Identifying the source of excess fine-grained sediments in New Jersey rivers using radionuclides

Fine-grained sediment is a major pollutant in streams and lakes, affecting feeding and reproduction of aquatic animals, aesthetics, recreation and water supply. One barrier to controlling sediment load is that it is often difficult to determine whether the source of sediment is widespread but shallow surficial erosion from overland flow occurring in the watershed or from the lateral erosion of vertical channel bank material. However, these two sources of sediment are identifiable by their different radionuclide signatures, including 7Be, 210Pb, and 137Cs. We propose to sample channel bank material, watershed soils, and in-stream fine sediment and analyze them for radionuclide activity to identify the relative contributions of sediments from the watershed and channel banks in New Jersey. This knowledge will allow for improved stream and watershed management and the possible initiation of sediment-reduction programs.