United States:; ';.-.
Environmental.Protection
Agency, _
Office of Water
(4503F)
EPA-841-F-96-004K
March 1996
Non point Pointers
Understanding and managing nonpoint source pollution in your community
Managing Wetlands to
Control JMonpoiht
Source Pollution
" - States/territories, and tribes identify nonpoint source (NFS) pollution as
the Nation's leading source of surface water and ground water quality
r impairments; When properly managed,~wetlands can^help prevent NFS ,;._
pollutionfrom degrading water quality. Wetlands include swarnps/-
marshes, fens, and bogs. '"-- ' " "!:,-,-_ "--.^
.Properly managed wetlands can intercept runoff and transform and store
NFS pollutants like sediment, nutrients, and certain heavy metals without-
being degraded. In addition, wetlands vegetation can keep stream channels
intact by slowing runoff and by evenly distributing'the energy in runoff.'"
\ Wetlands vegetation also regulates stream temperature by providing
streamside shading. Some cities have started to. experiment with wet-
lands as an effective tool to control runoff and protect urban
•~-~~ ' - - • • -- - streams,- , ' •'-': , ~~ , ~?
Improper development or -
excessive pollutant loads can "
damage wetlands; The .degraded
wetlands can no longer provide
water quality benefits and become
significant sources of NPS'pollu-
tion. Excessive-amounts of decay-
ing wetlands,vegetation, for -
~~- ;-'--- "-•'- —'-"'' f .'^ "': ~"'' "''" "' example, canihcrease-bioGhemical
> „, " '. ^"Joxygen demand, m'aking habitat
unsuitable for fish ancj. other aquaticlife. Degraded wetlands also release
stored nutrients arid other chemicals into surface water and ground water
',•,.' ' ~:~~ , "'' , »~ ~~:.~r : , ,,^-", ,„ "; -' .^^.--,1 ,,~-^ ~.'.~ .' ,< < , -—;•_, ^ . ^
The_U,S. Environmental Protection Agency (EPA)I recommends three"
management strategies to maintain the wate/quality benefits-provided by
wetlands: preservation, restoration,-and construction of engineered systems
that pretreat runoff before it reaches receiving waters and wetlands.' ^ -
._ -'-.. ' • ." '. •._, •.•'-• . '• • . ': -'—-l^1' , - •, ..- ~^/'~ ", • _;- . '•~~f!' ,_.
Wetlands Preservation "
The first strategy protects theJiill range"of wetlands functions bydis- [,
couraging development activity. At the same time, this strategy encourages
proper management of upstream watershed activities, such as agriculture, _
forestry, and urban development. Several programs administered by EPAr
JProperly. managed wetlands can
" intercept r-anoff and transform
-and store NFS pollutants like
sediment, nutrients, andcer-
\. tain heavy metals -without . -~ ~
*" being degraded.~ , ..-.'" .
series ^
of fact sheets !^^
on nonpoint j
source (NFS) pcbllution
V
receive signilieant
,, amounts of NS
they are typically
thejowest point
the landscape?
NFS pollution occurs when
water runs over land or through
the ground, picks up pollutants,
and deposits them in surface
waters or introduces them into
ground water. -
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RELATED PUBLICATIONS
• Additional fact sheets in the
Nonpoint Pointers series
(EPA-841-F-96-004)
• Guidance Specifying
Management Measures for
Sources of Nonpoint Pollu-
tion in Coastal Waters,
Chapter 7 (EPA-840-B-92-
002)
• The Quality of Our Nation's
Water: 1994 (EPA-841-S-95-
004)
To order any of the above EPA
documents call or fax the
National Center for Environmen-
tal Publications and Information.
Tel (513)489-8190
Fax (513)489-8695
To order the following EPA
documents, call EPA's Wetlands
Hotline at 1 -800-832-7828.
• America's Wetlands (OPA-
87-016)
• Constructed Wetlands for
Wastewater Treatment and
Wildlife Habitat (EPA-832-R-
93-005)
• Natural Wetlands and Urban
Stormwater: Potential
Impacts and Management
(EPA-843-R-001)
• " Wetlands Fact Sheets (EPA-
843-F-95-001)
FOR MORE INFORMATION
U.S. Environmental Protection
Agency
Nonpoint Source Control Branch
Washington DC 20460
Internet Address:
http://www.epa.gov/owow/rips/
!ndex.html
the U.S. Department of Agriculture, the National Oceanic and. Atmospheric
Administration, the U.S. Army Corps of Engineers, and the U.S. Department
of the Interior, as well as other government agencies, protect wetlands by
either controlling development activities that would affect wetlands or
providing financial assistance to people who wish to protect them. In
addition, nongovernmental groups that purchase wetlands for conservation
purposes, such as The Nature Conservancy, The Trust for Public Land, and
local land trusts, are playing an increasingly important rol&in protecting
water quality. • . ,
Wetlands/Riparian Restoration
The second strategy promotes the restoration of degraded wetlands and
riparian zones with NFS pollution control potential. Riparian zones are the
vegetated ecosystems along a water body through which energy, materials,
and water pass. Riparian areas characteristically have high water-tables and
are subject to periodic flooding and influence Jirpm the adjacent water body.
They encompass wetlands and uplands, or some combination of .these two
landforms. •; -'_•-" "1.._
Restoration activities-should recreate the full range of preexisting .wet-
lands functions. That means replanting degraded wetlands with native
plant species and, depending on the location and the,degree of degradation,
using structural devices to control water flows. Restoration projects factor in
ecological principles, such as habitat diversity and the connections between
different aquatic and riparian habitat types, which distinguish these kinds
of projects from wetlands that are constructed for runoff pretreatment.
Engineered Systems
The third strategy promotes the use of engineered vegetated treatment
systems (VTS). VTS are especially effective at removing suspended solids "
and sediment from NFS pollution before the runoff reaches natural wet-
lands.
. One type of VTS, the vegetated filter strip (VPS), is a swath of land ;
planted with grasses and trees that intercepts uniform sheet flows of runoff,
before the runoff reaches wetlands. VFSs are most effective at sediment
removal, with removal rates usually greater than 70%. Constructed wet- '
lands, another type of VTS, are typically engineered complexes of water,
plants, and animal life that simulate naturally occurring wetlands. Studies
indicate "that constructed wetlands can achieve sediment removal rates
greater than 90 percent. Like VPS, constructed wetlands offer an alternative
to other systems that are more structural in design.
Saving a Precious Resource
Healthy wetlands benefit fish, wildlife, and humans because they protect
many natural resources, only one of which is clean water. Unfortunately,
over half of the wetlands in the lower 48 states were lost between the late
1700s and the mid-1980s, and undisturbed wetlands still face threats from
development. To help prevent NFS pollution from further degrading the
Nation's waters and to protect many other natural resources, wetiancts .
protection must remain a focal point for national education campaigns,
.Sfished protection plans, and local conservation efforts.
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