Value of Wetlands

Wetlands are found all across the state, and many are forested. Wetlands include marshes, bogs, and swamps, and may include other areas which are only flooded or saturated for fairly short periods of time. Nontidal wetlands are identified on the ground by the presence of wetland hydrology, wetland soils, and wetland vegetation. Wetlands provide many benefits:

• Flood Control
  Flood water flows naturally into stream and river channels as it drains off the land. When surface water moves through wetlands adjacent to water courses, flood flows are temporarily retained by dense stands of vegetation in wetlands and slowly released downstream.
  
• Water Supply
  Wetlands may also provide a domestic or commercial supply of water. Flood waters may flow from wetland into a ground water aquifer and recharge it. For example, a five-square-mile bog in Wisconsin controls the groundwater supply for a 165- square-mile area.
  
• Sediment and Erosion Control
  Wetlands maintain water quality by controlling erosion and sedimentation. Vegetative cover over the soil will absorb most of the shock from the impact of the water, so it is less likely to loosen soil. Sediment carried by runoff will tend to be trapped in wetlands and held by ground vegetation. In shallow waters, submerged aquatic vegetation acts as a filter, as sediment clings to plants instead of floating in the water. Aquatic plants also reduce water velocity, so additional sediment tends to sink to the bottom instead of floating freely. Shoreline vegetation decreases the force of wave action and reduces erosion in tidal areas.
  
• Nutrient Retention and Removal
  Wetlands remove nutrients such as nitrogen and phosphorus from the environment. Wetland plants absorb the nutrients for their own growth, making them unavailable to algae. Without this absorption, algae blooms in open water may grow and dominate the system so that little oxygen is available for other aquatic life. Wetlands efficiently remove nutrients but cannot remove all of them. The algae blooms in the Chesapeake Bay result from nutrient "overload," beyond the capacity of the wetlands and aquatic plants to remove all of them.
  
• Pollution Control
  Wetlands filter pollutants and treat sewage. Heavy metals accumulate in wetland soils, not plants or water which may be consumed by people or wildlife.
  

Last modified: Monday, 10-Mar-2008 15:32:22 EDT