Screening-Level Assessment of Water Quality Improvement from Wetlands

BACKGROUND: Water quality improvement is potentially an important function of wetlands. Mechanisms that occur in wetlands, such as sedimentation, filtration, adsorption, precipitation, decomposition, and uptake and metabolism, can act to reduce concentrations of problematic water quality constituents flowing into wetlands. Similarly, streams, ponds, and lakes can act as natural treatment systems, but wetlands seem to be especial]y effective because of the abundance of plants that help filter and remove constituents and the shallow depths which increase contact with bottom sediments that can adsorb and decompose substances. Therefore, wetlands, whether natural or constructed, have been recognized as a potential y cost-effective means of water quality treatment.