Abstract

Wetlands are highly efficient at storing and transforming chemicals. The primary input of these chemicals are from overland flow. The characteristics of these chemicals are dependent on the sources in the watershed. The rate of input to riparian zones, however, is dependent on landscape features, such as slope and surface resistance and soil properties, including grain size and cohesive strength. For large flows and loose soils, a significant portion of these chemical inputs can be a result of sediment transport. Wetlands are intimately tied to soils through sedimentation processes. Accretion of sediments accelerates the aging of wetlands, reduces infiltration through bottom substrates increasing water heights, and removes phosphorous, a limiting nutrient in many freshwater ecosystems. In this entry, the mechanics of sedimentation are discussed in relation to natural and constructed wetlands, and ecological engineering principles are suggested as a way to mitigate the effects of excessive sedimentation.