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Schlagwörter:
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Zusammenfassung:
Worldwide, sediment is a major pollutant degrading ecologic health, impacting infrastructure and water supply. To develop strategies for reducing sediment loads it is important to determine the sources of sediment. Using the sediment fingerprinting approach to determine sediment-source contributions, 332 wadeable streams (contributing areas ranging from 2.31 to 3280 km2) for 4 regions of the United States (Southeast, Northeast, Pacific Northwest, and Central California) were investigated between 2014 and 2017. Fallout radionuclides, 137Cs, and 210Pbex, were used to apportion bed and suspended sediment into three sources, topsoil, streambanks, and sediment on impervious surfaces. Sample site selection focused on urban land use with additional sites in agricultural and forested watersheds. Structural equations were used to assess the relationships among watershed characteristics (land use, soil, hydrology, and geomorphology) and sediment sources. Results for 3 of the 4 regions (Southeast, Northeast, and Central California) indicated streambanks were the major source of sediment ranging from 70 to 86%. In the Pacific Northwest, topsoil was the major source of sediment (61%) followed by streambanks (30%).
