Suspended sediments are a problem in the Chesapeake Bay. Determining the source of sediment is an important step in controlling suspended sediment. In this study, we compare two methods for determining the source of sediments in an urban subwatershed: sediment fingerprinting and GIS aggregated data assessment.

We propose to use a sediment fingerprinting model to determine the sources of suspended sediments. Channel bank and upland samples will be tested for chemical and radionuclide characteristics. We will develop a composite fingerprint from these characteristics that can be used to determine sediment source. Using a statistical mixing model, the spatial location and quantity of sediment sources will be determined for suspended sediments collected during storm events. The sources of sediment will be assessed by a factorial design of land use, landscape position, and soil characteristics. Land use will be determined from NLCD data and observation, then divided into urban permeable, urban impermeable, agricultural, and forested classes. Landscape position will be determined by topography and include bank, floodplain, and upland areas.

The GIS data assessment will use publicly accessible data to determine probable sources of sediments. Indicators analyzed will include soil erosion K factor; NLCD; and LiDAR data.

By comparing the areas that the GIS aggregated data assessment indicated as sediment sources with the sediment fingerprinting data, we will develop and test a method that is inexpensive, less labor-intensive, and generally accessible for determining sediment sources.