Quantifying relative contributions from sediment sources in Conservation Effects Assessment Project watersheds

• Published in: Journal of soil and water conservation Vol. 63; no. 6; pp. 523 - 532
• Main Authors: Wilson, C.G., Kuhnle, R.A., Bosch, D.D., Steiner, J.L., Starks, P.J., Tomer, M.D., Wilson, G.V.
• Format: Journal Article
• Language: English
• Published: Ankeny Soil and Water Conservation Society 01.11.2008; Soil & Water Conservation Society
• Subjects: Atmosphere; Best management practices; Causes of; Cosmic rays; Environmental aspects; Freshwater; Load; Protection and preservation; Sediment transport; Soils; Source studies; Watersheds; United States
• ISSN: 0022-4561; 1941-3300; 1941-3300
• DOI: 10.2489/jswc.63.6.523

A technique using the relationship between the naturally occurring radionuclide tracers, 7 Be and 210 Pb xs , was used to differentiate eroded surface soils and channel-derived sediments in the fine suspended sediment loads of runoff events in five Conservation Effects Assessment Project watersheds. A simple two end-member mixing model was used to determine the relative contribution from each source. Results suggest that eroded surface soils were more prevalent in the suspended load early in a runoff event, but channel contributions dominated the suspended load at later stages. The method proved useful for multiple sites due to a constant proportion of the atmospheric deliveries of the two radionuclides globally. Use of only two radionuclide tracers simplifies the differentiation of sediment sources within a watershed but limits precision.