ARS | Publication request: Using environmental radionuclides as fingerprints to study streambank erosion

Submitted to: American Water Resources Association Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 2008
Publication Date: June 10, 2008
Citation: Ritchie, J.C., Nagle, G.N., Pedone, P. 2008. Using environmental radionuclides as fingerprints to study streambank erosion [abstract]. American Water Resources Association 2008 Summer Speciality Conference, Riparian Ecosystems and Buffers: Working at Waters Edge. 2008 CDROM.

Technical Abstract: The identification of sediment source areas in the watershed is a key component for designing management strategies to reduce sediment and chemical loads from the watershed. Potential sediment sources in a watershed can be characterized (fingerprinted) using diagnostic environmental radionuclides, chemical, and/or physical properties. Comparison of these properties with equivalent properties for suspended (or deposited) sediment samples permits the relative importance of the potential sources to be evaluated. The objective of this study was to show the use Cesium-137 (Cs-137) to determine the relative importance of streambank erosion. Fallout Cs-137 can be used as a tracer or fingerprint to identify sediment sources within a watershed. In order to understand the relative contribution of streambank erosion, samples are collected from the various geomorphic surfaces (upland soils, colluvial slopes, floodplain deposits, streambanks, and suspended sediments) within a watershed and analyzed for fallout Cs-137 concentration. Then using simple mixing models the relative importance of the different geomorphic surface can be determined. Application of the fingerprinting techniques in several watersheds will be used to illustrate the technique. These studies (along with many that are published) show the potential for using Cs-137 to determine the relative importance of different sediment sources in a watershed. Environmental radionuclides (Cs-137) have been shown to be a key and useful tracer in environmental processes. Used in combination with other key properties (fingerprints), the relative importance of sediment sources can be determined.