Three-Dimensional Hydrodynamic Simulation of Flows for Fish Passage at the Dalles Dam

The Dalles Dam is located at river Mile 192 on the Columbia River, USA. Fish passage is considered one of the important operational functions for the hydropower dams on the Columbia River. The U.S. Army Corps of Engineers, Portland District (CENWP) and the Regional Resource Agencies (Region) have been evaluating fish passage concepts to protect downstream migrating juvenile salmonids at The Dalles Dam. To assist in this evaluation, a three-dimensional (3D) computational fluid dynamics (CFD) model, developed at IIHR-Hydroscience & Engineering, was selected to conduct CFD simulations, providing hydrodynamic flow information for fish passage efficiency assessment. The CFD model solves the Reynolds Averaged Navier-Stokes (RANS) equations closed with the standard k-ε model with wall function. The Dalles Dam forebay CFD model covers approximately 2,134 m from the spillway face to its upstream boundary. GRIDGEN of Pointwise®, Inc. was used to generate the 3D multi-block structured meshes. The model was validated using the ADCP stationary target field data, and then applied to prediction of scenarios corresponding to flow conditions which occurred during 2002 to 2004, referred as FY02, FY03, and FY04.