Spillway Tailwater Erosion at Little Goose Dam, Snake River, Washington. Hydraulic Model Investigation.

Underwater inspection of the Little Goose Dam roller bucket and tailwater channel following about 10 years of operation revealed foundation erosion around various structures and the end of the bucket. A 1:50-scale movable-bed model was used to evaluate the effect of high spillway discharges on the erosional tendencies in the tailwater channel. Studies were accomplished to establish the most desirable spillway operating schedule which would flush the riverbed material and debris from the roller bucket.