Submitted to: United States Society on Dams Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2005
Publication Date: 6/6/2005
Citation: Temple, D.M., Hanson, G.J., Neilsen, M.L., Cook, K.R. 2005. Simplified breach analysis model for homogeneous embankments: Part I, Background and model components. Proceedings of the 2005 U.S. Society on Dams Annual Meeting and Conference, Salt Lake City, Utah. p. 151-161. Interpretive Summary: Aging of the water control infrastructure in the United States and increases in population worldwide have increased the need for improved means of predicting the performance of earth embankment dams that are overtopped during extreme floods. The United States Department of Agriculture, through programs administered by the Natural Resources Conservation Service, has assisted in the design and construction of over 10,000 flood control reservoirs (Caldwell, 1999). Many of these reservoirs are now approaching the end of their planned service life with associated filling of sediment pools and deposition of sediment in the flood pool. Development in the watersheds has, in some instances, changed watershed characteristics and increased the potential for loss of life should these structures fail. Therefore, there is an increased need for analysis tools to allow dam safety professionals to predict the performance of overtopped earth embankment dams. Research involving large scale tests of earth embankments in the United States and Europe has increased scientist's understanding of the erosion processes governing this performance. This has allowed the development of a computer simulation model that is presently serving as a research tool. This simulation model produces results consistent with the physical tests. Work is presently underway to refine this model for incorporation into application software for use in predicting the performance of earth embankment dams subjected to overtopping.
Technical Abstract: Research conducted over the past few years has led to a greater understanding of the overall breach process of overtopped embankment dams. This increased understanding allows the development of computational models that better reflect the complex physical action observed during embankment dam breach. One approach to quantification of the complex erosive action associated with an embankment breach is to link simplified component models such that the dominant processes are properly represented for the various stages or phases of the overall breach process. Application of this approach has resulted in the development of a SIMplified Breach Analysis computer model (SIMBA) that is capable of reproducing the key features of breaches observed at various scales in the indoor and outdoor laboratory. In its present form, the model addresses only homogeneous embankment conditions. The model is presently research oriented, but work is underway to incorporate it into a dam overtopping analysis routine for application to field conditions. This application model is structured to allow consideration of non-homogeneous conditions and associated alternate failure scenarios in future versions. This report describes the SIMBA model and the underlying component models in terms of the observed breach processes for earth embankments and spillways. The interrelation of the various failure stages or phases represented by the component models is discussed. A companion report discusses the ability of the model to reproduce the results of embankment breach tests.