Numerical modeling for fish diversion studies

A 3D numerical model, validated with data from field and laboratory measure ments, is applied to simulate the flow in a 7-km-long reach of the Columbia River, upstream from Wanapum Dam, Wash. As a tool for analysis and design of alternative fish diversion schemes, the model provides mean flow pattern s, turbulence levels, acceleration patterns, and other flow characteristics that are believed to be important to fish behavior. The paper describes th e features of the model. Because of the pronounced three-dimensionality of the flow field and the need to capture it in the simulation, the river reac h is divided into subreaches with different length scales and grid sizes. T he model is applied successively to the three subreaches. An example is pre sented showing particle tracking through the flow field using a Monte Carlo technique.