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Tony L. Wahl. 2009. "Numerical Modeling of Headcut Erosion in Auxiliary Spillway Channel at Glendo Dam". Bureau of Reclamation, Report Number HL-2009-03.

Abstract: A new uncontrolled auxiliary spillway to be excavated through Brule siltstone at Glendo Dam, Wyoming was evaluated to determine the potential for headcut erosion in the unlined spillway channel. The SITES numerical model developed by USDA was used to simulate headcut erosion for the 100,000-yr flood event and for smaller floods likely to occur during the service life of the project. A variety of scenarios were considered ranging from best-case to worst-case combinations of the parameters that describe the erodibility of the materials in the spillway channel. The results were most sensitive to the detachment rate coefficient. Values of this parameter were estimated using field and laboratory jet erosion tests and by comparison to erodibility parameters measured by other investigators on cohesive soils that are likely to be more erodible than the Brule siltstone material. Although very significant headcut erosion was predicted by the SITES model for some scenarios, a complete breach of the spillway was not predicted for any case. As a result of the modeling, the current design of the spillway was deemed to be acceptable from an erosion standpoint.


Web Link: http://www.usbr.gov/pmts/hydraulics_lab/pubs/HL/HL-2009-03.pdf

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