ABSTRACT
Low water velocities, coupled with the presence of plant litter (in FWS wetlands) or sand/gravel media (in HSSF and VF wetlands), promote settling and interception of solid materials. This transfer of suspended solids from the water to the wetland sediment bed has important consequences for the quality of the water, as well as the properties and function of the wetland ecosystem. Many pollutants are associated with the incoming suspended matter, such as metals and organic chemicals, which partition strongly to suspended matter. In FWS wetlands used for municipal wastewater treatment, the accretion of solids contributes to a gradual increase in the bottom elevation of the wetland. However, wetlands used to treat urban or agricultural stormwater, or those exposed to periodic ancillary flooding, may have rapid accretions in the inlet zone.
