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A. Management Measure for Protection of Wetlands and Riparian Areas

Protect from adverse effects wetlands and riparian areas that are serving a significant NPS abatement function and maintain this function while protecting the other existing functions of these wetlands and riparian areas as measured by characteristics such as vegetative composition and cover, hydrology of surface water and ground water, geochemistry of the substrate, and species composition.

1. Applicability

This management measure is intended to be applied by States to protect wetlands and riparian areas from adverse NPS pollution impacts. Under the Coastal Zone Act Reauthorization Amendments of 1990, States are subject to a number of requirements as they develop coastal NPS programs in conformity with this management measure and will have flexibility in doing so. The application of management measures by States is described more fully in Coastal Nonpoint Pollution Control Program: Program Development and Approval Guidance, published jointly by the U.S. Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA) of the U.S. Department of Commerce.

2. Description

The purpose of this management measure is to protect the existing water quality improvement functions of wetlands and riparian areas as a component of NPS programs. The overall approach is to establish a set of practices that maintains functions of wetlands and riparian areas and prevents adverse impacts to areas serving an NPS pollution abatement function. The ecosystem and water quality functions of wetlands and riparian areas serving an NPS pollution abatement function should be protected by a combination of programmatic and structural practices.

The term NPS pollution abatement function refers to the ability of a wetland or riparian area to remove NPS pollutants from runoff passing through the wetland or riparian area. Acting as a sink for phosphorus and converting nitrate to nitrogen gas through denitrification are two examples of the important NPS pollution abatement functions performed by wetlands and riparian areas.

This management measure provides for NPS pollution abatement through the protection of wetland and riparian functions. The permit program administered by the U.S. Army Corps of Engineers, EPA, and approved States under section 404 of the Clean Water Act regulates the discharge of dredged or fill material into waters of the United States, including wetlands. The measure and section 404 program complement each other, but the focus of the two is different.

The measure focuses on nonpoint source problems in wetlands, as well as on maintaining the functions of wetlands that are providing NPS pollution abatement. The nonpoint source problems addressed include impacts resulting from upland development and upstream channel modifications that erode wetlands, change salinity, kill existing vegetation, and upset sediment and nutrient balances. The section 404 program focuses on regulating the discharge of dredged or fill materials in wetlands, thereby protecting wetlands from physical destruction and other pollutant problems that could result from discharges of dredged or fill material.

The nonpoint source pollution abatement functions performed by wetlands and riparian areas are most effective as parts of an integrated land management system that combines nutrient, sediment, and soil erosion control. These areas consist of a complex organization of biotic and abiotic elements. Wetlands and riparian areas are effective in removing suspended solids, nutrients, and other contaminants from upland runoff, as well as maintaining stream channel temperature (Table 7-1). In addition, some studies suggest that wetland and riparian vegetation acts as a nutrient sink (Table 7-1), taking up and storing nutrients (Richardson, 1988). This function may be related to the age of the wetland or riparian area (Lowrance et al., 1983). The processes that occur in these areas include sedimentation, microbial and chemical decomposition, organic export, filtration, adsorption, complexation, chelation, biological assimilation, and nutrient release.

Pollutant-removal efficiencies for a specific wetland or riparian area may be the result of a number of different factors linked to the various removal processes:

  1. Frequency and duration of flooding;
  2. Types of soils and slope;
  3. Vegetation type;
  4. The nitrogen-carbon balance for denitrifying activity (nitrate removal); and
  5. The edge-to-area ratio of the wetland or riparian area.
Watershed-specific factors include land use practices and the percentage of watershed dominated by wetlands or riparian areas.

A study performed in the southeastern United States coastal plain illustrates dramatically the role that wetlands and riparian areas play in abating NPS pollutants. Lowrance and others (1983) examined the water quality role played by mixed hardwood forests along stream channels adjacent to agricultural lands. These streamside forests were shown to be effective in retaining nitrogen, phosphorus, calcium, and magnesium. It was projected that total conversion of the riparian forest to a mix of crops typically grown on uplands would result in a twenty-fold increase in nitrate-nitrogen loadings to the streams (Lowrance et al., 1983). This increase resulted from the introduction of nitrates to promote crop development and from the loss of nitrate removal functions previously performed by the riparian forest.

3. Management Measure Selection

Selection of this management measure was based on:

  1. The opportunity to gain multiple benefits, such as protecting wetland and riparian area systems, while reducing NPS pollution;

  2. The nonpoint pollution abatement function of wetlands and riparian areas, i.e., their effectiveness in reducing loadings of NPS pollutants, especially sediment, nitrogen, and phosphorus, and in maintaining stream temperatures; and

  3. The localized increase in NPS pollution loadings that can result from degradation of wetlands and riparian areas.

Separate sections below explain each of these points in more detail.

a. Multiple Benefits

The preservation and protection of wetlands and riparian areas are encouraged because these natural systems have been shown to provide many benefits, in addition to providing the potential for NPS pollution reduction (Table 7-2 (15k)). The basis of protection involves minimizing impacts to wetlands and riparian areas serving to control NPS pollution by maintaining the existing functions of the wetlands and riparian areas, including vegetative composition and cover, flow characteristics of surface water and ground water, hydrology and geochemical characteristics of substrate, and species composition (Azous, 1991; Hammer, 1992; Mitsch and Gosselink, 1986; Reinelt and Horner, 1990; Richter et al., 1991; Stockdale, 1991).

Wetlands and riparian areas perform important functions such as providing a source of food for a variety of wildlife, a source of nesting material, habitat for aquatic animals, and nursery areas for fish and wildlife (Atcheson et al., 1979). Animals whose development histories include an aquatic phaseÄamphibians, some reptiles, and invertebratesÄneed wetlands to provide aquatic habitat (Mitsch and Gosselink, 1986). Other important functions of wetlands and riparian areas include floodwater storage, erosion control, and ground-water recharge. Protection of wetlands and riparian areas should allow for both NPS control and other corollary benefits of these natural aquatic systems.

b. Nonpoint Pollution Abatement Function

Table 7-1 is a representative listing of the types of research results that have been compiled to document the effectiveness of wetlands and riparian areas in serving an NPS pollution abatement function. Wetlands and riparian areas remove more than 50 percent of the suspended solids entering them (Karr and Gorman, 1975; Lowrance et al., 1984; Stuart and Greis, 1991). Sixty to seventy-five percent of total nitrogen loads are typically removed from surface and ground waters by wetlands and riparian areas (Cooper, 1990; Jacobs and Gilliam, 1985; James et al., 1990; Lowrance et al., 1983; Lowrance et al., 1984; Peterjohn and Correll, 1984; Pinay and Decamps, 1988; Stuart and Greis, 1991). Phosphorus removal in wetlands and riparian areas ranges from 50 percent to 80 percent (Cooper and Gilliam, 1987; Peterjohn and Correll, 1984; Stuart and Greis, 1991).

c. Degradation Increases Pollution

Tidal wetlands perform many water quality functions; when severely degraded, however, they can be a source of nonpoint pollution (Richardson, 1988). For example, the drainage of tidal wetlands underlain by a layer of organic peat can cause the soil to rapidly decompose and release sulfuric acid, which may significantly reduce pH in surrounding waters. Removal of wetland or riparian area vegetation along the shorelines of streams, bays, or estuaries makes these areas more vulnerable to erosion from storm events, wave action, or concentrated runoff. Activities such as channelization, which modify the hydrology of floodplain wetlands, can alter the ability of these areas to retain sediment when they are flooded and result instead in erosion and a net export of sediment from the wetland (Reinelt and Horner, 1990).

4. Practices

As discussed more fully at the beginning of this chapter and in Chapter 1, the following practices are described for illustrative purposes only. State programs need not require implementation of these practices. However, as a practical matter, EPA anticipates that the management measure set forth above generally will be implemented by applying one or more management practices appropriate to the source, location, and climate. The practices set forth below have been found by EPA to be representative of the types of practices that can be applied successfully to achieve the management measure described above.

  • a. Consider wetlands and riparian areas and their NPS control potential on a watershed or landscape scale.

    Wetlands and riparian areas should be considered as part of a continuum of filters along rivers, streams, and coastal waters that together serve an important NPS abatement function. Examples of the practice were outlined by Whigham and others (1988). They found that a landscape approach can be used to make reasonable decisions about how any particular wetland might affect water quality parameters. Wetlands in the upper parts of the drainage systems in particular have a greater impact on water quality. Hanson and others (1990) used a model to determine the effect of riparian forest fragmentation on forest dynamics. They concluded that increased fragmentation would lead to lower species diversity and an increased prevalence of species that are adapted to isolated conditions. Naiman and others (1988) discussed the importance of wetlands and riparian areas as boundary ecosystems, providing a boundary between terrestrial and aquatic ecosystems. Wetlands and riparian areas are particularly sensitive to landscape changes and fragmentation. Wetland and riparian boundaries covering large areas may persist longer than those on smaller spatial scales and probably have different functional values (Mitsch, 1992).

    Several States have outlined the role of wetlands and riparian areas in case studies of basinwide and statewide water quality plans. A basinwide plan for the restoration of the Anacostia River and associated tributaries considered in detail the impacts of wetlands creation and riparian plantings (USACE, 1990). In Louisiana and Washington State, EPA has conducted studies that use the synoptic approach to consider wetlands' water quality function on a landscape scale (Abbruzzese et al., 1990a, 1990b). The synoptic approach considers the environmental effects of cumulative wetlands losses. In addition, this approach involves assembling a framework that ranks watersheds according to the relative importance of wetland functions and losses. States are also encouraged to refine their water quality standards applicable to wetlands by assigning wetlands-specific designated uses to classes of wetlands.

  • b. Identify existing functions of those wetlands and riparian areas with significant NPS control potential when implementing NPS management practices. Do not alter wetlands or riparian areas to improve their water quality function at the expense of their other functions.

    In general, the following practices should be avoided: (1) location of surface water runoff ponds or sediment retention basins in healthy wetland systems and (2) extensive dredging and plant harvesting as part of nutrient or metals management in natural wetlands. Some harvesting may be necessary to control the invasion of exotic plants. Extensive harvesting for surface water runoff or nutrient management, however, can be very disruptive to the existing plant and animal communities.

  • c. Conduct permitting, licensing, certification, and nonregulatory NPS pollution abatement activities in a manner that protects wetland functions.

    There are many possible programs, both regulatory and nonregulatory, to protect wetland functions. Table 7-3 contains a representative listing of Federal, State, and Federal/State programs whose primary goals involve the identification, technical study, or management of wetlands protection efforts. Table 7-4 (31k) provides a list of Federal programs involved in the protection and restoration of wetlands and riparian areas on private lands. Federal programs with cost-share funds are designated as such in Table 7-4 (31k). The list of possible programmatic approaches to wetlands protection includes the following:

    Acquisition. Obtain easements or full acquisition rights for wetlands and riparian areas along streams, bays, and estuaries. Numerous Federal programs, such as the U.S. Department of Agriculture (USDA) Wetlands Reserve, administered by USDA's Agricultural Stabilization and Conservation Service (USDA-ASCS) with technical assistance provided by USDA's Soil Conservation Service (USDA-SCS) and U.S. Department of the Interior - Fish and Wildlife Service (USDOI-FWS), and the Fish and Wildlife Service North American Waterfowl Management Plan can provide assistance for acquiring easements or full title. Acquisition of water rights to ensure maintenance of minimum instream flows is another means to protect riparian/wetland areas, and it can be a critical issue in the arid West. In Arizona, The Nature Conservancy has acquired an instream water rights certificate for its Ramsey Canyon preserve in the Huachuca Mountains. The certificate gives the Arizona Nature Conservancy the legal right to maintain instream flows in the stretch of Ramsey Creek along their property, which in turn preserves instream and riparian habitat and wildlife (Andy Laorenzi, personal communication, 5 October 1992). in turn preserves instream and riparian habitat and wildlife (Andy Laurenzi, personal communication, 5 October 1992).

    Zoning and Protective Ordinances. Control activities with a negative impact on these targeted areas through special area zoning and transferable development rights. Identify impediments to wetland protection such as excessive street standards and setback requirements that limit site-planning options and sometimes force development into marginal wetland areas.

    Baltimore County, Maryland, has adopted legislation to protect the water quality of streams, wetlands, and floodplains that requires forest buffers for any activity that is causing or contributing to pollution, including NPS pollution, of the waters of the State. Baltimore County has also developed management requirements for the forest buffers, including those located in wetlands and floodplains, that specify limitations on alteration of the natural conditions of these resources. The provisions call for public and private improvements to the forest buffer to abate and prevent water pollution, erosion, and sedimentation of stream channels and degradation of aquatic and riparian habitat.

    Water Quality Standards. Almost all wetlands are waters of the United States, as defined in the Clean Water Act. Ensure that State water quality standards apply to wetlands. Consider natural water quality functions when specifying designated uses for wetlands, and include biological and hydrologic narrative criteria to protect the full range of wetland functions.

    The State of Wisconsin has adopted specific wetlands water quality standards designed to protect the sediment and nutrient filtration or storage function of wetlands. The standards prohibit addition of those substances that would "otherwise adversely impact the quality of other waters of the State" beyond natural conditions of the affected wetland. In addition, the State has adopted criteria protecting the hydrologic conditions in wetlands to prevent significant adverse impacts on water currents, erosion or sedimentation patterns, and the chemical and nutrient regimes of the wetland. Wisconsin has also adopted a sequenced decision-making process for projects potentially affecting wetlands that considers the wetland dependency of a project; practicable alternatives; and the direct, indirect, and cumulative impacts of the project.

    Regulation and Enforcement. Establish, maintain, and strengthen regulatory and enforcement programs. Where allowed by law, include conditions in permits and licenses under CWA .401, .402, and .404; State regulations; or other regulations to protect wetlands.

    Restoration. Programs such as USDA's Conservation Reserve and Wetlands Reserve Program provide opportunities to set aside and restore wetlands and riparian areas. Also, incentives that encourage private restoration of fish and wildlife productivity are more cost-effective than Federal acquisition and can in turn reduce property tax receipts by local government.

    Education and Training. Educate farmers, urban dwellers, and Federal agencies on the role of wetlands and riparian areas in protecting water quality and on best management practices (BMPs) for restoring stream edges. Teach courses in simple restoration techniques for landowners.

    Comprehensive Watershed Planning. Provide a mechanism for private landowners and agencies in mixed-ownership watersheds to develop, by consensus, goals, management plans, and appropriate practices and to obtain assistance from Federal and State agencies. Establish a framework for multiagency program linkage, and present opportunities to link implementation efforts aimed at protection or restoration of wetlands and riparian areas. EPA's National Estuary Program and the Fish and Wildlife Service's Bay/Estuary Program are excellent examples of this multiagency approach. A number of State and Federal agencies carry out programs with compatible NPS pollution reduction goals in the coastal zone. For example, Maryland's Nontidal Wetlands Protection Act encourages development of comprehensive watershed plans for addressing wetlands protection, mitigation, and restoration issues in conjunction with water supply issues. In addition, the U.S. Army Corps of Engineers (USACE) administers the CWA .404 program; USDA implements the Swampbuster, Conservation Reserve, and Wetlands Reserve Programs; EPA, USACE, and States work together to perform advanced identification of wetlands for special consideration (.404); and States administer both the Coastal Zone Management (CZM) program, which provides opportunity for consistency determinations, and the CWA .401 certification program, which allows for consideration of wetland protection and water quality objectives.

    As an example of a linkage to protect NPS pollutant abatement and other benefits of wetlands, a State could determine under CWA .401 a proposed discharge or other activity in a wetland that is inconsistent with State water quality standards. Or, if a proposed permit is allowed contingent upon mitigation by creation of wetlands, such mitigation might be targeted in areas defined in the watershed assessment as needing restoration. Watershed- or site-specific permit conditions may be appropriate (e.g., specific widths for streamside management areas or structures based on adjacent land use activities). Similarly, USDA's Conservation Reserve Program or Wetlands Reserve Program could provide landowner assistance in areas identified by the NPS program as needing particular protection or riparian area reestablishment.

  • d. Use appropriate pretreatment practices such as vegetated treatment systems or detention or retention basins (Chapter 4) to prevent adverse impacts to wetland functions that affect NPS pollution abatement from hydrologic changes, sedimentation, or contaminants.

    For more information on the technical implementation and effectiveness of this practice, refer to Management Measure C in this chapter and Sections II.A and III.A of Chapter 4.

    5. Costs for All Practices

    This section describes costs for representative activities that would be undertaken in support of one or more of the practices listed under this management measure. The description of costs is grouped into the following categories:

    1. For implementation of practice "a": costs for mapping, which aids in locating wetlands and riparian areas in the landscape and determining their relationship to land uses and their potential for NPS pollution abatement.

    2. For implementation of practices "b" and "c": costs for wetland and riparian area protection programs.

    3. For implementation of practice "d": costs for pretreatment such as filter strips, constructed wetlands, and detention or retention basins.

    a. Mapping

    The identification of wetlands within the watershed landscape, and their NPS pollution abatement potential, involves using maps to determine the characteristics as described in the management measure. These may include vegetation type and extent, soil type, distribution of fully submerged and partially submerged areas within the wetland boundary, and location of the boundary between wetlands and uplands. These types of features can be mapped through a variety of methods.

    Lower levels of effort would characteristically involve the acquisition and field-checking of existing maps, such as those available for purchase from the U.S. Fish and Wildlife Service in the National Wetlands Inventory and U.S. Geological Survey (USGS) land use maps (information on these maps is available by calling 1-800-USA-MAPS). An intermediate level of effort would involve the collection and analysis of remote-sensing data, such as aerial photographs or digital satellite imagery. Depending on the size of the study area and the extent of the data to be categorized, the results of photo interpretation or of digital image analysis can be manipulated manually with a computerized database or electronically with a Geographic Information System. The most costly and labor-intensive approach involves plane-table surveys of the areas to be investigated.

    Three separate costs are reported below from actual examples of recent projects involving wetland identification and assessment for purposes similar to the goal of the management measure. The examples represent different levels of effort that could be undertaken in support of practice "a" under the management measure.

    1. A project in Clarks Fork, Montana, used remote sensing data for identification of wetlands that were potentially impaired from NPS pollution originating in adjacent portions of the watershed. In addition to identifying the type and extent of wetlands and riparian vegetation along Clarks Fork and the tributary streams, the mapping effort categorized land use in adjoining portions of the landscape. The results were used to identify areas within the watershed that could possibly be contributing NPS pollution in runoff to the wetlands and riparian areas (Lee, 1991).

      Total costs for this project were estimated at $0.06 per acre. The items of work include project management, collection of aerial photographs, film processing, and photo interpretation (Lee, 1991).

    2. Remote sensing data have also been used as part of a statewide assessment of wetlands in Wisconsin. The purpose of the project is to determine areas within the landscape where changes are occurring in wetlands. Three or four counties are evaluated each year. The results are used to provide an ongoing update of changes to wetlands characteristics such as hydrology and vegetation (Lee, 1991).

      Total costs for this project are approximately $0.07 per acre. The items of work include collection of aerial photography, film processing, photo interpretation, and development and maintenance of a Geographic Information System (Lee, 1991).

    3. The National Wetlands Inventory (NWI) has maps for 74 percent of the conterminous United States, 24 percent of Alaska, and all of Hawaii. Wetlands maps have been updated for wetlands assessment in three areas of the southeastern United States. The purpose of the project is to provide current data on the distribution of wetlands for project reviews, site characterizations, and ecological assessment (Kiraly et al., 1990).

      Total costs reported for this work are listed in Table 7-5. The items of work include staff time, travel expenses, and per diem (Kiraly et al., 1990).

    It is important to note that each of these three cases is presented for illustration purposes only. It is not necessary to acquire new data or maps to implement the practices and meet the management measure. Existing maps, surveys, or remotely sensed data (such as aerial photographs) can easily be used. These typically exist in files of State and local governments or educational institutions. Additional data on wetlands functions, locations, or ecological assessments can be culled from existing environmental impact statements, from old permit applications, or from watershed inventories. These sources of information in particular should be evaluated for their usefulness in categorizing historical conditions.

    Where the need for new maps is recognized to meet the management measure, several Federal agencies provide mapping products that could be useful. Examples include the following:

    • USDA aerial photography. Depending on the locality, this photography is available in black-and-white, color, or color-infrared (color-IR) formats.

    • USGS aerial photography. A variety of photo products are available, for example, through the National Aerial Photography Program (NAPP).

    • EPA Environmental Monitoring and Assessment Program (EMAP). Some opportunities for cost-shared projects are available to collect and analyze new imagery on the ecosystem or watershed level (Kiraly et al., 1990).

    b. Wetland and Riparian Area Protection Programs

    Examples of programmatic costs for implementing practices "b" and "c" under this management measure include costs for personnel, the administrative costs of processing applications for permits, and costs for public information brochures and pamphlets. Since some programs may already be in place, the need for apportionment of existing programmatic capabilities to NPS-related issues regarding wetlands and riparian areas will vary widely, depending on the size of the local jurisdiction, the nature and extent of wetland and riparian ecosystems present within the jurisdictional boundaries, and the severity of the NPS problem. Other programs may need to be adapted to include NPS-related issues regarding wetlands.

    Six separate examples of costs for existing State wetland programs are shown in Table 7-6 for illustrative purposes. The costs reflect a range of low to high levels of effort, as measured through the assignment of individual full-time equivalents (FTEs) and the task-specific dedication of discrete levels of clerical and administrative support. A low-level scenario consists of costs for one FTE. A high-level scenario consists of staffing of 10 or more FTEs, including clerical and administrative positions.

    If the costs for individual FTEs are estimated at $50,000 each, which includes salary plus fringe benefits, then some of the reported program budgets on the list mentioned above exceed reasonable estimates of salaries. This indicates that additional funding has been allocated for activities ranging from office support to technical assistance in the field.

    c. Pretreatment

    The use of appropriate pretreatment practices to prevent adverse impacts to wetlands that ultimately affect NPS pollution abatement involves the design and installation of vegetated treatment systems such as vegetated filter strips or constructed wetlands, or the use of structures such as detention or retention basins. These types of systems are discussed individually elsewhere in this guidance document. Refer to Chapter 4 for a discussion of detention and retention basins. See the discussion of Management Measure C later in Chapter 7 for a description of constructed wetlands and filter strips. The purpose of each of these BMPs is to remove, to the extent practicable, excessive levels of NPS pollutants and to minimize impacts of hydrologic changes. Each of these BMPs can function to reduce levels of pollutants in runoff or to attenuate runoff volume before it enters a natural wetland or riparian area.

    Whether these BMPs are used individually or in series will depend on several factors, including the quantity and quality of the inflowing runoff, the characteristics of the existing hydrology, and the physical limitations of the area surrounding the wetland or riparian area to be protected.

    Costs are reported below for three potential scenarios to implement practice "d" under this management measure.

    1. One filter strip at a cost of $129.00

      • Includes design and installation of a grass filter strip 1,000 feet long and 66 feet wide.
      • Most effective at trapping sediments and removing phosphorus from surface water runoff.

    2. One constructed wetland at a cost of $5,000.00

      • Includes design and installation of a constructed wetland whose surface area is 0.25 acre in size. The constructed wetland is planted with commercially available emergent vegetation.
      • Most effective to remove nutrients and decrease the rate of inflow of surface water runoff into the natural wetland located further downstream.

    3. One combined filter strip/constructed wetland - $5,129.00

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      This page last updated October 4, 1999