Authors: K. Hansen, M. Haque, L. Weber, C. Mannheim
Waterpower XV in Chattanooga, Tennessee, July 23-26, 2007
Abstract
As part of a comprehensive program to enhance juvenile fish passage at McNary Lock
and Dam to improve the survival of downstream migrating juvenile salmonids, the Walla
Walla District has an initiative to develop a surface passage route at McNary Dam on
the Columbia River. The primary goal for a surface passage route is to create an
attractive entrance at a location in the forebay where it creates a flow pattern that
provides maximum opportunity for fish discovery and passes them safely over and
downstream of the dam. Successfully developing a permanent installation that can
achieve this goal without reliable information presents risks and uncertainties. Prototype
testing is a method of acquiring information to help minimize risk. A temporary spillway
weir (TSW) is being implemented to provide the characteristics for a good prototype test
for surface passage effectiveness at McNary Dam. Ultimately, the desirable result will
be development of a permanent installation to improve downstream migration with less
impact on power generation and lower potential for spill-related issues including
downstream total dissolved gas levels. Physical and computational fluid dynamic
hydraulic models were used to develop the final prototype design geometry, to better
assess the fish passage performance, and to determine dam operations that optimize
the surface passage routes. The purpose of this paper is to provide context for the
overall and surface passage objectives of McNary Dam, present the TSW prototype
objectives and expected performance that led to its development, and explain the
benefits of laboratory and numerical model simulations. Companion papers will discuss
the laboratory model results and computational fluid dynamic model simulations.
