&EPA
United States
Environmental Protection
Agency
Office of Municipal
Pollution Controi(WHH546)
October 1987' .
EPA43KB6&Q05
Water
Report on the Use of
Wetlands for Municipal
Wastewater Treatment
and Disposal
Printed on Recycled Paper
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EPA 430/09-88-005
REPORT ON THE USE OF WETLANDS FOR
MUNICIPAL WASTEWATER TREATMENT AND DISPOSAL
Submitted to:
SENATOR QUENTIN N. BURDICK, CHAIRMAN
COMMITTEE ON ENVIRONMENT AND PUBLIC WORKS
Prepared by:
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF WATER
OFFICE OF MUNICIPAL POLLUTION CONTROL
October, 1987
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Acknowledgments
Tills document was prepared for the Office of Water by Robert K.
BastIan, Peter Shanaghan, and Brian Thompson In the Office of
Municipal Pollution Control with considerable assistance and support
from the following Individuals: Caren Rothstein and Karen Tarnpw, ,
Office of Water; David Davis, John Meagher., Suzanne Schwartz, and
others. Office of Wetlands Protection; Steve Bugbee, Office of Water
Enforcement and Permits; Nandan Sen&eremath and Gall Cooper,; Office
of General Counsel. /
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Abstract
Tlxls document contains a rec^iil5'Agency report which, reviews
knowledge^ of the -use of botfc ^natural and constructed wetlands- for
municipal wastewater treatment -and disposal, including tlie extent" and
circumstances of'this practice, and summarizes the regulatory Issues
Involved in response to 'a request toy the Honorable Quentin ;H\ v '- p
Burdlcfc, Chairman of the U.S. Senate Committee on Environment and
Public Works. Additional information and guidance concerning
projects in which, wetlands play a role in the treatment and disposal
of municipal wastewater effluent more recently issued by the Office
of Water to supplement the report is provided as an attachment to the
original report.
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Contents
Page
I. introduction ... .. . ... 1
II. Wetland Treatment Systems 2
A. Natural Wetlands 2
B. Constructed Wetlands 3
III. Number and Types of Wetland Treatment Systems ..... 5
IV. Standards and Permit Requirements 8
A. Requirements for Discharge 8
1. MiT^™"™ Technology Requirements 8
• ' 2. Water Quality Standards 9
B. Section 404 Permit Requirements 11
V. EPA Approach 12
A. Natural Wetlands 12
B. Constructed Wetlands 12
C. Construction. Grant&.,Eligibility,-. ........ 13
VI. Repommendations 14
A. Actions by the Congress 14
B. Actions by EPA . 14
Attachment A. Excerpts from "Freshwater Wetlands for
Wastewater Management Environmental Assessment Handbook"
Attachment B. Some Recent Detailed Technical References
Attachment C. Letters to/from Senator Burdlck
Attachment D. September 20, 1988 Guidance to Supplement
the October 1987 Burdick Report
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REPORT ON THE USE OF WETLANDS FOR
MUNICIPAL WASTEWATER
INTRODUCTION
wetlands were once regarded as wasted uland. It ^is, now
clear that they'provide Irreplaceable-benefits to, people; and • ^
thS envi?onmenti Wetlands'provide .natural flood prevention
and pollutant filtering systems and contribute significantly , .
to ground water recharge. Many sport fish, migratory
waterfowl, furbearers, and other valuable wildlife live and
breed in wetlands. ;; , , ,:;..-
Freshwater, brackish, and-saltwater-wetlands, have ..'.;/, .....
inadvertently served as natural water .treatment.systems^for
centuries. Because of their transitional position in the
landscape between terrestrial and aquatic ecosystems, some
we^andfhave been subjected to wastewater discharges from
both municipal and industrial sources. Wetlands have also
received agricultural and surface mine, runoff, irrigation
return flows, urban stormwater,discharges, leachjtes;,^and -
other sources of water pollution. The impacts of such. , ;
discharges on 'different wetlands has been quite variable.
it is only in the past few decades,, however, -that th% ^-'
claimed use of wetlands for meeting wastewater treatment and
othSr watK 'quality objectives has been studied and
?mSlLerited. The -Iunc£ional .role pf wetlands in water quality
impediments, has been identified,asVacompelling-argumen^ for ^
wetland preservation and in, some cases r for their creation, ^A ,,, f:
wetiana pire Q^er iagfc. ^.. nave found evidence -r,
. •- •'. '.•.•. i__l: • -a _:' _••' w 3 J.W '• IgVel 'O f r-T=l"'0'1" <*«» t"'.J&¥~!
^-----.pn^ -However, concern, has also", been .
SS SSiile harmful effects p'f' toxic materials and^pathogenj
in wastewaters, and the long-term degradation of wetlands^due
to the additioAal nutrient hydraulic loadings from wastewater
discharges. -,, .••-•. , . •_•-..• -. .- .-..:;;-.^ •--;•. . , •- . ., . ,...<,..
Due to these concerns, as well'a's other factors, there has
been considerable interest in, us ing .constructed (or •<•••,.•>•
artificial) wetlands for wastewater treatment. Constructed;
wetlands are engineered systems that have been designed: and
constructed to employ wetland type vegetation to-assist
treating wastewater in a more controlled environment than
occurs in natural wetlands. ^ ' ' - • "•
This report reviews current knowledge of the use of^both
natural and constructed wetlands for municipal wast.eyater
??eStment and disposal. TUB extent and circumstances of this.
Dracticeare reviewed and summaries of the regulatory issues
involved, as well as EPA policies are presented. <• \ - > ,>;,,;,
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TREATMENT SYSTEMS
A. Natural Wetlands
The teirm "wetlands" is a relatively .new expression,
encompassing what for years have simply been referred to as
marshes, swamps,'bogs, and so on. Wetlands occur in a wide,
?Sge of physical settings at the interface of terrestrial and
aquatic ecosystems.
Wetlands are defined by Federal regulatory agencies as
those areas that are inundated or saturated by surface or
ground water at a frequency and duration sufficient to
support, and that under normal circumstances do support, a
prevaleAce of vegetation typically adapted for life in . .,
laturated soil conditions. They ate vegetated systems,
ranging from marshes to forested swamps. Wetlands occur in a
wide range of natural settings and encompass a diversity of.
ecosystem types, while exhibiting a wide array of primary
functions and values such as providing wildlife habitat,
around water recharge, flood control, water quality
enhancement and recreational opportunities (See Attachment A).
For regulatory purposes almost all natural wetlands are
considered waters of-the United States.
Wetlands appear"to perform to at least some degree all of
the biochemical transformation of wastewater constituents that
take place in conventional wastewater treatment plants, in
septic tanks and their, drain fields, and in other forms of
land treatment. The submerged and emergent plants-, their
associated microorganisms, and the wetland so^s- are _ . .
responsible for the;majority of the treatment effected by,the
wetland. (See list of some recent detailed references in
Attachment B.)
The use of natural wetland treatment systems is limited to
providing further treatment of secondary effluent to meet
downstream water quality standards. (Any applicable ^ter
quality standards for the wetland itself must be met near the
point of discharge to the wetland.) Usually the objective is
to reduce the concentration of Biochemical Oxygen Demand
(BOD), Suspended Solids (SS);: and the nutrients nitrogen and
phosphorus in secondary effluent. Most natural wetlands can
effectively remove BOD, SS and nitrogen from secondary
effluents. However, phosphorus.. removal capability varies
among individual wetlands and depends largely on site-specific
factors, especially soil type. ,
Other pollutants of concern in secondary effluent may also
be removed, in a natural wetland. Removal and die-off rates of
pathogens from wastewater discharged into wetlands have been
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reported as* very high 'in, some-places1, but "highly variable .in c
others. However, the variable numbers of coliform bacteria-,;-£>
and salmonella (which are "routinely lised as^indicators of
human pathogens but are also produced by wildlife), greatay ,, .
complicate moriitoring for human pathogens in-wetlands which
receive wastewater discharges. The levels of many of the ,
inorganic arid organic compounds present in wastewater are
greatly reduced as they pass through wetlands. At least
initially heavy metals appear to be mainly removed by sorption
to wetland soils and sediments, although long-term studies
have not been conducted to determine exactly how they are
cycled or lost. It appears that many of the organic compounds
that are removed by wetlands are degraded.by microbial
activity associated with the wetlands soil, sediment and
vegetation. ..,-.... ..... -• « t
While it appears that many wetlands have some, capacity for
improving water quality of wastewater, runoff, or industrial
discharges, some wetlands are clearly not appropriate for
continuous day-in/day-out use as a part of a wastewater
disposal or treatment system. The potential for altering the
biotic communities' of natural wetlands when including them in
wastewater management is of great concern to EPA and groups
interested in preserving existing wetlands. ,
The major' costs and energy requirements associated with a
natural wetlands treatment system, are involved .with
preapplicatioh treatment, land costs, minor earthwork, and the
wastewater distribution system. In addition:to-the n
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uses. This can be done relatively simply where wastewater
treatment is the only function sought. They,,can be built in
natural scsttings; or they may lentail extensive earthmbving,
construction of impermeable barriers, or building of
containment such as tanks or trenches. Wetland vegetation has
been established and maintained on substrates ranging from
gravel or mine spoils to clay or peat, some systems are set
up to recycle at least a portion of the treated wastewater by
recharge of the underlying ground .water. Others act as flow-
through systems, discharging the final effluent to surface
waters. '
Constructed wetlands have diverse applications and are
found across the country and around the world. They can be
designed to accomplish a variety of treatment objectives. The
influent to various constructed wetlands treatment systems
ranges from raw wastewater to secondary effluent.
The advantages of constructed wetlands are many, and
include: flexibility in siteilocation; optimized size for
anticipated waste load; potential to treat more wastewater in
a smaller area than is possible with natural wetlands; less
rigorous preapplication treatment, and no alteration of
natural wetlands. Concurrently, there are. some disadvantages
to using constructed wetlands for treatment relative to
natural systems. The cost and -availability of suitable land
•and the construction costs for grading the site are added
expenses. In addition, the sites are unavailable for use in ,
treatment during the construction period, and reduced
performance can generally be expected during the period in .
which vegetation becomes established. Other possible
constraints are the costs of plant biomass harvesting and
disposal if required and the fact that artificial wetlands,
like their natural counterparts, provide breeding habitat for
nuisance, insects or disease vectors, and may generate odors.
When toxics are a significant component of the municipal
wastewater to be treated, adequate pretreatment should_be.
provided to avoid problems of bioaccumulation in wildlife
(particularly waterfowl) attracted to the site.
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Under appropriate conditions,' both natural and constructed
treatment systems have achieved higheremoval« efficiencies for,;
BOD, suspended solids, nutrients, heavy metals/trace organic
compounds as well as natural die-off, of pathogens from ' ,
wastewater. More that 25 wetland-^related municipal wastewater
treatment projects have been at least partially funded by EPA
construction grants funds, involving projects in essentially ^ "
all regions of the country (see Figure I which depicts the "
locations of many of the wetland-related treatment projects in
the U.S. and Canada). However, rather than a single concept '•
for the involvement of wetlands-in~ wastewater treatment, there
are a number of approaches whereby wastewater and wetlands
have or could be effectively combined as a part of water-
quality management .projects. These include:
.,'-'. ' " -.'••-
natural Wetlands for Wastevater Disposal .... In many
areas natural wetlands serve as the receiving water for
permitted discharges of treated wastewater. More than 400
such discharges exist in the southeastern States alone, while
there are another 100 or more in the Great Lakes States. In
addition much of the runoff from both rural and urban areas ;an
many parts of the country receives considerable "treatment1' as
it passes through natural wetlands prior to entry into ground
water, estuaries, streams and lakes. However, any use of
natural wetlands for^treatment purposes requires (extensive
pre-project review to ensure that,the wetland ecosystem; is not
unacceptably altered. " ; ;; * -••-•'•
:ion
or Creation
In- the"
more arid parts of the country, .it is not uncommon for : . - .
wastewater effluents to serve as the water supply used to .
create> maintain, restore, or enhance wetlands. In some cases
wastewater effluent is;the sole or major water source for
valuable wetland habitat (e.g., "the Mt; View Sanitary District,
project near Martinez CA, built as an alternative to a
deepwater outfall into Suisun Bay; the Bitter Lake National
Wildlife Refuge near Roswell, NM, which depends on the Roswell
sewage treatment plant effluent as its main supply of
freshwater). Considerable opportunity may exist for treating
and utilizing wastewater effluents, drainage water, runoff, or
other sources as a water supply to enhance or restore existing
wetlands that are stressed due to lack of an adequate water
supply or other reasons. However, some serious environmental
problems have occurred in such situations where proper
management practices were not observed (e,g., the Kesterson
National Wildlife Refuge in Merced County, California, which
received extremely high levels of selenium in the agricultural
drainage water from the western San Joaquin Valley).
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ss:
water quality. ;
.... The use
„* .
less chance for causing adverse environmental effects, in
systems nave ben built to simulate natural wetlands,
(.g.. Aicata.: CA; Incline village. HV;
Harriman,, NY)
motoring and evaluation of many of these sites.
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Rgure
I. Location of Some Known Wetland Wastewater Treatment Projects.
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TV. STANDARDS MTO PERMIT REQUIREMENTS
A. Requirements for Discharge
The Clean Water Act, together with EPA's implementing
regulations, governs the discharge of wastewater to waters of
the United States, including any wetlands which are considered
waters of the United States (40 CFR Part 122.2). Municipal
discharges to those wetlands which are considered waters of
the United States, must meet minimum technology requirements
and conform with State water quality standards. The exact
level of treatment required for any discharge is specified in
its National Pollutant Discharge Elimination System (NPDES)
Permit issued by EPA or an authorized State.
1. Minimum Technology Requirements
All municipal wastewater treatment systems, except
'for certain ocean discharges and aquaculture systems,must
.achieve the degree of effluent reduction attainable
through the application of secondary treatment prior to
discharge to waters of the U.S. (including almost all
natural wetlands). Secondary treatment is most often
defined as attaining an average effluent quality for both
five-day Biochemical Oxygen Demand (BOD5) and Suspended
Solids (SS) of 30 milligrams per liter Tmg/L) in a period
of 30 consecutive days,-an average effluent quality of 45
•' mg/L'for the same pollutants in a period of 7 consecutive
days and 85 percent removal, of the same pollutants in a
period of 30 consecutive days. Although this definition
is based upon the performance of a large number of
properly qperating wastewater treatment plants of various
types, EPA's secondary treatment regulation does not
require the use'bf any of these specific technologies to
achieve the effluent limits, only that the limits be
achieved.
The Clean Water Act and its implementing regulations
do provide for relaxing some aspects of the definition of
secondary treatment under certain circumstances. The
most notable case is when Waste stabilization Ponds (WSP)
and Trickling Filters (TF): are used as the principal
biological treatment process. When this is so, the
facility may be considered as achieving treatment
equivalent to secondary treatment if it achieves average
SOU, and SS of'45 mg/L during a 30 day period, average
BOD§ and SS of 65 mg/L during a 7 day period, and 65%
removal of these pollutants. Where WSP's are used the
State may further adjust upward the SS limit for
, treatment equivalent to secondary treatment to reflect
the effluent quality achieved within a specific
geographical area. This provision allows differing
geographical/climatic conditions which effect WSP
performance to be taJcen into account.
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Permit limits for WSP's or TF's may only be adjusted
where violation of water quality standards will not
result. In attempting to understand how an average SS
level in excess of 45 mg/L could be considered
equivalent to secondary treatment (average SS of 30
mg/L) it is important to remember that the SS
contained in WSP effluent are -largely the result of
the biological treatment process occurring in the pond
and are quite different from the SS in raw wastewater.
WSP effluent SS are, for the most part, algae, which
occur widely in natural water bodies. Thus, depending
upon the water body, a WSP effluent high in SS may not
pose an undue burden.
2. Water Quality Standards
In addition to meeting minimum technology
requirements, discharges to waters of the United
States must comply with applicable State water quality
standards. Very few States have established separate
water quality standards for wetlands and EPA has not
yet developed water quality criteria specifically for
wetlands. An internal EPA task force recently
concluded that the lack of EPA water quality criteria
for wetlands and the resulting absence of State water
quality standards for wetlands is one of the most
serious impediments to a consistent national policy on
use of wetlands for wastewater treatment or discharge.
EPA is now beginning to look into the feasibility of
developing water quality criteria and numerical or
narrative- biological., quality^maintenance,criteria for
wetlands, which would serve as the basis for ,,.<.' >
establishing separate State water quality standards
for wetlands. Some activity has been initiated in
this area. For example, EPA is hosting a scientific
workshop later this year to help prepare a research
plan for developing water quality standards for
wetlands. This workshop will explore the feasibility
of a two-fold approach to water quality standards for
wetlands, addressing both chemical water quality and
biological integrity of these ecosystems. Chemical
water quality standards would aim to protect wetlands
and the fish and wildlife that use them from water
pollution. The objective of standards for biological
integrity would be to address impacts from activities
that physically alter wetlands so that ecosystem processes
are impaired (e.g., discharges of dredge and fill
material).
A related project is being planned to improve State
programs under Section 401 of the Clean Water Act for
Certifying that discharges into wetlands and other
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aquatic sites comply with existing water quality
standards. The programs of states that have
particularly effective or innovative approaches to
their responsibilities under Section 401 will be
reviewed in detail. Subsequently, other States will
be encouraged to adopt and build upon the best
approaches that are identified. Both efforts have
significant potential for improving the level of
protection for wetlands habitat. However, the
availability of funding for the actual development of
water quality standards for wetlands is contingent
upon budget decisions for FY 89 and beyond.
In lieu of separate wetland standards some States
have simply applied water quality standards, for
adjacent streams or lakes to wetlands. These water
quality standards are often inappropriate for wetlands
because wetlands are vastly different ecosystems.
Research has shown that wetlands can effectively
provide additional removal of.pollutants from
secondarily treated wastewater prior to its entering a
stream or lake without significant impact on the
wetland itself. Thus many wetlands can, without harm,
accept higher loadings of nutrients and SS from . ,
municipal wastewater sthan can many.. streams or lakes.
This, of course, assumes that contaminated materials
are not contained in the SS at levels that would be
harmful to fish and wildlife, or would pose threats" to
human health. Water quality standards for wetlands
need to reflect these concerns.
There are a number of cases where advanced polishing
by natural wetlands has been recognized in State-issued
NPDES permits. In these cases the permit calls• >for the
wastewater entering the wetland to meet secondary
treatment limits and-the water quality standards for the
wetland while the water flowing out of the wetland into an
adjacent stream must meet more stringent water quality
standards for the adjacent stream, , ;
,; In some cases permits contain seasonal variations in
discharge requirements. For example, a higher level of
nutrient removal may be required during the summer than
during the winter. Natural wetlands may be well suited to
meeting such seasonal requirements since their peak
pollutant removal and transformation capacity occurs
during the summer growing season.
The State of Florida, in 1986, established standards
for the use of wetlands for treatment. These standards
are considerably more complex than conventional water
quality .standards. Florida's wetland standards include
design criteria and regulation at three levels: effluent
limits; standards to be met within the treatment wetland;
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and standards for discharge from the wetland to downstream
water bodies. The Florida standards contain traditional
physical and chemical parameters as well new "wetland
biological quality" standards. Thus the standards
recognize and allow wetland treatment. capacity to be used
while at the same time protecting the unique values and
functions of wetlands and the water quality standards of
the receiving waters.
However, Florida is the only state having such
standards at present. In most cases the NPDES permitting
authority must review the use of wetlands systems to
achieve downstream water quality standards on a case-by-
case basis. This situation has led to different findings
in similar situations where .questions .have- been raised
concerning the use of natural wetlands for providing
advanced treatment of secondary effluents.
B. Section 404 Permit Requirement
Generally proposals to use natural wetlands for wastewater
treatment involve some alteration of the wetland, such as
building dikes. It is generally necessary to obtain a permit
for the discharge of dredged or .fill material from the Army
Corps of Engineers (or appropriate State Agency) under Section
404 of the Clean Water Act before such construction would be
allowed.
Regulations established by EPA under Section 404(b)(l) are
primarily intended to protect existing wetland values. The
Corps of State review for the Section 404 permit will require
determination that the impacts of dredged or fill material on
the wetland do not constitute significant degradation; that .,
there are no practicable-, environmentaliy'-preferable
alternatives; that unavoidable impacts have been minimized; •
and that unavoidable impacts are mitigated through practicable
compensatory actions. An additional determination by the
Corps also requires that the proposed wetland alteration is in
the public interest. The proposed modification will also
require a review under the National Environmental Policy Act
(NEPA), consideration of other applicable Federal laws and
executive orders (such as the Endangered Species Act), and
any applicable State laws governing wetland filling or other
alteration.
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V. EPA APPROACH
A. Natural Wetlands
EPA regulates wastewater discharges to those natural
wetlands which are considered waters of the United States
through the Clean Water Act NPDES permit program. Municipal
discharges to such wetlands must meet minimum 'technology-based
requirements and conform with applicable State water quality
standards. In the current absence of separate water quality
criteria or State water quality standards for wetlands, EPA
considers a conservative case-by-case approach, often combined
with pilot testing, to be most appropriate for evaluating the
use of natural wetlands for municipal wastewater discharge and
treatment. , "'
A recent internal EPA Task Force concluded that .natural
wetlands should continue to be viewed primarily as protected
water bodies, and that, in the absence of water quality
criteria for wetlands, it is not possible to broadly identify
conditions where they could be safely regarded as part of the
"treatment system". Therefore, the agency continues to review
requests for treatment systems involving discharges (treated
to secondary- or equivalent to secondary levels) to natural
wetlands using a conservative, case-by-case approach. For
example, EFA's Region IV (in Atlanta) has prepared a _
Freshwater Wetlands for Wastewater Management Handbook (EPA
•904/9-85-135) which provides guidance for such case-by-case
evaluation. -
B. Constructed Wetlands
•EPA encourages -the "use' of-constructed (artificial) wetland
systems through the innovative and alternative technology
provisions of its construction grants program. Constructed
wetlcind treatment systems can often be an environmentally
acceptable, cost-effective, treatment option particularly for
small communities. This 'technology also has the advantage of
expanding wetland-type habitats, although these systems rarely
achieve the same level of biological complexity as natural
wetlands systems, and their ecological values are
correspondingly'"less than for natural systems:
in general, current EPA regulatory and construction grants
policies create fewer problems for consideration of
constructed wetlands as a treatment option. In those cases
where €he constructed wetlands systems are designed, built and
operated for the purpose of wastewater treatment, the
constructed wetlands treatment systems are not considered
waters of the U.S. (40 CFR Part 122.2). As a result some
constructed wetland systems are currently.being used to treat
primary effluents to meet secondary or advanced treatment
requirements in a number of locations across the.country.
Operational controls can be designed to closely regulate flow,
.' "
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application rate, and detention time to meet desired seasonal
variations in operation and treatment needs. Plant species
can be selected and utilized on various bases such as nutrient
uptake efficiency, ease of culturing or harvesting, value as
biomass, etc.
C. Construction Grants Eligibility
As with other -land treatment systems, land purchases for
constructed wetland treatment systems are clearly eligible for
funding under the construction grants program. The
eligibility of natural wetlands for funding, however, remains
a more complicated issue due to the case-^by-case approach
which is necessary in determining eligibility. Still, under
certain limited circumstances natural wetlands-may be
considered eligible for grant funding. Such projects must
involve the wetlands in meeting more stringent downstream
water quality requirements, and must be found to be both cost-
effective and environmentally sound. In addition, the
facility must have a current NPDES permit that reflects
minimum treatment technology and State water quality
requirements into and out of the wetlands. As noted above,
these proposals must be reviewed on a case-by-case basis and
may require a Section 404 permit.
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VT. RECOMMENDATIONS
A. Action by tne Congress
We do not believe that any legislative changes are
necessary at this time to provide additional authorities
concerning wetlands for wastewater treatment and disposal.
B. Action by EPA
EPA is talcing a number of actions which may help resolve
the questions regarding the extent to which natural wetlands
may be used to help treat municipal wastewat-er.-. The most
important of these is EPA's exploration of water quality
criteria for wetlands. The first step is to examine the
current scientific data and possible approaches, and to
develop a research plan to fill in the missing information. A
kev component to developing, appropriate criteria is additional
information on the response of wetland ecosystems to various
tvpes and rates of discharges. In addition, EPA will
encourage and (when funds are available) participate in
monitoring current wetland wastewater treatment sites to^
determine the fate of toxics and their impact on wildlife
uling tnl system; and the differences in ecological functions
of constructed versus natural wetlands. Currently, use of
constructed, rather than, natural, wetlands is generally
preferred by EPA when projects for Wastewater treatment are
proposed.
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U. S. ENVIRONMENTAL PROTECTION AGENCY
REGION IV - ATLANTA, GEORGIA
FRESHWATER WETLANDS FOR WASTEWATER MANAGEMENT
ENVIRONMENTAL ASSESSMENT
HANDBOOK
September 1985
CTA Environmental, Inc.
Gannett Fleming Corddry and Carpenter, Inc.
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OVERVIEW OF WETLAND FUNCTIONS AND VALUES 2~7
OVERVIEW OF WETLAND,FUNCTIONS AND VALUES
. . Wetlands have many important roles in, the maintenance of
ecosystems and watersheds. The terms functipn and value are
often used together to describe or characterize a wetland. Wet-
land functions are the inherent processes or capabilities of
wetlands. Most of the values of wetlands relate directly to these
functions: for example, the'water quality enhancement func-
tions of wetlands are one of their great values. Some wetland
. values, such as visual-cultural values, are somewhat inde-
pendent of wetland function. Typically the functions and
values of wetlands are interrelated.
The following 16 functions Tanrf-values of wetlands summarized
in Table 2-2 are widely accepted.
Table 2-2. Primary Wetland Functions and Values
Geomorphology
Erosioncontrol
•r •'••••• • . ' • ' . •; . .,.%...•".-,
Hydrology /Meteorology
Flood control
Saltwater intrusion control
Grouridwater supply
r, Microclimate regulation ,
Water Quality
Water quality enhancement
Ecology ;
Habitat for threatened and endangered species
, Waterfowl breeding and habitat
Wildlife habitat
Freshwater fish (and some marine species)
Aquatic productivity
Nutrient/material cycling
Cnlttrral Resources , T
1 - .. 'TV' . ...
Harvest of natural products
Recreation and aesthetics
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OVERVIEW OF WETLAND FUNCTIONS AND VALUES 2-8
2.3.1 Geomorphology
Erosion Control. Located between watercourses and up-
lands, wetlands help protect uplands from erosion. Wetland
vegetation can reduce shoreline erosion in several ways, includ-
ing: (1) increasing stability of the sediment through binding
with its roots, (2) dampening waves through friction and (3)
reducing current velocity through friction. These processes
reduce turbidity and thereby improve water quality. Rich,
alluvial soils, which build up in wetlands, also contribute to
productivity.
V/etland vegetation has been successfully planted to reduce
erosion along U.S. waters. While most wetland plants need calm
or sheltered water for establishment r they will effectively con-
trol erosion once established. Willows, aiders, ashes, cotton-
woods, poplars, maples and elms are particularly good stabil-
izers. Successful emergent plants in freshwater areas include
reed canary grass, reed, cattail, and bulrushes. Sediment
deposition in freshwater wetlands also acts to decrease siltation
in downstream systems such as estuaries. ,
i
2.3.2 .Hydrology/Meteorology ,
Flood Control. Wetlands temporarily store flood waters and
thus reduce downstream losses of life and property. Since de-
struction from floods in the U.S. runs'from $3 to $4 billion each
year, the damage-diminishing function of wetlands is vitally
important. , ,
Rather than having all flood waters flowing rapidly down-
stream and destroying private property and crops, wetlands
slow the flow of water, store it for some time and slowly release
stored waters downstream. ,.In this ..way, .flood .peaks of tribu-
tary streams are desynchronized and all flood waters do not
reach the mainstem river at the same time., This function
becomes more important in urban areas, where development has
increased the rate and volume of surface water runoff and the
potential for flood damage (U.S. FWS 1984).
Saltwater Intrusion'Control. The flow of freshwater through
wetlands creates groundwater pressure that prevents saltwater
from invading public water supplies. This is important only
where freshwater wetlands interface with-an estuarine environ-
ment (U.S. FWS 1984). ,.'•••• ' ' f
Groandwater Supply. There is considerable debate over the
role of wetlands in ground water recharge. Recharge potential
"of wetlands varies according to numerous factors, including
wetland type, geographic location, season, soil' type, water
.table location and precipitation. Depressional; wetlands like
cypress domes in Florida and prairie potholes in the Dakotas may
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OVERVIEW OF WETLAND FUNCTIONS AND VALUES
contribute to groundwater recharge. Floodplain wetlands also
may do this through overbank water storage (U.S. FWS 1984).
As a result, the protection of this function could be a factor in
addressing current and future water supply problems.
Microclimate regulation. Although less is known about the
role of wetlands in regulating climatic conditions than about
many other wetlands functions, available data indicate this may
be a significant wetland function. In some cases wetlands
appear to modify air temperatures, affect localized precipitation
and maintain global atmospheric stability. Most available
information concerning the modification of air temperatures and
regional precipitation is pertinent for Florida wetlands, which
comprise such a large percentage (30%) of the state. It has been
suggested that thunderstorm activity could decrease in Florida
as a result of draining wetlands, thereby modifying water
budgets (EPA 1983).
2.3.3 Water Quality
Water Quality Enhancement. Wetlands act as natural water
purification mechanisms. They remove silt, and filter out and
absorb nutrients and many pollutants such as waterborne toxic
chemicals.
Water quality enhancement is dependent on wetlands soils,
vegetation, flow through-time, water depth and related pro-
cefses. Many communities throughout the United State?, includ-
ing more than 400 communities in the Southeast, have benefitted
from the capabilities of wetlands to enhance water quality by
incorporating wetlands into their wastewater management
systems (EPA 1983).
2.3.4 Ecology
Habitat for Threatened and Endangered Species. More than
20 percent of all the plant and animal species on^ the Federal
Endangered or Threatened Species list are dependent on wet-
lands for food and/or habitat. Fifteen wetlands dependent
species on the federal list are found only in the Southeast. Addi-
tionally, each state has a list of protected species and many of
these in each state are wetlands dependent: Alabama - 25
species; Florida - 31 species; Georgia - 6 species; Kentucky -14
species; Mississippi -.14 species; North Carolina - 8' species,
South Carolina - 13 species; Tennessee - 13 species (EPA 1983).
Waterfowl Breeding and Habitat. Over 12 million ducks nest
and breed annually in northern U.S. wetlands. This area, when
combined with similar habitats in the Canadian .Prairies,
accounts for 60 to 70 percent of the continent's breeding duck
population. Waterfowl banded in North Dakota have been recov-
ered in 46 states, 10 Canadian provinces and territories, and t*
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OVERVIEW OF WETLAND FUNCTIONS AND VALUES 2-10
other countries. Some 2.5 jmillion of the 3 million mallards in the
Mississippi Fly way and. nearly 100 percent of our 4 million wood
ducks spend the winter I in flooded bottomland forests and
marshlands throughout the South.
' 'i . ,. . ,
Bottomland forested wetlands of the South are primary win-
tering grounds for North American waterfowl areas, as well as
important breeding areas for wood ducks, herons, egrets and
white ibises. Even wild turkeys nest in bottomland hardwood
forests. Other common bird inhabitants include barred owls,
downy and redbellied woodpeckers, cardinals, pine warblers,
wood peewees, yellowthroats and wood thrushes (U.S. FWS
1984).
Wildlife Habitat. Wetlands provide food and shelter for a
great variety of furbearing animals and other kinds of wildlife.
Louisiana marshes alone yield an annual fur harvest worth $10 to
.$15 million (U.S. FWS 1984);
"fuskrats, beavers and nutria are the most common fur bear-
ers dependent on wetlands. Muskrats are the most wide ranging
of the three, inhabiting; both coastal and inland marshes
throughout the country. :In contrast, beavers tend to be re-
stricted to inland wetlands, with nutria limited to coastal
wetlands of the South. Other wetland-utilizing furbearers
include otter, mink, raccoon, skunk and weasels. Other mam-
mals also frequent wetlands, such as marsh and swamp rabbits,
numerous mice, bog lemmings and shrews. Larger mammals may
also be observed. Black bears find refuge and food in shrub
wetlands in South Carolina, j for example (U.S. FWS 1984).
Turtles, snakes, reptiles and amphibians are all common
residents., of .wetlands -in., the .Southeast..., Alligators. range from
Florida to North Carolina to !the north, and Texas to the west.
Freshwater Fiah. Many iof the 4.5 million acres of open water
areas found in inland wetlands are ideal habitat for such sought
after species as bass, catfish, pike, bluegill, sunfish, and
crappie.
Most freshwater fishes can be considered wetland-dependent
because: (1) many species feed in wetlands or upon wet-
land-produced food; (2) many fishes use wetlands as nursery
grounds and (3) almost all important recreational fishes spawn in
the aquatic portions of wetlands. Bottomland hardwood forests
of the South serve as nursery and feeding grounds for young
warmouth and largemouth bass, while adult bass feed and spawn
fh these, wetlands. River swamps in Georgia produce 1,300
pounds of fish per acre. The bottomlands of the Altamaha River
in Georgia are spawning grounds for the hickory shad and
blueback herring. Southern bottomland forested wetlands are
also the home of the edible red swamp crayfish, which burrow
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OVERVIEW OP WETLAND FUNCTIONS AND VALUES
down to the water table when Hooding waters recede (U.S. FWS
1984).
Aquatic Productivity. Wetlands are among the most produc-
tive ecosystems in the world. Wetland plants are particularly
efficient converters of solar energy. Through photosynthesis,
plants convert sunlight into plant material or biomass and
produce oxygen as a by-product. This biomass serves as food
for a multitude of animals, both aquatic and terrestrial. For
example, many waterfowl depend heavily on seeds of marsh
plants, while muskrat eat cattail tubers and young shoots.
Generally, direct grazing of wetland plants is limited, so the
vegetation's major food, value is produced when it dies and frag-
ments, forming detritus. This detritus forms the base of an
aquatic food web which supports higher consumers. Wetlands
can be regarded as the farmlands of the aquatic environment,
producing great volumes of food annually. The majority of
non-marine aquatic animals depend, either directly or indirect-
ly, on this food source (U.S. FWS 1984).
Nutrient and Material Cycling. Implicit in the discussion of
several other wetland functions and values is the importance of
wetlands to downstream ecosystems. Wetlands that are hydro-
loglcally connected to surface waters often serve as an import-
ant source of nutrients and organic matter. Wetlands serve to
break down organic matter, such as dead vegetation, and to
cycle nutrients so these materials are useable in downstream
ecosystems. This function is essential to many freshwater and
marine organisms in downstream waters and estuaries (Day
1981).
2.3.5. Cultural Reaiodvees •"-«-•
Harvest of Natural Products. A variety of natural products
are produced in freshwater wetlands, including timber, fish,
water fowl, pelts and peat. Wetland grasses are hayed in many
places for winter livestock feed. During other seasons, live-
stock graze directly in wetlands across the country. These and
other products are harvested by man for his use and provide a
livelihood for many people. The standing value alone of south-
ern wetland forests is $8 billion. Conversion of bottomland
forests to agricultural fields (e.g., soybeans) in the Mississippi
Delta has reduced these wetlands by 75 percent.
Wetlands also support fish and wildlife for man's use. Com-
mercial fishermen and trappers make a living ^.™£
resources. Many commercial species (catfish, carp and buffalo
fish) depend on freshwater wetlands for habitat, nutrients or
organic matter» Furs from beaver, muskrat, mink, nutria and
otter yielded roughly $35.5 million in 1976. Louisiana is the
largest fur-producing state, and nearly all furs come from
wetland animals.
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OVERVIEW OFi WETLAND FUNCTIONS AND VALUES 2-12
Many wetlands produce peat, a resource used mainly for
horticulture and agriculture in the United States. Peat raining,
however, destroys wetland|s and their many associated values
(U.S. FWS 1984). i
.1 '
Recreation and Aesthetics. Many recreational activities take
place in and around wetlands. Hunting and fishing are popular
sports. Waterfowl hunting is a major activity in wetlands, and
bJg game hunting is also important locally.
Other recreation in wetlands is largely non-consumptive:
hiking, nature observation and photography, swimming, boating
and ice-skating. Many people simply enjoy the beauty and
sounds of nature aiid spend their leisure time walking or boating
in or near wetlands observing plant and animal life. The
aesthetic value of wetlands [is extremely difficult to evaluate or
place a dollar value upon. Nonetheless, it is very important. In
1980 alone, 28.8 million people (17 percent of the U.S. popula-
tion) took special trips to observe, photograph or feed wildlife.
Figure 2-3 graphically depicts many of the major wetlands
functions .and values. These functions and values are important
to the use of wetlands for. waste water management for several
reasons. First and foremost, th«y provide the basis for water
quality standards and th4 nphdegradation of existing uses
Existing uses, as represented by the list of beneficial wetlanu
functions and values, must be clearly identified and protected
by a waste water management plan incorporating wetlands.
While few wetlands will exhibit all 16 attribu.tes_liated,,.lhe.-
existing values must be identified for each prospective site. Not
only do these functions and values serve as a basis for regula-
tory considerations, they also impact site screening, engineering
design, operation and monitoring of a prospective wetlands dis-
charge. Wastewater management objectives must be considered
in light of environmental protection. The Handbook emphasizes
the importance of wetlands' functions and values in each of the
three major subject areas I addressed: institutional, scientific
and engineering considerations.
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2-13
Figure 2-3. Relationship Between Wetland Functions and Values.
Periodic Inundation Wetland Functions Ecological Services
Fooa and naoitat
Food cnam support
FleodMiuc rMueuon
ater aualitv
> Shor«uw •ration control
SOURCE 0".c. at r«mcw«T *IM>HMI>II
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• SOME RKCENT, DETATT.KD TECHNICAL REFERENCES
U.S. EPA. September 1985. Freshwater Wetlands for Wastewater
Management Environmental Assessment Handbook. EPA 904/9-85-
135. U.S. EPA Region IV, Atlanta. GA. 474pp.
U.S. EPA, 1983.' The Effects of Wastewater Treatment
Facilities on Wetlands in the Midwest. Technical Report. EPA
905/3-83-002. U.S. EPA Region V, Chicago, IL. 264pp.
U.S. EPA/U.S FtWL Service, 1984. The Ecological Impacts of
Wastewater on Wetlands, An Annotated Bibliography. EPA 905/3-
84-002. 300pp.
Bastian. R.K. and J. Benforado, In Press. Water Quality
Functions of Wetlands: Natural and Manmade System. IN: D.
Hook (ed) Proceedings of the International symposium on
Ecology and Management of Wetlands. Croom Helm LTD,
Beckenham, Kent.UK
Brinson, M.M. and F.R. Westall, 1983. Application of
Wastewater to Wetlands. Rpt. No. 5, Water Research inst.,
Univ. of North Carolina, Raleigh, NC. 26pp.
Godfrey, P.J., E.R. Kaynor, S. Pelczarski and J. Bentorado
(eds.). 1985. Ecological Considerations in Wetlands Treatment
of Municipal Wastewaters. Van Nostrand Reinhold Co., New
York. N.Y. 473pp.
Hammer, D.E. and R.H. Kadlec, 1983. Design Principles for
Wetland Treatment Systems. EPA 600/2-83-026. 243pp.
Horwitz, E.L., 1978. Our Nation's Wetlands, An Interagency
Task Force Report Coordinated by the President's council on
Environmental Quality. CPO, Washington, D.c. 70pp.
Kadlec, R.H., June 1987. Using Wetlands to Mitigate the Water
Quality of sewage Effluent. IN: Nix, S.J. and P.E. Black
(eds). Proceedings of the Symposium on Monitoring, Modeling,
and Mediating Water Quality, AWRA, Bethesda, MD. pp. 415-427.
Kadlec, R.H. and J.A. Kadlec, 1979. Wetlands and-Water
Quality. IN: Wetland Functions and Valuesi , The State4Of,Our
Understanding. AWRA, Bethesda, MD. pp.436-456.
Mudroch, A. and J.A. Capobianco, 1979. Effects of Treated
Effluent on a Natural Marsh. JWPCF 51<9):2243-2256.
Nichols, D.S., 1983. Capacity of Natural Wetlands to Remove
Nutrients from Wastewater.' JWPCF "55(5):495-505.
Nixon, S.W. and* V. Lee, In Press. Wetlands and Water Quality:
A Regional Review of Recent Research in the U.S. on the Role
of Freshwater and Saltwater Wetlands as Sources, Sinks, and
Transformers of N, P and Heavy Metals. Prepared by the Univ.
of Rhode Island for the U.S. Army Corps of Engineers, WES,
Vicksburg, MS.
Reddy, K.R. and W.H. Smith (eds.:, 1987. Ao^iatic Plants tor
Water Treatment and Resource Recovery. Magnolia Press, Inc.,
Orlando, FL. 1032pp.
Zedler, J.B. and M.E. Kentula, 1985. Wetlands Research Plan,
Novemoer 1985. U.S. EPA ERL-Corvallis, OR. 118pp.
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UNITED "STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. D.C 2:460
NOV 2I98T
THE ADMINISTRATOR
Honorable Quentin N. Burdlck
Chairman, Committee on Environment
and Public Works
United States Senate
Washington, O.C. 20510
Dear Mr. Chairman:
I an pleased to forward to you our report on the use of wetlands for
municipal wastewater treatment and disposal, prepared 1n response to your
May 4, 1987 request.
The report indicates that there are a number of approaches whereby
wastewater and natural or constructed wetlands may be effectively combined as
a part of water quality management projects. Almost all natural wetlands are
waters of the United States and discharges to these wetlands must comply with
Clean Water Act requirements. Such wetlands may be used tc provide nutrient
removal or high level effluent polishing for municipal wastewater discharges.
On the other hand some constructed wetlands are designed and built for the
express purpose of treating municipal wastewater. Such wetlands are not
waters of the United States and may be used to comply with the minimum
techno 1 ogy requirements of the Clean Water Act. Land purchases for
constructed wetlands treatment systems, and under certain*limited i
circumstances natural wetlands, are eligible for funding under the
construction grants program.
We do not recommend any legislative changes at this time. However, the
Agency is taking actions which may help resolve the questions regarding the
circumstances under which natural wetlands may be used to help treat municipal
wastewater.
Please do not hesitate to contact me if you have any further questions.
Sincerely,
*-•• » *4»»'»'tf»-» ^ A
:10/a/87;ID»078SH
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tVIHBJIMPff a»0 PU«Ue
"ASMNOTCM.ecas 104171
May 4, 1987
Hz. Lee Thomas
Administrator
Environmental Protection Agency • . ,
401 K St S.W. -.. ,
Washington, D.C. 20460 '
Dear Mr. Thomas:
I racantly learned that the Environmental Protection Agency has
.considered the option o£ using wetland areas for disposal or
traataent qf municipal savage.
1 have a particular interest in plans to use wetland areas for
disposal of sewage from the City of Devils Lake in my hone State
oto North Dakota., While I understand that the wetlands disposal
cctun is no -longer under active consideration in tne case of the
City off Devils Lake, I am interested in, and concerned about, the
general question of the use of wetland areas for sewage disposal
or treatment. '
I would like you to prepare a report on the. general, subject of
use of wetlands for municipal sewage disposal and discharge and
related activities.
'. • ' .' ' , ' • r
Your report should provide a full assessment ofi the extent and
circumstances of this practice, summarize the legal issues
involved, review the Agency's policy with regasd to this.
practice, and provide recommendations of actions which .should be
taken by the EPA or the Congress to address this issue.
i
Please provide this report to my office within thirty days. I
you are.unable to prepare this report within this time period,
plisase contact Mr. BoblDavison (224-7139) or Mr. Jeff Peterson c
the Environment and Public Works Committee staff • (224-7069) . '
Thank you for your "cooperation in this important siattar. .
f - * jf* • - '••-•
Sincerely,
Quantir. M. 3urdicl<
Chairman
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UNTIED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
2 0 1988
wnceop
WATER
MEMORANDUM
SUBJECTi/TJse of Wetlands for Municipal Wastewater Treatment
Disposal
FROM: Rebecca W. Hanmer, Acting Assistant Administrator
for Water (WH-556)
TO: Water Division Directors, Regions I - X.
Tills memorandum provides information and guidance concerning
projects in which wetlands play a role in the treatment and
disposal of municipal wastewater effluent. Attached you will find
OW Guidance to Supplement tla.e October 1987 Burdlck "Report on the
Use of Wetlands for Municipal Wastewater Treatment: and Dlpsosal",
as well as a copy of the Burdick report.
The report was prepared by the Office of Water at the request
of Senator Quentin N. Bur dick. Chairman of the Senate Committee on
Environment and Public Works, to attempt to provide a full
assessment of the extent and circumstances of the use of wetlands
for municipal wastewater treatment and disposal, a summary of the
legal issues Involved, a review of pertinent agency . policy , and
recommendations of actions which need to be taken by EPA or the
Congress to address this issue. The supplemental guidance was
developed to summarize a- number -of internal- agency -issues
addressed during preparation of the report, and to provide some
general guidance.
The following are the Headquarters contacts on this matter who
had the lead in their respective offices for preparation and
review of the report. Please feel free to contact them if you
have any questions: Karen Tarnow (382-5686) on my immediate
staff, Bob Bastian (382-7378) in OMPC, John Meagher (382-5043) in
OWF, Steve Bugbee (475-9539) in OWEF, Nandan Kenkeremath
(382-7700) in OGC.
Attachments
cc: CG Branch Chiefs
Water Permits /Compliance Branch Chiefs
Section 404 Coordinators
Regional Counsels
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
* : ' OFFICE or
September 20, 1988 .WATER
SUBJECT: OW Guidance to Supplement the October 1987 Burdick
"Report on the Use of Wetlands for Municipal Wastewater
Treatment and Disposal"
When Are yfl-ftT~n*g Wa-fcerg of 1:he United States?
The definition of waters of the U.S.' under 40 CFR Part 122.2
includes most wetlands. Wetlands which are adjacent to other
waters of the United States (other than wetlands) are
automatically waters of the U.S. In addition, other wetlands
(often called "isolated wetlands") are waters of the U.S. if their
use, degradation or destruction would or could affect interstate
or foreign commerce. Some examples of an adequate interstate
commerce connection are if the wetlands are or could'be used by
interstate or foreign travelers for recreational or other
purposes, contain or could contain fish or shellfish which could
be sold in interstate or foreign commerce, or are or could be used
for industrial purposes by industries in interstate commerce. In
addition. Isolated wetlands that are or could be utilized by
migratory waterfowl are regulated as waters of the U.S.
As discussed below, constructed wetlands which are designed,
built -and operated as wastewater treatment systems are in general
excluded from the definition of "waters of the U.S." (see 40 CFR
122.2, exclusion for waste* treatment'. systems). • Pending additional
rulemaking, the decisions of whether these waste treatment systems
are considered waters of the U.S. must be made on a case-by-case
basis. /.,'''
jfre*-n Can TTa-biriral Wfttf1 *-"rt*i H* XlnaA T?rrr K-p-Pl-nati-fc PQl±sh±pg?
Almost all natural wetlands are waters of the U.S. ' Municipal
discharges to those wetlands which are considered waters of the
U.S. are, therefore, subject; to the provisions of the Clean Water
Act and must meet minimum technology requirements and conform with
all applicable State water quality standards including the "free
froms" and other narrative standards. Thus, nothing less than
secondary effluent (or equivalent to secondary effluent where
trickling filters or waste stabilization ponds are used), may be
discharged.to a natural wetland., If State water quality standards
applicable to the wetland require more stringent,,or additional
-------
effluent limitations \ they, too must be met at the point of
discharge to the wetland. However, tinder circumstances where
secondary (or equivalent to secondary) effluent limitations are
met and all State water quality standards applicable to the
wetland are also met, If more stringent water quality criteria
apply to a downstream surface water body, natural wetlands can be
used to provide additional assimilation of conventional and
nonconventlonal pollutants. In limited situations natural wetland
treatment systems could provide certain communities, especially
small communities, with alternatives to more costly and complex
advanced treatment plants. However, effluent found to contain
potentially harmful levels of toxins should not be discharged to
natural wetlands or any constructed wetlands serving habitat
functions. . .
gase—By-Ca,se Evaluation of Proposed Natural Wetland Treatment
Systems .
Some natural wetlands can provide advanced effluent polishing
for conventional and nonconventlonal pollutants on a seasonal If
not year-round basis without damage to their ecological functions
and values. The Office of water and several Regional Offices have
been looting into many of the technical and administrative issues
associated'with such practices!for several years. However, in the
absence of appropriate water quality criteria for wetlands it Is
impossible to broadly identify the conditions under which they can
safely function as part of the treatment system, mien such
practices are allowed, a comprehensive monitoring system must be
in place. At a minimum, the monitoring program should be designed
to help avoid harmful accumulations of toxic materials present in
trace amounts in the wastewater and to detect changes in the plant
and animal communities due to changes in water flow and
characteristics caused by the wastewater discharge.
Therefore, proposals for treatment systems involving discharge
of secondary (or equivalent to secondary) effluent to natural
wetlands that are to provide additional treatment to the effluent
to meet higher downstream treatment requirements for conventional
and nonconventlonal pollutants should be reviewed by the Regions
on a case-by-case basis. 'The Region's wetlands protection staff
should be consulted ,on all such cases. Region IV's Freshwater
Wetlands for Wastewater Management Handbook (EPA 904/9-85-135;
September 1985) provides one source of guidance for such
case-by-case evaluations.
Proposals to use natural wetlands for effluent polishing may
Involve some alteration of'the" wetland, such as building dikes.
Such construction activity may require a Section 404 permit,
review under the National Environmental Policy Act, consideration
of other applicable Federal laws and executive orders (such as the
Endangered Species Act), and any applicable State laws governing
wetland filling or other alteration.
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-3-
. Wetlands Treatment Systems NPDBS Permit Recnii-rements
All effluent discharges Into wetlands which, are waters of the
U.S. require a National Pollutant Discharge Elimination System
(NPDES) permit. Municipal NPDES permits must contain minimum
technology-based limits and conform with all applicable State
water quality standards including the "free froms" and other '
narrative standards. In those cases where a natural wetland will
be used either on a seasonal or year-round'basis for effluent
polishing, the NPDES permit must contain secondary (or equivalent
to secondary) effluent limits consistent with 40 CFR Part 133,
plus any additional limits and/or monitoring requirements
necessary to protect the wetlands and achieve water quality
standards for the wetlands, adjacent and downstream waters. These
water quality-based limits must be implemented in the NPDES permit
at the point of discharge into the wetlands (i.e., at
end-of-pipe). In addition to meeting wate-a? quality standards in
the wetlands, the end-of-pipe water quality-based limits necessary
to achieve adjacent and downstream water quality standards may be
established based on the degree of effluent "polishing" provided
by the wetlands.
There are a number of cases where effluent polishing by
natural wetlands has been recognized in State-issued NPDES
permits. See, for example, the attached case summaries for the
Eoughton Lake, HI and Cannon Beach, OR projects. .
Const Tti ot Ion Grants Eligibility of Natural Wetlands ; .
Under certain limited circumstances the acquisition of a
natural wetland which will serve to polish municipal wastewater
. effluent may be eligible for construction grant funding.A
determination as to eligibility can be made only after a thorough
case-by-case evaluation has shown that the natural wetland
alternative is both cost effective and. environmentally sound. The,
latter determination must be made in consultation .with ..the *-•-.,
Region's wetland protection staff. In the case of Houghton Lake,
MI. pond treated secondary effluent is applied to state-owned
wetlands on a seasonal basis to achieve phosphorus and ammonia
removal while the wetland is maintained open and acceptable for
public access. On the other hand, at Cannon Beach, OR, natural
wetlands, which were purchased as a construction grant eligible
component, receive secondary pond effluent on a seasonal basis to
meet seasonal advanced treatment requirements for BOD and SS prior
to discharge to the receiving stream.
Such funding is only available where the management of the
wetlands is recognized in a NPDES permit as the method for
achieving*downstream water standards. This management may occur
beyond the discharge point, which would be the discharge to the
wetlands itself. In addition, the NPDES permit must require that
discharges into the wetlands must meet secondary (or equivalent to
secondary)' treatment limits and'any limits based on water quality
standards for the wetlands before funding can be made available.
Natural wetlands treatment systems can be funded as either
innovative or alternative technology under provisions of the .
Innovative and Alternative Technology program, depending upon the
experience with the type of wetland system to be used.
-------
Can Cmagfearnctetl Tte-falanAs Be tTsed For Wastewater Treatment?
tfhen assessing constructed wetlands for municipal wastewater
treatment a distinction should be made between those constructed
wetlands deisigned, built and operated as wastewater treatment
systems, and those constructed wetlands designed, built and
operated to provide many of the functions and values of natural
wetlands (e.g., wildlife habitat) in addition to providing
wastewater treatment. This is necessary in order to help
determine which wetlands are waters of the U*S. and, therefore,
the degree of wastewater treatment that is necessary prior to
placing the wastewater into the constructed wet land unit for
further treatment. Generally, man-made bodies of water which are
designed, built and operated as i wastewater treatment systems are
not waters of the U.S.
flnTlfitfTOn1sad- Waetewa-bor Treatment Wetlands
Constructed wastewater treatment wetlands can be designed,
built and operated as municipal j wastewater treatment systems .
See, for example, the attached case summary for the Gustine, CA
project. These are highly engineered systems designed to maximize
the treatment of municipal wastewater. Any other functions they
may provide must be 'incidental -fco the treatment of wastewater.
Through the Innovative and Alternative technology provisions of
the construction grants program1, EPA has been encouraging the use
of constructed wastewater treatment wetlands. The construction
costs for these systems, including land acquisition, have been and
remain eligible for up to 75% construction grants funding.
Constructed wastewater treatment wetlands that are designed, .
built , and operated as wastewater treatment systems are generally
not considered to be waters of the U.S. Thus the restrictions
which apply to natural wetlands do not generally apply to such
constructed wastewater treatment wetlands. Influent, to these
constructed wastewater treatment wetlands may range from raw ,
wastewater to secondary effluent or better. ,
Multiple Use Wetlands
There are many constructed wetlands which are designed, built
and operated to provide, in addition to wastewater treatment,
functions and values similar to those provided by natural
wetlands. See, for example, the attached case summaries for the
Martinez, CA; Arcata, CA; and Incline Village, NV projects.
The Martinez project involves wetlands which provide only
incidental treatment of secondary effluent from a regulatory
point-of-view because they were constructed for the benefit of
wildlife habitat, as an alternative to a more expensive deepwater
Bay outfall and diffuser. On the other hand, the Arcata project
involves wetlands constructed to provide year-round wastewater
treatment followed by a wetland discharge, in lieu of a Bay
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outfall and diffuser, through a pre-existing coastal wetland area
managed as a wildlife sanctuary to help enhance wildlife habitat
and overall Humboldt Bay area use. Finally, the Incline Village
project involves wetlands designed for both effluent disposal into
a non-discharging wetland and wildlife habitat enhancement.
Under certain circumstances such constructed multiple use
wetlands may be considered waters of the U.S. and as such would be
subject to the same protection and restrictions on use as natural
wetlands. This determination must be made on a case-by-case
basis and may consider factors such as the size and degree of
isolation of the constructed wetlands and other appropriate
factors Where such constructed multiple use wetlands are found
to function as waters of the U.S., municipal discharges to such
systems must be limited to secondary or equivalent to secondary
effluents and any more stringent «ffluent-requirements necessary
to meet applicable water quality standards. The Region's wetlands
protection staff should be consulted on all such cases.
Finally, in some cases a municipal wastewater discharge may
be the sole water supply for a constructed multiple purpose
wetland which becomes waters of the U.S. As long as the discharge
to such a wetland continues, the wetland would continue to be
considered waters of the U.S. However, aside from any contractual
arrangements which may be entered into, a municipal discharger is
not bound to supply water to the constructed wetland in
perpetuity, even if the wetland achieves a high level of
ecological complexity.
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CANNON BEACH, OREGON
CASE SUMMARY
PROJECT TYPE: Use of seasonally operated natural wetlands to upgrade
existing wastewater stabilization ponds treating the wastewater from a
permanent population of 1,200 which swells with, summer tourists1to
4,000. The ponds provide secondary equivalent treatment (30 mg/1 BOD
and 50 mg/1 SS as monthly averages) prior to stream discharge from
November 1 through .April 30. Prom May 1 through October,31, pond
effluent is further treated in the wetlands system to achieve monthly
average BOD and SS levels of 10 mg/1 prior to discharge to Ecola Creek.
GRANT FUNDING: 75%, including 10% I/A grant awarded in 1982; eligible
grant expenses included land acquisition costs. The capital costs and
the operation and maintenance requirements were significantly lower
than those of any of the conventional alternatives.
PRE-EZISTING SITUATION: Secondary treatment via three-cell
stabilization pond system, followed by chlorination and discharge into
a small tidal slough that drains into Ecola Creek. System incapable
of meeting summer discharge requirements.
PROJECT EVOLUTION: The project as originally envisioned would have
involved creation of a 15-acre constructed wetland within an existing
natural wetland located adjacent to the secondary treatment ponds.
After receiving an approved Section 404 permit, the 15 acre site was
to be stripped of its existing vegetation and re-planted with
bullrush, burreed, and wapatto to be harvested each fall. Concerns
raised by the U.S. Fish tf wildlife Service and other resource agencies
forced reconsideration of this proposal. It was determined that the
adverse effects of redistributing and destroying most of the wetland
could not be effectively mitigated by enhancement of waterfowl and
aquatic species habitat, and that, if .possible, the existing wetland
should be used in its natural condition. The project as ultimately
built uses the natural filtering capacity of the existing wetland
vegetation. t * ,
PROJECT DESIGN: Enclosure of approximately 15 acres of'existing ,
alder/spruce/sedge wetland by earthen dikes 12 feet wide and 0.5'to 7
feet high (2.5 ft. average). Detention time in the wetland is
approximately 10 days; Sections of the dike were intentionally made of
gravel » cobbles to help alleviate the potential effects of flooding
by allowing flood water from the nearby stream to flow through the
treatment site to downstream areas. .
NPDES PERMIT: Specifies seasonal discharge limitations of 10 mg/1 BOD
and SS as monthly averages at the point of the wetland discharge to the
creek for the period May 1 to October 31; and specifies .limitations at
the point of the secondary treatment ponds' discharge to the creek for
the period November 1 to April 30.
MONITORING: Conducted on the quality of lagoon influent, lagoon
effluent (at Outfall *1), wetland influent, wetland effluent (at
Outfall #2), and wetland background (in diversion ditch upgradient of
wastewater introduction). ......
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EOUGHTON LAKE, MICHIGAN
CASE SUMMARY
PROJECT TYPE: Upgrade of aerated ponds treating the wastewater from a
seasonally variable population, averaging approximately 8,000, by
establishment of a seasonally operated natural wetlands wastewater
treatment/discharge system. The ponds provide secondary treatment as
well as storage during the non-irrigation season. Unchlorinated
secondary pond effluent is applied to the Porter Ranch peat lands of
the Houghton Lake Wildlife Research Area from approximately May 15 to
September IS. The project is required to achieve year-around monthly
averages of 30 mg/1 BOD, 4 mg/1 CBOD, 20 mg/1 SS, and 0.5 mg/1 Total P,
as well as a requirement of 0.5 mg/1 NE3-N (as N) from Hay 16 to
October 15 for its two points of surface water discharge to Bear Creek
and Dead Horse Creek which flow into the Huskegon River.
GRANT FUNDING: 75% grant awarded in 1977; no grant funds for land ,
acquisition Involved since the wetlands are State-owned and their use
for the wastewater project is authorized through a special use permit
issued by the Wildlife Division, Department of Natural Resources,
State of Michigan. The capital costs and the operation and maintenance
requirements of the wetland system were significantly lower than those
of any available alternative.
PRE-EXISTING SITUATION: Individual household septic tanks with leach
field drainage entering Houghton Lake. Secondary treatment via aerated
ponds alone was incapable of meeting advanced treatment/discharge
requirements. Discharge to Great Lakes watershed required phosphorus
removal. ,
PROJECT: EVOLUTION: The wetlands system was developed as a more
cost-effective alternative to expanding existing seepage beds and
upland irrigation system for disposal of secondary effluent while
providing advanced ..treatment. Research and pilot scale testing
provided background data; full scale (1.1 MGD design) system was
constructed Jind placed in operation in 1978.
PROJECT DESIGN: Pond treated secondary effluent is distributed over a
16-week period each year across the width of the 1,500 acre
sedge-willow/leatherleaf-bog birch peatland at a rate of about 1 MGD
(not to exceed 2.5 MGD) through a series of 100 small gated openings
in a 3,200 ft. irrigation pipeline system mounted oh a wooded walkway
across the wetland which is maintained by the wastewater authority.
NPDES PERMIT: Specifies seasonal (May 16 to October 15) ammonia
nitrogen and fecal collfprm limits and year-round BOD, CBOD, SS, and
Total P requirements for the wetland discharges to the creeks and
compliance jwith requirements of the DNR Wildlife Division's special
use permit for applying secpndary effluent to the stateowned wetland -
including maintaining the wetland open and acceptable for public
access. , , . .
MONITORING: Conducted on pond effluent (i.e., wetland influent),
within wetland surface & ground water quality, wetland effluent
discharges to Bear Creek and Dead Horse Creek, and downstream water
quality; wetland hydrology, soils, vegetation & wildlife.
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MARTINEZ-, CALIFORNIA
;' CASE SUMMARY
PROJECT TYPE: Establishment by tie Mt. View Sanitary District (MVSD)
of a constructed wetland system with chlorinated secondary effluent to
create a wetland environment for the benefit of wildlife and migratory
waterfowl that would also improve water cjuality and avoid the building
of an .expensive deepwater outfall into Suisun Bay.
GRANT FUNDING: 75% grant awarded in 1974; no grant funds involved In-
land acruisition since the wetland area that was created as an
alternative to a deepwater outfall was not considered to be an integral
part of the treatment system in terms of the discharge permit issued by
the Regional California Water Resources Control Board. The capital
costs and operations and maintenance reoTiirements were significantly
lower than those of any available alternatives— :
PRE-EXISTING SITUATION/PROJECT EVOLUTION: The wetlands system was
developed in 1974 by MVSD as an alternative to constructing a 15-inch
diameter, 9,000 ft. long pipeline and outfall plus pumping facilities
C1977 estimated capital costs were $2.8 million and .$130,000/yr OtfM) or
abandonment of the existing treatment facilities and transport of _
untreated wastewater to a nearby community's treatment plant that would
have to be expanded to handle the additional flow (1977 estimated costs
to MVSD for conveyance of the wastewater and. expansion of the treatment
facilities were $8.9 million; MVSD's share of OffM costs were
$230,000/yr).
PROJECT DESIGN: Conventional treatment proceeding the wetland involves
comminution, primary and secondary sedimentation, high rate trickling
filtration and. effluent drlorination/deciilorination design to provide
full secondary treatment of 1.6 MGD dry weather flow with a hydraulic
capacity of 8 MGD wet weather flow. The wetland system was created on
20 3 acres jof, land that had. previously been a brackish water marsh, but
had been diked and drained early in the 1800's. The wetland was
designed to provide maximum wildlife habitat while avoiding nuisance
situations. Habitat types include open water mixed with stands of
emergent vegetation, islands, areas covered by floating vegetation, and
areas with cultivated wildlife foods, plus mud flats, levees, and
adjacent land With grasses, brush and trees. The total plant flow
passes through the wetland into Peyton Slough which discharges into
Suisun Bay. When the project flow was 0.7 MGD there was a 10-day
detention time in the wetland; land usage was 17 acres/MGD. At design
capacity of the treatment plant, there will be a ,5-day detention time
using 12 acres/MGD.
NPDES PERMIT: Specifies discharge limitations of 30 mg/1 BOD and TSS
as monthly .averages at the discharge from the high rate trickling
filter following chlorination/dechlorination.
MONITORING: In addition to standard monitoring of the effluent quality
from the conventional portion of the treatment plant, MVSD keeps "^ack
of the numbers and types of animals and plants supported by the wetland
habitat, including numerous species of migratory waterfowl and
shorebirds.
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GUSTINE, CALIFORNIA
CASE SUMMARY
PROJECT TYPE: Upgrade of existing stabilization ponds with, a design
capacity of 1 MGD treating a relatively high strength! wastewater
(ranging between 300 and 3,000 mg/1 BOD) from a small agricultural
town, including both, domestic and commercial sources - primarily from
dairy products industries. The ponds serve as the pretreatment system
for the constructed wetland cells to meet monthly average BOD and TSS
levels of 30 mg/1 prior to discharge to Los Banos Creek which flows
into the San Joaquin River. i
GRANT FUNDING: 75%, including 10% I/A grant and pilot testing awarded
in 1986; no grant funds for land acquisition involved since city-owned
land for the constructed wetland was available; a one-year pilot test
program (using a 0.4 ha constructed cattail marsh) was undertaken to
develop the final design criteria for the .system. . -The capital and .
operations costs and energy requirements made the stabilization
pond/constructed wetlands system considerably more cost-effective than
any of the other alternatives considered.
PRE-EXISTING SITUATION: Advanced primary treatment via 14
stabilization ponds; discharge of final effluent to adjacent duck
hunting clubs for land irrigation and wildlife was terminated by the
adjacent land owners. Modified disposal operation involving discharge
into Los Banos Creek could not consistently comply with secondary
effluent limitations. ,
PROJECT DESIGN: Effluent taken fr|om any of the last seven of 11
stabilization ponds, operated in series, is further treated in 24
constructed cattail marsh cells (each about 0.4 ha in size; 11.6 m
wide, 337 m long) which are operated in parallel. Effluent from each
cell flows over an adjustable weir which controls water depth in the
cell. Detention time in the constructed cattail marsh cells can be
controlled at 4 to 11 days.
NPDES PERMIT: Specifies discharge limitations of 30 mg/1 BOD and TSS
as monthly averages at the discharge to the creek and that the average
daily discharge shall not exceed 1.0 MGD.
MONITORING: Conducted on water quality of influent, effluent, and
receiving waters.
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ARCATA, CALIFORNIA
CASE SUMMARY
^
Bay.
land acquisition because land was city-owned.
PRE-EXISTING SITUATION/PRESENT EVOLUTION: Original plans developed in
iS;«irttiiad £ or Arcata to be part of a $25 million Humboldt Bay
oSam began operation in 1980 to evaluate this concept as^an
tvl t5 complete^ phase out of the pond discharge from Humboldt
ay accordance with the State Water Resources Control Board s Bays
and Estuaries Policy." '
Three 1-acre marshes were constructed as treatment
.
wildlife populations in the Humboldt Bay area. The Poshing
ds are operated at a depth of 0.5 m providing a theoretical
resdnle tLePof about 189 days. Th631"-acres- of disposal wetlands
are Slrtted at a hydraulic loading of 0.07 USD/acre- as -recommended .for
Sols?ll conservancy marshes also help reduce BOD and ammonia l^els
Shils achieving some removal of phosphorus from the effluent leaving
Si polishing wetlands. Cattail and bullrush dominate the PP^J^^
marshes whili a wide diversity of vegetation is present in the Arcata
Marsh and Wildlife Sanctuary.
NPDES PERMIT: Preliminary project standards for BOD and SS Cor NR -
would mle? these standards. The- disposal marshes allowed the *ȣ
svStem to meet NPDES requirements consistently,- in spite of start . up
Sobfems associated with the conventional portion of the P^ -"^^
upgrades. , Fecal coliforms were also greatly reduced by the polishing
marsh during, this period. ^ . :,>;/,; _ _..,; ^ , ..: ', . _•; '..' ,.,% .,; „. ;.
MONITORING: An integrated monitoring program deveiaPedMa^5;a|n
Snot Srofiram is being continued to monitor the. Arcata.. Marsh and
5Sdlll I laSStuary aria for water quality, fish tissue' ^sid^kes
vegetation patterns, and various special studies in conjunction with
Humbolt State University.
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INCLUDE VILLAGE, NEVADA
CASE SUMMARY
PROJECT TYPE: Establishment by the Incline Village General Improvement
District (IVGID) of a constructed, nondischarging wetland system that
was designed for both, effluent disposal and wildlife habitat
enhancement. The wetland system is part of a no-discharge wastewater
treatment/disposal-system initially being implemented as an alternative
to providing nutrient removal prior to effluent discharges to the
Carson River. The wetland system was put into operation in 1984. The
wastewa,ter treatment system serves a permanent population of about
8,000 which swells seasonally to about 15,000, treating a dry weather
flow of approximately 1.6 MGD. Effluent is used to irrigate pasture
from April 15 - October 1 until 1995 when the wetlands will be the sole
disposal method and accomplish the goal of no direct discharge to the
Carson River.
GRANT FUNDING: 85%, including 10% I/A, grant, awarded in 1982; eligible
grant expenses included land acquisition costs. The nondischarging
system, which initially combines seasonal pasture irrigation with
seasonal discharge to a constructed wetlands, was found to be the most
cost effective alternative to nutrient removal for continued river
discharge during winter and to eventually achieve the goal of no direct
discharge to the Carson River.
PRE-EXISTING SITUATION/PROJECT EVOLUTION: IVGID, which is located on
the north shore of Lake Tahoe, could not discharge its effluent into
Lake Tahoe. Consequently the District pumped its secondary effluent
out of the Lake Tahoe Basin via a 30 km pipeline and discharged to the
Carson River. The effluent was used to irrigate pasture from April 15-
October 1 and discharged to the Carson River during the winter. The
wetlands concept was developed inj response to an order from the Nevada
Division of Environmental Protection prohibiting future direct
discharges to the Carson River.
PROJECT DESIGN: The 906-acre project site's created wetlands contains
four cells that can be operated in series or in parallel, but are
normally operated in series. They include central channels and
islands. Each cell is divided into four subcells. Separate outlets to
the cells allow for individual management of each cell as required.
Water depths in the created wetlands range from 15 cm to about 1 m. An
overflow area receives all effluent in excess of the percolation and
evapotranspiration capacity of the created wetlands. Seasonal storage
(which contains an area of open water with three islands for wildlife
use) is provided to store excess effluent during cool, wet seasons.
Habitat enhancement includes the creation of entirely new permanent and
seasonal wetlands. Bullrush and cattail are dominating the seasonal
wetlands. The created wetlands also serve to expand a nearby warm
water (-spring fed) wetland area used extensively for migratory
waterfowl.
NPDES PERMIT: No NPDES permit is currently required for this
1 non-discharging system, although one may be obtained in the future to
deal with any potential releases.:
MONITORING: Very limited i
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