. This would reverse the serious decline
of productivity and diversity in aquatic habitats
in the urban setting.
It is fair to say that most mitigation
consultants find the typical permit-by-permit
approach of regulatory agencies ineffective in
advancing long-term goals for aquatic ecosystem
conservation and a deterrent to strategic system
restoration. Further, individual permit reviews
should be evaluated wherever and whenever
possible through a regional strategy for
restoration. I recommend that goals and targets
should be determined in advance according to a
regional strategy and used to guide subsequent
permit actions involving restoration and
enhancement. For example, Sorensen (1982)
concludes that "...the relative scarcity and
abundance of the resource needs to be determined
on a region-wide basis in order to set priorities
on the types and locations of habitats that should
be provided in a restoration site plan".
The ideas expressed in this chapter are
particularly applicable to the urban settings of
coastal cities and their surroundings. But the
principal recommendations involving regional
strategies, goal-setting, ecosystem focus, and
predetermination of restoration needs and sites
could apply to less urbanized seacoast and
freshwater areas.
THE NEED FOR ADVANCED CRITERIA
If urban developers (whether public agencies
or private corporations) are to cooperate in
restoration of aquatic habitats through either
mitigation or voluntary enhancement, they must
have some guidance. They should know what is
expected of them in the context of the regional
ecosystem in which the project is located. If
voluntary enhancement is to be encouraged, they
should know what specific opportunities exist and
what public interests they can best serve.
Moreover,they should know this information at
the time they are planning their projects, not
after the application has been submitted and the
Section 10 or 404 Public Notice has been
circulated by the Army Corps of Engineers
(COE).
In the mitigation process, the COE usually
defers to the U.S. Fish and Wildlife (FWS) to
assess mitigation requirements and expects to
receive FWS advice after the developer's permit
is submitted (COE 1985) and the developer is
already committed to a certain plan. If the COE
does not agree with FWS or other commentators,
including EPA and the National Marine
Fisheries Service (NMFS), a prolonged and
expensive delay will often result (months or even
years). For example, Zagata (1985) states, "The
mitigation requirement in 404 of the Clean
Water Act has been a source of controversy
between the regulating agencies and permit
applicants. The need to mitigate is considered at
the end, rather than the beginning, of the permit
88
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process, after other alternatives have been
examined. Thus, industry frequently perceives
mitigation as an additional source of delay and
money...an add-on-cost since it is considered
after completion of the proposed project's normal
budgeting and planning process". All of which
may be welcome if you're only trying to stop a
project but not if you're trying to promote
restoration of urban aquatic ecosystems.
In order to succeed, effective restorative
mitigation must be a cooperative venture between
developer and agencies. As of now, the
developers' opinion of mitigation is typically one
of frustration (Wilmar 1986):
"The Corps usually recommends that the
applicant embark upon a series of
negotiations with the various
commenting agencies. This is gen-
erally a frustrating exercise because
there are few rules, and commenting
agencies have broad discretion to
interpret those standards that do exist.
Moreover, the applicant has usually
already obtained approvals from the
local and state agencies, each of which
has extracted concessions as the price of
project approval. Thus, the unsophis-
ticated, generous, or inexperienced
applicant often has no more to give, and
the federal agencies have little other
incentive to reach an agreement."
By the time the application has been
submitted, positions have hardened and options
have been closed for both the developer and the
regulator. Aware of this situation, EPA and other
principal agencies including state agencies will
often meet with the developer in "pre-application"
conferences that FWS mitigation policy
presumably encourages (FWS 1981). This can be
beneficial if various agency staff can come to
agreement among themselves and give
unambiguous advice to the developer (Is high
marsh lower priority than low marsh? Are bird
breeding islands a beneficial substitute for open
water surface, water column, and bottom? Are
piers over bare bottom beneficial or detrimental?
Should mudflats be converted to marshland? Are
ducks more important than fish?). However, all
too often an agency's staff has not had a chance
to come to consensus in advance on the issues of
habitat option preferences. The developer is too
often left to gamble on which mitigation approach
might be best to get him through the permit
process. It is a major problem for the permit
process that a formal method for prior consensus
on regional mitigation priorities does not exist. It
is also a major problem that current mitigation
manuals or guidebooks on mitigation methods
and preferences are not available to development
planners to consult throughout the siting and
design process.
What can an individual EPA or other agency
permit reviewer do to improve this situation in a
region where no organized mitigation policies
and programs are in place? The answer is to
work to clarify and reach consensus among
agency colleagues on mitigation procedures and
priorities, and to assist in conveying the results
to the applicant at the earliest possible time. An
appreciation of the urgent necessity for restoring
urban wetland-related ecosystems using
mitigation is, of course, the precursor to
agreement on mitigation targets. While FWS
and COE are the main Federal agency actors in
early permit skirmishes, EPA has a strong
influence because of the agency's ultimate "veto"
power.
The advantages of advance criteria and
early coordination in project planning are stated
by Dial et al. (1985): "To be most effective in
preserving habitat, mitigation activities should
begin during the planning phase of a project. It
is usually only at this phase that the avoidance or
minimization of the impacts is possible, and
mitigation in the literal sense of the word
occurs".
THE ADVANTAGE OF THE REGIONAL STRATEGY
A major challenge to EPA and other
agencies is to make the fundamental shift from
a site-by-site focus to a regional focus for urban
areas. Because permit actions are typically
confined to a project site, often there may be little
knowledge or concern about the relationship
between that site and the regional ecosystem
incorporating the project site. Ecosystem
thinking is engendered by the regional approach.
One can't think of each individual wetland as a
unit of landscape in isolation, but rather in
terms of the whole system.
A major advantage of taking the regional
ecosystem view by thinking beyond the
immediate project site to consider the whole, is
that most wetland functions that we value
involve a related aquatic system that is larger
than the affected wetland itself. The wetland unit
often depends on the larger aquatic system to
actually realize the potential of a particular
wetland function. For example, detrital output is
a value only if there is a living community
beyond the wetland to utilize it. Likewise, if a
wetland is to serve as a nursery for fish it must
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be accessible to an adjacent healthy, functioning,
major aquatic system which depends upon many
components other than wetlands. For example, a
snook nursery area needs to have a shallow
intertidal area with mangrove edge and an
admixture of fresh water and, outside, a
productive feeding and cryptic habitat of
seagrass beds. After this period (1/2 year or so)
the snook move into deeper waters and utilize a
variety of habitats in enclosed waters of estuaries
and around channels, where good water quality
becomes important. Obviously, we need to be
concerned about more than acres of wetlands
(mangrove) if we want to improve the snook's lot
(now greatly depleted). We want to reverse the
degradation of the whole aquatic system and
achieve a positive direction in various permit
review and mitigation activities. Consequently,
in restoring or creating wetland units in
mitigation, we have to decide what is the
optimum balance of, say, high wetlands, low
wetlands, flats, channels, and open shallow
waters (Clark 1986b).
When the potential for mitigation or
voluntary enhancement arises, the question
follows of what specific restoration projects
should be recommended. With private
developers, the question is most often fielded by a
consultant; with public projects, a staff
professional usually provides advice. Interaction
of these professionals with regulatory agency
personnel is most often the key to efficiency in
subsequent review of the permit and in approval
of the mitigation/restoration program. This is
all that would be necessary in a perfect world
characterized by mutuality, omniscience, and
altruism. However, in the real world of
permitting, the process is typically an
adversarial one, each permit is handled
de nouveau. advance goals are absent, and
agency reviewers are often unsympathetic to
development and reluctant to commit to specifics
and foreclose their post-submittal options. Thus,
the official pre-application conference (as
advocated, for example, by PWS mitigation
guidelines, Fed. Reg., Jan. 23, 1981, Vol. 46, No.
15, p. 7644 et seq.) may fall short of developer
needs and may discourage restoration
initiatives. This confirms the strong need for
directive guidelines to make the process
predictable to developers and to make available
to their environmental experts advance
mitigation criteria for use at early planning
stages. This can only be accomplished effectively
in a regional context.
The shift from the reactive to the strategic
approach would bring a shift from "supply-side"
to "demand-side" thinking about wetlands. That
is, assessing the condition of a wetlands system
begs the strategic question "What are the societal
demands for natural goods and services from
this system and how well are they being met?".
This replaces the reactive question "What
natural goods and services does this wetland
supply?".
Effectiveness in aquatic habitat restoration
requires understanding the regional ecosystem,
its present condition (how far degraded), and
what values are most important and should be
given priority for rehabilitation (plant
productivity? bird habitat? nursery area?). Given
this, one can formulate goals and advance
criteria for permit review and mitigation and
even reverse the trend of negative cumulative
impacts and bring about a positive cumulative
impact sequence.
REGIONAL ORGANIZATION
It is within the purview of the EPA or other
agency reviewers to consider each wetland unit
as part of a greater ecological and hydrologic
system when dealing with restoration and
reversal of cumulative impacts. Thinking
discriminately is important, including
considering the variety of configurations,
functions, and social needs that restoration
projects can meet. From the ecological
engineering point of view, given the money, one
can do almost anything to a wetland. It can be
regraded, reshaped, rewatered or replanted. The
substrate can be changed, the elevation,
topography, or the supply of water (Clark 1986a).
But beyond the technical issues, there are
judgmental questions to be answered: What
wetland design would yield the highest
socioeconomic benefit, considering regional
needs for natural goods and services? If
waterfowl habitat is critical, then a relatively
shallow open water area would be most
appropriate (Figure 3), If shorebird habitat,
shoreline stabilization, or run-off water
purification are the priority needs, then different
designs are indicated. The strategic approach to
mitigative restoration requires that someone
other than the project developer or permit
reviewer—preferably a regional entity—select the
regional priorities for aquatic ecosystem outputs
of natural goods and services. Once that is
accomplished, an environmental professional
can convert these priorities to functional criteria
and engineers can convert the criteria to design
specifications and construction (Clark 1986a).
90
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jk. 1L v?. • w*l«*sw*t s,, *
Figure 3. Degraded streambed on the Port Liberte site scheduled for rehabilitation to enhance its
value to waterfowl, shorebirds, and nursery size fishes and to remove high concentrations
of toxics in the streambed.
Because of the variety of public interest
questions involved in mitigative restoration,
individual agency permit reviewers would
benefit from advance formulation of regional
goals and restoration priorities by a recognized
entity charged with balancing the variety of
private and public interests. Where regional
entities have been established to deal with
aquatic habitats and permits and have
formulated guidelines and criteria, the results
seem to have been helpful.
Federal/state programs that can be used to
explore regional possibilities include the
following:
1. EPA's authority for "advance
identification" or "predesignation" of
wetlands (under Sect. 404{c) or Sect. 230.80 of
the Guidelines) which enables EPA to list
those that are off limits to dredging and
filling in a particular region (e.g. the
Hackensack Meadows). The procedures for
advance identification provide for input from
a variety of interests, scientific evaluation of
wetlands values, and a plan for priority
protection of critical habitats. But the program
may or may not deal effectively with whole
ecosystems or with restoration needs (Studt
1987).
2. The COE's long-term management strategy
(LTMS) for dredging activities on a regional
basis strongly encourages and assists
Districts in developing LTMS's within their
boundaries (Klesh 1987). Districts with
LTMS's in place or in planning include St.
Paul, Rock Island, Seattle, and Portland.
3. States' authority under the Federal
Coastal Zone Management Act (1980
Amendments) to do regional Special Area
Management Plans (SAMP's), whereby all
aspects can be considered in a regional
planning context. SAMP's can effectively
establish regional strategies for aquatic
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habitat restoration, including restoration
criteria, identification of mitigation sites,
preparation of guidelines, and mechanisms
for incorporating mitigation into a
restoration master plan. Federal agencies
must be consistent with approved state
SAMP's (Studt 1987). A major example of a
successful SAMP is that for Rhode Island's
salt pond region (Olsen and Lee 1985)
whereby strong guidelines for development
and aquatic system restoration in the salt
ponds were formulated with the participation
of a wide spectrum of agencies and
environmental and private interests. The
main example of the difficulty of the SAMP
approach is Gray's Harbor, Washington, in
which Federal and state agencies and the
local planning entity and port authority have
spent more than 8 years trying to agree to a
plan.
4. "Area wide" advance Environmental
Impact Statements developed by the COE, and
often advocated by FWS, provide an
opportunity to review the condition and
restoration needs for regional ecosystems.
These need to be set up for wide consensus,
public interest balancing, formulation of
policy, and implementation of positive
programs.
5. Use of the Estuarine Reserves program,
authorized by the Federal Coastal Zone
Management Act to organize regional
aquatic ecosystem conservation programs.
Examples of strong local estuarine reserve
programs which have enhanced restoration
and provided an advance framework for
permit decisions include Apalachicola Bay
(Florida) and Tijuana Estuary and Elkhorn
Slough (California) National Estuarine
Reserves (Clark and McCreary 1987).
6. State-organized advance designation of
mitigation sites. This approach, currently
operating in California and proposed by New
Jersey, is especially applicable to the urban
setting where on-site mitigation opportunities
are limited (however, they do imply advance
acceptance of the idea of offsite mitigation,
which is not viewed favorably by some
agencies). Such programs are an excellent
way to pinpoint the need for restoration and
to take definitive steps to establish priorities
for restorative mitigation.
To the extent possible, regional needs and
opportunities for restoration should be included
in any initiatives under the above programs.
Locally organized programs designed for
specific regional aquatic ecosystems have been
successful in many coastal urban areas.
Although not usually designed specifically for
restorations, these locally organized programs
can be most helpful in generating a consensus
on restoration needs and guiding regulatory
agencies toward restoration priorities in permit
decisions involving mitigation and voluntary
enhancement. Examples of such programs in
urban coastal areas are:
1. The Bay Conservation and Development
Commission (BCDC), the original regional
organization for aquatic ecosystem conserva-
tion, was founded in 1965. All development
around the shoreline of San Francisco Bay
must be permitted by BCDC which has worked
to find broad consensus on aquatic ecosystem
conservation and to formulate mitigation
guidelines. A major restoration mitigation
goal is to require opening of diked wetlands
in compensation for any filling allowed.
2. The Environmental Enhancement Plan for
Baltimore Harbor (1982) by the Regional
Planning Council for the Baltimore
Metropolitan Area (a Maryland state body)
broke a 10-year deadlock over fill, dredging,
and dredge spoil (dredged material) disposal
when it was modified to be acceptable to
Federal agencies (by eliminating a
mitigation bank). The Plan includes
rehabilitation of aquatic habitats and
creation of wetlands. Five sites were selected
in advance for mitigation activity. This
approach made mitigation more rational and
expedited the permit process.
3. The Tampa Bay Regional Planning Council
initiated aquatic habitat management
planning action that resulted in a cooperative
agreement with FWS to, among other things,
identify mitigation options and select
mitigation sites. This action has resulted in
enhanced cooperation among various
interests and has expedited permit approvals.
4 The Ports of San Pedro and Los Angeles
jointly developed the "2020 Plan" for port
expansion which includes specific mitigation
commitments according to a Memorandum
of Understanding signed by the interested
agencies. Mitigation requirements will be
met by off-site restoration (there being
extreme limits on available mitigation sites
in the Los Angeles harbor area).
Specifically, as a first goal the entire
Bataquitos Estuary ecosystem will be restored
to a prescribed level of function.
5. The Bataquitos Lagoon restoration project is
a regional effort, organized cooperatively
with several Federal and state agencies and
local institutions with a goal to restore the
entire aquatic ecosystem of the lagoon (ca.
1,000 acres) by off-site, out-of-kind (mostly)
mitigation. Included is sediment removal,
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building of least tern nesting sites, beach
nourishment, inlet stability, creation of
freshwater marsh, etc. This project, funded
as mitigation for dredge-and-fill by the Port
of Los Angeles, is seen as the first in a
series of restorations under a long-term
cooperative integrated regional plan
(Marcus 1987).
6. Fraser River Estuary Management
Programs (British Columbia, Canada)
initiated in 1977, resulted in a plan in 1982
and 1985 for the joint management and
restoration of the estuary by a network of
national and provincial government
authorities. The plan was preceded by a
thorough inventory, consensual ng, goal
setting, and criteria formulation process.
The management plan makes decision
making predictable. Under the coordinated
Project Review System, developers get a 30-
day response (the interagency committee
meets bi-weekly). The North Fraser Harbour
component has a mitigation bank with
preselected littoral sites for restoration and a
system to intercalibrate relative values of
different wetland types and other shallow
aquatic habitats (Williams and Colquhoun
1987).
7. The Biscayne Bay Management Project
(Florida) has integrated a variety of
authorities and actions toward a master plan
approach to water quality and aquatic habitat
restoration and conservation. While manage-
ment is less centralized than examples
above, the integrated consensus formation
and networking have enhanced restoration
and made development constraints more
predictable.
REGIONAL GOALS AND MITIGATION TARGETS
Any regional strategy for aquatic habitat
restoration requires formulation of goals, often
followed by objectives, guidelines, and criteria
for project evaluation. The process of goal
setting should incorporate the policies of agencies
and the views of the full spectrum of private and
public interests involved. Even when completed,
the strategy will most likely be advisory and not
a substitute for existing agency authorities and
prerogatives.
The following is recommended as a
conceptual approach to the goal setting process
(Josselyn and Buchholz 1984, quoted in
Quamman 1986):
"The government agencies involved in
managing and regulating natural
resources need to identify restoration
goals which state the habitats and
functions deemed to be important within
each ecoregion. This will result in
improved project coordination within an
ecoregion, and also allow for
identification of the cumulative effects
of piecemeal alterations in the region.
The initial step in identifying
restoration goals involves determining
the types and area of the different
habitats present, as well as their rates of
losses and gains. This determination,
coupled with knowledge about the
importance of each habitat to the
ecoregion's key species, will provide the
information needed to decide which
habitat types should be restored or
replaced."
An example of Regional Restoration Goals
generated by the California Coastal Commission
is the following for the South Region of the
California Coast (Calif. Coastal Comm. 1987):
"The predominant restoration goal for
this region should emphasize the creation
of open circulation, low intertidal habitat
interspersed with salt marsh patches to
enhance shorebird, diving duck, and
marsh and wading bird populations. The
open circulation pattern will enhance
local fish and invertebrate populations
and keep mosquitos and flood control
activities relatively easy. The salt marsh
areas should be sufficient in size to
maintain endangered species
populations."
Such goals provide a good starting point for
the technical realization of restoration but
obviously need to be extended with detailed
criteria.
If you are fortunate enough to be reviewing
permits for an aquatic ecosystem that is covered
by a regional strategy with goals and criteria for
restorative mitigation where previous analytic
steps have been taken, you have only to match the
development project with identified-in-advance
restoration targets and procedures. If not, you
may nevertheless be able to analyze the regional
ecosystem involved and identify targets that
would be acceptable to your colleagues in the
other agencies, environmentalists, and the
developer. One major issue is to evaluate the
mitigation or voluntary restoration in the context
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of the needs of the wider ecosystem. Most
wetlands do not exist in isolation; they are
coupled to wider aquatic ecosystems (Figure 4).
Another major issue is to recommend mitigation
targets that have high priority in terms of your
perception of regional ecosystem needs.
This approach is different from the familiar
acre-for-acre compensation requirements because
of its urban orientation. Urban aquatic systems
are always in need of repair. These needs can be
diagnosed and specific treatments prescribed that
will be of much greater value than formula acre-
for-acre replacement of a particular marsh,
mudflat, or beach habitat type. For example,
ducks may be more in need of protected shallow
water area than of emergent marsh, or terns
more in need of sandy nesting islands than
mudflats. Critical habitat needs such as these
can be identified in most urban aquatic
ecosystems. In another chapter of this volume,
Erwin suggests giving priority to defining
mitigation goals specifically in terms of fish
and wildlife targets and in fulfilling those
goals, allowing the maximum flexibility and
creativity.
Trying to restore an existing wetland to its
original, pristine condition may not always
produce the most appropriate result in terms of
meeting the region's critical need for wetland
output. For example, creating a coastal high
marsh area of sea daisy and saltwort, although a
close replication of the original wetland, may be
of far less value than a replacement low marsh
of mixed cordgrass and mangrove with open
channels, which would both provide a nursery
area for fishes and an export of detritus to the
estuary. Often there is a current regional
demand caused by shortages of particular
types of wetland function that are recognized for
a particular region (Clark 1986b). Whether the
shortage has occurred because of wetlands
conversion or wetland dysfunction, the demand
can be at least partially provided through repair
of dysfunctional ecosystem units in many
circumstances (Figure 5).
Any regional strategy can be organized to
respond to "cumulative impacts" and to provide
"offsets" for any environmental damage in
degraded ecosystems (as for air quality "non-
attainment" areas). Under a regional strategy,
a priority goal would be to reverse the
accumulation of negative impacts, and begin a
trend of positive cumulative impacts for the
regional ecosystem. The regional authority
would determine a baseline condition, or
threshold level, for attainment by examining
historical trends of resource losses for the
ecosystem. Future restorative mitigation would
have an overall target to return the system, via
positive cumulative impacts, to an earlier
designated level of productivity (e.g., for the
Chesapeake Bay, return to the status of the year
1950 seems to be favored).
MULTIPLE IMPACT PROJECTS
In urban waterfront projects, several
different impact types can often be identified;
some positive and some negative. In this
situation, the balance of net benefits and losses
must be determined in some fashion based on
qualitative and quantitative factors. If no
predetermined scheme is available to convert
"apples to oranges", the process may have to be
more judgmental than analytical. In the
previously cited official FWS mitigation policy
(p. 765f2) it is stated that: "... the net biological
impact of a project proposal is the difference in
predicted habitat value between the future with the
action and the future without the action". In
effect this encourages the developer to present an
actual "balance sheet" in support of his
application (including voluntary enhancements)
which shows for each of the important functional
categories the extent to which the project will
benefit or harm the ecosystem in the "without
project" and "with project" scenarios. Table 1
illustrates a very simplified example of a
summary sheet.
Sophistications that can easily be introduced
into such comparisons include FWS "resource
categories", HEP analysis, and relative value
calibrations.
This approach encourages the developer (with
his consultant's advice) to incorporate a variety
of voluntary restorative enhancements into
project design in the early planning stages.
However, ambiguity is introduced by the FWS
interest in holding to itself the determination of
"...whether these positive effects can be applied
towards mitigation" (FWS mitigation policy, p.
7652). If such interpretation is actually delayed
until permit application is submitted, no improve-
ment in predictability is achieved and developer-
supported restorative mitigation is frustrated.
Where restorative mitigation will be in the
offing, it behooves EPA and other agency
reviewers to provide secure advice to developers
as early in the pre-application process as
possible.
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Figure 4. This Spartina patens marsh on the Port Liberte site appears isolated but it is strongly
linked to the lower Hudson Estuary through runoff drainage, tide action, detrital outflow,
animal movements, and other factors
Figure 5. Repair of this shallow, polluted, marsh/tideflat/slough is part of the Port Liberte
enhancement program.
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Table 1. A very simplified example of a summary sheet that could be used to review the possible
impacts of a proposed project.
Gate o
Without
Project
With
Project
Net
Impact
Comments
Channel
circulation
Restricted,
stagnation,
eutrophic
Free flow
non-stagnant,
non-eutrophic,
improved access,
fewer mosquitos
Highly
positive
Depth of 4'
specified;
range of 3-5'
would be acceptable
Macrophytes Unimpeded
insolation
Piers.
boardwalks
will shadow
3-1/2 acres
Moderately
negative
Plank spacing
of 1-1/4"
will reduce
shading effect
MITIGATION BANKS AND ALTERNATIVES
In the urban setting it is most difficult to
avoid going off site with mitigation where it is
required of a development. Waterfront is so
scarce and valuable that land parcels for develop-
ment are small and use is intensive. Therefore,
land available for mitigation is at a premium.
On the other hand, waterfront redevelopment
creates extensive benefits through value added to
the land, taxes, jobs, and particularly, through
ridding the waterfront of the blight of decaying
warehouses, collapsing docks, and health and
security nuisances. Most communities will
vigorously support waterfront renewal. This
must be strongly considered by COE in its public
interest review.
These two factors, motivation for intensive
use of waterfront parcels and the limited options
for onsite mitigation, create strong pressure to
find offsite solutions for mitigation demands,
often through some type of "mitigation bank".
One solu- tion is a mitigation bank whereby
developers are "taxed" for impacts and the
proceeds "deposited" in a habitat
creation/restoration account similar to the
"impact fees" for infrastructure often charged to
dryland developers. A second solution is a
different kind of bank whereby areas in need of
habitat restoration or suitable for habitat creation
are "banked" so as to be available in the future
for mitigation requirements levied against
developers.
A third solution is a regional cooperative
restoration plan, whereby mitigation for various
projects is done at predesignated sites. It would
be as though, at Bataquitos Lagoon for example,
several developers had participated sequentially
in the restoration project. The major
requirement is advance designation of sites for
restoration as the COE does now for dredge spoil
(dredged material) disposal areas. Designation
can be done by a regional body (e.g., North
Fraser River), a state (e.g., California coast, or
New Jersey's proposed advance site program), a
Federal agency, or a special agency like the
California Conservancy (McCreary and Zentner
1983). This approach avoids the appearance of a
developer "buying" a permit, as in the first
solution (which is not looked on favorably by
most agencies; e.g., the Baltimore Harbor plan
was rejected by the COE for this reason).
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CASE STUDY PORT LffiERTE
This case study describes aspects of an
innovative residential project in Jersey City,
N.J. along the shores of the Hudson River. A 125-
acre parcel of previously filled land (by the U.S.
Army in the early 1940's) was excavated to
provide 2 linear miles of canals for waterside
housing (Figure 6). The developer engaged a
panel of experts to prepare a series of
enhancements (to be paid for by the developer) in
advance of formal permit review.
Port Liberte, bounded by the Caven Point
Natural Area and Liberty State Park is a canal
side residential marine community currently
under construction with 1690 condominium
units, commercial space and marina. Caven
Point Natural Area represents one of the few
remaining remnants of the natural estuary with
a Spartina salt marsh and tidal mudflat (Burger
and Clark 1987). The genesis of the Port Liberte
project was and continues to be one of sound
environmental planning whereby appropriate
geological and biological expertise guided the
development, architectural design, and
construction schedule of the project and the
monitoring programs. With the acquisition of
the permits, major construction began in 1986 but
careful monitoring of water quality, fish
populations (Figure 7) and avian use (the three
critical resources on the site) continues and will
continue during the project. This is one of a few
projects to involve a year of monitoring prior to
permitting, with continued monitoring during
buildout. Monitoring data obtained before
construction was used to physically design the
marina, channels, canals, and boardwalks as
well as the timing of particular construction
schedules. One notable and unusual aspect of the
Port Liberte project was the cooperative nature of
the interactions between project personnel,
government personnel, scientists, and
environmentalists, rather than the usual more
adversarial approach (Burger and Clark 1987).
That the complex project received its New
Jersey permit in less than 1 1/2 years is owed to
the collaborative spirit in which the project
evolved. Another important factor was that, due
to confidence in the process, the state permitting
authority was willing to extensively "condition"
the permit rather than wait until the multitude of
details were settled and the COE was agreeable.
By this means, the project could get underway
and the issues could be worked out
simultaneously, requiring an extended in-
process dialogue with state and federal agencies
(still ongoing) and continuing ecological
baseline and monitoring studies. Also, full use
was made of the opportunity for pre-application
conferences and informal dialogue with state
and Federal agency personnel (Burger and
Clark 1987).
The Port Liberte Restoration Design Panel,
an interdisciplinary group of ecological experts,
(academics and consultants) was formed to
review Port Liberte development plans and to
provide advice on ecological enhancement. At
this point no specific mitigation requirements
had been mandated, but permit review authorities
did expect a good and sufficient enhancement
effort which was strongly supported by the
developer, the Port Liberte Partners.
Consequently, the Panel was encouraged to
brainstorm freely and to formulate an optimum
variety of ecological enhancements for the
project.
The panel was concerned with using the
opportunity to fulfill current ecological demands.
That is, rather than simply planning to supply so
many acres of habitat, the panel wanted to meet
responsible local demand for ecological goods
and services. For example, it was recognized
that the endangered Least Tern needed safe
nesting sites and that the profusion of aquatic
birds using the littoral zone of the project area
needed both an adjacent source of fresh to
slightly brackish water and continued access to
low cover on the beach berms at high tide, as well
as protection from disturbance. A second priority
goal was to see that adversely impacted aquatic
areas were rehabilitated. While accomplishing
the above, the panel recognized that many
constraints were operating and attempted to stay
within the limits of practicality imposed by
permit conditions and project requirements.
The Port Liberte Restoration Design Panel
met in September, 1985 to develop criteria for
ecosystem enhancements, including restoration,
rehabilitation, and creation of aquatic
subsystems. The enhancement concepts had been
reviewed in advance by the State of New Jersey
(Department of Environmental Protection,
Division of Coastal Resources) and conditions
had been imposed. Consequently, the Design
Panel was simultaneously considering the
developer's proposals, the state's reactions and
requests, and the individual ideas of panel
members.
The mandate was specifically to advise the
developer on restoration and enhancement of
natural systems within and adjacent to the
project area, particularly in regard to the
following:
1. Rehabilitation and rerouting of Caven Creek,
a drainage channel that transects the
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Figure 6. General plan for the Port Liberte waterfront community. The artificial canal system is
open to tidal flow on the north, south, and at the main boat entrance at the southeast. The
canals shallow from the central trunk to the laterals. Deadends have been virtually
eliminated.
98
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I
-,,..
Figure 7. Biological baseline and monitoring activities include seining in the shallow waters of the
east beach at Port Liberte along with offshore trawls, benthic and water quality samples,
and intensive bird censusing.
99
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2.
property near its northern boundary along
with ecological improvements of the Caven
Point Peninsula.
Rehabilitation of the North Slough, a tidal
embayment lying west of Caven Peninsula
that has been adversely affected by pollution.
3. Enhancement and maintenance of the
Spartina -beach-dune system that fronts the
east side of the project along Caven Cove
on the Hudson Estuary (Figure 8).
4. Creation of a special nesting habitat for the
endangered (New Jersey state list) Least
Tern.
5. General ecological enhancement of Caven
Point Peninsula with considerations for
public access and education.
The Panel's charge was to generate
recommendations with sufficient detail to enable
project planners to draw detailed plans and write
specifications for the work (Figure 9). After
receiving its mandate, the six-person panel
worked with full independence, generating some
recommendations that neither the state nor the
developer might have favored, but which the
panel was obliged to offer by virture of its
knowledge or the principles involved. While it
is still too early to determine the panel's success,
all recommendations were accepted and acted
upon by developers and regulators.
SUMMARY
In dense urban settings, restoration is a
priority goal for mitigation or voluntary
enhancement of aquatic habitats. Therefore the
needs of regional ecosystems must be considered,
not just project sites or single wetland units. In
expanding urban areas a combination of
protection, set-aside, and restoration may be
required. Because strategies for aquatic
ecosystem restoration are planning programs,
they conflict strongly with the ad hoc nature of
regulatory programs. Adjustments are necessary
to enable permit evaluations to respond to the
goals of regional restoration strategies. Effective
restorative mitigation depends upon coopera-
tion from private and public development
entities; this means that unambiguous advice
can be given to developers in project planning
phases.
LITERATURE CITED
Batha, R. and A. Pendleton. 1987. Mitigation: A good tool
that needs sharpening. Calif. Waterfront Age
3(2):15-17.
Burger, J. and J. Clark. 1987. Port Liberte. An example
of collaborative planning for a coastal development
on the lower Hudson River. Paper presented at
Conference on the Impacts of New York Harbor
Development on Aquatic Resources, Hudson River
Foundation.
California Coastal Commission. 1987. Draft working
paper on wetland restoration goals.
Clark, J. 1979. Mitigation and grassroots conservation
of wetlands urban issues, p. 141-151. In The
Mitigation Symposium: A National Workshop on
Mitigating Losses of Fish and Wildlife Habitats.
Genl. Tech. Rept. RM65, U.S. Forest Service, Fort
Collins, Colorado.
Clark, J. 1985. A perspective on wetland rehabilitation,
p. 342-349. In J. Kusler, R. Hamaan (Eds.),
Wetland Protection: Strengthening the Role of the
States. Center for Government Responsibility, U. of
Florida, Gainesville.
Clark, J. 1986a (in press). Assessment for wetlands
restoration, p. 250-253. In J. Kusler and P.
Riexinger (Eds.), Proceedings: National Wetlands
Assessment Symposium. (Portland, Maine). Assoc.
of State Wetland Managers, Berne, New York.
Clark, J. 1986b. Setting the agenda for new research,
regulations, and policy, p. 309-318. In E.D. Estevez,
J. Miller, J. Morris and J. Hatnman (Eds.),
Managing Cumulative Effects in Florida Wetlands
Conference Proceedings. Mote Marine Lab., E.S.P.
Publ. 38.
Clark, J. and S. McCreary. 1980. Prospects for coastal
conservation in the 1980's. Oceanus 23(4): 22-31.
Clark, J. and S. McCreary. 1987. Special area
management at estuarine reserves, p. 49-93. In D J.
Brower and D.S. Carol (Eds.), Managing Land-Use
Conflicts. Duke Univ. Press.
COE. 1985. Regulatory Guidance Letter, Nov. 8, 1985.
U.S. Army Corps of Engineers, Office of Chief of
Engineers.
Dial, S., M. Quamman, D. Deis and J. Johnston. 1985.
Estuary-wide mitigation options for port development
in Tampa Bay, Florida, p. 1332-1344. In O. T.
Magoon and H. Converse (Eds.), Coastal Zone '85,
Vol. 2, American Society of Civil Engineers.
100
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•Jf.
Figure 8. Restoration of the east beach is a major enhancement activity at Port Liberte. The beach is
screened and protected from landside disturbance by a buffer zone of Phragmites.
101
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BLACK TOM CHANNEL
Figure 9. General enhancement plan for the natural areas lying east and north of the Port Liberte
project site.
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Vol. 2, American Society of Civil Engineers.
Josselyn, M.N. and J.W. Buchholz. 1984. Marsh
Restoration in San Francisco Bay: A Guide to
Design and Planning. Technical Report #3.
Tiburon Center for Environmental Studies, San
Francisco State University.
Klesh, W.L. 1987. Long-term management strategy for
the disposal of dredged material: Corps-wide
implementation. In Proc. North Atlantic Regional
Conf. on the Beneficial Uses of Dredged Material,
12-14 May 1987, Baltimore, Md. p. 185-192.
Marcus, L. 1987. Wetland restoration and port
development: the Bataquitos Lagoon case. p.
4152-4165. In O. T. Magoon, H. Converse, D. Miner,
L. T. Tobin, D. Clark, and G. Domurat (Eds.),
Coastal Zone '87, Vol. 4, Am. Soc. of Civ. Eng.
McCreary, S. and T. Zentner. 1983. Innovative
estuarine restoration and management, p. 2527-2551.
In O. T. Magoon and H. Converse (Eds.), Coastal
Zone '83, Vol. 3. Am. Soc. of Civ. Eng.
Olsen, Stephen and V. Lee. 1985. Rhode Island's Salt
Pond Region: a special area management plan.
Coastal Resources Management Council,
Providence, Rhode Island.
Quamman, M.L. 1986. Measuring the success of
wetlands mitigation. National Wetlands
Newsletter. Sept.-Oct.: 6-8.
Sorensen, J. 1982. Towards an overall strategy in
designing wetland restoration, p. 85-96. In M.
Josselyn (Ed.), Wetland Restoration and
Enhancement in California. California Sea Grant,
U. of California, La Jolla.
Studt, J.F. 1987. Special area management plans in the
Army Corps of Engineers regulatory program.
National Wetlands Newsletter. May-June: 8-10.
United States Fish and Wildlife Service. 1981. United
States Fish and Wildlife Service Mitigation Policy.
Federal Register 46(15):7644-7655.
Wessel, A.E. and M.J. Hershman. (In press).
Mitigation: Compensating the Environment for
Unavoidable Harm. In M.J. Hershman (Ed.),
Urban Ports and Harbor Management: Changing
Environments Along the U.S. Waterfront. Taylor
and Francis, N.Y.
Williams, G.L. and G.W. Colquhoun. 1987. North
Fraser Harbour environmental plan, p. 4179-4192. In
Coastal Zone '87, Vol. 4, Am. Soc. of Civ. Eng.
Wilmar, M. 1986. Mitigation: the applicant's
perspective. National Wetlands Newsletter. Sept.-
Oct.: 16-17.
Zagata, M.D. 1985. Mitigation by "banking" credits a
Louisiana pilot project. National Wetlands
Newsletter. 7(3):9-ll.
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WATERFOWL MANAGEMENT TECHNIQUES FOR
WETLAND ENHANCEMENT, RESTORATION AND CREATION
USEFUL IN MITIGATION PROCEDURES
Milton W. Weller
Caesar KLeberg Professor in Wildlife Ecology
Department of Wildlife & Fisheries Sciences
Texas A & M University
ABSTRACT. Waterfowl and other wetland wildlife managers have long been involved in
wetland restoration and enhancement, and have developed functional techniques for
management of certain wetland types in various geographic regions. These procedures can
serve other wetland managers in many useful ways, and are worthy of experimentation for
other purposes. Most use natural processes to tap natural seed banks, modify cover-water
ratios, or control weeds via water level control and herbivores. Wetland types where
procedures have been standardized include those dominated by palustrine persistent
emergents, moist-soil nonpersistent emergents, estuarine emergents, and forested palustrine
communities.
This chapter presents some general concepts based on a selection of the extensive literature
designed to facilitate adaptation of these strategies to the special situations of restoring,
enhancing or creating wetlands to meet mitigation requirements. The procedures described
also can be used to enhance various wetland functions such as water quality, shoreline
protection, and esthetic values.
Major information gaps include: long-term ecological effects of management processes;
methods for speeding natural events that aid in wetland restoration; and lack of quantitative
information on other groups of wildlife such as fish, herptiles, and even nongame birds and
mammals.
INTRODUCTION
Mitigation efforts requiring enhancement of
established wetlands, restoration of former
wetlands, or the creation of new wetlands where
none existed, often are viewed as new efforts that
are untested and uncertain. In fact, wildlife
managers and some fisheries managers have
been involved in such efforts for many years.
Local wildlife or fisheries managers often are
the best source of wetland restoration techniques
that have been tried and work in that region.
Most of the habitat management techniques are
based on natural processes in wetland systems,
and thus also influence other wetland values and
functions. However, few of these practices have
been subjected to long-term experimental testing
and evaluation. Much of this material has been
published but it is not available in a single
document that covers all wetland types and their
regional variations.
This chapter brings together some
generalizations, a selection of the extensive
literature, and a few examples of wetland types
and procedures that have been standardized in
certain areas. Such efforts have emphasized
waterfowl and muskrats and occasionally other
furbearers; very little work has dealt with other
groups although some work indicates that
successful efforts for game species also may
favor nongame species. These procedures can be
used equally well to enhance other wetland
functions, such as reducing turbidity, protecting
shorelines from erosion, and esthetic values.
Thus, a review of the backgrounds of this
management for waterfowl will facilitate
consideration of all available strategies to the
special situations of restoring, enhancing or
creating wetlands to meet mitigation
requirements.
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DEFINITIONS OF MANAGEMENT STRATEGIES AND MANIPULATIONS
Although a fairly complex and somewhat
inconsistent terminology has evolved among
wetland managers and consultants, wildlife
managers generally include a variety of
situations and problems under the terms "habitat
development" and "management" (e.g.,
Sanderson and Bellrose 1969, Atlantic Flyway
Council 1972). However, there have been several
typical patterns: Restoration of drained wetlands
has been common where there was an opportunity
to reclaim a major wetland of high wildlife
value that has been degraded. The usual
situation involves a failed drainage project
where land values have declined, so that federal
or state agencies can purchase the land and
attempt restoration. Numerous National
Wildlife Refuges (NWR) such as Tule Lake
NWR in California and Aggasiz Lake NWR in
Minnesota fall into this category (Laycock 1965).
Still older examples are available in the
European literature (Fog 1980).
Enhancement of wetlands involves an
attempt to improve the wildlife values of a
wetland that has not been drastically perturbed,
but one that managers believe could be producing
wildlife at a higher level more of the time.
Periodic manipulations of water levels to
enhance nesting conditions or modify plant
succession rates would be typical examples.
If we define creation of wetlands as
establishment of wetland communities and
functions where none existed, this has been a
less common practice among wildlife managers.
However, this is partly a matter of terminology
as procedures have not been categorized in
relation to the nature and status of the wetland.
The typical pattern has been the conversion of
terrestrial communities to wetlands via
identification of a natural drainage or basin that
has had some history of moist-soil vegetation
resulting from periodically wetter years. This
conversion is usually done by creating an
impoundment or diverting water to provide more
regular flooding and encourage wetland plants
and associated game species. Large
impoundments created for other purposes such as
water supply or flood control also may result in
wetland development at the margins or upper
reaches of the pool. Additionally, mining
operations such as gravel removal may result in
suitable wildlife habitats and considerable
information is available (Svedarsky and
Crawford 1982). The reverse of this, the
conversion of aquatic areas to wetland, has been
less common but has been accomplished by
diking to keep out water and reduce continual
deep flooding—as has been common at refuges
and other wildlife management areas along
coastlines of large lakes or oceans.
GOALS AND OBJECTIVES
Most conservation agencies have long-range
planing processes for management areas that
involve 3-to 10-year plans, often with annual
updates. By their legal charge (e.g., migratory
bird treaty or Federal-Aid funding) or by policies
of guiding groups such as commissions, wetland
managers in charge of specific areas or regions
usually attempt to maximize wildlife attractive-
ness and wildlife production. This target could
be in conflict with other wetland values and
functions, but this is not always the case.
Philosophically, many of the goals of
wildlife managers overlap with those of other
wetland managers: There is a desire to preserve
natural landscape units and functional values.
Managers differ, however, in whether they prefer
to use artificial methods that may give more
immediate results, versus the use of more
natural processes that tend to take longer but are
less expensive and longer lasting (Weller 1978).
Benefit-cost ratio strongly influences the choice
of strategy as some functional but very expensive
techniques such as hand transplants can be more
easily justified in mitigation procedures than in
conservation efforts for wildlife. Short-term
goals often have been the driving force in habitat
management of wetlands for wildlife: 1)
increased production of game for hunting via
creation of more and better nesting sites,
increased food supplies, resting and roosting
condition, or reduced predation; 2) improved
conditions for hunters in pursuit of game, such
as cover patches or blind sites; or 3) improved
access to wetland areas for hunting by means of
roads and boat channels.
Many wetland wildlife managers cherish
the rich natural values and aesthetic aspects of
the natural system. They expound a natural
management philosophy as a code of ethics
(Errington 1957), and are dedicated to preserving
a naturally functioning ecosytem in perpetuity
(Weller 1978, 1987) and maintaining or adding
diversity (Sanderson 1974, Mathisen 1985).
Others place first priority on maximal
production of the targeted game species, but not
intentionally in opposition to other natural
values and functions. Ideally, these approaches
should both be incorporated into a unified plan
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that involves other wetland functions as well.
The consideration of multiple interests and
approaches has been enhanced by the use of
public hearings for local residents, laypersons
and experts so that greater unity of goals is
possible.
REVIEW OF PRODUCTION, SUCCESSION
AND VEGETATION STRUCTURE
Research biologists working with marsh and
other wetland wildlife have long recognized the
importance of natural ecological processes such
as seed germination, plant growth and
production, succession, flooding, and water
quality in regulating the plant community that
ultimately dictates the diversity and populations
of wildlife. As a result, there have been
numerous vegetation studies oriented toward
understanding habitats for waterfowl, including:
vegetation community, structure and dynamics
(Dane 1959, Kadlec 1962, Weller and Spatcher
1965, Weller and Fredrickson 1974);
germination and plant growth (Weller 1975,
Beule 1979); effects of drawdowns or dewatering
(Kadlec 1962, and others); hydroperiod and other
water-driven vegetation patterns (Meeks 1969,
Knighton 1985); wetland wildlife responses to
changes in structure and availability of
vegetation (Weller and Fredrickson 1974, Ortega
et al. 1976); influence of vegetation on predation
rates (Keith 1961, Duebbert and Lokemoen 1976);
and competition between wildlife species
(Weller and Spatcher 1965).
Much of this work has been done on inland
freshwater marshes, but there has been some
excellent work on interior saline (Bolen 1964,
Christiansen and Low 1970) or alkaline
wetlands (Stewart and Kantrud 1972). Tidal
regime, turbidity and salinity influences on
plant growth and survival in coastal marshes
have been the subject of numerous
wildlife-oriented plant succession studies
(Chabreck 1972, Palmisano 1972, and others),
and have provided a basis for sound
management. Some studies by botanists and
plant ecologists have preceded and supplemented
these studies by wildlife biologists, but their
research questions often were directed toward
different goals. There are many opportunities to
improve upon this foundation with management
applications in mind, but the effectiveness of
such studies will depend upon the questions
asked.
PRECONSTRUCTION CONSIDERATIONS
GEOMORPHOLOGY, LANDSCAPE,
PATCH SIZE AND PATTERNS
It has become increasingly apparent that
waterfowl and other migratory birds, and some
wetland fish, amphibians, reptiles and
mammals, do not satisfy all their needs in one
wetland. This is particularly true of the
breeding period when very specific requirements
for foods or nest sites may exist in comparison to
post-breeding activities such as migration or
wintering. Thus, wetland diversity and density
may figure prominently in satisfying these
needs, a consideration that may not be met with
the restoration or creation of only one wetland
when a complex may be necessary. Wetland
complexes have been recognized as important by
many workers (Swanson et al. 1979, Weller 1981)
and data presented by Brown and Dinsmore
(1986) suggest that complexes increase species
richness over solitary wetlands of similar size.
General studies of wetland density in Prairie
Pothole habitats, where water cycles influence
wetland numbers from year to year, show
general correlations between wetlands and
waterfowl abundance, as one would expect
(Sugden 1978, Leitch and Kaminski 1985). The
diversity of wetland types also is deemed vital as
the loss of small wetlands in drought years has a
particularly great impact on certain species
(Evans and Black 1956). Patterns of vegetation
(cover-water ratios or cover-cover interspersion
patterns) also influence bird use and are
important designs for management of wetlands
intended to enhance bird use (Weller and
Spatcher 1965, Patterson 1976, Kaminski and
Prince 1984).
Larger wetlands are known to provide greater
numbers of habitats, and therefore are more
likely to attract greater number of species (i.e.,
species richness) (Brown & Dinsmore 1986).
There is a tendency to acquire and restore large
units for these reasons, but it is also recognized
that small areas also may provide specialized
habitats for certain species, and management for
those may require size considerations (Evans
and Black 1956).
Configuration (e.g., length of shoreline in
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relation to area of the wetland) seems to be an
important influence on numbers of territorial
species that an area can support, but there are
little substantiating data (Mack and Flake 1980,
Kaminski and Prince 1984). Some workers have
suggested that other vegetation patterns are more
influential than shoreline length (Patterson
1976). Managers often successfully create
artificial wetlands with complex configurations
to provide isolation for breeding pairs.
Contiguity between wetlands is especially
important to fish (e.g., Herke 1978) and some
other vertebrates, and one obvious conclusion is
that it provides habitat diversity that meets
various needs throughout life.
PKECONSTRUCTION DESIGNING
FOR WATER DEPTH
Preconstruction planning involving detailed
contour mapping of prospective sites is essential
(Verry 1985). Site observations during natural
flooding periods also are useful because contour
maps may not provide the precision essential in
water level regulation. For example, large-scale
contour intervals are unusual on construction
maps, when the ultimate precision required for
water level control may be a matter of
centimeters.
Contouring with earth-moving equipment is
commonplace, and should be used to create water
depths associated with the desired plant
community. Islands, bays and other structural
features can be created during construction if
soil character and shoreline protection are
considered. Where such work is done on areas
with a rich seed bank, soil should be moved
off-site and returned as topsoil both for the merits
of its organic content and as a seed bank. This
will reduce invasions by exotics where they are
an issue and the necessity of seeding with
cultivated varieties that result in low natural
diversity.
or enhancement projects, water control structures
must be carefully engineered to handle these
added burdens. Additionally, up-slope protection
can be achieved through water diversions to
streams, grass plantings to absorb more rainfall,
or smaller impoundments that serve as catch
basins for both water and silt.
These solutions also are relevant where
wetlands are created from terrestrial sites, in
which case site selection is extremely crucial
and requires knowledge of the slope, area, and
rainfall data of the watershed (Verry 1985).
Storm events always seem to exceed runoff
projections and are particularly damaging in the
early stages of wetland development. In coastal
areas, tidal action and wind fetch are important
influences that must be considered, and
considerable work has been done on shoreline
protection.
CONTROLLING EROSION AND
TURBIDITY
In any wetland management program,
modified water levels, exposed banks and
unvegetated bottom are vulnerable to wave and
current action. Decreased wetland productivity
may result from erosion of shorelines,
elimination of vegetation, and increased water
turbidity. Most wildlife managers have dealt
less successfully with these problems than have
other wetland designers, due in part to factors of
need and cost. Importing firmer soil, gravel or
rock may be necessary, and prepared rip-rap can
be used in extreme cases of erosion. Several
steps can be taken to prevent erosion: 1) exposing
the shoreline by dewatering until vegetation has
become established, and 2) delaying flooding
until the bottom has been stabilized with
emergent and preferably submergent vegetation.
These measures will reduce turbidity that may
prevent vegetation establishment when reflood-
ing occurs.
REGULATING RUNOFF-EVAPORATION
RATIO AND FLOW-THROUGH RATES
Rainfall-evaporation patterns and
watershed-wetland size ratios are of special
importance in impoundment site selection
(Verry 1985). Special considerations are
necessary where uplands have been modified by
land-use practices. Farming may increase the
mean annual silt load and eutrophication, and
intensive grazing on the waterway slopes can
increase peak surges of water entering the
wetland during storm events, washing out
vegetation and water control structures. Urban
development may increase runoff due to parking
lots, roadways and roofs. In wetland restoration
CONSIDERING SPECIAL WILDLIFE
NEEDS
Waterfowl and other wildlife are highly
selective in their choice of habitat: it must supply
vegetation cover, nesting sites, protection from
predators, reduced disturbance and food supplies.
On a worldwide basis, systems have been
developed to manage for these needs (e.g., Scott
1982). In recent years, it has become clear that
habitat quality is very important, and providing
a place to live must also include nutritional food
at the proper time of the reproductive cycle
(Fredrickson 1985). Work on invertebrates of
wetlands still is inadequate but several workers
have demonstrated how patterns vary and how
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wildlife seem to respond (Voigts 1976, Swanson et
al. 1979), which managers more and more take
into account in their management strategies
(Whitman 1976, Reid 1985).
PROCEDURES BY PROCESS AND PROXIMATE OBJECTIVE
MANAGING THE SEED BANK
Although the longevity and abundance of
seeds of wetland plants has been known at least
since the 1930's (Billington 1938), and early
marsh managers advised location and utiliza-
tion of sites with a natural seed bank (Addy and
MacNamara 1948, Grail 1955, Singleton 1951),
managers have varied in their utilization of this
general principle. Seeding of Japanese millet or
use of native millets (Echinochloa crus-galli)
and smartweeds (Polygonum spp.) for seed
sources were widespread among National
Wildlife Refuges in the 1940's and 1950's
(Linduska 1964). Planting of millets, smart-
weeds, and agricultural crops was used to feed
large numbers of migrant and wintering
waterfowl in preference to less predictable
processes that capitalized on natural sources
(Givens and Atkeson 1957). More recently,
moist-soil management and other types of
strategies that use natural seed banks have been
viewed more positively by a generation of
managers who favor natural diversity and
minimal expenditures on machinery and
manpower. Management of both water depth and
hydroperiod is the major strategy employed (see
for example studies by Fredrickson and Taylor
1982) and the techniques are now more widely
recognized and appreciated.
Another aspect of seed banks generally
recognized by wetland ecologists but unknown to
many others is the importance of preserving the
seed bank in a newly created wetland. Dams
and levees often are built with borrowed soil
taken from the water side to create some
deep-water sites or to facilitate installation of
water control structures. When basin shape is
modified by scraping, a barren substrate may be
created (Kelting and Penfound 1950) that must be
reseeded or await the natural processes of seed
transport, germination and local seed produc
tion. Marsh hay cut at seeding times (as occurs
with seeding of wildflowers on highway
right-of-ways) may be a good seed source, but I
know of no experiments in wetlands to
demonstrate this.
Despite their common longevity, seed banks
may be limited in diversity or even non-existent
in situations of long inundation where wetland
emergents have not existed for many years;
aquatic plants or long-lived terrestrial plant
seeds may survive, but species of value to the
wetland restoration may not occur (Pederson and
van der Valk 1984). Where available, use of soil
from local wetlands may be useful in resolving
this problem.
MANAGING PLANT SUCCESSION
THROUGH WATER LEVEL
MANIPULATION
Because it has long been recognized that
hydroperiod and water depth dictate plant species
composition, density, and growth, waterfowl
managers have studied the availability and
germination characteristics of seed banks (Crail
1955), the physical and physiological re-
quirements of the seed for germination,
germination rates and rates of growth, tuber
production, plant productivity, and plant
life-history strategies (Weller 1975, Beule 1979)
that influence wetland succession (Dane 1959).
To provide the water conditions that induce
germination seed and plant growth, most
wetlands created or modified for wildlife make
provisions for complete dewatering via control
structures (Atlantic Flyway Council 1972). The
latter is a vital consideration if any influence
over plant community is desired, and the
engineer should be alerted to the need for total
dewatering. Subsequent modifications of dike
height must consider water control structures
and the potential of dam failure or erosion.
Strategies for achieving the desired goals will be
discussed under examples of several wetland
types that have been commonly and successfully
managed.
Although the terminology of succession may
not be very useful in many wetlands (Weller
and Spatcher 1965, van der Valk 1981),
manipulations involve dewatering to return the
plant community to mudflat annuals and
seeding perennials that are characteristic of
more shallow marsh (Bednarik 1963, Linde 1969,
and others). Plant growth rates or germination
also can be influenced by extreme flooding or
drying, by enhancing nutrients with fire or
fertilizers, and by weed control.
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MODIFYING WATER DEPTH AFTER
WETLAND FORMATION
The most common method of deepening a
natural or created wetland for waterfowl has
been to install a dam or dike to impound more
water, and to incorporate a water-control
structure that limits the pressure on the dam and
allows dewatering. Increasing water depths in
basins that do not have an adequate supply can
best be accomplished most economically by
gravity flow systems such as stream diversions
and up-slope reservoirs. A more reliable but
expensive alternative is a well and pump, but
this is a perpetual expense, and may be a source
of disagreement among different user groups.
Modifying shallow wetlands to create open
pools and deeper water can be done by
dewatering and a bulldozer, by drag-line
removal of basin substrate, or by blasting with
dynamite (Strohmeyer and Fredrickson 1967) or
ammonium nitrate fertilizer charged with a
more volatile explosive (Mathiak 1965).
REGULATING VEGETATION VIA
HERBIVORES AND FIRE
Wetlands, especially those dominated by
persistent, perennial emergent plants, are
renowned for their attractiveness to native
muskrats (Ondatra zibethicus) and the intro-
duced nutria (Mvocaster covou). Overpopulations
resulting in "eat-outs" are well documented in
northern and midwestern marshes (Errington et
al. 1963), and dramatic population changes also
exist in eastern brackish marshes (Dozier 1947),
and southern deltaic and chenier marshes
(Lynch et al. 1947, O'Neil 1949, Palmisano 1972).
Muskrat populations in particular expand
rapidly because of their high reproductive
potential and adaptability to new food resources.
Ultimately, the area is denuded and populations
of other wildlife are drastically impacted
(Weller and Spatcher 1965). Managers often are
unprepared for this event and may lack methods
for control because of harvest regulations. In
large areas, control may be impossible due to
size and logistics of trapping. The resultant open
water may persist for many years unless
dewatering is used to induce revegetation.
Beavers (Castor canadensis) likewise can
impact on willows (Salix spp.), cottonwood
(Populus deltoides) and other highly palatable
plants, whether the plant are used only for food or
for lodges and dams as well (Beard 1953). Flood-
ing by beavers of other terrestrial or wetland veg-
etation often is regarded as serious by managers
not only because of plant mortality but because
water level stability within a wetland may not be
conducive to maximal community diversity and
productivity of many wetland species.
Another group of herbivorous animals are
fish such as the introduced common carp
(Cvprinus carpio). and more recently, white
amur or grass carp (Ctenopharvngodon idella).
Whereas sterile hybrids of grass carp are being
used to reduce the chances of reproduction in the
wild, the common carp reproduces readily and is
spread by fishermen. It also moves upstream
into shallow wetlands. Invading carp can be
extremely serious because of their direct
consumption of submergent plants and inverte-
brates, and indirectly because of the turbid
waters they induce which reduces light
penetration and therefore plant production (Robel
1961).
Livestock such as cattle, sheep and goats can
be useful management tools, but such grazing
may be difficult to regulate because of public
pressure for grazing rights or due to our lack of
understanding of the carrying capacity of
wetlands under variable and often uncontrol-
lable conditions. Grazing exposes tubers then
utilized by grubbing geese such as snow geese
(Anser caerulescens) in both southern and
eastern coastal marshes (Glazener 1946), but can
also can eliminate favored duck food plants
(Whyte and Silvy 1981). Grazing in northern
areas is generally regarded as detrimental to
nesting waterfowl (Kirsch 1969), but obviously
can be beneficial to species like upland
sandpipers (Bartramia longicauda) that prefer
short vegetation. Fencing is the simple tool used
by managers all over the world to change the
character of overgrazed wetlands (Fog 1980), but
better management may require regulation of the
grazing level and not merely total exclusion.
Fire has been used by farmers and ranchers
for years to increase forage and hay crops, but it
can be devastating to nesting ducks and other
birds (Cartwright 1942). The response of
wintering geese to fire has resulted in a policy of
periodic burning on refuges to reduce vegetation
and expose tubers for grubbing geese (Lynch
1941). Fire also has been used in northern
marshes with peat bottoms to create deep water
openings; however, control of the fire is often
difficult (Linde 1985). Considerable work has
been done recently to explore the role of fire in
marsh succession (Smith 1985a, 1985b), and
clearly much more of this type of work is needed
in all vegetation types (Kantrud 1986).
SEEDING AND TRANSPLANTING
Both seeding and transplanting were used
extensively in the 1940's for marsh edge plants,
and sometimes for emergent plants along the
shallow water's edge (Linduska 1964). Planting
Japanese millet and other seeds available from
farm suppliers and wildlife nurseries is still
widely done on small areas, especially by
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private landowners, but is less widespread as an
operational procedure on refuges and waterfowl
management areas because of cost. Upland
farming is more common because equipment is
available or sharecropping is a cost-effective way
to produce wildlife foods while appeasing local
farmers over local land lost to agriculture
(Givens and Akeson 1957). Planting in wetland
areas used for waterfowl hunting may involve
legal issues because of "baiting" laws, and must
be done in counsel with local wildlife officers.
Planting natural rootstocks or runners and
other plant parts has been used with cattail
(Bedish 1967) and other perennials, but is
labor-intensive and of questionable success—not
just because of plant growth potential but because
of losses due to their attractiveness to muskrats
and other herbivores. Erosion on wave-swept
shores is an equally serious problem, and
floating boards have been used to protect as well
as facilitate wetland establishment and survival.
CONTROLLING WEEDS
Part of maintaining a wetland that is
attractive to wildlife requires a balance of open
water and vegetation. Because nesting birds and
migratory waterfowl are especially influenced
by these conditions, considerable effort goes into
creating suitable habitat. In addition to the
control of succession and cover-water ratios
through water-level management (Weller 1978)
or fire (Kantrud 1986), more direct (artificial)
and immediate methods have been utilized such
as chemical sprays (Martin et al. 1957, Beule
1979); mechanical destruction by roller or cutting
(in or out of water) (Nelson and Dietz 1966, Linde
1969); and grazing (Kirsch 1969).
EXAMPLES OF COMMONLY MANAGED WETLAND
TYPES BY OBJECTIVE
PALUSTRINE PERSISTENT EMERGENT
WETLANDS
For nesting waterfowl and other marsh
wildlife, most managers prefer sturdy water
level control structures and a reliable source of
water for use in modifying water depths to
control plants for nest sites (birds) and food
sources (muskrats as well as birds). A diversity
of plants of various life forms is preferred to
serve various animals. Marginal nonpersistent
emergent plants produce large seed crops; deeper
water persistent emergents are excellent for nest
sites and provide tuberous bases useful to
herbivores; and submergent plants often provide
food directly or serve as substrates for
invertebrates.
Water depths dictate dynamic vegetation
patterns in wetlands subject to seasonal and
annual variation in water supply. These may
vary from lake-like aquatic conditions to
near-terrestrial vegetation due to hydrologic
perturbations. Wildlife respond directly and
vary greatly in species richness and population
abundance (Weller and Spatcher 1965).
Examples of plant succession following
drawdowns to re-establish vegetation were
provided by Kadlec (1962), Harris and Marshall
(1963), and Weller and Fredrickson (1974). Sub-
sequent changes in vegetation due to the
influence of water level and muskrats
(Errington et al. 1963, Weller and Fredrickson
1974) and common carp (Robel 1961) demonstrate
that: 1) the natural short-term water dymamics of
midwestern wetlands must be dealt with in
restoration projects, and 2) the inherent
adaptability of wetland plants provides them with
great powers of recovery and repair.
A well-established technique to reestablish
vegetation after it has been eliminated by high
water or muskrat "eat-out" is to dewater
("drawdown") the area by use of a water control
structure or pumping. Germination from the
natural seed bank (van der Valk and Davis
1978) provides most of the source of plants but
enhanced production of persistent plants via
tubers and rhizomes also results (Weller 1975).
Re-establishment may result in excessively
dense vegetation not suitable for the intended
wildlife, whereupon the natural herbivores may
move in and create suitable openings.
Modification of this pattern occurs with
various methods of creating artificial openings
described elsewhere, and these may be useful in
intensive management or restoration projects
where time is vital. The drawdown-revegetation
cycle is commonly practiced by conservation
agencies in many midwestern states (Linde
1969), and in situations where time is less
important relative to costs. This method seems to
simulate natural processes and events without
lasting damage. Even fish populations of those
areas seem responsive and pioneering.
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MOIST-SOIL IMPOUNDMENTS FOR
NONPERSISTENT EMERGENTS
Migratory waterfowl feed less on high
protein animal foods in fall and winter and
instead use seeds or foliage. Seed production is
especially enhanced by creating or maintaining
shallow water areas where nonpersistent
emergents such as millets, smartweeds,
spikerushes (Eleocharis spp.) and other marsh
edge plants germinate and produce seed
(Fredrickson and Taylor 1982). This requires
mud flat conditions, typical of any marsh
drawdown, except that such wetlands are
normally not breeding marshes for waterfowl
(although they may be suitable for some rails
and songbirds). Drawdowns are performed
early in the year to allow sufficient drying so
that annual seeds will be produced. Because of
the climatic regime in southerly areas, both
spring and late summer crops may be produced
where water is available and levels can be
controlled. The usual procedure is to construct
low dams or dikes to impound water equipped
with a simple structure for water level control.
In rice areas, low-level terraces that are opened
and closed by machinery work quite well, but the
intended crop of annuals must determine the
structure design and water depth.
Areas flooded in spring and dewatered
gradually create mudflat conditions attractive to
migrant shorebirds and ducks (e.g., green-
winged teal, Anas crecca). but also induce
germination from the seed bank (Fredrickson
and Taylor 1982, Rundel and Fredrickson 1981).
Too rapid drying produces more terrestrial
species (Harris and Marshall 1963), so soil
conditions and water level regulation are
extremely important. The retention of some
moisture on the flat is essential to ensure full
maturity of seeds and the germination of late
maturing plants like smartweeds. Here, as in
any drawdown, a thunderstorm can produce
flooding and the loss of a year's crop.
Typically, such areas are reflooded in the fall
prior to the arrival of waterfowl and other
migrants. Flooding to make food available to
migrant waterfowl involves regulation of the
water control structure (except in cases of high
rainfall and flow-through rates) to maintain
depths of 6 to 18 inches so that birds can swim but
still dabble and tip up for food. Dabbling ducks
like green-winged and blue-winged teal (A.
discors). mallards (Anas platyrhynchos) and
pintails (A. acuta) find ideal food and water
conditions in such situations. Deeper areas may
be utilized by shallow divers like the ring-
necked duck (Avthya collaris) (Fredrickson and
Taylor 1982),
Undesirable plants, particularly willow and
cattail can be extremely troublesome as they
outcompete annuals and eliminate openings
favored by ducks. The capability to dry out the
area, or to flood it to excessive depths, may allow
control of some nuisance species (Fredrickson
and Taylor 1982).
TIDAL ESTUARINE (BRACKISH AND
SALT) WETLANDS
Many of the processes that occur in fresh
marshes also occur in brackish marshes, and
can be influenced by muskrats or nutria
populations. However, sites under a tidal regime
usually cannot be dewatered for revegetation,
and serious marsh loss can occur (as considered
elsewhere by other authors in this volume).
Herbivore control is one of the most important
and effective methods of preventing this loss as it
is in freshwater wetlands lacking water source
and level control. Such marshes also may serve
as nesting and feeding areas for waterbirds,
although no long-term studies seem available.
The usual management strategy for
attracting breeding, migrant and wintering
waterfowl has been to build freshwater
impoundments as catch basins that exclude salt
water. This approach developed in part from the
adaptation of rice impoundments for use by
waterfowl along the eastern U.S. coast
(MacNamara 1949). It is still commonplace on
many coastal refuges, but is now strongly
discouraged by the National Marine Fisheries
Services to ensure free access of marine
organisms such as finfish and shellfish to
brackish and fresh tidal marshes that are vital
for feeding, breeding and nursery areas. Hence,
weirs are often used in place of dikes, and these
semi-impoundments reduce turbidity but may not
affect salinity markedly (Chabreck and
Hoffpauir 1962, Chabreck et al. 1979). In this
way, submergent vegetation attractive to
waterfowl and also to marine organisms that
frequent these shallow areas is enhanced. There
has been intensive study of this type of
impoundment on fish and shrimp populations in
Louisiana (Herke 1978). Undoubtedly there are
changes in the species composition and diversity
of benthic invertebrate populations caused by this
more continuous flooding of areas that once were
periodic mudflats. Impounding areas for private
waterfowl hunting areas has been legally
challenged by federal agencies on the east coast,
and this practice may demand extensive
evaluation before it is allowed to continue.
Nevertheless, it is widely regarded as the best
way to enhance waterfowl habitat in saline
coastal areas. In South Carolina coastal
impoundments, brackish rather than fresh water
has been used in the management of such areas
(DeVoe and Baughman 1986). Waterfowl
capitalize on brackish food species like
widgeongrass or musk grass. Dewatering by the
use of dikes and water-control structures can
112
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also be used to produce the mudflat plant,
Sesuvisum (Swiderek et al. 1988) which has
small but highly palatable seeds. Waterfowl
response in these situations has been impressive,
but the species composition may shift.
Additionally, such areas may be attractive to
shorebirds at low water stages.
Burning has previously been mentioned as a
tool for seasonally opening up vegetation for
geese, but this more commonly occurs in higher
marshes that are only periodically flooded.
GREEN-TREE IMPOUNDMENTS
(FORESTED PALUSTRINE WETLANDS)
The natural winter flooding of flood plain
oxbows, sloughs and backwaters, especially in
the southeastern United States, provides superb
wintering habitat for mallards and other ducks
that eat acorns and other large tree seeds and
fruits (Allen 1980). Additionally, beaver ponds
have been important to waterfowl, but tree
mortality results from such water stabilization
(Beard 1953). Flooding is erratic and dependent
on the timing and the rate of rainfall. Moreover,
flooding that occurs during the growing season
may kill trees that are not tolerant to prolonged
inundation at that time. To enhance the
reliability of water and food supplies for
migrants, low level impoundments have been
used with water control structures to flood
mast-producing trees during the dormant season
(Cowardin 1965, Schnick et al. 1982, Mitchell and
Newling 1986). Typically, a stream is diverted to
fill the area, and some flood prevention plan
often is necessary. Some areas use low level
dikes that will withstand overflowing water but,
as in any wetland impoundment, the potential
for complete drawdown is essential. If a water
control structure is not used, the impounding
dam may be cut with a front-end scoop, and then
repaired after the drying has occurred.
To take advantage of natural seed crops, site
selection for impoundments is crucial and must
include those mast producing species such as
willow oak (Quercus Phellos ) and water oak (Q.
nigra) that tolerate prolonged flooding, but also
produce acorns of a size suitable for ducks (Allen
1980). Depending upon the forest species
composition and flood duration, some tree
mortality may occur due to the reduced drainage
capacity of the area. However, these openings
are attractive to waterfowl and will produce
moist-soil annual seed crops if the areas are
naturally or artificially exposed during late
summer and early fall. Some managers are
creating openings by clear-cutting small patches
of less desirable species with the intent of
combining the moist-soil management technique
with the mast production of the green-tree
impoundment strategy (Harrison and Chabreck
1988).
CONCLUSION
Waterfowl and other wetland wildlife
managers have been involved in wetland
enhancement and modification for many years,
and have developed a series of techniques that
are fairly standard for management of various
wetland types and geographic regions. These can
serve other wetland managers in many useful
ways, and are worthy of exploration and
experimentation. Some of these techniques could
result in highly significant cost reduction where
time is available for the use of natural processes.
However, because of the Gleasonian nature of
succession in many wetlands (van der Valk
1981), plant communities are difficult to predict
and the desired or original ecotype may not
develop; therefore some range in specifications is
essential.
Understanding natural patterns and processes
of wetlands is a vital first step to proper and
lasting restoration, enhancement or creation.
Additionally, one must tap the expertise of the
many disciplines that can contribute to such
wetland preservation processes. As long-term
evolutionary products of extremely dynamic
systems, wetland plants and animals are
quickly responsive to the availability of
resources in newly created and enhanced areas.
But we must not become over-confident that we
can "create" a normally functioning and
naturally diverse system. In most situations, we
can provide the environmental needs to allow
dominant wetland plants and animals to
succeed, and the product will satisfy many if not
most viewers. We cannot, however, expect to
replace the complex and diverse natural systems
that are a product of many centuries of evolution
and randomness, and we should not let the ease
of creating the structure and simple features of a
wetland for mitigation lead us to accept
unnecessary and perhaps unsatisfactory
substitutes.
113
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WETLAND AND WATERBODY RESTORATION AND
CREATION ASSOCIATED WITH MINING
Robert P. Brooks
School of Forest Resources
Forest Resources Laboratory
Pennsylvania State University
ABSTRACT. A review of published and unpublished reports was combined with personal
experience to produce a summary of the strategies and techniques used to facilitate the
establishment of wetlands and waterbodies during mine reclamation. Although the emphasis
is on coal, phosphate, and sand and gravel operations, the methods are relevant to other types
of mining and mitigation activities. Practical suggestions are emphasized in lieu of either
extensive justification or historical review of wetlands mitigation on mined lands.
The following key points should receive attention during planning and mitigation processes:
* Develop site specific objectives that are related to regional wetland trends. Check for
potential conflicts among the proposed objectives.
* Wetland mitigation plans should be integrated with mining operations and reclamation at
the beginning of any project.
* Designs for wetlands should mimic natural systems and provide flexibility for unforeseen
events.
* Ensure that basin morphometry and control of the hydrologic regime are properly
addressed before considering other aspects of a project.
* Mandatory monitoring (a minimum of three years is recommended) should be identified
as a known cost. Rely on standard methods whenever possible.
Well-designed studies that use comparative approaches (e.g., pre- vs. post-mining, natural
vs. restored systems) are needed to increase the database on wetland restoration technology.
Meanwhile, regional success criteria for different classes of wetlands need to be developed by
consensus agreement among professionals. The rationale for a particular mitigation strategy
must have a sound, scientific basis if the needs of mining industries are to be balanced
against the necessity of wetland protection.
OVERVIEW
The protection of wetlands is an issue of
national concern. Of primary concern is how to
mitigate for wetland losses. Few cost-effective
opportunities exist to restore and create wetlands,
thereby helping to reverse the trend in wetlands
loss and perhaps create an increase. Surface
mining, which historically has had substantial
negative impacts upon the landscape, may offer
some realistic and inexpensive mitigation
options, if mitigation plans are integrated into
mine reclamation plans at an early stage. To
help guide those who make day-to-day decisions
about wetland mitigation, this review provides a
summary of the methods used to create and
restore wetlands and waterbodies during mine
reclamation. The recommendations presented at
the end of this review can serve as a checklist to
help ensure that constructed wetland systems
function properly.
This review focuses on surface mining for
coal, phosphate, and sand and gravel. It must be
recognized that mining of these materials will
continue in the U.S. into the foreseeable future.
Coal is an essential component of electrical
energy production, the fertilizer and chemical
industries depend heavily on phosphate rock, and
the construction industry requires continued
access to sand and gravel reserves. Therefore,
mitigation decisions should be based on
consensus agreement among knowledgeable
individuals who are familiar with both mining
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operations and wetland trends in the particular
physiographic region in question.
The principles pertaining to these three
extractable materials will, of course, have a
bearing on other types of mining and severe
landscape disturbances (e.g., placer mining;
hydraulic mining and in-stream dredge
mining; open pit mining and sand mining for
metal ores, limestone and other rocks; peat
extraction). Important literature on wetland
mitigation from other types of mining is cited
where it is relevant to the discussion. The
extraction of peat differs markedly from
mineral mining, and is beyond the scope of this
review. Readers are referred to the following
publications regarding peatland values, impacts
and mitigation (Carpenter and Farmer 1981,
Minnesota Department of Natural Resources
1981, Damman and French 1987).
The impacts of surface mining activities on
wetlands and waterbodies have been
well-documented (Darnell 1976, Cardamone et al.
1984). They differ depending on the material
extracted, the methods used, and regional
differences in topography, geology, soils, and
climate. Even if it is assumed that reclamation
is performed according to current regulations,
mining will have significant effects upon the
environment. In addition to the direct removal
and filling of wetlands, the removal of soil and
overburden severely alters local topography.
This in turn disrupts local and regional
groundwater and surface water flow patterns.
Mining activities typically result in a decrease
in groundwater tables and an increase in
surface water runoff, both of which significantly
affect the restoration and creation of aquatic
systems. The removal of vegetation and
disturbance of land surfaces increases
sedimentation rates, with resultant increases in
water turbidity. Access roads cause erosion in
steep terrain, and can block the flow of water in
areas of low relief, resulting in the formation of
ponds. Exposed coal mine spoils readily oxidize,
causing pollution problems such as acidic mine
drainage. There are increases in the formation
and deposition of materials, such as iron,
manganese, aluminum, and sulfur, sometimes
in amounts toxic to biota. Tailings from metal
mines also can produce biologically-toxic
discharges. Sedimentation rather than metal
toxicity is a major problem associated with
phosphate and sand and gravel mining.
In summary, habitat loss, chronic
environmental stress, and toxic levels of
pollution can occur during the mining process,
especially if reclamation practices are poorly
implemented (Darnell 1976). Any efforts to
encourage wetland and waterbody creation on
mined lands, whether to mitigate for losses
attributable directly to mining, or as a means of
increasing wetland area, should be cognizant of
mining impacts on surficial and groundwater
hydrology as outlined above.
Ten years have passed since the Surface
Mining Control and Reclamation Act of 1977
(SMCRA, P.L. 95-87) was enacted. This federal
act, coupled with the appropriate state statutes, has
halted many of the past environmental abuses
associated with surface mining, particularly
with respect to the mining of coal. Although
viewed as among the most encompassing and
detailed pieces of environmental legislation, the
Act often relies on vague notions, such as
"higher and better uses" to guide decision-
makers about reclamation strategies (Wyngaard
1985). Thus, the overall success of this law must
be tempered by an examination of the relatively
sterile landscapes that are often created under
the guise of reclamation. Wetlands and
waterbodies are allowed under existing
regulations, but provisions are strict, and
anything but encouraging. Decades of
pre-SMCRA experience with polluted waters have
resulted in cautious approaches to managing
water on mined lands. Permanent
impoundments are allowed under SMCRA
guidelines, but "are prohibited unless authorized
by the regulatory authority" (Sec. 816.49a). Thus,
unless variances are sought, it is often viewed as
less expensive to remove an impoundment or wet
depression rather than to develop plans to leave it
in place (Grandt 1981).
The Experimental Practices section of
SMCRA (Sec. 711) produces the same result.
Virtually any innovative reclamation technique
can be tried if the operator is willing to justify
the practice to state and federal regulatory
authorities (Thompson 1984). This additional
effort is often perceived as adding expense to a
project, but overall costs may actually be reduced
if permanent wetlands or waterbodies are left in
place (Fowler and Turner 1981). The net result
of these regulatory stumbling blocks has been to
discourage the intentional creation of wetlands
on surface mined lands (e.g., Gleich 1985) unless
they are either demanded by an informed
landowner, or based on in-kind replacement of a
wetland that has been lost or degraded during
mining. The vast majority of wetlands and
waterbodies on mined lands exist not because of
astute planning, but by accident.
Mining and related activities have disturbed
less than 0.2% of the land mass of the U.S.
(Schaller and Button 1978), yet in mining
regions, disturbances can exceed 20% of a given
land area (e.g., coal mining in Clearfield
County, Pennsylvania; phosphate mining in
Polk County, Florida). Coal reserves occupy
large areas in selected regions of the U.S. (Fig.
1). Phosphate deposits, although large in area,
occur only in a few regions. Wetland mitigation
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MAJOR COAL RESERVES OF THE UNITED STATES
Amhrecto
Bhumirtoui Coal
Subbtauninou* Cod
Ugnitt
0
I-
0
500 US
_____ I
1000 AK
km
Figure 1. Major coal reserves of the continental United States and Alaska (modified from Energy
Information Service 1984).
issues related to phosphate mining occur
primarily in Florida (Fig. 2). Sand and gravel
deposits are dispersed throughout the U.S.
Mining activity has not always resulted in a
net decrease in wetlands. The gain in
open-water, palustrine wetlands nationwide
during the 1950's to the 1970's (Frayer et al. 1983)
is apparent in land use surveys of mined lands.
Brooks and Hill (1987) reported that mined lands
in Pennsylvania supported 18% more palustrine
wetlands than unmined lands, primarily
because of a 270% gain in permanent, open
water wetlands in the glaciated coal region of
the state. Conversely, Hayes et al. (1984) observed
a reduction in the number of impoundments,
particularly shallow, vegetated waterbodies,
following passage of SMCRA in 1977. Palustrine
vegetated wetlands are often converted to
open-water wetlands, which may result in a
significant change in regional wetland types
(Tiner and Finn 1986, Brooks and Hill 1987).
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N
PHOSPHATE RESERVES |
OF FLORIDA
Figure 2. Major phosphate reserves of Florida (modified from Florida Defenders of the
Environment 1984).
120
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Before examining specifically how wetlands
and waterbodies have been restored and created
on mined lands, it is useful to discuss the
characteristics and functions of volunteer
wetlands, which are much more abundant than
those purposefully designed. As mining practices
differ, so do the types of aquatic environments
left behind. The following will profile the
inadvertent creation of aquatic environments by
past mining and reclamation practices.
SURFACE MINING FOR COAL
Based on a survey of the literature, the
following types of wetlands (listed approximately
in order of declining numerical abundance) are
commonly found on coal-mined lands: 1)
sediment basins; 2) shallow wet depressions and
emergent marshes; 3) moss-dominated springs
and seeps; 4) final-cut and other deep lakes; 5)
intermittent streams; and 6) slurry ponds and
other coal refuse disposal areas.
During surface mine reclamation for coal,
wetlands and waterbodies are created
intentionally for erosion and sedimentation
control as sediment basins. Basin size is
determined by the anticipated runoff for a mine
site and thus, is a function of the area of land
disturbed. Sediment basins are usually <0.5 ha
in size (Brooks and Hill 1987); often only 0.1 ha
(Fowler and Turner 1981). They are
geometrically shaped (i.e., circular, oval,
rectangular), and have steep slopes (usually
>30°), and flat bottoms. Volunteer palustrine
wetlands also occur as a function of local
changes in hydrology following reclamation.
These include moss-dominated springs and
seeps, persistent and non-persistent emergent
marshes, and shallow wet depressions (similar
to the prairie potholes of the northcentral
U.S. (Cole 1986).
Before the advent of reclamation legislation,
final-cut lakes were left inadvertently when the
final excavation was not back-filled. Char-
acteristics of these lacustrine waterbodies vary
considerably, but they are often linear in shape,
large (1-50 ha), deep (2-30 m), and have poorly
developed littoral zones (Jones et al 1985a, Hill
1986). Other deep water bodies are formed after
pits are excavated in regions with water tables
near the surface. Lakes of varying shape and
size have formed in this manner in glaciated
regions of Pennsylvania (Brooks and Hill 1987),
and several midwestern states (Jones et al. 1985b,
Klimstra and Nawrot 1982); 6,000 ha of these
lakes exist in Illinois (Coss et al. 1985) and 3,600
ha in Ohio (Glesne and Suprenant 1979) (Fig. 1).
After coal is processed, coal fines and
associated particles are discharged into
basins known as slurry ponds. The usual
reclamation procedure for these typically acidic
disposal areas is to cover them with at least 1.3 m
of topsoil. However, a variety of vascular
hydrophytes will colonize slurry ponds, thus
establishing emergent wetlands (Nawrot 1985)
(Fig. 3).
Although a discussion of streams and rivers
is beyond the scope of this review, intermittent
streams containing emergent vegetation are also
fairly common, and therefore, constitute another
wetland type. Relocation and restoration of
major streams is discussed in another chapter of
this document (see Jensen and Platts).
A variety of ecological functions and
economic uses have been documented for the
types of wetlands listed above, including wildlife
and fisheries habitat, agricultural and
recreational activities, sediment retention,
treatment of acidic mine drainage, and public
water supplies.
Sediment basins provide for uses beyond
their intended purpose. They provide habitat for
a variety of vertebrate taxa, including birds
(Burley and Hopkins 1984, Sponsler et al. 1984,
Brooks et al. 1985a), mammals (Brooks et al
1985a), and herpetofauna (Fowler and Turner
1981, Brooks et al. 1985a). A diverse
macroinvertebrate community also has been
identified with sediment basins (Hepp 1987).
Mine lakes are known to produce excellent
fisheries (Jones et al. 1985b, Mannz 1985), in part
due to adequate primary production (Brenner et
al. 1985) and macroinvertebrate production
(Jones et al. 1985a). They can serve as foci for
recreational activities such as fishing, boating,
and waterfowl hunting (Klimstra et al. 1985).
Other uses, particularly in the Midwest, include
lake-side housing and community open spaces,
crop irrigation and livestock watering, and
water supplies for homes, fire protection, and
industrial purposes (Glazier et al. 1981).
Vegetated wetlands dominated by either
vascular or non-vascular species can effectively
sequester some of the constituent of mine
drainage. Observations on the removal of metals
by naturally occurring Sphagnum moss (e.g.,
Wieder and Lang 1986) has led to further investi-
gations of how mosses, algae and macrophytes
with their associated bacteria, can be used to
ameliorate the effects of mine drainage (see
Girts and Kleinmann 1986 for a review).
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Figure 3. Seasonally inundated zone of a wetland created on coal slurry in Indiana showing four
years 01 growth. (Courtesy of Jack Nawrot, Cooperative Wildlife " " * "
Southern Illinois TT '
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SURFACE MINING FOR PHOSPHATE
Primary phosphate deposits in the U.S. occur
in Florida, Tennessee, South Carolina, and the
Phosphoria Formation of Montana, Wyoming,
Idaho and Utah. However, surface mining
activities affecting wetlands occur almost
exclusively in Florida, where wetlands typically
comprise 8-17% of the landscape area (Florida
Defenders of the Environment 1984) (Fig. 2).
The principal focus of reclamation in Florida
has been on mitigating for wetland losses.
Substantial progress in developing restoration
and creation technology has been made through
the combined efforts of the phosphate industry
and state regulatory agencies. Florida provides
an example of how regulatory pressures can
accelerate a desired technology if the pressures
are firmly and reasonably applied.
Reclamation of phosphate mines in Florida
was voluntary until 1975, when the Department of
Natural Resources developed regulations
(Florida Administrative Code Section 16C-16,
16C-17) in response to legislation (Florida Statute
211.32, 370.021). Due to extraordinary residential
and commercial development, there have been
increasing efforts to push reclamation
technology toward the goal of replicating
original wetland conditions as a provision of
mining. Public pressure combined with a flat
topography suitable for wetland establishment
and awareness of wetland functions and values
has led to sophisticated efforts to restore and
create complex wetland systems.
Historically, the removal of phosphate ore by
draglines produced mounds of sand tailings
interspersed among waterbodies and clay
settling ponds. Many of these waterbodies were
used by wintering waterfowl that were attracted
by volunteering hydrophytes (e.g., Naias spp.).
Gradual filling of these waterbodies with clay
produced a successional trend from submergent
species, to emergents (e.g., cattail, Typha spp.),
and finally to shrubs (e.g., willow, Salix spp.)
(Clewell 1981). Wildlife use diminished during
this process (King et al. 1980). After 1975,
reclamation required regrading of the sand
tailings, and planting them to pasture. De-
pressions left from the removal of phosphate ore
fill with water, producing a mosaic of pastures
and lakes. Marion and O'Meara (1983) reported
that the reclamation laws had produced both
positive and negative effects on wildlife. One of
the positive impacts, was an increase in wetland
edge following reclamation.
Boody (1983) studied 12 reclaimed lakes, 6
classified as deep, and six that were considered
shallow. Deep lakes had a mean area or 59 ± 113
ha (range = 2-287 ha) with depths of 3-5 m.
Shallow lakes had a mean area of 9 ± 17 ha
(range = 2-30 ha) with depths of 2-3 m. The pH
was typically 5-7, but ranged from 4.2-9.3. Most
reclaimed lakes supported fewer species of fish
(mean = 10 i 6 species, range = 4-22) than the 4
natural lakes that were studied (mean = 18 +. 2
species, range = 16-20). Of the 29 fish species
collected, 27 were native and 2 were introduced
(Brice and Boody 1983).
Recent reclamation plans have included
littoral zones and periodically flooded areas as
part of the lake ecosystem. Freshwater emergent
marshes have been successfully established, and
to a lesser extent, forested wetlands have been
created (Haynes 1984).
The clay settling ponds, which usually
occupy >50% of a mine site, continue to pose
problems and are perceived negatively by the
public. Waste clays from the mining process are
suspended in a slurry and pumped into settling
ponds. Attention has been focused on de-watering
these ponds as rapidly as possible; typically
within 10 years. Although the ponds support
fewer plant species than natural wetlands, site
management in conjunction with planned
species introductions can create a heterogeneous
mix of wetland vegetation and open water
(Robertson 1983). Montalbano et al. (1978)
discussed the value of clay settling ponds as
wintering habitat for waterfowl (7 species
reported), and suggested that water level
manipulation would help create high inter-
spersion of emergents and open water. Haynes
(1984) believes that these settling ponds may have
substantial positive values, and thus should be
manipulated and managed as productive
wetlands. The settling ponds are large (81-405
ha) and are currently increasing at a rate of
1,000 ha/yr beyond the 30,000-f ha already present.
Several authors advocate a drainage basin
approach for mitigating wetland losses in the
phosphate region, so that areas beyond the
individual mining unit are considered in the
planning process (Breedlove and Dennis 1983),
although Fletcher (1986) believes that the current
knowledge is only suitable for restoration of
small drainage basins.
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SURFACE MINING FOR SAND AND GRAVEL
Sand and gravel is defined as
unconsolidated mineral and rock particles.
Generally the particles have been transported by
water, and therefore, many deposits still occur in
and around waterbodies. Inland deposits are
typically classified as fluvial, glacial or
alluvial depending on their origin.
Sand and gravel is vital to the construction
industry. Excavation is the chief method of
removal, and 18% of the lands disturbed by
mining are for sand and gravel. Sand and
gravel operations are regulated primarily
through state laws. Demand continues to
increase, with deposits near urban areas in
highest demand. More excavation can be
expected in nearly every state in the U.S.
(National Research Council 1980). Concurrently,
opportunities for restoration and creation of
wetlands on reclaimed sand and gravel sites
will also increase.
Although waterbodies that remain following
sand and gravel mining have been used for a
variety of purposes, reclamation plans have often
lacked advanced planning and imagination
(McRae 1986). Fishing, boating, and wildlife
observation commonly take place in water-filled
sand and gravel pits in both the U.S. and Great
Britain (Koopman 1982, McRae 1986, respec-
tively).
Lomax (1982) found that reclaimed lakes in
the southern coastal plain of New Jersey were
colonized first by emergents (e.g., Tvpha spp.,
Cvperus spp., Juncus spp., Scirpus spp.), and then
by woody vegetation such as black willow (Salix
nigra). red maple (Acer rubrum). and black
tupelo (Nvssa svlvatica). Occasionally, bog-like
communities developed in pits <1 ha in area.
Lomax recorded use by 194 species of vertebrates
over a 16-year period. Gallagher (1982) found
that the Delta Ponds of Eugene, Oregon became
completely revegetated through volunteer
colonization. Species found included cattail,
pondweed (Potamageton spp.), willow, and alder
(Alnus spp.). Birds (78 species), mammals, and
fish were observed using the 65-ha area.
Street (1982) reported on the gravel-pits of
Great Britain. Pits ranged in size from 1-100 ha,
and were 3-30 m deep. Most had steep sides and
flat bottoms. A restoration project was initiated
at the gravel-pit complex of the A.R.C. Wildfowl
Centre in Great Britain in 1972, and has
developed into a highly productive 37-ha wetland
system. Waterfowl density within the managed
site ranged between 2.4 to 38.7 birds/ha, whereas
avian density on unmanaged gravel pits did not
exceed 2.8 birds/ha. By manipulating basin
morphometry, plant communities, and the
availability of organic matter, both vertebrate
and invertebrate numbers and diversity were
increased.
RECOMMENDATIONS FOR RESTORATION AND CREATION
WETLANDS AND WATERBODIES ON MINED LANDS
There have been recent efforts to stimulate
the restoration and creation of wetlands on
mined lands (e.g., Klimstra and Nawrot 1982,
Brooks 1984, Brenner 1986, Brooks 1986, Haynes
1986, McRae 1986). Sufficient recommendations
exist to provide guidance for wetland mitigation
on mined lands. Due to procedural and regional
differences in mining coal, phosphate, and sand
and gravel, the recommendations will be
discussed under separate headings below.
One cannot incorporate all possible
mitigation into a single wetland project. It is
best to work within clearly stated objectives that
are tied to specific wetland functions. Only then
can the wetland be designed optimally with
respect to the desired objectives. There may be
conflicts among objectives which should be
resolved in the planning process (e.g., public
water supply vs. ecological productivity,
recreational fishery vs. habitat for diverse
amphibian community). Whenever possible,
pre-mining conditions and regional reference
wetlands should be used as guides to how a
wetland ought to be created or restored.
WETLANDS AND WATERBODIES ON
COAL MINED LANDS
Basin Morphomfitrv
Area-
The area covered by a wetland or waterbody
is constrained both by objective and site location.
Peltz and Maughan (1978) suggested that several
ponds of small size (0.25-1.0 ha) were preferred to
a few large ones with regard to fish production;
0.1 ha being the minimum recommended size.
Sandusky (1978) found that some species of
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waterfowl (e.g., blue-winged teal, Anas discors)
nested on ponds as small as 0.04-0.2 ha. Hudson
(1983) recommended pond areas >0.5 ha for
waterfowl production in stock ponds, as did
Allaire (1979) for wildlife in general. Based on
an inventory of 35 existing wetlands on mined
lands in Pennsylvania, Hill (1986)
recommended areas of 1-3 ha to maximize
wildlife diversity. For natural habitats, bird
species richness has been found to increase with
wetland area, but to level off for areas >4 ha
(Williams 1985). As sediment ponds are
typically less than 0.5 ha in area, a slight
increase in pond size, while still maintaining a
diversity of sizes, would seem to meet multiple
objectives.
Mine lakes can be as large as the
remaining mined pit or depression. Lakes
exceeding 10 ha are not uncommon (Jones et al.
1985a), Glazier et al. (1981), Nelson (1982), and
Doxtater (1985) provide scenarios for planning
multiple-uses of large, deep-water lakes.
Depth-
The need for water permanence will
determine the appropriate depth of a given
wetland or waterbody. Again, project objectives
coupled with mining operations will influence
the eventual depth characteristics of the wetland.
It is important to remember that deep water lakes
will tend to be either mesotrophic or oligotrophic,
whereas shallow waterbodies and vegetated
wetlands usually have higher primary
productivity, tending toward eutrophic
conditions.
To enhance year round survival for fish,
Peltz and Maughan (1978) recommended depths
of 2-3 m for ponds with groundwater sources, and
>5 m for ponds supplied by surface runoff alone.
Although water depth in excess of 3 m may be
desirable for fish survival, retention of flood
waters, as a water supply reservoir, and for some
recreational activities, most investigators have
stressed the need for construction of an extensive
littoral zone. Many species of sport fish require
depths of 0.5-2.0 m for spawning (Peltz and
Maughan 1978, Leedy 1981). Some submergent
hydrophytes grow better in depths >0.5 m (e.g.,
Potomageton spp., Chara spp.). The regulatory
guidelines of SMCRA require stability of water
levels in impoundments, but this may not be
feasible or desirable for many wetlands.
Colonization by emergent hydrophytes requires
fluctuating water levels. Cole (1986) found that
water volume, and hence depth, varied by >40%
in five ponds on mined land in Illinois. These
changes in water level exposed the littoral zone
much like the wetlands of the Prairie Pothole
region further west. Fluctuating water depths of
<0.5 m are recommended to promote the growth of
emergent hydrophytes, which in turn encourage
macroinvertebrate production in the littoral zone.
Slope-
Whereas a shelf 1 m in depth may benefit
aquatic species such as fish, other species benefit
from slopes that grade gently from upland to
wetland, A wetland basin that has a variety of
slopes, ranging from <5° to almost 90° will
benefit a diversity of wildlife species and provide
visual variety. The majority of the shoreline
should have gentle slopes. Amphibians, reptiles,
and some fishes require gentle slopes, typically
<15°. Sand and mud flats used by foraging
shorebirds should have slopes of <5°. Access
areas for swimming and boating also require
gently sloping terrain. Some species will benefit
from steeply sloped or overhung banks,
including burrow-dwelling muskrats (Ondatra
zibethicus. Brooks and Dodge 1986), belted
kingfisher (Cerle alcyon. Brooks and Davis
1987), swallows, cliff-nesting raptors, and some
fishes.
Shape-
The shorelines of wetlands and waterbodies
should be convoluted to produce an irregular
shape (Brooks 1984). Basins with a high
shoreline development index (i.e., length of
shoreline divided by the circumference of a
circle of equal area, Wetzel 1975) provide more
edge for wildlife, and reduce wind and wave
action on larger waterbodies (Coss et al. 1985).
Coves, peninsulas, and islands contribute
substantially to shoreline development (Leedy
and Franklin 1981, Brooks 1984). Islands ( >3 m
in diameter, Emerick 1985) and even large rocks
(0.5-1.5 m in diameter, O'Leary et al. 1984)
provide nesting and resting places for many
species of waterfowl and shorebirds. Ir-
regularities in basin shape tend to disperse water
flows thus helping to maximize retention time in
the basin if flood control or water treatment are
desirable characteristics of the wetland.
Soils-
It is important to consider both hydric soils
within a wetland and the soils of adjacent
uplands. Proper management of upland soils
will protect aquatic systems from unnecessary
sediment, chemical, and thermal pollution
(Rogowski 1978, Leedy 1981).
Upland Soils--
During reclamation of mined land it is
preferable to have topsoil cover the overburden to
protect and conserve the available water and
provide a better medium for plant growth.
Vegetated topsoil will reduce evaporation, allow
more infiltration into groundwater supplies,
produce temporary ponds in depressions, and
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reduce peak infiltration rates that lead to
abnormal fluctuations in the water table and
droughty surface conditions (Rogowski 1978).
The ability of a soil to retain water is dependent
on its texture (i.e., sand is more droughty than
clay), depth, the content of organic matter, and
the distribution of pore size (Schaller and Sutton
1978). Thus, a careful study of soil conditions
will enhance the probability of successful
restoration and creation of wetlands, and the
reclamation of upland areas.
Sediment yields from exposed soils are
typically highest in the first 6 months after
regrading, and are halved in subsequent
6-month periods as the site progressively
revegetates (Schaller and Sutton 1978). Silts and
sediments that enter waterbodies tend to reduce
light transmission (and hence, photosynthesis),
raise water temperature, and cover sensitive
organisms (Leedy 1981). Thus, it is important to
revegetate exposed soils as rapidly as possible to
avoid interfering with wetland establishment.
Based on the reclamation literature for
upland portions of mined sites, several
recommendations can be made to protect aquatic
systems from upland runoff. Exposed soils must
be seeded, fertilized, and mulched as soon as
possible. Rafaill and Vogel (1978) recommended
60 Ibs/acre (67 kg/ha) of nitrogen and 100
Ibs/acre (112 kg/ha) of phosphorus, but no
potassium for reclaiming mined land in
Appalachia. In acidic areas, soil should be
limed to a pH of at least 5.5. Use of high quality
seeds is advised (i.e., high germination and
purity percentages, McGee and Harper 1986).
Seeds and fertilizer should be applied first,
followed by an appropriate mulch to avoid
perching seeds above the ground's surface
(Schaller and Sutton 1978). Straw and hay were
suggested as the best mulch to use, particularly if
applied by a mulch blower that cuts, shreds, and
evenly spreads the material. Estimated costs for
purchase and application of straw were
$100-200/ton (909 kg) with an application rate of
1-2 tons/acre (2,245-4,490 kg/ha), whereas nets
and mats may cost > $l,500/acre ($3,700/ha),
especially on steep slopes (Mining and
Reclamation Council of America and Hess and
Fisher Engineers 1985). Advice for selecting the
appropriate plant species, and seeding,
fertilizing, and liming rates for a given soil type
are generally available from mining agencies
(e.g., Office of Surface Mining, U.S. Bureau of
Mines, state mining agencies) and county
offices of the Soil Conservation Service.
Vegetative buffers should be installed
around wetland basins. Although recom-
mendations for buffer widths range from
1-300 m, vegetated strips as narrow as 15-20 m
can remove 50-75% of the sediments (Barfield
and Albrecht 1982). Whenever appropriate for a
given region, buffers should include shrub and
forested zones. Gilliam (1985) studied unmined
agricultural areas in North Carolina and found
that wooded buffers about 100 m wide removed
>50% of the sediment, including much of the
nitrogen and phosphorus. In addition to serving
a water quality function, vegetative buffers can
act as travel corridors and refugia for wildlife,
thereby reducing the isolation of the wetland. If
desired, wetland edges can be shaded by planting
properly oriented tree species that will grow to a
height of twice the distance to the water (Leedy
1981).
In severe cases of upland runoff, structural
diversions may be necessary to divert
sediment-laden waters. Diversion ditches,
concave depressions, and sediment traps are
some of the techniques available. Mining
agencies, the Soil Conservation Service, or
experienced consultants can provide the expertise
needed to design these systems.
Hydric Soils--
Hydric soils, or those previously saturated,
usually must be constructed, unless soil is
available from a wetland scheduled to be altered
or removed. Routine cleaning of roadside
ditches or other wet depressions can also act as a
source of hydric soil, although pollutants such as
road salt, oil, or lead may be present in
substantial quantities. Hydric soils should be
stockpiled, preferably for less than one month,
and then spread to the desired thickness in
newly constructed basins. These soils typically
have a relatively high organic matter content,
and often act as a seed source or seed bank.
Longer storage periods will result in desiccation
of plant materials, and possibly re-oxidation of
metals and other potentially damaging
materials.
When existing hydric soils are not available,
they can be constructed by using a relatively
fertile topsoil. Good plant survivorship and seed
germination rates have been obtained by mixing
about 30% (by volume) livestock manure in with
the topsoil to act as a source or organic matter
and nitrogen (Brooks, unpublished). Small
quantities of superphosphate were added to the
soil around each planted propagule. Chemical
fertilizers have been recommended as an
additive to ponds and lakes designed for fish
production; 12-12-12 or 8-8-2 (nitrogen-
phosphorous-potassium; Glesne and Surprenant
1979, Leedy 1981, respectively). Leedy (1981)
suggested that no more than 200kg/ha of 8-8-2
fertilizer be added at one time, although
application rates for infertile waters might
exceed 1,500 kg/ha/yr.
Whenever possible, soil tests should be made
to provide more accurate estimates of fertilizer
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and lime additions for both hydric, and adjacent
upland soils depending on the plant species
desired and the intended use of the wetland or
waterbody. Basins constructed on mined lands
often contain acidic soils. Assuming that a
circumneutral pH is desired (although some
wetland plants require acidic or alkaline
conditions), the pH of the bottom soils should be
raised to about 6.5 using lime (Peltz and
Maughan 1978). If the pH of the soil is less than
5.5, then at least 1,000 kg/ha of lime is probably
needed (Leedy 1981). Slurry ponds with acidic
soils require more alkaline additions to promote
growth of hydrophytes; >20,000 kg/ha of
limestone (Nawrot 1985). Warburton et al. (1985)
reported improved growth rates for bulrushes
(Scirpus spp.) with addition of slow-release
fertilizer tablets (22-8-2) to each propagule. If
acidophilic plants occur naturally on the site or
their presence is a desired objective of
reclamation, then it may not be necessary to
adjust pH. The presence of certain species of
moss and algae in springs and seeps is a good
indicator of waters with low pH and usually low
concentrations of nutrients (Brooks, un-
published).
Basins constructed below the water table
rarely need to be sealed, whereas perched
wetlands need a water-conserving layer of
material on the bottom and sides of the basin.
Clay is commonly used in this manner and
should be compacted to a thickness of about 30 cm
(Soil Conservation Service 1979). Bentonite, and
synthetic membranes can also serve as sealants.
Specifications for a specific soil type and climate
are generally available from county offices of
the Soil Conservation Service or mining
agencies.
Vegetation
Studies of existing wetlands have shown
that a diversity of hydrophytes will volunteer
over time. Cattail (Typha latifolia) is by far the
most successful vascular hydrophyte on mined
lands. Cattail, soft rush (Juncus effusus). and
woolgrass (Scirpus cyperinus) were the first
invaders of four wetland basins in central
Pennsylvania; all were present within 1-1.5
years of regrading (Hepp 1987). Twelve species of
vascular plants had volunteered on one site after
6 years. Fowler et al. (1985) found that cattail,
soft rush, and spike rush (Eleocharis obtusa)
rapidly invaded sediment ponds in Tennessee;
10 species were eventually present. Coss et al.
(1985) found 14 species of vascular hydrophytes
growing in four lake complexes in Illinois. The
lake with the greatest hydrophyte diversity had 7
species.
After volunteer macrophytes were observed
on slurry ponds in southern Illinois (e.g.,
reedgrass (Phragmites australis)f a planting
program was started in that has led to
revegetation of more than 200 ha of wetlands on
12 sites (Nawrot 1985). Investigators found that
perennial rootstocks of hardstem bulrush
(Scirpus acutus). three-square (S. americana).
and prairie cordgrass (Spartina pectinata) were
more dependable than seed because sub-surface
conditions were more amenable to plant
establishment than surface conditions. Root-
stocks were collected at a rate of 75-100
propagules/man-hour, and hand-planted with
bars and shovels. Collection of propagules in
early spring is preferred over autumn collection.
Spacing was on 0.3-1.5 m centers, and each
propagule was planted in 5-13 cm of soil,
depending on the species. They recommended a
water-level control structure to assure adequate
control over seasonally variable water levels.
Plants collected locally under similar conditions
had better survival rates than commercially
available stock. Whenever possible, local
planting stock should be used.
We have constructed smaller wetlands,
designed specifically for treating acidic mine
drainage (Brooks, unpublished). Cattail
rhizomes were collected from existing sediment
basins at a rate of 50-100/man-hour, and planted
at a rate >100/man-hour. Multi-stemmed clumps
of sedges (Carex gyandra) and soft rush (20-cm
dia. plugs) were also collected. Both were planted
on 0.5-1.0 m centers. We had 75-80% survival of
these plants after one year. Costs for constructing
wetlands designed to treat mine drainage are
slightly less than $10/m2 ($l/ft2) (Girts and
Kleinmann 1986, Rightnour, pers. comm.),
including all planting and basin construction
costs.
There are several ways to enhance the
proliferation of aquatic vegetation if a decision
is made to encourage volunteer colonization.
The morphometry of the basin, as previously
discussed, must be suitable with respect to depth
and slope. The desired zones of vegetation can
be controlled by manipulating morphometric
variables. Emergent species will colonize the
littoral zone up to about 1 m in depth. Shrubs will
be restricted to very shallow or seasonally
flooded zones. By creating topographic diversity
within a site, there will be more opportunities for
a variety of species to successfully colonize.
Mitigated wetlands that have hydrologic
connections with natural wetlands or other
mitigated sites will be more likely to receive
plant propagules, either through wind, water, or
animal dispersal.
Fauna
Diverse vertebrate and invertebrate
communities have been found in wetlands and
waterbodies on coal surface mines. Brooks et al.
(1985a) reported that 125 vertebrate species were
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observed on 35 wetlands studied in western
Pennsylvania (86 birds, 19 mammals, 11
reptiles, and 9 amphibians). The mean number
of vertebrates per wetland was 23 ± 12 (1 SE), with
a range of 7-60 species/wetland (Hill 1986). Hepp
(1987), in a more intensive study on four
wetlands in the same region, reported use by 90
vertebrate species (64 birds, 15 mammals, 3
reptiles, and 8 amphibians) and more than 39
invertebrate taxa. O'Leary et al. (1984) observed
76 avian species, including 18 species of
waterfowl, and 10 mammalian species on 47
wetlands in southwestern Illinois. Also in
Illinois, Coss et al. (1985) studied four mined
lake complexes and found 89 vertebrate species.
In nine sediment ponds in Tennessee, Fowler et
al. (1985) reported use by 61 invertebrate taxa, 6
fish species, and 12 amphibian species. Jones et
al. (1985a), in a study of 33 mine lakes in
Illinois and Missouri, identified almost 200
invertebrate taxa and 33 fish species. Nineteen
species of fish were collected from one 86-ha
mine lake in Illinois (Jones et al. I985b).
With the exception of fish species and some
invertebrate taxa (e.g., Mollusca), most species
voluntarily colonize surface mine wetlands.
Some invertebrates can be introduced by water
birds as larvae attached to feet and feathers.
Fish are also introduced by local anglers. If
wetlands are hydrologically connected with other
reclaimed or natural systems, the opportunities
for rapid colonization are greatly improved. If
wetlands are juxtaposed to a variety of upland
habitats that provide shelter and travel corridors,
colonization rates and numbers probably will be
greater. Hepp (1987) reported rapid colonization
rates (within 3 years of final grading) for both
invertebrate (e.g., dipterans, coleopterans,
hemipterans) and vertebrate (e.g., amphibians,
some small mammals, and many birds) species,
followed by a period of stabilization in com-
munity structure. Pentecost and Stupka (1979)
found that common amphibian species invaded
sediment ponds within one month of formation;
founder populations were located 100 m away.
Artificial structures and substrates can be
introduced to supplement existing shelter, such
as nest boxes for cavity nesters and artificial
reefs for fish and invertebrates. As with flora,
wetlands designed with specific objectives will
provide suitable habitat for the desired species,
whether fish, waterfowl, or a diversity of faunal
groups.
WETLANDS AND WATERBODDZS ON
PHOSPHATE MINED LANDS
Basin Morphometrv
The same parameters discussed for coal
mined lands are equally important for phosphate
areas (e.g., area, depth, slope, shape). A major
difference exists for the Florida landscape,
however, because of its low relief. To
accommodate the sheet flow of water over flat
lands and to match the adaptions of plant species
to subtle changes in elevation, the slopes of basin
banks and bottoms need to be carefully
established. In addition, hydroperiod variations
between wet and dry seasons must be considered
in project design. Wetland systems must be
capable of storing large quantities of water
during the wet season. This can be accomplished
by designing wetlands of sufficient size. During
the dry season, when the water table drops below
the land surface, there must be enough deep
depressions to harbor aquatic organisms, such as
fish, amphibians, and invertebrates (King et al.
1985). Depressions should be at least 2 m below
the high water marks to maintain aquatic habitat
during droughts (King et al. 1985). Reduced
slopes (<3%) will allow the development of wide
soil moisture zones. This will provide a wider
tolerance zone for many species of wetland
vegetation and compensate for environmental
disturbances, such as drought, fluctuating water
tables, and fire. Conversely, steeper slopes result
in narrow moisture zones that leave little room
for error in predicting the eventual composition
of the floral community.
Soils
Soils of the central phosphate region in
Florida are typically circumneutral and quite
fertile due to the abundance of phosphorus and
calcium, although potassium may be limiting
(Clewell 1981). Phosphate deposits further north
may be more acidic and less fertile. Soils being
prepared for the establishment of wetlands are
usually regraded to the proper elevation and
conformation using the sand tailings.
Additional overburden, if available, can then be
added up to a depth of 30 cm (Erwin 1985).
Numerous studies have shown that the addition
of wetland topsoil (i.e., mulch, organic muck)
from natural wetlands scheduled for mining
greatly enhances the chances for successful
reclamation (Clewell 1981, Dunn and Best 1983,
Erwin 1985). "Topsoiling" or "mulching" can
provide a variety of propagules (e.g., seeds, roots,
rhizomes) from native plant species that result in
a more natural vegetative community at the
exclusion of weed species.
Vegetation
Wetland restoration efforts in the Florida
phosphate region have focused on the
establishment of three major types of wetland
communities: open water, emergent marshes,
and forested wetlands. Open water areas are
primarily a function of water depth and need not
be discussed further. The two types of vegetative
communities will be discussed separately. The
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techniques developed have been influenced by
regulations that require rapid revegetation
(within one year) and the creation of a
self-sustaining community.
Emergent Marshes--
Techniques used to establish herbaceous
hydrophytes include: 1) transplanting from
natural wetlands; 2) application of hydric topsoil
from natural wetlands; and 3) reliance on
voluntary establishment. Florida allows licensed
individuals to remove native species from
natural wetlands for the purpose of mitigation.
In addition, plants from wetlands scheduled for
mining can be transplanted to newly prepared
sites. However, the availability of plants from
natural wetlands may not always match the
timing of mitigation projects.
For the Agrico Swamp project in central
Florida (restoration of 61 ha of wetland on a 148
ha project site) Erwin (1985) and Erwin and Best
(1985) reported that the application of wetland
topsoils resulted in the establishment of 41 plant
species in a restored marsh, whereas overburden
alone resulted in the establishment of only 26
species. The common species present included,
cattail (Tvpha latifolia). pickerelweed
(Pontederia cordata). rushes (Scirpus
californicus). dog fennel (Eupatorium
capillifolum). and arrowhead (Sagittaria
lanceolata). The topsoil areas contained both
perennial and annual species, whereas the
overburden areas contained primarily annuals.
The rapid establishment of late-successional
species, such as many perennials, either through
"topsoiling" or transplanting may help to
eliminate undesirable species such as cattail
(Erwin and Best 1985).
Volunteer plants contribute substantially to
restoration efforts in Florida. Certain factors
can increase the role of volunteers. When
natural communities are proximal to restored
sites, the likelihood of propagule dispersal is
enhanced. Hydrologic connections with streams
can also distribute the seeds and propagules of
desirable species. Self-sustaining seed banks
with their inherent benefits can become
established within 3 years if artificial planting
is done (Erwin 1985), and within 4-5 years if
based solely on volunteer species (Dunn and Best
1983).
Restoration of emergent marshes in Florida
is further enhanced if good quality planting
stock is used and if specific site preparation and
planting methods are properly applied (Haynes
1984). Several long-term monitoring studies of
wetland mitigation projects are underway in
Florida (e.g., Erwin 1985) which should
help determine how closely created match
natural conditions.
Forested Wetiands--
The slow growth of woody species prevents
rapid assessment of the success of creating
forested wetlands, but there are indications that
the techniques applied in Florida will be
successful. As part of the 61 ha of wetlands
created on the Agrico Swamp project site, 66,000
tree seedlings were planted. Twelve species were
represented. The most abundant species
included, cypress (Taxodium distichum).
Florida red maple (Acer floridium). loblolly bay
(Gordonia lasianthus), black gum (Nyss^
svlvatica). sweetgum (Liquidambar stvraciflua).
and Carolina ash (Fraxinus carolinia).
Seedlings were planted on about 2-m centers by
hand in the summer and fall of 1982.
Survivorship was 72% in 1982, 77% in 1983, 72%
in 1984, and dropped to 58% in 1985 following a
drought (Erwin 1985). Growth of some species
was apparently enhanced when water levels
during the wet season did not exceed 20 cm (Best
and Erwin 1984).
Gilbert et al. (1980) reported on the success of
planting 10,400 seedlings representing 16 species.
After the first year, survival was 85% for cypress
and green ash (Fraxinus pennsylvanica). 72%
for sweetgum, and 62% for red maple (Acer
rubrum).
Clewell (1981, 1983) also had tree seedling
survival in excess of 70% while creating a
riverine forested wetland in central Florida.
Mechanical planting of potted, nursery-grown
seedlings increased efficiency and enhanced
survival, but may not be feasible, depending
upon the substrate. Direct seeding may also be
possible, but germination and survival rates are
lower. Clewell (1983) suggested that enclaves of
saplings could be established through
transplanting to provide shade for shade-tolerant
species. A combination of seedlings, saplings,
topsoil, and natural colonization were
recommended.
Fauna
Studies of faunal communities on reclaimed
phosphate mines have been less common than
studies of vegetation. Erwin (1985) reported that
56-62 taxa of macroinvertebrates were collected
seasonally in open water, submergent, and
emergent wetland communities for an annual
total of 107 taxa. A total of 83 bird species were
recorded on the same 148 ha site. Use of clay
settling ponds by waterfowl and shorebirds has
also been reported (Montalbano et al. 1978). King
et al. (1985) provide extensive recommendations
for enhancing fish and wildlife habitat on both
wetland and upland mine sites in the phosphate
region. To maximize fish and wildlife diversity,
they suggest the creation of heterogeneous
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physical and vegetative habitats among a
diversity of aquatic systems.
WETLANDS AND
WATERBODEES ON SAND
AND GRAVEL MINES
As many of the recommendations discussed
for coal and phosphate mining apply to sand and
gravel, only those techniques that differ will be
included in this section. Mining of mineral
sands for rare metals (e.g., rutile, zircon) is a
unique type of sand mining. Although most
prevalent in Australian coastal zones, the
wetland restoration techniques developed by this
industry also warrant inclusion in this section
(e.g., Brooks 1987,1988).
Basin Morphometrv
Most authors recommend increasing the
area of wetland basins, and having a
heterogeneous shoreline. Slopes with a horizontal
to vertical ratio as gentle as 10:1 or 20:1 are
recommended to increase the zone widths of
plant communities (Street 1982, Crawford and
Rossiter 1982). Water-level control devices are
encouraged to allow optimal management of
vegetation.
Soils
The addition of topsoil to pit floors was
recommended where plant colonization is
desired (Crawford and Rossiter 1982). Leaving
some areas bare will meet the foraging
requirements of wading birds and shorebirds
(Lomax 1982), and the spawning needs of fish
(Herricks 1982). The bare zones should have a
variety of particle sizes as substrate to meet the
specific needs of various species. Compaction of
bottom material is an effective means to
discourage volunteer plant species. In newly
reclaimed sites, organic matter is often lacking,
so straw or hay can be added as food and
substrate for both plants and invertebrates; 1
kg/m2 of straw was suggested by Street (1982).
Nutrients are often lacking as well, so
fertilizing may be necessary. Stabilization of
upland banks and surrounds is also emphasized
to reduce erosion and sedimentation (Branch
1985).
Brooks (1987, 1988) identified three major
factors that enhanced the recovery of both
herbaceous and woody vegetation after mining
for mineral sands. First, basin morphometry
must be reclaimed properly to provide suitable
drainage patterns and water-level control.
Second, the use of drains before and after
mining under saturated conditions facilitated
the establishment of seedlings by avoiding
excessive drying or flooding. Drains were
removed once the plants adapted to the variable
water regime. Third, careful manipulation of
existing topsoil enhanced the survival of
propagules of native species. A
"double-stripping" method was used. The upper
20-25 cm was removed and stockpiled in large
lumps. A second layer that was 10-15 cm deep
was stockpiled separately. Topsoil layers were
returned in their original order after mining.
Storage time was usually 1-3 months. This
additional care later reduced planting costs
during reclamation. Other recommendations for
enhancing restoration of vegetation and fauna
were similar to those discussed for coal and
phosphate.
CONCLUSIONS AND RESEARCH NEEDS
There are examples throughout the U.S. and
other countries of innovative approaches to
successful restoration and creation of wetlands
during mine reclamation, however, specific
guidance applicable to different physiographic
regions is still needed. The recommendations
presented in this chapter should provide the basis
on which to build a mitigation plan for a specific
project. We are still in a rapid learning phase
in restoration technology, and thus, must be open
to new ideas and willing to experiment with
innovative methods.
Managers need to move away from easily
constructed geometric shapes and must attempt to
create landforms that mimic natural systems.
Overly engineered designs with specifications
that are difficult to meet are not appropriate
given the nature of biological systems and the
current level of understanding in restoration
technology. Designs and plans must be flexible
to allow room for error and unpredictable events.
Regulatory reform may be necessary to allow
this flexibility to occur.
One way to ensure that the proper
information is collected is to require mandatory
monitoring programs of all wetland mitigation
projects. It is suggested that a 3-year monitoring
period be part of the known costs to a permittee
before a project gets underway (e.g., Brooks and
Hughes 1987). Short-term monitoring of
individual sites coupled with a few long-term
research projects will enhance our ability to
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predict the outcome of mitigation policies. As
there is some scientific evidence for the
stabilization of emergent marsh systems after 3
years (e.g., Erwin 1985, Hepp 1987), a 3-year
period will allow evaluation of the project's
success after three growing seasons. Also, some
annual variability in climatic and growing
conditions can be assessed during this time
period. Finally, a modest 3-year monitoring
plan does not put an unbearable economic burden
on the permittee.
Long-term studies should seek to improve
our predictive capabilities regarding the
seasonal, annual, and successional variation
inherent in most wetland systems. How do
fluctuating water levels influence the
composition and abundance of floral and faunal
communities? What is an acceptable load of
pollutants for a wetland to absorb before
significant changes are observed in food webs
and the health of individual organisms?
A number of studies have used comparative
approaches to gain insight into how to replicate
the functions of natural wetlands. Pre-mining
and post-mining studies are valuable, as are
comparisons between natural and restored
systems, the latter being quite scarce (e.g.,
Brooks and Hughes 1987, Brooks 1988). Land
managers need to establish their mitigation
policies in the context of what changes are
occurring in wetland types throughout a given
physiographic region, not just on a particular
mine site. In some regions (e.g., glaciated)
wetland restoration has a greater chance for
success because of inherent water and soil
characteristics. Thus, what may work well for
one area, may fail in another.
Based on this survey of the literature, it
appears that the techniques appropriate to
restoration and creation of simple open water
and emergent marsh wetlands are fairly well
established. The success of shrub and forested
wetland projects, because of their slower rates of
succession, has been more difficult to assess, and
therefore, needs more attention. Questions
remain with regard to plant materials: Are the
proper propagules available? What is the best
mix of native and exotic species to use? How do
we balance the variable success of different
planting methods against economic realities?
How adept are we at predicting the successional
outcome of a newly restored wetland system?
Success criteria for wetland mitigation need
to be established. I do not believe, however, that
satisfactory criteria can be developed on a
national scale. Criteria necessarily vary with
the type of wetland being established (e.g., tidal
mud flats vs. freshwater emergent marshes vs.
evergreen forested swamps). They also vary with
the differential pressures placed on wetland
resources within a region. For some wetland
types, we may not yet know how to characterize
their hydrology or biotic diversity, let alone
satisfactorily replicate them.
At the current level of knowledge, it is
ludicrous to demand 100% replication of species
richness and abundance for all projects, but what
are the minimum standards for replacing
equivalent functions? Allowances must be made
for variable growth patterns among floral species
and for seasonally and annually fluctuating
hydrologic regimes. Naturally occurring
changes in wetland characteristics are
commonplace. How will these changes be
assessed, and then applied to a mitigation
project? As with many environmental
regulations, success criteria must evolve
incrementally as new information becomes
available. In time, a broad criterion such as
"establish locally-occurring plant species" will
be replaced by quantitative specifications for
designated species arranged in suitable patterns
on the landscape.
An interim solution is to establish regional
success criteria for major wetland classes
through consensus agreement among
knowledgeable individuals (e.g., academics,
regulatory scientists, industrial researchers,
professional consultants). These criteria should
be compatible with regional mitigation policies
that are established by even broader
representation from the community (i.e.,
planners, administrators, politicians, citizen's
groups, business and industry leaders). Dames
and Moore (1983) used a questionnaire sent to
phosphate mining companies to gather opinions
regarding success criteria for wetland
restoration projects. Combined with information
from regulatory authorities, this type of survey
could form the basis for establishing success
criteria for any physiographic region.
More attention must be placed on how to
decide among multiple objectives for a given
mitigation project. When are the utilitarian
functions of wetlands (e.g., water supply, water
treatment) to be substituted for in-kind
replications of natural systems? Numerous
authors suggested that planning and
decision-making by consensus among scientific,
industrial, regulatory, and citizen's groups is the
appropriate strategy for establishing mitigation
policy.
It needs to be mentioned that as wetland
restoration technology improves, the mining
industries will demand access to additional
reserves. Therefore, the rationale for a particular
mitigation strategy must have a sound, scientific
basis if we are to successfully balance the needs
of industry with the necessity of wetland
protection.
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RECOMMENDATIONS
PLANNING
1. Develop site-specific objectives that are
related to regional wetland trends. Check
for potential conflicts among the proposed
objectives.
2. Wetland mitigation should be integrated
with mining operations and reclamation
plans at the beginning of any project,
especially with regard to hydrologic plans
for the site.
3. Project planning and evaluation should
include input from trained professionals
and local constituencies.
4. Mitigation plans for single wetlands should
be related directly to the adjacent
waterbodies and uplands. Be cognizant of
regional trends and needs.
IMPLEMENTATION
1. Designs for wetlands should mimic natural
systems and provide flexibility for
unforeseen events.
2. The key elements to successful wetland
restoration and creation are basin morph-
ometry and hydrologic control. Assess these
parameters first before specifying re-
quirements for soil preparation or
establishment of floral and faunal
communities.
3. Varying the areas of the wetlands
and waterbodies constructed between 0.5-10
ha will meet the needs of many species, as
well as human users.
4. Bank slopes and basin bottoms should be
varied with emphasis on gentle slopes and
irregular bottoms unless dictated otherwise
by project objectives.
5. A heterogeneous shoreline is recommended to
increase habitat diversity. Extensive littoral
zones should be encouraged.
6. A capability to regulate the hydroperiod using
water-level control structures is highly
recommended.
7. The addition of upland or hydric topsoil
provides a good substrate for plant growth,
serves as a source for seeds and propagules,
and reduces moisture loss of exposed
substrates.
8. An integrated approach to establishing
vegetation that incorporates direct seeding,
transplanting, "topsoiling or mulching", and
natural colonization can increase plant
diversity and survivorship at a reasonable
cost.
9. Revegetate exposed substrates rapidly,
preferably with native species. Vegetative
buffers around wetlands and waterbodies are
essential.
10. Diverse vertebrate and invertebrate
communities will colonize newly restored
wetlands if basin morphometry and
vegetative communities are suitable.
LITERATURE CITED
Allaire, P.N. 1979. Coal mining reclamation in
Appalachia: low cost recommendations to improve
bird/wildlife habitat, p. 245-251. In G.A. Swanson
(Tech. Coord.), The Mitigation Symposium: A
National Workshop on Mitigating Losses of Fish and
Wildlife Habitats. Gen. Tech. Rep. RM-65, U.S. Dep.
Agric., For. Serv., Rocky Mt. For. Range Exp. Stn.,
Fort Collins, Colorado.
Barfield, B.J. and S.C. Albrecht. 1982. Use of a vegetative
filter zone to control fine-grained sediments from
surface mines, p. 481-490. In D.H. Graves (Ed.), Proc.
Symp. on Surface Mining Hydrol., Sedimentol., and
Reclam. University of Kentucky, Lexington.
Best, G.R. and K.L. Erwin. 1984. Effects of hydroperiod
on survival and growth of tree seedlings in a
phosphate surface-mined reclaimed wetland,
p. 221-225. In D.H. Graves (Ed.), Proc. Symp. on
Surface Mining Hydrol., Sedimentol., and Reclam.
University of Kentucky, Lexington.
Boody, O.C., IV. 1983. Physico-chemical analysis of
reclaimed and natural lakes in central Florida's
phosphate region, p. 339-358. In D.J. Robertson (Ed.),
Reclamation and the Phosphate Industry. Proc.
Symp. of Florida Inst. of Phosphate Res., Bartow,
Florida.
Branch, W.L. 1985. Design and construction of
replacement wetlands on land mined for sand and
gravel, p. 173-179. In R.P. Brooks, D.E. Samuel and
J.B. Hill (Eds.), Proc. Conf. Wetlands and Water
Management on Mined Lands. Pennsylvania State
Univ. University Park, Pennsylvania.
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Breedlove, B.W. and W.M. Dennis. 1983. Wetland
reclamation: a drainage basin approach, p. 90-99. In
D.J. Robertson (Ed.), Reclamation and the Phosphate
Industry. Proc. Symp. of Florida Inst. of Phosphate
Res., Bartow, Florida.
Brenner, F.J., W. Snyder, J.F. Schalles, J.P. Miller and
C. Miller. 1985. Primary productivity of deep-water
habitats on reclaimed mined lands, p. 199-209. In
R.P. Brooks, D.E. Samuel, and J.B. Hill (Eds.), Proc.
Conf. Wetlands and Water Management on Mined
Lands. Pennsylvania State Univ. University Park,
Pennsylvania.
Brenner, F.J. 1986. Evaluation and mitigation of
wetland habitats on mined lands, p. 181-184. In DJI.
Graves (Ed.), Proc. Symp. on Surface Mining
Hydrol., Sedimentol., and Reclam. University of
Kentucky, Lexington.
Brice, J.R., and O.C. Boody, IV. 1983. Fish populations in
reclaimed and natural lakes in central Florida's
phosphate region: a preliminary report, p. 359-372. In
D.J. Robertson (Ed.), Reclamation and the Phosphate
Industry. Proc. Symp. of Florida Inst. of Phosphate
Res., Bartow, Florida.
Brooks, D.R. 1987. Rehabilitation following mineral
sands mining on North Stradbroke Island, p. 24-34.
In T. Farrell (Ed.), Australian Mining Industry
Council, Canberra.
Brooks, D.R. 1988. Wetland rehabilitation following
mineral sands mining in Australia. Paper presented
at Mine Drainage and Surface Mine Reclamation
Conf., U.S. Dep. Interior Bur. of Mines, 17-22 April
1988, Pittsburgh.
Brooks, R.P. 1984. Optimal designs for restored
wetlands, p. 19-29. In J.E. Burris (Ed.), Treatment of
Mine Drainage by Wetlands. Contrib. No. 264, Dep.
Biology, Pennsylvania State Univ., University Park,
PA.
Brooks, R.P. 1986. Wetlands as a compatible land use on
coal surface mines. National Wetlands Newsletter
8(2):4-6.
Brooks, R.P., D.E. Samuel, and J.B. Hill (Eds.). 1985a.
Proc. Conf. Wetlands and Water Management on
Mined Lands. Pennsylvania State Univ., University
Park, Pennsylvania.
Brooks, R.P., J.B. Hill, F.J. Brenner, and S. Capets.
1985b. Wildlife use of wetlands on coal surface
mines in western Pennsylvania, p. 337-352. In R.P.
Brooks, D.E. Samuel, and J.B. Hill (Eds.), Proc. Conf.
Wetlands and Water Management on Mined Lands.
Pennsylvania State Univ. University Park,
Pennsylvania.
Brooks, R.P., and W.E. Dodge. 1986. Estimation of
habitat quality and summer population density for
muskrats on a watershed basis. J. Wildl. Manage.
40:269-273.
Brooks, R.P. and WJ. Davis. 1987. Habitat selection by
breeding belted kingfishers ( Ceryle alcvon). Am.
Midi. Nat. 117:63-70.
Brooks, R.P. and J.B. Hill. 1987. Status and trends of
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MITIGATION AND THE SECTION 404 PROGRAM:
A PERSPECTIVE
William L. Kruczynski1
U.S. Environmental Protection Agency
Region IV
ABSTRACT. Although the basic language of Section 404 of the Federal Water Pollution
Control Act Amendments of 1972 has not changed substantially since the Program's inception,
the Program has evolved through revisions in U.S. Army Corps of Engineers (Corps)
Regulations and Environmental Protection Agency (EPA) Guidelines, and the judicial history
of wetland case law. Compensatory replacement mitigation appeared early in the program as
an attempt to replace loss of wetlands, at least on paper. It appeared in projects for which
federal commenting agencies chose not to dispute issuance of a Corps permit.
The EPA and the Corps are currently negotiating a joint mitigation policy, but there
remains a difference of opinion between the agencies concerning how mitigation should be
considered in the permitting process. It is EPA's position that the presumption that there are
alternatives to the destruction of wetlands cannot be overcome by the applicant's promise to
create new wetlands. However, compensatory replacement mitigation may be appropriate for
projects for which there are no practicable alternatives and all appropriate and practicable
minimization has been required. There are three categories of proposed projects, those for
which impacts are: (1) significant regardless of proposed mitigation, (2) significant unless
sufficiently offset by mitigation, and (3) not significant. Consideration of the role of
compensatory mitigation for projects which are not immediately rejected from further
consideration because of the magnitude of the environmental losses must be made on a case-by-
case basis.
INTRODUCTION
Compensatory replacement mitigation is the
attempted replacement of the functions and
values of wetlands proposed for filling through
creation of new wetlands or enhancement of
existing wetlands.
In order to better understand the ongoing
controversy concerning the role of mitigation in
evaluating Section 404 permit applications, it
is necessary to discuss briefly the history of
wetlands mitigation and the role of the Section
404 (b)(l) Guidelines in the permit application
review process. This discussion will demonstrate
how the inappropriate application of mitigation to
projects can transform a straightforward review
procedure into a complex and confusing analysis
based more upon perceptions than scientific
principles.
HISTORY
A review of the legislative and judicial
history of the Section 404 program is given by
Liebesman (1984, 1986), Want (1984), and Nagle
(1985). Section 404 was enacted as part of Public
Law 92-500, The Federal Water Pollution Control
Act Amendments of 1972 (FWPCA), to control
pollution from discharges of dredged or fill
material into waters of the United States.
Although the Environmental Protection Agency
(EPA) is responsible for administration of the
Clean Water Act, Congress authorized the
Secretary of the Army, acting through the Corps
of Engineers, to issue permits under Section 404,
since that agency had been regulating dredging
and placement of structures in navigable waters
under the Rivers and Harbors Act of 1899.
However, Congress, in Section 404(b), directed
the EPA, in conjunction with the Corps, to develop
1The views expressed in this chapter are the author's own and do not necessarily reflect the views
or the policies of the Environmental Protection Agency.
137
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the environmental standards, known as the
Section 404(b)(l) Guidelines, for the program.
Nothing in Section 404 of the FWPCA delineated
the role of the Guidelines in the permit review
process, but Congress clearly intended that the
Guidelines should provide environmental
criteria by which to judge the suitability of
disposal sites. In addition to the Guidelines,
Congress, under Section 404(c), gave EPA the
authority to prohibit, withdraw or restrict the
specification of a 404 discharge site. This
authority, which is known as a 404(c) "veto", can
be used by EPA to prevent the unacceptable
adverse impact of a 404 project.
On September 5,1975, EPA, after consultation
with the Corps, published in interim final form,
the Section 404(b)(l) Guidelines, which
established regulatory considerations and
objectives to govern decisions concerning
issuance of Section 404 permits. These
considerations included avoiding discharges
that disrupt aquatic food chains and destroy
significant wetlands, avoiding degradation of
water quality, and protecting fish and shellfish
resources. These regulations also set forth a
presumption that a permit will not be granted for
work in a wetland unless the applicant clearly
demonstrates that, for non water dependent
projects, there are no less environmentally
damaging, practicable alternatives available.
In 1977, Congress amended the FWPCA
through passage of the Clean Water Act (CWA).
Although sections were added to Section 404 to
exempt certain discharges, such as normal
agricultural and silvicultural activities, and to
establish procedures for transfer of the program
to the states, Congress did not change the basic
outline of the program which had evolved through
Corps Regulations, EPA Guidelines and judicial
review.
From 1977 through 1980, there was little
conflict between the Corps and EPA in
implementing the Program. Although the Corps
initially wanted to restrict the extent of its
geographical jurisdiction, the Corps complied
with a court ruling (NRDC vs. Callaway) and
issued revised Regulations on July 19, 1977,
which expanded the definition of "waters of the
United States" to include wetlands. The
Regulations declared that "wetlands are vital
areas that constitute a valuable public resource,
the unnecessary alteration or destruction of
which should be discouraged as contrary to the
public interest". The Corps Regulations also
reiterated the presumption against filling
wetlands for non water dependent projects as
stated in the 1975 EPA Guidelines. The Corps
proposed that each District Engineer consult with
the U.S. Fish and Wildlife Service (FWS),
National Marine Fisheries Service (NMFS), Soil
Conservation Service, EPA, and state agencies
in reaching a decision on whether "the benefits
of a proposed alteration outweigh the damage to
the wetland resource" and whether "the proposed
alteration is necessary to realize those benefits".
This has been called the Corps' public interest
review. The District Engineer also had to
"consider whether the proposed activity is
primarily dependent on being located in, or in
close proximity to, the aquatic environment and
whether feasible alternative sites are available".
The Corps Regulations place the burden of proof
on the applicant to provide information on the
water dependency of a project and evaluation of
alternative sites.
The EPA promulgated revised Guidelines on
December 24, 1980. These Guidelines reiterated
the water dependency tests and presumption
against alteration of wetlands found in the 1975
interim Guidelines and the 1977 Corps
Regulations. The Guidelines also expanded these
presumptions to include special aquatic sites
which include sanctuaries and refuges,
wetlands, mudflats, vegetated shallows, coral
reefs, and riffle and pool complexes. These
Guidelines establish a fundamental premise that
"the degradation or destruction of special aquatic
sites ... may represent an irreversible loss of
valuable aquatic resources" and that "dredged or
fill material should not be discharged into the
aquatic ecosystem, unless it can be demonstrated
that such a discharge will not have an
unacceptable adverse impact".
The binding, regulatory nature of the
Guidelines was emphasized in the 1980
Guidelines because some Corps Districts were
issuing Section 404 permits for non water
dependent activities when there were less
environmentally damaging alternatives. Prior
to 1982, when EPA, FWS, or NMFS objected to
issuance of a Corps permit, the objecting agency
could elevate the permit decision to higher
authority. In Region IV during the mid and late
1970's, the threat of elevation of a District
Engineer's decisions was usually enough to
result in modification, withdrawal, or denial of
permit applications for environmentally
unacceptable projects. Few permits were elevated
each year to Corps Divisions and fewer yet were
elevated to the Office of Chief of Engineers,
Washington, D.C.
In 1981, the President's Task Force on
Regulatory Relief targeted the Section 404
Program for reform. This reform effort seemed
to question, among other things, the extent to
which the EPA Guidelines should be treated as
binding and regulatory. The Corps issued new
Regulations as a regulatory relief measure in
July 1982 in interim final form. The intent of
these Regulations was to expedite the permit
issuing process and expand the nationwide
permit program.
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In July 1982 the Corps revised the
memoranda of agreement MOA with EPA, FWS,
and NMFS regarding elevation of permit
decisions. The new MOA's stated that only
specific, higher level, officials of those agencies
could request elevation and that the Assistant
Secretary of the Army (Civil Works) had the sole
discretion to grant such requests. As a result,
federal agencies charged with protection of
natural resources were less able to influence
Corps permitting decisions. Because of shortened
processing time, increased workloads, logistics,
and interagency politics, compensatory
replacement mitigation was frequently used in
some parts of the country to resolve differences of
opinions between federal agencies concerning
the "public interest review". Other Corps
Districts issued permits over agency objections
without any mitigation. Consideration of
compensatory mitigation appearance in
permitting decisions was seemingly justified by
some promising results in wetland creation
projects which had appeared in the scientific
literature.
Since the inception of the Program, various
factors made compensatory replacement
mitigation a popular option in the federal
permitting process. The FWS and NMFS did not
have any authority similar to the EPA veto
authority under Section 404(c). Thus, as early as
1975 agencies would compromise their positions
on a permit application as long as there was, at
least on paper, no net loss of wetlands. Federal
agencies recommended compensatory replace-
ment mitigation, in part, due to EPA's hesitancy
to use its 404(c) authority. Also, elevation of
Corps decisions was difficult at best, even before
regulatory relief measures were adopted. Some
agencies may have rationalized that since the
Corps, in some cases, would issue permits for
projects which were non water dependent and
which had practicable alternatives, replacement
mitigation was a method of getting some
environmental benefit in exchange for filling
activities. Agencies within Region IV began
writing letters in response to the Corps' public
notices which stated that they would not object to
permit issuance provided that a similar area of
wetlands was created in exchange for the
wetlands to be filled. Work in the mid and late
1970's seemed to show that certain wetland
systems could be created by man; this was used
as a further rationalization to support
replacement mitigation. Response of agencies to
Corps public notices which included a request for
compensatory replacement mitigation became
more common after regulatory relief measures
were in place and were a clear signal to the
Corps that agencies would not elevate permit
decisions. A decrease in elevations assured the
Corps that it could meet its goal of shortening
processing time for permit applications.
Commenting federal agencies, particularly after
regulatory relief measures were in place, felt
that they had "no practicable alternatives" other
than to recommend that wetland losses be
mitigated through attempted wetland
replacement. "Mitigation" came to mean
minimize adverse impacts regardless of
alternatives, and when that cannot be
accomplished, attempt to replace wetlands lost.
On the surface, requiring replacement
mitigation seemed to be an equitable solution to a
problem. However, the Section 404(b)(l)
Guidelines were regularly being ignored in
some regions when compensatory mitigation was
offered. This was rationalized by concluding
that any losses of fish and wildlife habitat and
other wetland functions were replaced through
attempted wetland creation. Also ignored was
the hidden environmental cost of changing or
altering existing habitats with values in their
present states in hopes of improving these
wetland values.
Consultants for applicants quickly adopted
mitigation as a means of obtaining permits and
undermanned and overworked agency review
staffs were soon faced with many difficult
decisions. In many cases, because there were
little or no data upon which to base decisions,
inconsistent recommendations were made
concerning acceptable replacement mitigation,
including buying and donating lands,
mitigation banking, out-of-kind replacement,
and off-site replacement. Typically, a permit for
filling a wetland, for whatever reason, could be
obtained if the applicant was willing to create a
similar wetland by scraping down uplands to
wetlands elevations and planting the area with
appropriate species. There was little or no data
available regarding the scientific capability of
replicating many kinds of wetlands,
particularly during the early years of the
program. Also, little or no monitoring of wetland
creation projects was required.
Although numbers fluctuated at first, it
became standard practice in the southeastern
United States to require replacement mitigation
at a ratio of 1.5:1 on an acre for acre basis.
Agencies rationalized that greater than 1:1 was
justified because of the uncertainty of wetland
creation and to compensate for the length of time
that it would take to replace fully functional
systems. Corps Districts in Region IV generally
accepted this argument and included 1.5:1
mitigation as a condition to Corps permits.
Wetland creation practices developed
concurrently with the regulatory history. Ex-
amples of some pioneers in the field on the
Atlantic and Gulf Coasts include Savage (1972),
Woodhouse, Seneca, and Broome (1972),
Eleuterius (1974), Garbisch et al. (1975), and
Lewis and Lewis (1978). At this same time, in
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response to growing environmental awareness
and the increasing problem of acceptable
disposal of dredged material, Congress
authorized the Corps' Dredged Material Research
Program in 1973. One of the primary efforts of
that program was to assess the feasibility of
developing habitats on dredged material
substrate. Although research in wetlands
creation originally began as attempts to stabilize
dredged material and eroding shorelines, it soon
developed in the 1970's into the business of
planting wetlands in exchange for wetland acres
permitted to be filled. A symposium which
started modestly in 1974 as a "Conference on the
Restoration of Coastal Vegetation in Florida"
soon became a major scientific vehicle to
demonstrate what kinds of mitigation for dredge
and fill projects were available. The conference
is now entitled "Conference on the Restoration
and Creation of Wetlands" and is international
in scope and interest. Initial successes of marsh
creation projects in 1975 through 1978 were used
as further justification of replacement mitigation
for Section 404 permits.
Revised Corps Regulations, published in July
1982, provided little recognition of the regulatory
role of the Section 404(b)(l) Guidelines in the
review of permit applications for certain types of
wetlands and contained Nationwide Permits for
all dredge or fill activities in two categories of
waters, isolated waters and waters above
headwaters. The National Wildlife Federation
challenged these Corps Regulations on several
counts including the role of the Guidelines in the
review process and the cumulative
environmental impacts of the nationwide
permits for activities in the two categories of
waters. This suit was settled in February 1984
and the Corps agreed to promulgate new
regulations which acknowledged, among other
things, the regulatory nature of the EPA
Guidelines. The Corps also agreed to establish
acreage limitations for Nationwide Permits for
isolated and headwater waterbodies. The Corps
published revised regulations in October 1984
and again in November 1986. The primacy of the
Guidelines in the Section 404 review process was
settled and the Corps agreed that no permit can be
issued unless it complies with the requirements
of the Section 404(b)(l) Guidelines. A permit that
complies with the Guidelines will be issued
unless the District Engineer determines that it
would be contrary to the public interest. This
sequencing clearly and explicitly highlights the
priority of the Section 404(b)(l) Guidelines in
permitting decisions.
In 1985, the agencies negotiated new
memoranda of agreement which reestablished a
first stage elevation of permitting decisions to the
Corps Division Engineers. In EPA's case a
difference in interpretation of the Guidelines is
one criterion by which a permit decision may be
elevated.
In 1981, the FWS formalized its mitigation
policy and included Guideline precepts (FR 456,
15:7644-7663). The policy also established
"resource categories" which defines "significant
impact" by delineating wetland types which
receive different levels of review. Mitigation
can be considered by FWS for proposals that:
1. Are ecologically sound.
2. Select the least environmentally dam-
aging alternative.
3. Avoid or minimize loss of fish and wildlife
resources.
4. Adopt all measures to compensate for
unavoidable loss.
5. Demonstrate a public need and are clearly
water dependent.
EPA and the Corps are currently working on
a joint mitigation policy. However, as previously
mentioned, there remains a difference of opinion
between the agencies concerning if and when
mitigation should be considered in the
permitting process. The recent Attleboro Mall
404(c) case highlighted the differences of opinion
between the Corps and EPA on the place of
mitigation in the stepwise application of the
Guidelines. Although it is beyond the scope of this
document to discuss that case fully, it is
important to recognize that the Corps position in
this case was that if mitigation will theoretically
offset the adverse impacts to wetlands with a net
result of "zero impact", a permit applicant need
not seek a less environmentally damaging
alternative. Several other Corps Districts also
appear to be taking this position on the
application of mitigation in the review process.
Conversely, a recent paper by Thompson and
Williams-Dawe (1988) presents legal, scientific,
and policy grounds to reject this interpretation of
the Guidelines in the decision process. They
state that the Guidelines support a sequential
approach to mitigation and that mitigation
cannot substitute for the alternatives test. The
presumption that there are alternatives to
destruction of a wetland cannot be overcome by
the promise to reduce wetland destruction or
create new wetlands elsewhere.
Thompson and Williams-Dawe (1988) state
further that failure to follow the stepwise
approach of review given in the Guidelines
creates practical difficulties. For example, it has
become commonplace to contemplate, "What
acreage of created permanent waterbodies is
adequate mitigation for filling of seasonally
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flooded wetlands for residential development?"
Elaborate procedures such as the U.S. Fish and
Wildlife Service Habitat Evaluation Procedures
and the U.S. Department of Transportation
Wetland Functional Assessment Technique, and
other methods are available to answer such
difficult questions. But proper application of the
Guidelines may obviate the need to ask such
questions in most cases.
GUIDANCE ON THE APPLICATION OF THE GUIDELINES
The Section 404 Guidelines establish specific
restrictions which require that no discharge
should be permitted unless:
1. There are no less environmentally
damaging practicable alternatives to the
proposed plan. These alternatives are
presumed for non water dependent activities
in special aquatic sites.
2. The discharge will not result in a. violation
of the water quality standards, toxic effluent
standards, jeopardize and endangered
species, or violate requirements imposed to
protect a marine sanctuary.
3. The discharge will not cause or contribute to
significant degradation, either individually
or cumulatively, of:
a. Human health or welfare, water quality
supply, fish, plankton, shellfish,
wildlife, or special aquatic sites;
b. Life stages of aquatic life or water
dependent wildlife;
c. Aquatic ecosystem diversity, productivity
or stability; or
d. Recreation, aesthetics or economic
values.
4. All practicable steps are taken to minimize
adverse impacts.
During the evolution of the Section 404
program, and in accordance with the 404(b)(l)
Guidelines, the fourth restriction includes
compensatory replacement mitigation as a form
of impact minimization. Historically, the role of
replacement mitigation in the decision making
process has been inconsistent and has resulted in
confusion in the application of the Guidelines.
ANALYSIS OF THE APPLICATION
OF THE GUIDELINES
Since EPA and the Corps are seeking to
develop a joint policy on mitigation, it is
therefore premature to give a definitive statement
on the role of mitigation in the application of the
Guidelines. Thus, the following discussion is an
analysis of the author's interpretation of the
application of the Guidelines in the review of a
permit application.
For many years, EPA has publicly taken the
position that mitigation should occur in the
sequence of avoidance first, then minimization
and, lastly, compensation of unavoidable
impacts. EPA considers these specific elements
to represent the required sequence of steps in the
mitigation planning process as it relates to the
requirements set forth in the 404(b)(l)
Guidelines. A review of a proposed permit's
acceptability under the Guidelines should follow
a sequence of events: (1) avoidance [Section
230.10(a)], (2) impact minimization [Section
230.10(d)], and finally, (3) compensation by
techniques such as restoration and creation
[Subpart H]. The highest level of mitigation
appropriate and practicable (as practicable is
defined in the Guidelines at Section 230.3) should
be achieved at a given step prior to applying
techniques in the next step.
In light of the above, compensatory
mitigation of wetlands should not be considered
in the initial analysis. That analysis should be
confined to a consideration of alternative sites or
designs, construction methods, or other logistical
considerations. If all impacts cannot be avoided,
other forms of minimization can be factored into
a determination of whether there are less
environmentally damaging alternatives. If an
applicant fails to demonstrate that there are no
practicable, less environmentally damaging
alternatives to the proposed action, the applicant
fails to meet the test of the first restriction even if
the applicant proposes to replace the wetlands
intended for filling.
Both minimization of impacts and
replacement of wetlands could be factors in
determining whether a project passes the second
restriction. For example, a project which would
result in a violation of a water quality standard,
such as turbidity, could be redesigned to reduce
the size of the project or treat runoff, and these
modifications could result in meeting the
standard. It is possible that wetlands created to
compensate for wetlands unavoidably lost
through filling could also be part of the treatment
system.
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There is general agreement concerning the
relationship between the third and fourth
restriction concerning minimization of impacts.
It is conceivable that impacts could be minimized
to a level which is no longer considered
significant. Thus, as proposed impacts of a
project are reduced, the significance of the
impacts can be reevaluated and, if found
acceptable, a project could be determined to
comply with the Guidelines. Appropriate and
practicable compensatory mitigation will be
required for unavoidable adverse impacts which
remain after all other appropriate and
practicable minimization has been required.
However, there have been different
interpretations on the role of compensatory
mitigation in the test of significant impacts. The
underlying reason for conflicting opinions on
this matter is the lack of a standard definition of
what constitutes a "significant" impact. There
are good reasons for the lack of a standard
definition of "significant" since the determina-
tion must be made at a local or regional level
because of differences in the sensitivity of
habitats nationally. Because of the uncertainty
regarding the success of compeatory mitigation,
a cautious approach should be taken in reaching
a finding of no significant degradation based on
this type of mitigation. Further, there are some
wetland habitats in which any filling would
result in significant degradation regardless of
the apparent example, it is inconceivable that
filling for residential development could be
allowed in a vast area of fully functional
Everglades wetlands or a pristine intertidal red
mangrove swamp. Wetland habitats can be, and
indeed have been, ranked locally or regionally
and some of these listings provide notice of
habitats in which any filling activity would
be considered to be significant.
CONCLUSION
In summary, consideration must be made on
a case-by-case basis of the role of compensatory
mitigation for projects which are not
immediately rejected from further consideration,
because of the magnitude of the environmental
losses they pose. Discharges into wetlands can be
significant regardless of mitigation, significant
unless offset through mitigation, or not
significant. The second category is most
complex. For projects in this category,
consideration of whether a proposed mitigation
plan will actually prevent the significant
impacts from occurring must be carefully
evaluated. Factors to be considered in making
this determination are considered in the next
chapter.
LITERATURE CITED
Eleuterius, L.N. 1974. A Study of Plant Establishment on
Spoil areas in Mississippi Sound and Adjacent
Waters. Contract Report DA 1-72-C-0001, U.S. Army
Corps of Engineers, Mobile District.
Garbisch, E.W., Jr., P.B. Woller, and R.J. McCallum.
1975. Salt Marsh Establishment and Development.
Technical Manual 52, U.S. Army Corps of Engineers,
Coastal Engineering Research Center, Fort Belvoir,
Virginia.
Lewis, R.R. and C.S. Lewis. 1978. Tidal marsh creation
on dredged material in Tampa Bay, Florida, p. 45-67.
In Proc. Fourth Annual Conf. Restoration Coastal
Vegetation Florida, May 14, 1977. Hillsborough
Comm. Coll., Tampa, Florida.
Liebesman, L.R. 1984. The role of EPA's Guidelines in
the Clean Water Act Section 404 permit program-
Judicial interpretation and administrative
application. Environmental Law Reporter. News and
Analysis 14:10272-10278.
Liebesman, L.R. 1986. Recent Developments under the
Clean Water Act Section 404 Dredge and Fill Permit
Program. American Bar Assoc., Water Qual. Comm.
Workshop, January 10, 1986, Washington, D.C.
Nagle, E.W. 1985. Wetlands protection and the neglected
child of the Clean Water Act: A proposal for shared
custody of Section 404. Virginia Jour. Nat. Res. Law
5:227-257.
Savage, T. 1972. Florida Mangroves as Shoreline
Stabilizers. Fla. Dept. Nat. Res. Prof. Papers Ser. No.
19.
Thompson, D.A. and A.H. Williams-Dawe. 1988. Key
404 Program Issues in Wetland Mitigation, p. 49-53.
In J.A. Kusler, M.L. Quammen, and G. Brooks
(Eds.), Proceedings of the National Wetland
Symposium: Mitigation of Impacts and Losses.
Association of State Wetlands Managers, Berne,
New York.
Want, W.L. 1984. Federal Wetlands Law: The cases
and the problems. Harvard Environ. Law Rev. 8(1):
1-54.
Woodhouse, W.W., E.D. Seneca, and S.W. Broome.
1972. Marsh Building with Dredge Spoil in North
Carolina. Bull. 445, Agric. Exper. Sta., North
Carolina State University, Raleigh, North Carolina.
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OPTIONS TO BE CONSIDERED IN PREPARATION AND
EVALUATION OF MITIGATION PLANS
William L. Kruczynski1
U.S. Environmental Protection Agency
Region IV
ABSTRACT. Consideration of compensatory mitigation should be confined to projects which
comply with the Environmental Protection Agency's Section 404(b)(l) Guidelines. The
complexity of designing a successful mitigation plan is due to specific characteristics of
many types of wetlands and the many options available at mitigation sites. The types of
compensatory mitigation, in order of preference, are: restoration, creation, enhancement,
exchange. Preservation should only be considered when the ecological benefits of
preservation greatly outweigh the environmental losses of an unavoidable filling activity.
A methodology based upon rating of the options is presented to aid in the selection of an
acceptable mitigation plan. In general, on-site, in-kind, up-front mitigation is the preferred
option. However, other options may be acceptable based upon availability of sites, plant
material, and other variables. The proposed methodology should be used as a guide and not
as the only criterion in decision making. Monitoring of mitigation sites is essential to
demonstrate creation of functional wetland systems.
INTRODUCTION
This chapter will discuss the advantages and
disadvantages of compensatory mitigation
options which are available for projects which
receive Section 404 permits. This guidance is
based upon my experience. It is intended for both
preparers and reviewers of mitigation plans.
This analysis is proposed for use as part of the
analytical framework for evaluating proposals to
mitigate the environmental losses of dredge and
fill projects. It is not meant to be a step-by-step
approach to selecting the most desirable
mitigation option. Development of such an
approach would be difficult since the site specific
characteristics of the wetland community which
will be lost and the available mitigation sites
and options cannot be anticipated. Discussion is
confined to compensatory mitigation and
assumes that a project meets the Section 404(bXl)
Guidelines. Examples given in the text to
illustrate specific points reflect the author's
knowledge of ecosystems in the southeastern
United States, but the conclusions and
recommendations are intended to be generally
applicable to wetland ecosystems. The
recommendations in this chapter have not, at this
time, been embraced in the form of formal
Environmental Protection Agency (EPA) policy
or guidance.
The complexity of designing a successful
mitigation plan is due to specific characteristics
of the many types of wetlands and the many
options available for the manipulation of biotic
and abiotic factors at mitigation sites. A brief
discussion of the common mitigation options is
given below. Factors have been arranged from
very general to specific. This order reflects the
recommended order in the decision process for
preparing a mitigation plan.
GOAL OF COMPENSATORY MITIGATION
The goal of compensatory mitigation should
be consistent with the goal of the Clean Water Act
which is "to restore and maintain the chemical,
physical, and biological integrity of our Nation's
views expressed in this chapter are the author's own and do not necessarily reflect the views
or policies of the Environmental Protection Agency.
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waters". Replacement wetlands should be
designed to replace all the ecological functions
provided by the destroyed wetlands such as
wildlife habitat, water quality, flood storage, and
water quantity functions. Sometimes it is
suggested that wetland functions can be provided
with the successful regrowth of wetland plant
species, but often special project designs, such as
slope or channel characteristics or watershed
area, are necessary to assure replacement of
wetland functions such as flood storage.
Monitoring of mitigation sites is also essential to
demonstrate creation of fully functional
compensatory wetland systems.
PREPARATION AND EVALUATION OF MITIGATION PLANS
Preparation of mitigation plans is an
exceedingly complex matter. Federal project
managers are often forced to make difficult
decisions based upon little or no specific
information concerning expected or actual
success rates or times necessary to achieve the
full functions of created communities. Lack of
information is due to either the historical lack of
environmental monitoring associated with
mitigation efforts or poorly designed monitoring
programs for new projects. There are several
ongoing efforts to revisit sites where wetlands
creation mitigation projects have been attempted
as a condition of issued Corps permits. For
example, mitigation sites in Florida and in New
England are being studied by the Corps of
Engineers Waterways Experiment Station.
However, there are few published follow-up
studies of mitigation sites, and the lack of
detailed studies of many community types
necessitates a cautious approach concerning
decisions on anticipated values of created
wetlands.
EPA or U.S. Army Corps of Engineers
(Corps) project managers may also not have the
broad scientific background or field experience
to design mitigation plans for any or all of the
many types of wetland systems which exist in
each region. In addition, as a matter of policy,
the federal agencies are not environmental
consultants; design of a project should carry with
it assurance of success, and the burden to assure
success should be completely on the applicant and
his technical consultants. However, while
federal project managers should guide applicants
through this process, federal agencies should
require that applicants prepare and submit
detailed mitigation plans for review, rather than
actually aiding them in the preparation of plans.
Initial input by federal agencies should be
limited to generic considerations pertaining to
community type, suitable sites, area, source of
water, slopes, and watershed size and position.
The complexity of preparing mitigation
plans is due to the plethora of options concerning
factors such as availability of plant materials,
genetic compatibility of stock material with local
populations and environmental conditions,
handling of plant material, planting schemes,
slopes, water depth and periodicity, soils, and
fertilization rates. Seasonal timing of planting,
flooding and fertilization may be critical to the
success of mitigation projects. It would be very
unusual for a land owner or developer to have the
technical background to personally plan or
undertake even a small scale mitigation project.
Good intentions alone do not assure mitigation
success. Thus, it is recommended that all
replacement mitigation be performed by a
qualified environmental consultant.
Currently, there are no restrictions on who
may call themselves environmental consultants
or mitigation specialists. Thus, it is very
important that applicants examine the
credentials of companies or individuals who
may bid on compensatory mitigation projects.
Reputable firms which have a long, established
record of success in mitigation should be
qualified to discuss options which have worked
in the past and will be able to give accurate cost
estimates. Environmental consultants should be
encouraged to publish brochures which list and
illustrate their successful and unsuccessful
projects. It has been recommended that a
national or regional certification process be
adopted for environmental consultants
specializing in compensatory mitigation. Such a
process, modeled after the certification process
for professional engineers, has been initiated in
Florida. Choice of capable, certified
environmental scientists with regional
knowledge would reduce the frequency of
mitigation projects doomed to failure due to
improper planning and design.
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OF COMPENSATORY MITIGATION
There are three basic types of compensatory
mitigation which are available as options to
replace wetlands lost to dredging and filling
activities: restoration, creation, and
enhancement (Table 1). The following
discussion will demonstrate that restoration and
enhancement are part of a continuum which can
be extended to include a fourth and least
desirable mitigation option, namely wetland
exchange.
Wetland restoration refers to the
reestablishment of a wetland in an area where it
historically existed but which now performs no or
few wetland functions. Disturbance of historic
wetland functions could be due to human
activities, such as filling, channelization, or
eutrophication, or due to natural events such as
lake level rise, shoreline erosion, sediment
deposition, beavers, or decreased flooding.
Typically, wetland soils remain at disturbed
sites, but they might be drained, oxidized, or
buried.
Wetland creation refers to the construction of
a wetland in an area which was not a wetland in
the recent past. Typically, wetlands are created
by removal of upland soils to elevations which
will support growth of wetland species. Removal
of soils to achieve proper elevation can, by itself,
establish proper hydrology for wetland plants,
such as along gently sloping shorelines, or may
prepare the site to receive necessary inundation
from streams or runoff from upland watersheds.
Development of the correct elevation and
establishment of a proper hydroperiod is the
critical factor in the success of created wetlands.
In an area where soils have been thoroughly
disturbed, such as through surface mining, any
replacement of previously existing wetlands
must be considered creation. This is particularly
true if the soil stratification and the surficial
aquifer have been modified.
Enhancement refers to increasing one or
more of the functions of an existing wetland,
such as increasing the productivity or habitat
value by modifying environmental parameters,
such as elevation, subsidence rate, or wind fetch.
Enhancement sites differ from restoration sites
because they already provide some wetland
functions. Enhancement implies a net benefit,
but a positive change in one wetland function
may negatively affect other wetland functions.
The net overall result of enhancement depends
upon established management goals. For
example, the habitat value of a swamp forest can
be increased for wood ducks by increasing the
amount of open water. Increased flooding will
provide more food for ducks and may kill less
water tolerant trees and provide more nesting
cavities. However, this type of enhancement may
lower the value of the wetland for other species,
such as the spotted salamander, deer, or marsh
rabbit.
Enhancement taken to the extreme merely
exchanges wetland types. For example, habitat
value of open water may be enhanced for some
species by establishing an emergent marsh or
swamp forest on fill material placed in open
water. This type of enhancement is more
properly called exchange since it results in the
replacement of one habitat type (submerged) with
another (emergent). The net ecological value of
this mitigation option depends upon acceptable
management objectives. For example, a diverse
forested wetland can be clearcut and planted with
one tree species. If the planted species is a mast
producer, it could be argued that the habitat value
for deer or ducks has been enhanced. However,
increased food for a few species has been
accomplished through elimination of the complex
food web of the swamp forest.
The choice of restoration, creation, or
enhancement mitigation for any project depends
upon the site specific characteristics of available
locations. The choice should be based upon an
analysis of factors that limit the ecological
functioning of the watershed, ecosystem, or
region. The first question to ask in reaching
this decision is, "Are there degraded wetland
communities on-site or nearby which could be
restored to full function?" If there are, the first
choice of mitigation options should be to restore
historic wetland functions of the degraded
system.
Restoration of degraded systems should be
the first option to be considered since it would
reestablish the natural order and ratio of
community composition in the regional
ecosystem. Moreover, likelihood of success of this
type of mitigation is greater than for other
options. If a portion of a particular community
has been removed from an ecosystem through
degradation, it would be ecologically beneficial
to restore that same community back into the
system. In some cases a sizable wetland area
can be restored with little effort. For example, a
wetland area which has been diked and drained
through ditching to create a pasture may be
returned to a functional wetland through
removal of all or part of the dike which separates
it from flood waters. Because a wetland
previously existed on the site, and provided that
the soils are still intact, albeit drained, the
chances of success of restoring this area to a
fully functional wetland are good once the
hydrology is reestablished. If the organic
component of the soils has substantially oxidized,
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Table 1. Compensatory Mitigation Options.
Compensatory Mitigation Options
MITIGATION TYPES RECOMMENDED ACREAGE
Restoration - former wetland, no or few functions 1.5:1; 1:1 upfront
Creation - made from different community 2:1; 1:1 upfront
Enhancement - increase certain functions 3:1; 1:1 upfront
Exchange — enhancement to the extreme case by case
Preservation - purchase and donation case by case
TIMING OF MITIGATION
Before - most prudent; require if unknowns
Concurrent - encouraged for typical projects
After - discouraged
LOCATION OF MITIGATION
On-site - same locale in watershed or ecosystem
Off-site - different locale or different ecosystem
COMMUNITY TYPE
In-kind - same species
Out-of-kind - different species
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resulting in subsidence, reflooding of the area
may create an open water lake, rather than an
emergent wetland.
Restoration grades into enhancement
depending upon how many functions have been
removed from the ecosystem. A previously wet
area which was historically filled may be
restored to full wetland function by grading,
planting, and restoring the historic hydrological
regime. If the wetland had been partially
degraded and had lost one or several of its
functions, the area could be enhanced to provide
full wetland functions. For example, a wetland
which has been impounded, retains wetland
vegetation, and is managed for ducks, could be
enhanced by removing the impoundment dike.
This would reestablish a seasonally flooded
wetland which provides pulsed export of organic
matter to food chains of receiving waters.
It could be argued that the duck
impoundment itself was an enhanced wetland
since it produced a significantly greater duck
population than unimpounded wetlands. But it
can only be considered enhanced for that one
function, namely duck habitat. It has lost its
function to provide detritus on a timely basis for
fishery food chains because of its altered
hydroperiod. Thus "enhancement" often reflects
little more than preference for certain habitat
types or values over others.
Another example of wetland habitat
exchange is establishment of an emergent marsh
on fill material placed in open water. This has
been called marsh creation in the past. It also
enhances the primary productivity of an area;
but, it is an exchange of one functional habitat
type for another. Because it results in a loss of
functions of existing aquatic habitats, exchange
should often be the last option in the choice of
mitigation type. Exchange should only be used
when there is ample scientific evidence
demonstrating that the functions of an ecosystem
or region are limited by the lack of a particular
community type. For example, exchange may be
the option of choice if data demonstrate that the
fisheries productivity and ecological stability of
an embayment would be significantly increased
by establishing a fringe marsh along an
unvegetated shoreline and shallow water habitat.
If restoration of a degraded wetland is the
first option, and wetlands exchange is the last
option and should only be used when
scientifically justified, then enhancement and
creation are intermediate options. There are good
ecological arguments for consideration of
wetland creation before wetland enhancement
since the former will add to the total wetland
area of a site, while the latter may only provide
one or more additional functions to an existing
wetland. Thus, a logical and defensible order of
consideration of the types of compensatory
mitigation is: restoration, creation,
enhancement, and exchange. This order of
preference may be different for a specific
mitigation project in light of regional or site
specific circumstances, such as quality of
wetlands and availability of mitigation sites.
Preservation of existing wetlands through
acquisition should not normally be considered as
compensatory mitigation for unavoidable
wetland losses since there is a net loss of
wetland functions and acreage, and wetlands
proposed for preservation are usually already
regulated through the Section 404 program and
provide ecological functions to the public.
However, there could be circumstances of such
an unusual character that would justify wetland
preservation as a mitigation option. For
example, if the environmental effects of the
proposed filling are very minimal and the
benefits of placement of a large area of wetlands
(and/or uplands) into public ownership are great,
then preservation may be consistent with the
goals of wetland protection although some loss
may result. This is particularly true if an area
proposed for preservation is unique habitat,
subject to general or nationwide permitting, or
otherwise vulnerable to development. Any
agreement for preservation of existing wetlands
should explicitly indicate that the preservation
shall be required in perpetuity and shall provide
assurance for this requirement through an
appropriate method such as fee title conveyance to
a well established, responsible conservation
organization.
Preservation of a large, mixed community
might also be an attractive option if, without such
preservation, the full functioning of a system
could be destroyed through unregulated
development of upland portions of an upland-
wetland mosaic, such as a bottomland forest
mixed with upland bluffs and stands. Loss of
upland habitat corridors, edge, and ecological
niches could result in the degradation of the
functioning of the entire ecosystem, particularly
for larger animals, such as black bear. If the
ecological benefits of preservation greatly
outweigh the environmental losses which will
occur in permitting an unavoidable wetland fill,
then preservation through acquisition may be
considered.
Some have argued that preservation should
be considered as a prime mitigation option since
it places wetland areas which might be lost
through future permit actions or by the dissolu-
tion of the federal permitting program, into
public ownership or control. Most indications are
that the Section 404 program will be strengthened
as permitted losses of wetlands cumulatively
result in decreased fisheries production and
other losses to the national economy.
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CREDIT FOR COMPENSATORY MITIGATION
There is need for guidance to establish and
maintain consistency between project managers
and between EPA Regions and Corps Districts
concerning acceptable ratios between wetland
losses and compensation acreages for the
different mitigation options. One approach is to
require that the ecological functions of the
replacement wetland be at least equivalent to
those of the wetland proposed for destruction.
Attainment of functional equivalency should be
the goal of all mitigation activities. However,
this approach may result in loss of wetland
acreage and requires detailed knowledge of the
ecological contribution that the destroyed and
replacement wetland systems make to the
regional ecosystem. Also, the ecological
functions which are considered in the test of
equivalency must be carefully chosen. Proposed
replacement of a degraded wetland habitat by an
improved wetland is another complication which
requires thorough analysis. For example, if
primary productivity is a major function of a
wetland, establishment of less acreage of a very
productive wetland may adequately compensate
for the loss of more acreage of a low productivity
wetland. However, the replacement wetland may
provide much less habitat for a particular species
than was provided by the destroyed habitat,
despite overall improved productivity. Usually
there is not enough information available to
agencies to formulate scientifically valid,
functionally equivalent replacement acreage
within the processing period of a permit
application. This information must be supplied
by the applicant as part of the permit application
if he expects the agencies to consider "functional
equivalent wetland replacement" as a basis on
which to issue a permit.
General ratios between mitigation options
can be suggested as flexible guidelines to be
considered in each permit decision requiring
compensatory mitigation. The following ratios
are suggested for on-site, type-for-type (in-kind)
replacement mitigation. The analysis becomes
more complex when variables such as off-site
and out-of-kind mitigation options are
considered. The analysis is further complicated
by the many types of wetland communities, the
varying success rates of community
replacement, and the difficulty of justifying
ranking and exchange of different wetland
values.
RATIOS FOR RESTORATION
In general, the chances of success in
restoration of most destroyed herbaceous
wetlands (e.g., marshes) is good because this type
of wetland generally grows rapidly and because
a wetland previously existed at the site.
Restoration is a matter of removing the
perturbations and reestablishing the soils, plants,
and hydrology at the same site where a wetland
was created by nature. Restoration (or creation)
of forested streams or bottomland hardwood
floodplains has been attempted, but is much more
difficult. To date, no restoration projects are
known which are of a sufficient age to have
achieved a fully functional, self-reproducing
system; most are under twenty years of age.
Restoration (or creation) of submerged seagrass
communities seems to be a "hit or miss"
proposition with little documentation concerning
specific environmental conditions needed for
success.
Because of the varying rates of success of
restoration of different vegetative communities,
it is difficult to justify general criteria for
acreage credit for restoration of all types of
wetlands. Indeed, if it has not been demonstrated
conclusively that restoration of a particular
wetland community is possible, then the prudent
approach is to reject any proposed replacement
mitigation. If the ecological loss through filling
of such a wetland is determined to result in
significant environmental degradation, then
filling of such a wetland is unacceptable.
However, if it has been convincingly
demonstrated that a particular wetland type can
be restored, then 1.5 to 1 mitigation should be
required on an acre-for-acre basis; that is, 1.5
acres restored for each acre unavoidably lost.
The justification for requiring greater than
parity is due to the uncertainty that a particular
project will be successful and to compensate
partially for the length of time that the restored,
planted wetland system takes before becoming
fully functional. Planting of the restored system
is required unless it can be conclusively
demonstrated that a natural colonization will
result in the vegetative community of choice.
The ratio of wetlands restored to wetlands
lost can be reduced to 1 to 1 if wetland restoration
is performed "up front", that is before a filling
activity is initiated. Reduction of the ratio to
parity assumes that a replacement wetland has
been constructed and monitored according to an
approved plan and that it has been found to be
fully functional. Reduction of the ratio to 1 to 1
might also be justified if data demonstrate that
the restored site will provide increased ecological
and hydrological value to the area.
RATIOS FOR WETLAND CREATION
Wetland creation involves increased risk
since it is an attempt to establish a new wetland
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at a site where one has never existed, or where
the previously existing conditions which
supported a wetland community have been
greatly modified. Wetlands established on land
which has been thoroughly disturbed, such as
through surface mining, are created wetlands
even if they occur on the same geographical sites
as previously existing wetlands. Creation of
wetlands from existing uplands is the common
form of compensatory creation mitigation
associated with dredge and fill permits. If it has
been convincingly demonstrated that a
particular wetland type can be created, then 1.5 to
1 or 2 to 1 mitigation ratios should be required on
an acre-for-acre basis. Increasing the ratio to 2
to 1 can be justified on the basis of the greater
risk associated with any particular site. The
ratio may also be adjusted depending upon
whether planting or natural revegetation is part
of the proposal. If successful creation (i.e.,
similar value between created and natural
wetland) is performed upfront of proposed filling,
then the ratio can be reduced to 1 to 1.
RATIOS FOR WETLAND
ENHANCEMENT
Wetlands proposed for enhancement are
performing wetland functions, and it will often
be difficult to document net improvements to
wetland functions. There is a risk that although
some functions will be improved, other currently
existing functions could be degraded. Due to this
uncertainty, a 3 to 1 mitigation should be
required on an acre-for-acre basis. This ratio
can be lowered to 2 to 1 if it is performed upfront.
It can never be lowered to parity since there was
an existing wetland which provided some
wetland functions at the site.
Wetland types should not be exchanged
except under unusual circumstances. Since
exchange is the replacement of one wetland type
with another, it is, by definition, on a 1 for 1
basis. Gains in one wetland type cannot be
equated with losses of another type since each
performs different functions and are unique
assemblages of physical, chemical and
biological variables. To say that they are equal
and that the exchange of one wetland type for
another is acceptable is the same as trying to
equate apples and oranges; they are judged by
different sets of criteria. However, there may be
unusual circumstances where one wetland type
is particularly rare and one wetland type is
particularly abundant; such circumstances could
justify exchange of wetland types as
compensatory mitigation.
RATIOS FOR WETLAND
PRESERVATION
Wetland preservation through acquisition
should not be considered as compensatory
mitigation except in unusual circumstances
because a net overall loss in function and
acreage will occur. It can also be argued that
preservation through donation, conservation
easements, restrictive covenants and the like is
tantamount to purchasing a dredge and fill
permit, and is limited to developers with
sufficient capital to make the offer large enough
to be attractive to regulatory agencies. Small
landowners seeking an individual permit
usually lack the land resources or capital to
make such an offer. Thus, formalizing a policy
or an exchange ratio justifying such an action is
ethically and legally questionable.
ECOLOGICAL COSTS OF COMPENSATORY MITIGATION
There must be a careful analysis concerning
the ecological trade-offs associated with
conversion of one habitat type to another. This
analysis should consider the ecological value of
non-wetland as well as wetland sites proposed for
compensatory actions. An area proposed to be
restored to wetlands or an area proposed for
wetland creation may have ecological value in
itself. For example, an upland pasture which
was historically a wetland that was diked and
drained may have become important habitat for
terrestrial species, such as doves, quail, raptors,
bears, or bobcats.
Unless there are unusual site-specific or
regional circumstances, it is not justifiable to
scrape down a functional hydric or mesic forest
adjacent to an existing marsh to create equal or
greater area of marsh in exchange for filling of
another area. In a similar vein, an impounded
marsh may provide habitat for wading birds or
ducks in an area where there is little natural
suitable habitat for these species. Restoration of
such an impoundment to a seasonally flooded
system would disrupt the community which has
adapted to the existing conditions. The difficult
question which must be answered in analyzing
the ecological value of proposals of this sort is,
"Do the ecological changes associated with
habitat restoration, creation, or enhancement
outweigh the overall ecological functions of the
'donor' community?" This question is hard to
answer objectively because of the bias which
exists for dwindling wetland resources. It also
requires gathering and interpreting data for
upland or disturbed wetland systems and dredge
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and fill project managers may have little or no
experience in performing these analyses.
Comparing existing ecological values with
anticipated values of replacement systems is no
easy task. This analysis should be performed by
a team of experts representing a wide range of
disciplines and expertise. The multi-disciplinary
team of scientists and engineers at the Corps
Waterways Experiment Station is an excellent
model for interagency evaluation. They have
published many studies evaluating created
wetlands and comparing them to natural
reference sites; their methods provide an
excellent source for standardizing these
comparisons.
The use of a "quantitative" methodology,
particularly by inexperienced personnel, to solve
this problem may only add to the confusion. For
example, the Habitat Evaluation Procedures
(HEP) of the U.S. Fish and Wildlife Service has
often been used to calculate "habitat suitability
indices" for sites. These indices are often biased.
A HEP index is a numerical expression of the
potential use of a site for a particular species of
fish or wildlife chosen for evaluation. This
measure of potential (quality) of a site for these
species, when multiplied by area, yields the
number of "habitat units", a numerical
expression of the useful habitat within the
study area. Habitat units can be used to compare
different sites for chosen species and to calculate
acreage of replacement habitat as mitigation for
habitat lost through regulated filling.
HEP uses models which relate biological
needs and tolerances of evaluation species to
environmental conditions which occur in their
habitats. These conditions are expressed as
variables, such as water depth, flooding
periodicity, vegetation density, and soil type.
Through the use of formal, documented models,
HEP provides "standardized" numerical
expression of habitat suitability, and thus reduces
variability due to subjective differences of
opinion.
Because HEP appraises environmental value
according to habitat suitability for particular
species, the selection of species to be used in the
evaluation is one of the most controversial parts
of any study. The methodology can be easily
misused with improper selection of evaluation
species. HEP procedures advise forming an
interagency team to select the species list, so that
all constituencies can be represented. Those
interested in maintaining or enhancing historic
conditions commonly select the most sensitive
(habitat limited) species in the community;
others, wishing to modify or develop the site,
select species most consistent with the proposed
development or management plan. Moreover,
since it is impossible to exactly duplicate a
natural system, and since developers generally
prefer to replace a wetland with a retention pond
or lake, they usually prepare compensatory
mitigation plans with different environmental
conditions which will support a different species
assemblage than exists at the "donor" site.
During a recent application of HEP in a
seasonally flooded East Everglades wetland, a
consultant chose such a list of species which may
have historically existed at the site, but currently
occur infrequently due to hydrological
modifications to the wetlands. The HEP
calculations yielded low habitat units for the
chosen species under the existing conditions.
The procedure was repeated for the habitat which
would result when the site was developed as a
residential area; development included several
borrow lakes as enhancement (exchange)
mitigation. Because of the different, "improved"
hydrologic conditions, the HEP analysis
concluded that development of the site would be
ecologically beneficial (for the selected species).
The underlying premise of this conclusion
was that management should optimize habitat for
Everglade species which historically were more
widespread than they are today, such as large-
mouth bass and wading birds. The distribution
of these species is limited by suitable
hydrological conditions. However, the disruption
of historic hydrological conditions in the East
Everglades has also resulted in "disturbed"
Everglades habitats which are wetlands, and are
habitat for species other than wading birds and
bass. Thus, the trade of many acres of disturbed
Everglades, with the resultant loss of habitat for
bobcats, raccoons, red tailed hawks, etc. for a
residential community with a few acres of
enhanced wetlands (borrow lakes), which would
provide habitat for bass and wading birds, is not
ecologically equitable. Yet the choice of HEP
evaluation species supported that conclusion.
Regulatory agencies should be concerned
with habitat restoration, such as restoring
historic hydrologic conditions to the disturbed
wetlands, instead of enhancement or exchange of
a small portion of the wetlands through
inappropriate mitigation associated with filling
of a majority of the wetland area. Also,
regulators should consider all aspects of habitat
exchange and realize that advantages to the
species of choice may not be balanced by impacts
to other displaced species.
Another ecological cost which must be
considered in preparing mitigation plans is the
availability of appropriate plant material. Plant
material may be collected from a donor wetland
only if that action does not significantly degrade
the ecological functions provided by the donor
system. Vegetation plugs may be removed from
a herbaceous wetland donor site and planted at a
prepared mitigation site. But plugs should be
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harvested at sufficiently spaced intervals to
maintain the functional integrity of the donor
site.
If plant material is obtained from a
commercial source, care should be taken to
assure that the propagated plants are from a stock
which is reproductively compatible and has
similar ecological requirements as stands which
naturally occur in the locale, A method which
has recently been shown to be cost-effective in
restoring or creating large wetland areas in
some locales is mulching of a contoured
mitigation site with the upper soil horizon from a
donor wetland. This mulch contains viable seeds
and rhizomes which usually allows rapid
establishment of a diverse plant community.
Proper application of this technique has been
effective in creating or restoring both herbaceous
and wooded wetlands. Appropriate tree species
are planted in the mulched area, which provides
effective soil, moisture, and shading for young
trees. Choice of donor wetlands should be
carefully controlled so that existing mature
wetland systems are not avoidably lost in order
to create other wetlands. It is preferable that this
material be obtained from the wetland which is
proposed to be impacted, and can be stockpiled for
a short period if wetland replacement is not
concurrent with alteration of the donor site.
TIMING OF COMPENSATORY MITIGATION
Three options exist in timing of a mitigation
project relative to receipt of a Section 404 permit.
Mitigation can be performed before the permit is
issued, concurrent with project initiation and
completion, or after a filling activity is
completed. Often an initial Section 404 permit is
needed for the work performed as part of the
mitigation project itself since dredging or filling
in waters of the United States is usually required
to restore, create, or connect the mitigation site to
a source of water. Upfront mitigation is possible
as a separate permit action or as part of a phased
permit, with the receipt of the second phase,
project construction, contingent upon successful
completion of the first phase, demonstration of
successful mitigation.
Upfront mitigation is the most prudent of
mitigation timing options and should be required
for all projects which have considerable
ecological risks by virtue of their size,
complexity, or uncertainty of community
establishment at the mitigation site. For
example, a permit was issued by the Corps to a
mining company for the connection of two tidal
creeks, which were constructed in uplands, with
existing waters. These created systems were
monitored and only when success criteria were
satisfactorily met did the Corps process a permit
application to mine across an equal acreage of
natural, existing tidal creeks.
If mitigation cannot be completed in
advance, it should proceed concurrent with
project construction since mitigation becomes an
integral part of the proposed project; this
discourages viewing mitigation as an "add on"
cost of receiving a Corps permit. However, a
problem inherent in concurrent mitigation is the
association of timing of the receipt of a permit
and initiation of a project with the timing of
maximum anticipated success rate due to
seasonality of biological and/or hydrological
factors. In general, early spring is the best time
to plant most coastal herbaceous species, whereas
optimum transplanting times for scrub-shrub or
palustrine forested wetlands is during winter
when plant material is senescent. Obviously, the
Corps cannot refuse to process a permit
application if it is received at a time of year
when transplanting is not optimal. However,
an issued permit can be conditioned to include a
date for initiation of construction and mitigation
which is consistent with maximum survival
rates of transplanted material. Another option is
to allow earth moving associated with project
construction and mitigation to proceed
simultaneously and delay planting of the site to
conform with time of expected maximum
survival rates.
Regardless of the time of the year when
mitigation is initiated or completed, it is always
advantageous to require a guaranteed survival
rate of transplanted plant material with every
mitigation plan. This is particularly important
if the Corps issues a permit for project
construction and the applicant performs the
required mitigation during a time period when
expected transplant survival is less than
optimum. Typically in Region IV, a guaranteed
survival of 70% of transplants after two years is
requested. Replanting should be required until a
70% survival rate is obtained for one year. This
requirement necessitates monitoring of the
mitigation site.
Mitigation performed after a project is
completed should be discouraged since it
fragments the project into a construction phase
and a mitigation phase. Once the construction
phase of a project is completed, there is little
incentive to complete the mitigation phase in a
timely, satisfactory manner. If post project
mitigation is the only practical option, the
mitigation plan included in the Corps permit
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should always contain an initiation date and a
completion date. If one or both of these dates are
not honored, the Corps should be encouraged and
supported to take enforcement action for violation
of a permit condition. Post-project mitigation
should be restricted to small projects which have
a very high probability of success or for
situations where project construction must be
initiated before the time period when maximum
survival of transplants is assured. Even then, the
earth moving and other physical amenities
necessary for preparation of the mitigation site
for planting should be performed concurrent with
the remainder of the project. A performance bond
should be required from the developer for any
mitigation project which has an uncertain
chance of success.
LOCATION OF COMPENSATORY MITIGATION
The goal of mitigation is to replace the
functions which were provided by the wetland
area and which were unavoidably lost through a
permitted activity. Since the wetland area
provides ecological functions such as food chain
support or wildlife habitat to the ecosystem of
which it is a part, it is important that ecological
values of the replacement wetland be provided to
the same ecosystem which was impacted by the
filling activity. Thus, both on-site (same locale)
and off-site (different locale) mitigation should
usually be performed in the same ecosystem and
functional watershed as the filled wetland area.
The problem with this rule is the difficulty of
defining the limits of a particular ecosystem.
Ecosystems may be conceived and studied in
various scales. For example, an ocean, an
embayment, a lake, a pond, or a small aquarium
may be called an ecosystem. For our purposes, it
is best to define ecosystem as any area of nature
which is part of the same watershed which
includes interacting living organisms and
nonliving substances, and where there is an
exchange of materials and energy.
Restoration, creation or enhancement of
wetlands should, in most circumstances, occur
on-site, that is within the same ecosystem and in
the immediate vicinity of the proposed filling
activity. For example, if a permit is issued for
fill in wetlands to construct a boat ramp and
mitigation is required, a disturbed area along
the same reach of stream should be restored to
wetland elevation to replace the functions which
were lost. (Of course this assumes that it was not
practicable to locate the boat ramp in an area of
disturbed wetland.) There is adequate ecological
justification for this approach since the
ecosystem will remain unchanged and the
chance of success of the mitigation is maximized
since it is close to an area which already
supports the vegetative community which is being
replaced.
If there are no potential mitigation sites in
the immediate area, off-site locations within the
same embayment, stream reach, or watershed
(ecosystem) should be selected. If a thorough
analysis reveals that there are no adequate
mitigation sites within these areas, this may be
adequate reason to recommend that no permit be
issued for the proposed activity.
Only in unusual circumstances should off-
site mitigation in a different ecosystem or
functional watershed be considered as acceptable
mitigation. This is due to the difficulty in
equating the impacts of the loss to one
ecosystem with the advantages to another system.
The burden of proof rests with the applicant to
demonstrate that the anticipated advantages to
the off-site area greatly outweigh any losses that
would result through filling of a wetland site.
For example, a proposal to mitigate filling of an
intertidal marsh through creation of a forested
wetland must contain data which supports the
conclusion that the loss of intertidal marsh will
not individually or cumulatively result in
significant degradation to that portion of the
coastline and that the created wetland will
greatly improve the ecological functioning of the
adjacent, riverine ecosystem.
Wetlands mitigation banking is an off-site
compensatory mitigation concept which may be
used to aggregate smaller wetland impacts
towards restoration, creation, or enhancement of
larger wetland mitigation bank sites. However,
it also entails considerable legal, scientific, and
administrative complexity and has the potential
for being seriously misused. Therefore, due to
the experimental status of this concept, it is
recommended that development and use of a
mitigation bank for an individual project be
assessed by a thorough case-by-case review.
As with all forms of mitigation, a wetland
mitigation bank cannot justify a project not
otherwise in compliance with the Section
404(b)(l) Guidelines. Any restoration, creation,
or enhancement project should be carefully
designed by the applicant and agreed to by all
concerned parties through a legally enforceable
wetland mitigation banking agreement. The
bank should be located in the same geographical
area and consist of wetland types similar to the
wetland where impacts will eventually occur.
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The bank should be operational prior to allowing
any project to use the bank's value as
compensation for unavoidable impacts. Long-
term operational, maintenance, and monitoring
plans, and legal guarantees should be included
in the mitigation plan which assure that tasks
are feasible and will be undertaken by the
appropriate parties under the force of law.
COMMUNITY TYPE
Most recommendations provided thus far in
this discussion are based upon the assumption
that wetlands which are unavoidably lost will be
replaced by the same wetland community type.
The chances of replacement with the same
wetland community can be maximized by
planting the site. Natural recolonization of a
mitigation site is recommended only when there
is an adjacent seed source and the applicant
agrees in advance that if the desired density or
species composition are not present at the
mitigation site after one or two growing seasons,
that the site will be planted to achieve the
recommended plant community.
In-kind mitigation is desirable since it
replaces the same community type which was lost
and restores the equilibrium of community types
which had developed as a result of natural
causes. Out-of-kind mitigation should only be
approved under unusual circumstances in which
the data demonstrate that replacement of a
different vegetative type for the one destroyed
would clearly benefit the ecosystem or
geographical area being evaluated. For example,
if a mining company receives a permit to mine
ore which exists under a wetland vegetated
predominantly by cattails, a mitigation plan
may be approved which includes creating a more
diverse herbaceous community at this site. If the
created system provides increased diversity of
habitat or other ecological functions compared to
the monotypic stand of cattails, the replacement
ratio may be reduced to 1 to 1.
The decisions and value analyses of out-of-
kind mitigation proposals must be made
carefully and must include an evaluation of the
entire community which exists on the site. For
example, it is inappropriate to argue that the loss
of a wetland which has a hydroperiod which has
been reduced compared to historic levels can be
mitigated through creation of a smaller sized
lake with a permanent hydroperiod. That
conclusion overlooks the ecological values
provided to organisms which are currently using
the drier wetland site. Such a proposal could be
approved only if it could be demonstrated that the
acreage of drier wetland habitat was not a
limiting factor in the area and the presence of a
lake would significantly improve the ecological
functioning of the ecosystem. In no case should
the replacement ratio of this type of mitigation be
reduced to lower than 1 to 1.
Out-of-kind mitigation might also be
approved if there is a requirement to rapidly
stabilize an area, and there is ample assurance
that in-kind species will eventually invade the
planted area. For example, on suitable sites,
Spartina alterniflora may completely cover a site
in one growing season after planting at an
appropriate density. Rapid cover may be
desirable to stabilize the shoreline at the
mitigation site. If there is an adjacent marsh
vegetated by the slower growing Juncus
roemerianus. it may invade the planted Spartina
area and eventually achieve an equilibrium.
Thus, planting of an area with Spartina to
mitigate the destruction of a Juncus marsh may
be justified in this case.
SELECTION OF MITIGATION OPTIONS
Choice of a mitigation option should consider
site specific and cumulative impact assessments
conducted for the proposed site and should be
based on sound ecological principles based upon
large-scale, landscape considerations. The best
choice of a mitigation plan can only be made
when the status of the functions and values that
will be affected are known. For example,
enhancement of waterfowl habitat by creation of
a "green tree" reservoir may be inappropriate for
a watershed that already has several such
reservoirs, and particularly in a watershed
which has water quality problems, which such
reservoirs are known to exacerbate. Preserva-
tion may be a defensible option if the proposed
project is on a site with low functional values
and the area proposed for preservation is of high
functional value or threatened, and is located in
the same watershed. Only when the tradeoffs
associated with mitigation options are considered
on a scale that is ecologically appropriate (e.g.,
watershed) can decisions be made which
153
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effectively protect or replace wetland functions
and values.
success and overall effectiveness of replacement
mitigation.
The goal of the selection of any mitigation
plan is to replace, as near as possible, the
ecological functions of the wetlands which will
be destroyed. Potential options are summarized
in Table 1. One selection method is to rank all
potential options by assigned values. Values can
be regional or site specific. Options can be
evaluated through the development of a matrix
with assigned values based on assumptions
concerning preference of the options. An example
of such a matrix is given in Figure 1 which
includes all mitigation options and an example
of assigned values.
As discussed above, generally restoration is
the preferred option, followed by creation and
enhancement. Thus, these options have been
assigned values of 3, 2, and 1 respectively. These
values are almost exactly the opposite of the
recommended acre-for-acre replacement ratios
discussed above; that is, the recommended
replacement acreage is 1.5:1 for a restoration
project, 2:1 for a creation project, and 3:1 for an
enhancement project.
Values of 3, 2 and 1 have been assigned to
upfront, concurrent, and post project mitigation.
This is descriptive of the timing of the initiation
and completion of the replacement wetlands.
The rationale for this weighting is simply that
the faster the mitigation project is completed, the
faster the wetland functions are replaced in the
ecosystem. Having replacement wetlands in
place and functioning before the wetlands
permitted for filling are destroyed is most
desirable.
Values of 3 and 1 are assigned to in-kind
and out-of-kind community composition,
respectively. Generally, ecosystems reach an
equilibrium of community types which
maximizes trophic and nutrient cycling
efficiencies. Thus, replacement of the same
community as that which is lost to filling may
restore the integrity of the ecosystem.
Values of 3 and 1 have been assigned to on-
site and off-site replacement, respectively. On-
site mitigation fulfills the goal of compensatory
mitigation, that is to replace the functions that a
filled wetland community provides to the portion
of the ecosystem of which it was a part. Thus, on-
site mitigation is weighted more than off-site
mitigation.
The weighting of upfront, in-kind, and on-
site mitigation options are presumed equal since
each option represents a similar input toward the
The overall values of the 36 mitigation
options given in Figure 1 were calculated by
adding the value assigned to each component.
Values range from 12 to 4. By this method, on-
site, in-kind, upfront restoration is the most
desirable option, which is reflected in the high
value it received (12). Off-site, out-of-kind, post
project enhancement of an existing wetland is
the least desirable option (4).
It is recommended that project managers
and preparers of mitigation plans strive to
achieve the highest value of mitigation type
possible for each mitigation project. A limit of
acceptable mitigation options can be set. For
example, acceptable projects could be confined to
mitigation options with values of 9 or higher and
only in unusual circumstances would a
mitigation plan with a mitigation option lower
than 9 be approved. Project managers have more
flexibility in the acceptability of mitigation
options for community types for which success of
replacement has been conclusively demon-
strated. For example, the success of creation of a
Spartina alterniflora marsh at proper elevations
is well documented. Thus, an acceptable
mitigation plan might include creation of an £L.
alterniflora marsh in exchange for filling a
similar marsh if it is performed concurrently
and on site (10). Mitigation for this marsh might
also be possible by concurrently restoring a
Spartina marsh in the immediate vicinity (11).
However, it would take an unusual set of
circumstances to approve a mitigation plan for
the loss of this marsh which includes creation of
a cypress swamp at some other location (7).
Figure 1 will help simplify the selection of
ecologically acceptable mitigation options, and
can be used to quickly compare the "values" of
different options. However, because of the myriad
of site specific possibilities and restrictions,
Figure 1 and recommendations made herein
should be used as a guide and not as the only
criterion used in decision making.
Some reviewers of this method have
suggested determining the acreage of mitigation
which is required by the value of the mitigation
given in such a matrix. For example, if a value
of 10 is the acceptable level of mitigation options,
but the applicant can only perform mitigation
options with a value of 7, the option with the lower
value may be acceptable if the acreage was
increased by 10/7. It is possible that a refinement
of a general technique such as this may be
acceptable in some regions.
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RESTORATION
3
SCORE 12
UPFRONT
3
10
CONCURRENT
2
POS T
1
10
11
10
ON
3
OFF
1
ON
3
OFF
1
ON
3
OFF
1
ON
3
OFF
1
ON
3
OFF
1
ON
3
OFF
1
\
OFF
1
ON
3
OFF
1
ON
3
OFF
1
ON
3
OFF
1
ON
3
OFF
1
ON
3
OFF
1
SCORE 11
10
ON
3
OFF
1
ON
3
OFF
1
ON
3
OFF
1
ON
3
OFF
1
ON
3
OFF
1
ON
3
OFF
1
SCORE
10
Figure 1. Options to be considered in the preparation and evaluation of mitigation plans.
Interpretation of the scores is explained in the text.
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MONITORING COMPENSATORY MITIGATION PROJECTS
A serious problem in evaluating proposed
mitigation plans is the dearth of quantitative
data on existing mitigation projects, particularly
documentation of changes through time. As
stated above, several studies currently underway
will revisit sites to determine if the mitigation
which was recommended was performed. Data
will be collected to evaluate conditions which
contributed to success or failure of completed
projects. However, because there is so little
quantitative information on replacement of
many wetland communities, particularly
forested communities, it is recommended that all
mitigation plans contain an approved
monitoring plan. Further, it is recommended
that if success criteria established for a project
are not met, the applicant must be required to
take corrective actions until the criteria are met.
This is best accomplished by making the criteria
which define success, the monitoring plan, and
the corrective actions explicit special conditions
of the Corps permit. Performance bonding may
also be required in circumstances where
compensatory mitigation is required for large
projects, for projects where the anticipated
success is not high, and projects proposed by
applicants who have a poor record of compliance
with permit conditions or have a history of
enforcement actions.
A proposed monitoring plan should be
reviewed by an interagency team consisting of
representatives from the Corps, EPA, PWS,
NMFS (when appropriate), and State regulatory
and resource agencies. The basic question is to
ascertain whether the data collected through
monitoring will be sufficient to demonstrate that
the replacement habitat will adequately
compensate for the destroyed habitat. This may
be systematically analyzed by listing all known
wetland functions which are provided by the
wetland permitted for filling, and comparing
these with anticipated functions of the
replacement habitat. It is probable, especially in
forested wetland creation projects, that the
development of full ecological functioning of the
replacement community may take a number of
years. In these cases, some reasonable
judgement must be made concerning the level of
function to be used as a measure of success. For
example, the goal of swamp creation might be to
produce a functional, self reproducing, stable
community. This may take 30 years or more to
accomplish. It would be reasonable to predict
the potential success of such a project by
monitoring tree growth and survival and the
ability of the faster maturing species to produce
viable seeds for a much shorter period of time.
Recent evidence indicates that planted intertidal
marshes on dredged material may take many
years to develop soil characteristics, such as
depth to redox zone and organic matter,
comparable to naturally occurring marshes.
However, it may be adequate to monitor a created
or restored site for plant growth and survival,
and establish success based upon these easily
measured criteria. This approach assumes that
once the plants are established, the other
functions must necessarily follow. For systems
with many unknowns, the prudent approach is to
withhold judgement on success until a self-
sustaining community is achieved.
Success of mitigation projects can be
determined through use of a "mitigation
scorecard". This document summarizes the
success criteria which must be achieved before a
project is declared fully successful. The
scorecard should contain criteria for both biotic
and abiotic factors which are integral parts of the
community which is being mitigated.
Quantitative limits should be set using
reasonable, best available estimates, taking into
consideration factors such as time since
establishment, distance from a water source or
from donor communities, planting densities,
and natural processes. Applicants do not usually
have to supply continuous data which
demonstrate progress toward meeting the success
criteria, unless there are scientifically
justifiable reasons to require such monitoring.
When an applicant is ready to demonstrate that
success criteria have been met, the interagency
team which reviewed the monitoring plan should
examine the site, sampling locations, techniques
used, and the data.
Agreement upon the parameters and
quantitative limits on the scorecard constitutes a
contract between the regulators (Corps) and the
applicant. Anticipated remedial actions such as
replanting with the same or different species
should be agreed upon before a project is initiated
and must be made part of the contract. The
contract should only be changed through
agreement of all parties including the Corps, the
applicant, and the interagency review team.
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SUMMARY OF GENERAL RECOMMENDATIONS
FOR PREPARATION AND EVALUATION OF MITIGATION PLANS
The following is a list of specific issues
which should be explicitly addressed during the
permit review process to improve the prospects of
successful compensatory mitigation of wetland
losses for projects which otherwise comply with
the Section 404 Guidelines. A similar listing is
found in Reimold and Cobler (1986) and other
publications.
SLOPES AND GRADIENTS
A common problem to many unsuccessful
sites is steepness of slopes within the mitigation
area or in surrounding areas. A gentle slope of
1:5 to 1:15 (verticahhorizontal) is recommended
for successful wetland establishment since it
provides maximum flooding and minimizes
erosion.
SOILS
Plant growth can be facilitated by proper
soils. If it is not possible to supply proper wetland
soils, the area may be mulched to provide an
organic surface horizon, and/or fertilized to
stimulate plant growth. Some mitigation sites
are slow to become established because of the lack
of proper soil microflora. It is possible that such
soils must be inoculated with soil microflora
during site preparation to assure rapid and
healthy plant growth.
PLANT MATERIAL
Transplanting sprigs or other plant stock at
mitigation sites is usually preferred over
allowing natural colonization, since trans-
planting promotes favorable community
composition and hastens the establishment of a
functional wetland. Sites should be planted at
appropriate times of the year with stock or seeds
that are genetically compatible with vegetation
native to the locale. Planting density and
survival rates should be specified. Donor sites
should be protected from over-harvesting.
HYDROLOGY
Proper water depth and periodicity is the
most important element in planning a successful
mitigation plan. Long term stage records or tidal
data should be used to determine depth and extent
of flooding limits, and mitigation sites should be
planned at elevations within the flooding
tolerance limits of the community type. The
methodology of establishing frequency of
inundation in tidal areas which are distant from
a bench mark is given in Marmer (1951) and
Swanson (1974).
MONITORING
Success criteria should be agreed upon before
issuance of a permit. Post-project monitoring
should be continued by the applicant until success
criteria are met. Changes in the mitigation plan
or success criteria should be possible only with
approval of all members of the interagency
review team. However, the Corps has the final
authority on permits, including special
conditions to permits which might contain
mitigation plans and success criteria.
TIMING
Upfront mitigation should be encouraged,
particularly when it is determined that risk of
failure is high. Concurrent mitigation is
acceptable for projects where success is probable.
LOCATION
On site mitigation should be encouraged so
that there is no net loss of wetland type or
functions to the local ecosystem.
COMMUNITY TYPE
Replacement of the same kind of habitat
which was destroyed should be encouraged in
order to restore the natural balance of
community types in the ecosystem.
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LITERATURE CITED
Mariner, H.A. 1951. Tidal Datum Plans. Special Swanson, R.S. 1974. Variability of Tidal Datums and
Publication 135, Department of Commerce, Coast Accuracy in Determining Datums from Short Series
and Geodetic Survey. of Observations. National Oceanic and Atmospheric
Administration Technical Report NOS 64.
Reimold, R.J. and S.A. Cobler. 1986. Wetland
Mitigation Effectiveness. EPA Contract No. 68-04-
0015, Metcalf and Eddy, Inc., Wakefield,
Massachusetts.
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CONTRIBUTORS
ROBERT P. BROOKS
Affiliation:
School of Forest Resources
Forest Resources Laboratory
Pennsylvania State University
University Park, PA 16802
Related Experience:
Robert Brooks' primary research effort for the past 5 years has involved the characterization, restoration, and
creation of freshwater wetlands on disturbed landscapes in the northeastern U.S. Studies related to habitat
selection by wetland wildlife, monitoring methods for mitigation, coal-mined lands and mine drainage,
peatlands, and wetland-riparian systems impacted by agriculture have resulted in 13 publications.
Related Publications:
Brooks, R.P., D.E. Samuel, J.B. Hill (Eds.). 1985. Proc. Conf. Wetlands and Water Management on Mined Lands.
Pennsylvania State Univ., University Park, Pennsylvania.
Brooks, R.P., and J.B. Hill. 1987. Status and trends of freshwater wetlands in the coal-mining region of
Pennsylvania. Environ. Manage. ll(l):29-34.
Brooks, R.P., and R.M. Hughes. 1988. Guidelines for assessing the biotic communities of freshwater wetlands, p.
276-280. In J.A. Kusler, M.L. Quammen, and G. Brooks (Eds.), Proc. Nat. Wetlands Mitigation Symp.:
Mitigation of Impacts and Losses. Assoc. State Wetland Managers, Berne, New York.
STEPHEN W. BROOME
Affiliation:
Department of Soil Science
North Carolina State University
Box 7619
Raleigh, NC 27695
Related Experience:
Stephen Broome's involvement in creation and restoration of coastal salt and brackish tidal marshes began in
1969. His research includes studies of the establishment of marsh vegetation for dredged material stabilization,
shoreline erosion control, conversion of upland to intertidal vegetation for mitigation, and revegetation of a marsh
on the coast of France impacted by an oil spill. He has authored or co-authored a total of 30 publications related to
these projects.
Related Publications:
Broome, S.W., W.W. Woodhouse, Jr., and E.D. Seneca. 1975. The relationship of mineral nutrients to growth of
Spartina alterniflora in North Carolina: II. The effects of N, P, and Fe fertilizers. Soil Sci. Soc. Am. Journal
39(2):301-307.
Broome, S.W., E.D. Seneca, and W.W. Woodhouse, Jr. 1983. The effects of source rate and placement of N and P
fertilizers on growth of Spartina alterniflora transplants in North Carolina. Estuaries 6:212-226.
Broome, S.W., E.D. Seneca, and W.W. Woodhouse, Jr. 1986. Long-term growth and development of transplants of
the salt-marsh grass Spartina alterniflora . Estuaries 9:62-73.
Broome, S.W., E.D. Seneca, and W.W. Woodhouse, Jr. 1988. Tidal salt marsh restoration. Aquatic Botany 32:1-22.
159
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STEVEN W. CAROTHERS
Affiliation:
President, SWCA, Inc.
Environmental Consultants
1602E. Ft. Lowell
Tucson, AZ 85719
Related Experience:
Steven Carothers has studied the preservation and management of Southwestern riparian ecosystems for more
than 20 years. In recent years, he has become involved in a number of habitat restoration efforts, some of which
have included the salvage and transplanting of desert riparian trees and shrubs for major land development
projects. Prior to the establishment of SWCA, Inc. in 1981, Carothers was curator of biology at the Museum of
Northern Arizona for ten years. He has published numerous papers relating to riparian habitats in the Southwest.
Related Publications:
Carothers, S.W. 1977. Importance, preservation and management of riparian habitats: an overview. In R.R.
Johnson and DA. Jones (Tech. coords.). Importance, preservation, and management of riparian habitats. U.S.
Dept. Agric., For. Serv. Tech. Rep. RM-43. Rocky Mountain For. and Range Exper. Sta., Fort Collins, Colorado.
Carothers, S.W. and R.R. Johnson. 1975. Water management practices and their effects on nongame birds in range
habitats, p. 210-222. In Proc. of Symp. on Management of Forest and Range Habitats for nongame birds. U.S.
D.A. For. Serv. Gen. Tech. Rpt. WO-1. Washington, D.C.
Carothers, S.W. and R.R. Johnson. 1975. The effects of stream channel modification on birds in the southwestern
United States, p. 60-76. In Proc. of Symp. on Stream Channel Modification, U.S.D.I. Fish and Wildlife Serv., Off.
Biol. Serv., Washington, D.C.
Carothers, S.W., R.R. Johnson, and S.W. Aitchison. 1974. Population structure and social organization of
southwestern riparian birds. Am. Zool. 1437-108.
ROBERT H. CHABRECK
Affiliation:
School of Forestry, Wildlife and Fisheries
Agricultural Center Louisiana State University
Baton Rouge, LA 70803
Related Experience:
Robert Chabreck has worked for 31 years on coastal marsh research and management projects. He has planned,
supervised, or evaluated over 40 projects that involve wetland creation, restoration, or enhancement, and has 33
publications on the subject.
Related Publications:
Chabreck, R.H. 1972. Vegetation, Water, and Soil Characteristics of the Louisiana Coastal Region. La. Agric. Exp.
Sta. Bull. 664.
Chabreck, R.H. 1981. Freshwater inflow and salt water barriers for management of coastal wildlife and plants in
Louisiana. In R.D. Cross and D.L. Williams (Eds.), Proceedings of the National Symposium on Freshwater
Inflow to Estuaries; Vol. 2. U.S. Fish and Wildl. Serv. FWS/OBS-81/04. Washington, D.C.
Chabreck, R.H. 1988. Coastal Marshes-Ecology and Wildlife Management. Univ. of Minnesota Press.
Minneapolis, Minnesota.
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JOHN R. CLARK
Affiliation:
Rosenstiel School of Marine and Atmospheric Sciences
University of Miami
4600 Rickenbacker Causeway
Miami, Florida 33149
Related Experience:
John Clark has 16 years of experience in wetlands policy analysis and formulation, and in implementation of
wetlands regulations with the Conservation Foundation, Wetlands Technical Council, and in private practice. He
has been responsible for site specific project advice on planning and development projects since 1974 (Marco
Island). Most of his experience is with coastal wetlands in Florida, New Jersey, New York, South Carolina, and
California. He has twenty publications in this field.
ANDRE F. CLEWELL
Affiliation:
President
AJ. Clewell, Inc.
1447 Tallevase Road
Sarasota, PL 34243
Related Experience:
Andre Clewell earned his Ph.D. in botany from Indiana University in 1963 and served 16 years on the faculty at
Florida State University. He is currently President of A.F. Clewell, Inc., which specializes in vegetation
restoration, particularly for the Florida phosphate mining industry. He has 10 years experience in vegetation
restoration, including research and development, project design, and project monitoring. He is currently in
charge of 17 forest creation and restoration projects that collectively occupy 152 acres and include the creation of 7
headwater streams. He is the recipient of a 5-year research grant on tree establishment from the Florida Institute
of Phosphate Research. He is well known as a botanist and as the author of Guide to the Vascular Plants of the
Florida Panhandle (University Presses of Florida, 1985).
Related Publications
Clewell, Andre F., et al. 1982. Riverine forests of the South Prong Alafia River System, Florida. Wetlands 2:21-72.
Clewell, Andre F. 1988. Bottomland hardwood forest creation along new headwater streams. Assoc. State Wetland
Managers Tech. Report 3:404-407.
CHARLENE D'AVANZO
Affiliation:
School of Natural Science
Hampshire College
Amherst, MA 01002
Related Experience:
Charlene D'Avanzo has been involved in wetlands research for 15 years, primarily in salt marshes systems in
the northeast. She has published numerous articles on nutrient cycling, food chain dynamics, and primary
production in salt marshes. Her experience with wetland mitigation includes project reviews as a Conservation
Commissioner in Massachusetts and several papers and talks concerning mitigation and vegetation in northeast
wetlands.
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Related Publications:
D'Avanzo, C. 1986. Science base for freshwater wetland mitigation in the northeastern United States; Vegetation.
In J.S. Larson and C. Neill (Eds.), Mitigating Freshwater Wetland Alterations in the Glaciated Northeastern
United States: An Assessment of the Science Base. Publ. No. 87-1, The Environmental Institute, University of
Massachusetts, Amherst.
Van Raalte, C.D., I. Valiela, and J.M. Teal. Productivity of benthic algae in experimentally fertilized salt marsh
plots. Limnology and Oceanography 21:862-872.
KEVIN L. ERWIN
Affiliation:
President/Principal Ecologist
Kevin L. Erwin Consulting Ecologist, Inc.
2077 Bayside Parkway
Fort Myers, FL 33901
Related Experience:
Kevin Erwin has worked with wetland ecosystems for the National Marine Fisheries Service, Florida
Department of Natural Resources, and Florida Department of Environmental Regulation since 1971 and prior to
establishing his firm in 1980. His involvement in wetland creation and restoration covers over 50 projects
encompassing thousands of acres of mangrove, salt marsh, freshwater marshes and swamps. Current research on
sites in Florida ranging in size from 5 to 150 hectares has provided information on design, construction
techniques, tree survival and growth, macrobenthic community structure, water quality, wildlife utilization, and
evaluation and monitoring methods.
Related Publications:
Erwin, K.L. 1983-1988. Agrico Fort Green Reclamation Project, Agrico Swamp West Annual Reports. Agrico
Mining Company, Mulberry, Florida.
Erwin, K.L., G.R. Best, W.J. Dunn, and P.M. Wallace. 1984. Marsh and Forested Wetland Reclamation of a
Central Florida Phosphate Mine. Wetlands 4:87-103.
Erwin, K.L. 1986. A Quantitative Approach for Assessing the Character of Mitigated Freshwater Marshes and
Swamps in Florida. In Proceedings of National Wetland Symposium, New Orleans, LA. Association of State
Wetland Managers.
Erwin, K.L. 1989. An Ecological Inventory and Analysis of the Lee County, Florida, Coastal Zone and
Recommendations for Future Resource Management. The Sixth Symposium on Coastal and Ocean
Management, Coastal Zone '89.
VICKI M. FINN
Affiliation:
Graduate Assistant
School of Public and Environmental Affairs
Indiana University
Bloomington, Indiana 47405
MARK S. FONSECA
Affiliation:
Research Ecologist
National Marine Fisheries Service
NOAA, Beaufort Laboratory
Beaufort, NC 28516-9722
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Related Experience:
Since 1975, Mark Fonseca's research has centered on various aspects of the ecology of seagrass meadows
including: hydrodynamics, productivity and nutrient cycling, population growth and meadow development,
transplanting technology, application of basic seagrass ecology to management strategies, and succession of
restored seagrass beds. He has provided guidance on approximately 30 seagrass restoration projects, domestic and
foreign. He has authored 10 papers on seagrass restoration and management, and has authored or co-authored 36
papers on seagrasses.
Related Publications:
Fonseca, M.S. and J.S. Fisher. 1986. A comparison of canopy friction and sediment movement between four species
of seagrass with reference to their ecology and restoration. Mar. Ecol. Proy. Ser. 2915-22.
Fonseca, M.S., G.W. Thayer, and W.J. Kenworthy. 1987. The use of ecological data in the implementation and
management of seagrass restorations, p. 175-187, In M.D. Durako, R.C. Phillips, and R.R. Lewis (Eds.), Proc.
Symp. on subtropical-tropical seagrasses of the southeastern United States. Fl. Mar. Publ. Ser. No. 42.
EDGAR W. GARBISCH
Affiliation:
Founder and President
Environmental Concern Inc.
P.O. Box P
St. Michaels, MD 21663
Related Experience:
From 1972 through 1988, under the leadership of Ed Garbisch, Environmental Concern, Inc., has designed and
constructed over 290 wetland creation/restoration projects throughout the eastern United States. A majority of these
projects involve brackish tidal marshes and saltmarshes; however, many represent tidal freshmarsh, non-tidal
freshmarsh, and wooded wetlands. Approximately 120 of these projects relate to the application of wetland creation
for shore erosion control throughout the Maryland portion of the Chesapeake Bay. The majority of the balance of
these projects were constructed as compensation for wetlands lost or damaged by permitted developments.
However, some of these projects were constructed for (1) wetland habitat development on dredged materials, (2)
stormwater management, (3) waste water treatment, (4) wildlife habitat, and (5) education and aesthetics. Over
96% of these projects are considered successful, based on their construction according to planned hydrological
performance and vegetation establishment. The largest project completed is 100 acres of brackish tidal marsh at
Secaucus, New Jersey.
Related Publications:
Garbisch, Jr., E.W. and L.B. Coleman. 1978. Tidal Freshwater Marsh Establishment in Upper Chesapeake Bay:
Pontederia cordata and Peltandra virgrinica. In R.E. Good, D.E. Whigham, and R.L. Simpson (Eds.),
Freshwater Wetlands Ecological Processes and Management Potential. Academic Press, New York.
Garbisch, E.W. 1986. Highways and Wetlands: Compensating for Wetland Losses. U.S. Dept. of Transportation,
FHA Report No. FHWA-IP-86-22.
THEODORE GRISWOLD
Affiliation:
Pacific Estuarine Research Laboratory
San Diego State University
San Diego, CA 92182-0057
Related Experience:
Theodore Griswold has 4 years of experience in coastal wetland ecology, including one year as manager of San
Diego State University's wetland research facility, a 30-acre site containing 72 artificial wetlands.
163
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Related Publications:
Griswold, T. 1988. Physical factors and competitive interactions affecting salt marsh vegetation. M.S. Thesis,
San Diego State University.
AMANDA K. HILLER
Affiliation:
Graduate Assistant
School of Public and Environmental Affairs
Indiana University
Bloomington, Indiana 47405
GARRETT G. HOLLANDS
Affiliation:
Principal-in-Charge
Wetlands Group
IEP, Inc.
Northborough, MA 01532
Related Experience:
Garrett Hollands has 22 years of experience as a professional geologist and has worked on a wide range of
geologic projects throughout the U.S. and Canada. For the past 13 years, he has focused on wetland geology and
hydrology while working in New England, the Mid-Atlantic States, Wisconsin, Oregon, Washington, and British
Columbia. Clients have included federal, state and local agencies, environmental organizations, and the private
sector. He has been involved in the actual design, construction, and monitoring of man-made wetlands for
replication and urban runoff mitigation in a wide variety of geohydrologic settings.
Related Publications:
'Hollands, G.G. and W.S. Mulica. 1978. Application of Morphological Sequence Mapping of Surficial Geological
Deposits to Water Resources and Wetland Investigations in Eastern Massachusetts, Geological Society of
America Abstracts with Programs, Northeastern Section.
Hollands, G.G., and D.W. Magee. 1985. A Method of Assessing the Functions of Wetlands. In Proceedings of the
National Wetland Assessment Symposium, Association of State Wetland Managers, Berne, New York.
Hollands, G.G., G.E. Hollis, and J.S. Larson. 1987. Science Base for Freshwater Wetland Mitigation in the
Glaciated Northeastern United States; Hydrology. In J.S. Larson and C. Neill (Eds.), Mitigating Freshwater
Wetland Alterations in the Glaciated Northeastern United States: An Assessment of the Science Base. The
Environmental Institute, University of Massachusetts at Amherst, Publication No. 87-1.
SHERMAN E. JENSEN
Affiliation:
White Horse Associates
P.O. Box 123
Smithfield, UT 84335
Related Experience:
Sherman Jensen has studied riparian habitats since 1980. He has participated in 20 projects in 6 physiographic
provinces of the West and contributed to 8 publications pertinent to riparian and stream habitats. He is presently
involved in 2 projects to create riparian and wetland habitats in southern Idaho, and several projects to devise
management strategies to restore stream and riparian habitats.
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Related Publications:
Jensen, S., M. Vinson, and J. Griffith. 1987. Creation of riparian and fish habitats, Birch Creek Hydroelectric
Facility, Clark County, Idaho, p. 144-149. In K.M. Mutz and L.C. Lee (Eds.), Proceedings of the Society of
Wetland Scientists Eighth Annual Meeting, Seattle, Washington.
Platts, W.S., C. Armour, G.D. Booth, M. Bryant, J.L. Bufford, P. Cuplin, S. Jensen, G.W. Lienkaemper, G.W.
Minshall, S.B. Monsen, R.L. Nelson, J.R. Sedell, and J.S. Tuhy. 1987. Methods for Evaluating Riparian
Habitats with Applications to Management. U.S. Dept. Agric., Forest Service, Intel-mountain Research Station,
Gen. Tech. Rep. INT-221. Boise, Idaho.
R. ROY JOHNSON
Affiliation:
School of Renewable Natural Resources
Cooperative National Park Resources Studies Unit
University of Arizona
Tucson, AZ 85721
Related Experience:
Roy Johnson's research efforts have been largely concerned with botanical and zoological investigations in the
deserts of the southwestern United States and northern Mexico since 1952. For the past 20 years, he has
concentrated largely on the impacts of "water projects" on the riparian environment, and research and
management implications of those projects on recreational and wildlife values. Most of his 200 publications have
been on riparian issues, the most significant resulting from three national and international riparian conferences
for which he was Technical Co-Chairman.
Related Publications:
Johnson, R.R. and D.A. Jones (Tech. Coords.). 1977. Importance, preservation and management of riparian
habitat: a symposium. U.S. Dept. Agric., For. Serv. Tech. Rep. RM-43. Rocky Mountain For. and Range Exper.
Sta., Fort Collins, Colorado. 217 pp.
Johnson, R.R. and J.F. McCormick (Tech. Coords,). 1978. Strategies for the protection and management of
floodplain wetlands and other riparian ecosystems. [Proc. symp., Callaway Gardens, Ga., Dec. 11-13, 1978.] U.S.
Dept. Agric., For. Serv. Gen. Tech. Rep. WO-12. Washington, D.C. 410 pp.
Johnson, R.R. and S.W. Carothers. 1982. Riparian habitats and recreation: interrelationships and impacts in the
Southwest and Rocky Mountain region. Eisenhower Consortium Bull. 12, Rocky Mtn. For. and Range Exp. Sta.,
U.S.D.A. Forest Serv., Ft. Collins, Colorado.
Johnson, R.R. et al. (Tech. Coord.). 1985. Riparian ecosystems and their management: reconciling uses. Gen. Tech.
Rpt. RM-120. U.S.D.A. Forest Serv., Rocky Mtn. Forest and Range Exp. Sta., Ft. Collins, Colorado. 523 pp.
MICHAEL JOSSELYN
Affiliation:
Romberg Tiburon Center & Department of Biological Sciences
San Francisco State University
P.O.Box 855
Tiburon, CA 94920
Related Experience:
Michael Josselyn is an estuarine scientist focusing on the ecology and restoration of wetlands. Since 1978, he
has received support from federal, state, and regional agencies to study and monitor tidal and riparian wetlands
throughout California. His research interests include plant succession patterns, introduced wetland plants, habitat
use by wetland wildlife, and impacts of sea-level rise on wetlands. He has also consulted on over 60 restoration
and mitigation projects throughout the United States for the federal and state resource agencies and highway
departments. Dr. Josselyn is a Fellow of the California Academy of Sciences and Senior Scientist at the Romberg
Tiburon Center for Environmental Studies, an estuarine research facility of San Francisco State University.
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Related Publications:
Josselyn, M.N. (Ed.). 1982. Wetland restoration and enhancement in California. California Sea Grant College
Program. Report #T-CSGCP-007.
a. Josselyn, M.N. and J. Buchholz, Summary of past wetland restoration projects in California, p. 1-10.
b. Zedler, J., Josselyn, M., and Onuf, C. Restoration techniques, research, and monitoring: vegetation, p.
63-72.
Josselyn, M.N. 1983. Tidal Marshes of San Francisco Bay: A Community Profile. U.S. Fish and Wildlife Service,
Division of Biological Services, Washington, D.C. FWS/OBS-83/23.
Josselyn, M.N. 1988. Effectiveness of coastal wetland restoration: California. In J.A. Kusler, M.L. Quammen,
and G.Brooks (Eds.), Mitigation of Impacts and Losses. Assoc. State Wetland Managers, Berne, New York.
JOHN E. KLARQUIST
Affiliation:
Graduate Assistant
School of Public and Environmental Affairs
Indiana University
Bloomington, Indiana 47405
WILLIAM L. KRUCZYNSKI
Affiliation:
U.S. Environmental Protection Agency, Region IV
Environmental Research Laboratory—Sabine Island
Gulf Breeze, FL 32561
Related Experience:
While a research associate for the Wetland Ecology Project at Florida A & M University, William Kruczynski
conducted research on the zonation of tidal marshes, and the vegetative stabilization and colonization of dredged
material. From 1978-1986 he served as Project Officer and Chief of the Wetlands Section for Region IV of the
Environmental Protection Agency (EPA). There he was involved in the review of Section 10/404 permit
applications, mitigation plans and success criteria for projects including phosphate mine reclamation. Presently
William Kruczynski is the Wetland Scientist/Liaison Officer for EPA Region IV, stationed at Environmental
Research Laboratory, Gulf Breeze.
Related Publications:
Breitenback, G., C.L. Coultas, W.L. Kruczynski, and C.B. Subrahmanyam. 1978. Vegetative stabilization of
dredged spoil in North Florida. Jour. Soil and Water Conservation 33:183-185.
Kruczynski, W.L. 1983. Salt marshes of the Northeastern Gulf of Mexico, p. 71-87. In Roy R. Lewis (Ed.), Creation
and Restoration of Coastal Plant Communities. CRC Press, Boca Raton, Florida.
Durako, M.J., JA. Browder, W.L. Kruczynski, C.B. Subrahmanyam, and R.E. Turner. 1985. Salt marsh habitat
and fishery resources of Florida, p. 189-280. In W. Seaman (Ed.), Florida Aquatic Habitat and Fishery
Resources. American Fisheries Society.
RUSSLEA
Affiliation:
Director, North Carolina State Hardwood Research Cooperative
College of Forest Resources
North Carolina State University
Raleigh, NC 27695-8002
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Belated Experience:
Russ Lea has over ten years of research experience in soil science and forestry. For the past eight years he has
been associated with the North Carolina State Hardwood Research Cooperative. He directs the Cooperative which
has sixteen industrial and public agency members with land holdings in the thirteen Southern states. The
Cooperative conducts research and provides consulting on forested wetland systems (naturally occurring and
artificially created), and intensively managed hardwood plantations. The type of activity ranges from basic
research to applied operations and regulatory consulting. He served as a mitigation consultant to North Carolina
Phosphate Company, Savannah River Plant, Occidental Chemicals and Texas Gulf Phosphate. Lea has served on
Forestry Best Management Practice committees for several southern states and is a consultant on a 350 acre waste
water land application/hardwood tree plantation project in coastal North Carolina.
Related Publications:
Lea, R. 1986. Management of Eastern United States bottomland hardwood forests, p. 185-194. In D. Hook (Ed.), The
Ecology and Management of Wetlands, Vol. 2. Crown-Helm, London.
Lea, R. 1987. Response of wetland forests to pumped agriculture wastewater. North Carolina Water Resources
Research Institute Report No. 231.
Mader, S.F., W.M. Aust, and R. Lea. 1989. Changes in functional values of a forested wetland following timber
harvesting practices, p. 149-154. In D. Hook and R. Lea (Eds.), Forested Wetlands of the Southern U.S., Orlando,
Florida. '
DANIEL A. LEVINE
Affiliation:
School of Public and Environmental Affairs
Indiana University
Bloomington, Indiana 47405
Roy R, LEWIS m
Affiliation:
Lewis Environmental Services, Inc.
P.O. Box 20005
Tampa, FL 33622-0005
Related Experience:
Roy Lewis has 22 years of experience in marine wetland research. He has been involved with approximately
100 wetland restoration or creation projects in Florida and the Caribbean. He has forty publications on the subject.
Related Publications:
Lewis R.R. (Ed.). 1982. Creation and Restoration of Coastal Plant Communities. CRC Press, Boca Raton, Florida.
Lewis R.R. Management and restoration of mangrove forests in Puerto Rico, U.S. Virgin Islands, and Florida,
U.S.A. In Proceedings of the International Symposium on Ecology and Conservation of the Usumacinta
Grijalva Delta, Mexico. Villahermosa, Tabasco, Mexico. (In press).
Lewis, R.R., R.G. Gilmore, Jr., D.W. Crewz, and W.E. Odum. 1985. Mangrove habitat and fishery resources of
Florida, p. 281-336. In W. Seaman, Jr. (Ed.), Florida Aquatic Habitat and Fishery Resources. Fla. Chapter,
American Fisheries Society, Kissimee, Florida.
Lewis, R.R. and K.C. Haines. 1981. Large scale mangrove planting on St. Croix, U.S. Virgin Islands: second
year, p. 137-148. In D.P. Cole (Ed.), Proceedings of the 7th Annual Conference on Wetland Restoration and
Creation. Tampa, Florida.
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ORIEL. LOUCKS
Affiliation:
Department of Zoology
Miami University
Oxford, Ohio 45056
Related Experience:
One Loucka has conducted research on land-water interactions, emphasizing the wetlands interface, for nearly
20 years. His papers have addressed transport of water and nutrients into marsh and littoral zone wetlands, and
investigated effects through field studies and predictive models of the long-term functioning of wetland systems.
Related Publications:
Loucks, Orie L. and Vicki Watson. 1978. The Use of Models to Study Wetland Regulation of Nutrient Loading to
Lake Mendota, p. 242-252. In C.B. DeWitt and E. Soloway (Eds.), Wetlands, Ecology, Values, and Impacts.
Proceedings of the Waubesa Conference on Wetlands. Inst. for Env. Studies, Univ. of Wisconsin-Madison.
Livingston, Robert J. and Orie L. Loucks. 1978. Productivity, Trophic Interactions, and Food-Web Relationships in
Wetlands and Associated Systems, p. 101-119. In Wetland Functions and Values: The State of Our
Understanding. Amer. Water Resources Assn., Minneapolis, Minnesota.
Loucks, Orie L. 1985. Looking for Surprise in Managing Stressed Ecosystems. BioScience 35(7):428-432.
Loucks, Orie L. 1989. Wetland Characteristics—Their Land-water Interactions. In Wetlands and Shallow
Continental Water Bodies; Volume 1. Academic Publishing, The Hague, The Netherlands. (In press).
DENNIS J. LOWRY
Affiliation:
Wetland Ecologist
IEP, Inc.
P. O. Box 780
6 Maple St.
Northborough, MA 01532
Related Experience:
Since 1984, Dennis Lowry has been involved in the design of more than one dozen inland wetland creation sites.
On more than half of these projects, he has been actively involved in the construction process, including
supervising equipment operation, conducting the planting efforts, and monitoring the vegetative growth. He was
one of 20 scientists invited to participate in the University of Massachusetts' workshop, Mitigating Freshwater
Wetland Alterations in the Glaciated N.E. United States, An Assessment of the Science Base.
Related Publications:
Lowry, D.J., E.R. Sorenson, and D.M. Titus. 1988. Wetland replacement in Massachusetts: regulatory approach
and case studies, p. 35-56. In M.W. LeFor and W.C. Kennard (Eds.). Proceedings of the Fourth Connecticut
Institute of Water Resources Wetlands Conference, Storrs, Connecticut.
Golet, F.C. and D J. Lowry. 1987. Water regimes and tree growth in Rhode Island Atlantic white cedar swamps, p.
91-110. In A.D. Laderman (Ed.), Atlantic White Cedar Wetlands. Westview Press. Boulder, Colorado.
Daukas, P., D.J. Lowry, and W.W. Walker, Jr. 1988. Design of wet detention basins and constructed wetlands for
treatment of stormwater runoff from a regional shopping mall in Massachusetts, p. 686-694. In D.A. Hammer
(Ed.) Constructed Wetlands for Wastewater Treatment, Proceedings of the International Conference in
Constructed Wetlands for Wastewater Treatment. Chattanooga, Tennessee.
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G. SCOTT MILLS
Affiliation:
Senior Biologist
SWCA, Inc.
Environmental Consultants
1602 E. Fort Lowell
Tucson, AZ 85719
Related Experience:
Scott Mills has studied riparian ecology in the Southwest for more than 16 years. His research emphasis has
been the relationships between the structure of riparian plant communities and avian communities. He has
recently participated in two major riparian forest creation efforts along the Lower Colorado River. For the Mittry
Lake Project, Scott Mills created the planting design and calculated mitigation values for the planting of more
than 5500 trees. For a study of the terrestrial ecology of modified bankline habitats, he created an experimental
design to identify simple and cost-effective methods to revegetate rip-rapped banklines and to assess effects of
vegetation on wildlife use. These experiments included various planting techniques such as rooted cuttings,
dormant poles, and seeds, and a range of environmental parameters such as soil amount, planting location, depth
to water, and irrigation regime.
Related Publications:
Mills, G.S. and J.A. Tress, Jr. 1988. Terrestrial ecology of Lower Colorado River bankline modifications. Report
to Bureau of Reclamation, Boulder City, Nevada.
WILLIAM A. NIERING
Affiliation:
Botany Department
Connecticut College
New London, CT 06320
Related Experience:
William Niering has been involved in wetland research since he completed his Ph.D. thesis in the early 1950's
at High Point State Park, N.J. His major research has been on tidal marshes. In the late 1960's a joint project
involved an inventory of inland wetlands of the United States for the Department of the Interior. An extensive
survey of over 100 Connecticut marsh systems was undertaken in the early 1970's. Current research is a study of
four decades of vegetation change in the Barn Island marshes and the factors responsible. Niering is also a
member of the National Wetlands Technical Council.
Related Publications:
Niering, W.A. and R. Scott Warren. 1974. Tidal Wetlands of Connecticut: Vegetation and Associated Animal
Populations. Vol. I. Connecticut Dept. of Environmental Protection.
Niering, W.A. and R. Scott Warren. 1980. Vegetation patterns and processes in New England salt marshes.
BioScience 30(5):301-307.
Niering, WA. 1985. Wetlands. (The Audubon Society Nature Guides) A.A. Knopf, New York.
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WILLIAM S. PLATTS
Affiliation:
Platts Consulting
Don Chapman Consultants
3180 Airport Way
Boise, ID 83705
Related Experience:
William Platts has studied streams and riparian habitats since 1955. He has participated in hundreds of
projects throughout the United States and has published 166 articles. He is currently involved in studies to develop
grazing management for enhancing riparian habitat, and to identify types of stream and riparian habitat that will
respond similarly to management.
Related Publications:
Platts, W.S., C. Armour, G.D. Booth, M. Bryant, J.L. Bufford, P. Cuplin, S.E. Jensen, G.W. Lienkaemper, G.W.
Minshall, S.B. Monsen, R.L. Nelson, J.R. Sedell, and J.S. Tuhy. 1987. Methods for Evaluating Riparian
Habitats with Applications to Management. U.S. Dept. Agric., Forest Service, Intel-mountain Research Station,
Gen. Tech. Rep. INT-221. Boise, Idaho.
Platts, W.S. and J.N. Rinne. 1985. Riparian and stream enhancement management and research in the Rocky
Mountains. North Amer. Jour. Fish. Manag. 5(2A):115-125.
JOSEPH K SHISLER
Affiliation:
Vice President
Environmental Connection Inc.
P.O. Box 69
Perrineville, New Jersey 08535
Related Experience:
While on the staff at Rutgers University, Joseph Shisler has been involved in the evaluation of the management
of wetland systems for the control of mosquito populations for over 15 years. During this period, he has monitored
the effects of open marsh water management and tidal restoration of salt hay impoundments on over 30,000 acres of
wetlands. He has published over 100 manuscripts on the subject of wetland management and impacts on wetland
components. He directed the research on the evaluation of wetland mitigation for the New Jersey Department of
Environmental Protection. Governor Kean has appointed him a chairperson of the New Jersey Wetlands
Management Council.
Related Publications:
Shisler, J.K. and D.J. Charette. 1984. Evaluation of artificial salt marshes in New Jersey. New Jersey
Agricultural Experiment Station, Publ. No. P-40502-01-84.
Shisler, J.K., R.A. Jordan, and R.N. Wargo. 1987. Coastal Wetlands Buffer Delineation. New Jersey Agricultural
Experiment Station Publ. No. P-40503-01-87.
Shisler, JJC. and T.L. Schulze. 1988. Coastal wetland habitats as a beneficial use of dredged material, p. 55-58. In
M.C. Landin (Ed.), Beneficial Uses of Dredge Material, Proceedings of the North Atlantic Regional Conference.
U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi.
JOHN T. STANLEY
Affiliation:
The Habitat Restoration Group/John Stanley and Associates, Inc.
6001 Butler Lane
Scotts Valley, California 95066
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Related Experience:
John Stanley consults on the restoration, management and enhancement of watersheds, river systems and
wetlands. He has been a naturalist for the National Audubon Society and the Sierra Club, and has taught
conservation, environmental studies and natural history courses at San Jose State University and the University
of California, Santa Cruz. He has 16 years experience consulting for several flood control districts on the
assessment and mitigation of biotic impacts of flood control project plans on riparian and stream habitats. He has
supervised the preparation of revegetation plans for the re-establishment of riparian vegetation along numerous
rivers and streams in central California.
Related Publications:
Stanley, J.T., L.R. Silva, H.C. Appleton, M.S. Marangio, and B. Goldner. Lower Coyote Creek (Santa Clara County)
Pilot Revegetation Project. In D. Abell (Ed.), California Riparian Systems Conference: Protection,
Management and Restoration for the 1990's. U.S. Dept. Agric., Forest Service. (In press).
Stanley, J.T. and W.A. Stiles, III. 1983. Revegetation Manual for the Alameda County Flood Control and Water
Conservation District. County of Alameda Public Works Agency, Hayward, California.
MILTON W. WELLER
Affiliation:
Caesar Kleberg Professor in Wildlife Ecology
Department of Wildlife and Fisheries Sciences
Texas A & M University
College Station, TX 77843
Related Experience:
Milton Weller's long-term interests have been in wetlands as habitats for waterfowl and other wildlife. Most of
his research projects have dealt with the natural dynamics of wetlands and their effect on wildlife populations, as
well as on management strategies. Studies of emergent wetlands in the Prairie Pothole Region emphasized
experimental drawdowns for revegetation; studies of coastal marshes and forested wetlands in Texas have detailed
plant-water relationships important in management for wetland establishment and maintenance.
Related Publications
Weller, M. W. and C. E. Spatcher. 1965. The Role of Habitat in the Distribution and Abundance of Marsh Birds.
Iowa State Univ. Agric. & Home Econ. Exp. Sta. Spec. Sci. Rept. No. 43.
Weller, M.W. and L.F. Fredrickson. 1974. Avian ecology of a managed glacial marsh. Living Bird 112:269-291.
Weller, M.W. 1978. Management of freshwater marshes for wildlife, p. 267-284. In R.E. Good, D.F. Whigham,
and R.L. Simpson (Eds.), Freshwater Wetlands, Ecological Processes and Management Potential. Academic
Press, New York.
Weller, M.W. 1987. Freshwater Marshes; Ecology and Wildlife Management. 2nd Ed. Univ. Minn. Press,
Minneapolis, Minnesota.
DANIEL E. WILLARD
Affiliation:
Director of Environmental Science & Policy Programs Professor of Biology
School of Public and Environmental Affairs
Indiana University
Bloomington, Indiana 47405
Related Experience:
Daniel Willard has worked in wetlands since 1960. He has studied wetland regulation and natural history in
California, Oregon, Texas, Wisconsin, Illinois, Michigan, and Indiana. He served on the Office of Technology
Assessment's Wetland Committee; the Des Plaines River Project's Advisory Committee; the Environmental
Protection Agency's committees on Wetland Research Priorities and Wetlands and Water Quality; the National
Academy of Science, National Research Council's Committee on Agricultural Induced Water Quality Problems;
and as Advisor to the National Wetlands Forum.
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Related Publications:
Willard D.E. Persistence: the need for eternal care for urban wetlands and riparian habitats. Proc. Nat.
Wetlands Conf. on Urban Wetlands. Association of State Wetland Managers, Berne, New York. (In press).
Willard, D.E. 1988. Restoration and creation of wetlands in severely perturbed ecosystems, p. 115-122. In John
Cairns (Ed.). Rehabilitating Damaged Ecosystems; Volume I. CRC Press, Boca Raton, Florida.
Willard, D.E. 1987. Agricultural Wastewaters and Wildlife: An Overview. In annual papers, U.S. Committee on
Irrigation and Drainage. Denver, Colorado.
JOY B. ZEDLER
Affiliation:
Pacific Estuarine Research Laboratory & Biology Department
San Diego State University
San Diego, CA 92182-0057
Related Experience:
Joy Zedler's current research focuses on determining how well artificial wetlands replace the functional values
of natural ecosystems. This follows 15 years of research experience in coastal wetland ecology, including 6 years
of restoration work. With several collaborators, she has 10 funded projects on wetland ecosystem functioning,
including monitoring and restoration.
Related Publications:
Zedler, J.B. 1984. Salt Marsh Restoration: A Guidebook for Southern California. California Sea Grant College
Program. Report No. 7-CSGCP-009.
Zedler, J.B. 1988. Salt marsh restoration: lessons from California, p. 123-238. In J. Cairns (Ed.). Rehabilitating
Damaged Ecosystems; Volume I. CRC Press, Boca Raton, Florida.
Zedler, J.B. 1988. Restoring diversity in salt marshes: Can we do it?, p. 317-325. In E.G. Wilson (Ed.),
Biodiversity. National Academy Press, Washington, D.C.
U S Environmental Protection Asency
??W* jS BoulSd, 12th Floor
Chicago, IL 60604-3590
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