Dam Break for the Dalles Dam

The Dalles Dam consists of a powerhouse, a concrete spillway, a navigation lock, concrete nonoverflow sections, an earth-fill embankment on the Washington shore, a rock-fill embankment on the Oregon shore, and fish passage and appurtenant facilities. This dam is one of the largest navigation dams in the United States; it is approximately 8,735 feet in length and more than 200 feet high. This paper will discuss the hydrologic and hydraulic approaches for the dam failure analysis. It will also focus on the breach characteristics and type of failure and nonfailure simulations that were used in the model analysis. This paper will also spotlight the water resource engineering assumptions and techniques that were used in the HECRAS and HECGeoRAS models.