United States Environmental Protection Agency Office ot Water, Office of Wetlands, Oceans and Watersheds (4502 F) EPA843-F-95-001y February 1995 Wetlands and Runoff Since wetlands are typically the lowest area on the landscape, they often receive runoff from surrounding land. Several of the key programs that address such pollution are discussed in this fact sheet. Runoff (sometimes called "stormwater" or "nonpomt source pollution") is caused by rainfall or snow melt moving over and through the ground. Runoff carries natural and manmade pollut- ants into low areas such as wetlands, lakes, streams, and eventually into ground water. In addition, atmo- spheric deposition and hydrological modifications can contribute pollut- ants to runoff as well as directly into surface water. The quality or U.S. wetlands and other water resources is related to the quality of the environ- ment contributing to these waters. However, programs have historically focused on single goals or small sets of goals. These programs have succeeded in identifying and controlling, to some degree, the larger point sources of pollution. EPA has expanded its focus to use an approach that addresses the interconnections between water resources and the land, air, and water environment surrounding the resources. Untreated Runoff Impacts to Wetlands Untreated runoff from agricultural land, urban areas, and other sources is a leading cause of water quality impairment. Siltation; pollutants; excess nutrients; and changes to water flows, such as more frequent inunda- tion, and increased turbidity, are responsible for most of the impacts to wetlands from runoff. Impacts to wetlands have resulted in consequences such as changed species composition, increased pollutant loadings (e.g., heavy metals), and replacement of complex wetland systems with less desired open water. Modifications of wetlands associated with some runoff management practices have resulted in significant impacts to wetlands. Some impacts have been particularly tragic, such as in Kesterson and Stillwater Wildlife Refuges, where untreated, contami- nated runoff resulted in mortality and deformities of wildlife populations, particularly fish and migratory birds. Current Status EPA has developed technical informa- tion that landowners can use to protect the many functions of wet- lands, including water quality im- provement. An issue paper highlighting the impacts of stormwater on wetlands, entitled Natural Wetlands and Urban Stormwater: Potential Impacts and Management, is available through the EPA Wetlands Informa- tion Hotline (contractor operated). Other information that can be obtained includes a guide describing best management practices to pretreat stormwater runoff before it enters a natural wetland (in press). Additional materials on wetlands protection and restoration for nonpoint source benefits will be developed to assist in implementation of the wetlands and riparian areas chapter in the CZARA Management Measures Guidance (see box on page 2). EPA will continue to work to address potential opportunities ' and conflicts regarding wetlands and programs addressing runoff. For more information, contact the EPA Wetlands Information Hotline at 1-800-832-7828 (contractor operated). -------OCR error (C:\Conversion\JobRoot\00000A1B\tiff\2000U20Q.tif): Unspecified error ------- |