Water Resources Research Act Program

Principal Investigators: Walter Silva

Abstract: The amount of sediment transported during flow discharge periods is commonly estimated by using sediment transport functions. The common approach to select the most appropriate sediment load equation for a particular stream is to analyze a series of measured values of suspended and/or bed load in order to find the function that best fit the field data. This approach requires a long period of historic measurements and usually this information is not available; therefore, this methodology cannot be applied in many streams. However, the estimation of the potential amount of sediment moved towards the coastline during a storm event is of great importance for damage estimation on urban and coastal areas, marine habitat, and restoration projects. Significant differences in sediment amounts are obtained when several sediment transport functions are tested. This situation introduces great uncertainties in any analysis requiring the estimation of sediment movement . This research will select sediment transport functions for two watersheds in Saint Thomas, V.I., using a methodology which does not require periods of sediment discharge measurements. Instead, it uses grain size distributions, geometric and hydraulic parameters of the water course to identify those sediment transport functions more appropriate for the existing conditions. An urbanized and a more natural-state watershed will be selected in order to compare geomorphic impacts in guts do to urban development.