Will the Spillway Walls Overtop? 3D CFD Provides the Answer

Clear Lake Dam is a 113-year-old, high hazard-potential, embankment dam located on South Clear Creek above the Town of Georgetown, Colorado. The dam is located about 50 miles west of Denver, Colorado and the reservoir provides water for hydro-power and recreation and is a very valuable part of Xcel Energy’s water supply for its Metro Denver power plants. Clear Lake Dam has a long history of dam safety deficiencies and after evaluating a wide range for rehabilitation alternatives, Xcel Energy selected dam replacement as the preferred dam rehabilitation alternative.
During the Construction Potential Failure Modes Analysis risk review of the new dam design, a key question developed regarding overtopping potential of the training walls of the new Roller Compacted Concrete Clear Lake Dam. A three-dimensional, computational fluid dynamics (3D CFD) model was used to determine if the spillway training walls would overtop during the Spillway Design Flood. Additional benefits of the CFD model were development of a stage discharge rating curve, evaluation of scour potential at the toe of the spillway, and an evaluation of whether the discharge nap would spring free of the spillway.