The Pacific Northwest National Laboratory numerically modeled flow conditions upstream of the regulating outlets at Dworshak Dam, North Fork Clearwater River, Idaho. Simulations were performed using the computational fluid dynamics model Flow-3D, a peer reviewed and validated three-dimensional Reynolds-averaged Navier-Stokes hydrodynamic model. Results were studied to determine the impacts of water surface elevation and discharge though the three regulating outlets on flow velocities in the reservoir forebay. These simulations were in general support of a larger research program conducted by the Idaho Department of Fish and Game that is evaluating the efficacy of strobe lights to deter fish from entering the regulating outlets and powerhouse turbine intakes. Simulation results indicate that large variations in forebay water velocities occur over the typical range of regulating outlet operations and seasonal water surface fluctuations. As expected, water velocities generally increase with larger outlet gate openings and higher water surface elevations. Simulations span typical regulating outlet operations: forebay water surface elevations between 1460 ft and 1600 ft and regulating outlet gate valve openings between 1 ft and 10 ft open. In addition, simulations examined flow conditions when only one or two of the three regulating outlets were operating. The resulting matrix of 24 unique simulations have been distilled and summarized in this report.
Revised: March 23, 2004 |
Published: March 20, 2004