9629363 Owen This project will address the impacts of sediment deposition on the functions of non-tidal freshwater wetlands. Non-point source pollution such as stormwater runoff is often directed into wetland areas, sometimes resulting in changes in water quality and hydrology of the wetland. Although this stormwater may contain many types of pollutants, the focus of this stage of research is on the physical impacts of sediments in stormwater runoff on wetland processes. Sediment from construction sites, parking lots, roads, and farms may alter the ecological processes of wetlands. Wetlands are recognized for their ability to filter out sediments and improve water quality, however, there may be some point at which so much sediment is deposited in the wetland that the wetland is degraded, and its ability to perform some or all of its ecological functions is diminished. The general hypothesis of this study is that sediment deposited in a wetland will alter the wetland soil's natural characteristics such as capillarity, porosity and hydraulic conductivity. Highly organic soil is often very porous in the top layers, and as a result may be open to settling and compaction by sediment deposited in runoff; if the results of this sediment deposition is a significant change in soil moisture retention, hydraulic conductivity or other soil characteristics, then water flow and biological processes in the wetland may be altered. The ultimate goal of the study is to identify sustainable loads of sediment for a wetland. Here the term sustainable is used to mean the level of sediment that the wetland can receive without significantly altering its ability to perform its other functions besides sediment filtration, such as providing wildlife habitat, biodiversity, flood storage, streamflow maintenance and groundwater recharge or discharge.
