Lower Granite Fish Guidance Efficiency Study Snake River, Washington, Hydraulic Model Investigation
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS HYDRAULICS LAB
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Each year adult salmon migrate up the Columbia and Snake rivers to spawn. The juvenile salmon must migrate to the ocean along the same path their parents did. With the damming of the rivers for navigation and hydropower, the salmon encountered new obstacles. The juvenile salmon had to pass through the powerhouses on their trip to the ocean. Systems that diverted the juvenile salmon away from the turbines were designed. The system developed for the Lower Granite Powerhouse is not performing near its anticipated levels. Tests were conducted on a 125-scale one-bay intake unit model to improve the fish guidance efficiency of the juvenile bypass system. Modifications to the submerged traveling screen, different positions of the emergency closure gate, blocked trashracks, and various other modifications in the vicinity of the submerged traveling screen were tested to achieve this purpose. The modification that showed the most potential for improving the fish guidance efficiency consisted of the extended submerged traveling screen lowered 4 ft from the current position with the false gap device in place and the emergency closure gate raised 20 ft. Keywords Animal migrations paths Little goose dam Lower granite dam Flow intercept Juvenile salmon Bypass systems Submerged traveling screens.
- Civil Engineering