Elwha Watershed Information Resource

Wetlands are the interface between land (terrestrial ecosystems) and water (aquatic ecosystems). Under the Clean Water Act, the Environmental Protection Agency (EPA) defines wetlands 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 prevalence of vegetation typically adapted for life in saturated soil conditions."

Types of wetlands

There are four main wetland categories (EPA 2007):

• Marshes contain soft-stemmed vegetation.
• Swamps are dominated by woody plants.
• Bogs are freshwater wetlands with spongy peat deposits, evergreen trees and shrubs, and a sphagnum moss carpet.
• Fens are peatlands with grasses, sedges, reeds, and wildflowers that are fed by groundwater and are not as acidic as bogs.

Importance of wetlands

Wetlands are a unique part of a watershed and are important to its health because wetlands:

• Filter sediments containing nutrients and chemicals;
• Provide flood and erosion control; and
• Provide critical habitat to plants and animals.

Conducting visual encounter surveys for amphibians on the Elwha floodplain. U.S. Geological Survey

Wetlands provide nesting, feeding, and breeding areas for invertebrates, fish, amphibians, reptiles, birds, and mammals. According to the EPA (2007), about 35 percent of all plants and animals in the U.S. that are listed as threatened or endangered species either live in wetlands or depend on them. According to the Washington Department of Wildlife, morethan 315 species in Washington use wetlands as their primary nesting and feeding grounds (Lane and Taylor 1997).

Wetlands of the Elwha

Prior to the construction of the Elwha and Glines Canyon Dams in the early 1900s, there were an estimated 48 acres of vegetated wetlands and 122 acres of non-vegetated wetlands (that is, river channel and gravel bars) in the watershed (NPS 1996). Today, these areas are covered by reservoirs--a major loss to the watershed ecosystem.

It is estimated that dam removal will have both positive and negative effects on the wetlands:

• Initially, a portion of the 43 acres of wetlands that currently exist may be damaged or eliminated.
• However, an estimated 48 acres of palustrine forest or palustrine shrub wetland would naturally establish along the river.
• Additionally, 122 acres of channel and gravel bar wetlands would be created as well.

Wetlands Research

Researchers must have baseline (pre dam removal) data on the wetlands and the species that use them in order to develop restoration projects and judge the effectiveness of natural and assisted restoration efforts in the wetlands post dam removal. Several wetlands studies (pre dam removal) are currently underway.

Reference

Environmental Protection Agency. 2007. Wetlands.

Lane, R. C., and W. A. Taylor. 1997. "Washington’s wetland resources." Tacoma, Wash., U.S. Geological Survey, accessed October 14, 1997, HTML format [based on Lane, R.C., and Taylor, William A., 1996, Washington wetland resources, in Fretwell, Judy D., Williams, John S., and Redman, Phillip J., comps., National water summary on wetland resources: U.S. Geological Survey Water-Supply Paper 2425, p.393-397].

National Park Service. 1996. Elwha River Ecosystem Restoration, Draft Environmental Impact Statement. National Park Service, Olympic National Park, 600 East Park Avenue, Port Angeles, Washington, 98362.

Additional Information

Granger, T. and others. 2005. Wetlands in Washington State - Volume 2: Guidance for protecting and managing wetlands. Washington State Department of Ecology Publication #05-06-008. Download.

Stevens, M. L., and R. Vanbianchi. 1993. Restoring Wetlands in Washington: A guidebook for wetland restoration planning and implementation. Washington Department of Ecology and National Oceanic and Atmospheric Administration, Publication #93-17. Download.