CW2:9219

From Environmental Technology

1. A.Wetland refers collectively to marshes, swamps, bogs and similar areas found between dry land and water along the edges of streams, rivers, lakes, ponds, and coastlines and other bodies of water. Although most wetlands have standing or flowing water, many are dry for part of the year. For example, estuarine wetlands that are influenced by the tides may be dry twice a day. Several wetland types occur throughout the Chesapeake watershed due to its variability in typography, climate, soil, hydrology, salinity, vegetation and other factors.

B. Estuarine wetlands are tidally flooded by salt or brackish water and are found chiefly along the shores of the Bay and its tidal rivers. Palustrine wetlands are freshwater areas, situated on the floodplains bordering rivers and streams, fringing the shorelines of lakes and ponds, filling isolated depressions and covering broad flat areas at or near sea level. Wetlands also are characterized by their vegetation, as: Emergent wetlands, commonly called marshes and wet meadows, dominated by grasses, sedges and other herbaceous or non-woody plants; Shrub wetlands, including shrub swamps and bogs, characterized by low to medium-height woody plants; and Forested wetlands, largely wooded swamps and bottomland hardwood forests.

2. Wetlands Protect and Improve Water Quality

Healthy wetlands remove and retain excessive nutrients, such as nitrogen and phosphorus, from the water. Forested riparian (or streamside) wetlands remove about 80 percent of the phosphorous and 90 percent of the nitrogen from water, which act as water contaminants and may result in unhealthy algae blooms. Wetlands also can minimize sediment loads and absorb chemical and organic pollutants before they can enter the Chesapeake Bay.

Wetlands Help Control Flooding and Erosion

Wetlands often have been referred to as natural sponges that absorb flooding waters. By temporarily storing floodwaters, wetlands help protect adjacent and downstream property owners from flood damage. Wetlands in urban areas are especially valuable for flood protection, since urban development increases the rate and volume of surface water runoff, thereby increasing the risk of flood damage. Wetlands are often located between rivers and high ground and, therefore, are in a good position to buffer the land against erosion. Wetland plants can reduce erosion by binding soil with their roots.

Wetlands Provide Habitat for Terrestrial and Aquatic Wildlife

Tidal estuarine and palustrine wetlands provide vital habitat for fish, shellfish, waterfowl, wading birds and mammals. Striped bass, menhaden, flounder, oysters and blue crabs are among the most commercially important fish and shellfish that depend on estuarine wetlands. Palustrine wetlands also provide valuable fish habitat and support a variety of birdlife, including ducks, geese and many songbird species. Mammals that are commonly found in wetlands include muskrat, white-tailed deer and beaver. Wetlands foster the production of many species including fish, shellfish and waterfowl, and plants such as wild rice and blueberry. Forested wetlands, which are the most common type of palustrine wetlands, supply valuable timber products.