CRS-49 



Shoreline erosion control can be an important function, especially adjacent 

 to large water bodies in coastal areas. Many of the plant species found in wet- 

 land areas dampen the intensity of waves and dissipate their energy. They also 

 slow the rate of water flow, trapping sediments. Scientists debate under what 

 conditions wave energies prevent establishment of wetland areas along exposed 

 coasts and how effective these areas are, in fact, in controlling erosion. 26 / 



Wetlands have an important role in groundwater recharge. For example, 

 one of the principal identified functions of the Pine Barrens, an area of 

 swamps and forest in southern New Jersey, is as a water source stabilizing an 

 aquifer of immense dimensions. 27 / However, not all wetlands recharge ground- 

 water, and some actually discharge water, especially in coastal areas. 



Water Quality Maintenance 



Water flow is slowed when passing through wetlands, allowing increased 



sedimentation and some absorption of pollutants. One scientist summarized 



these processes: 



In the anaerobic soils of wetlands, denitrif ication removes 

 nitrogen from the water and during the growing season, plant uptake 

 of nitrogen and phosphorous removes the nutrients from water pass- 

 ing in and through wetlands. 28 / 



Major mechanisms for removing waste include filtration, sedimentation, 

 anaerobic decomposition, and biological assimilation. Each operates differ- 

 ently in different types of wetlands. For example, in most tidal wetlands, 

 wastes are assimilated during the summer growing season only, but in wetlands 

 of central Florida, nitrogen is assimilated throughout the year. Wetlands have 



26 / Clark and Clark, Scientists' Report, p. 62-64. 



27 / Representative William Carney has introduced a bill, H.R. 5362, to 

 protect the eastern portion of Long Island, also a groundwater recharge area. 



28/ Larson, Wetland Value Assessment, p. 6. 



