Northern Prairie Wildlife Research Center
Sedimentation of Prairie Wetlands
Most prairie wetlands are embedded in agricultural landscapes and tillage of their catchment areas facilitates increased surface runoff and sediment inputs relative to a grassland condition. Erosional sediment from anthropogenic sources greatly shortens the topographic life of prairie wetlands. Obviously, a filled basin has lost its capacity to provide natural wetland functions of value to society; however, less intuitive is the impact of altered hydrology and spates of sediment inputs on wetland functions. Often wetlands are highlighted as providing numerous functions and values, including improving water quality. A fundamental property of wetlands to improve water quality is that they filter and retain sediments, and through physical, chemical and biological processes they transform and sequester pollutants; however, there is a trade off between the importance of sediment removal as a water quality benefit and maintaining the topographic life of wetland basins. Obviously, wetlands play an important role in improving environmental quality, especially controlling the offsite impacts of agricultural runoff on rivers, lakes, and reservoirs. However, wetlands should only be used to remove sediments and other agricultural pollutants after agricultural best management practices have been implemented (Kuenzler 1990). Consequently, research is needed to evaluate the effectiveness of the various conservation practices that reduce sediment input and maximize the effective period of time wetlands can provide critical functions within the agriculturally dominated ecosystem of the PPR.
Previous Section -- Research Needs
Return to Contents
Next Section -- References