The improvements, funded under the American Recovery and Reinvestment Act of 2009 (ARRA), will involve replacing the bottom and side seals of the existing west roller gate at the dam, and adding a new horizontal seal to the bottom of the gate. These improvements will allow water to be controlled instead of being lost to leakage. The recovered water will be used to enhance fish passage and habitat for endangered species and to augment power production.
ARRA funds will also be used to attach 23 manually-operated weirs to the top of the west roller gate. The weirs can be raised or lowered to provide continuous flow for steelhead that are listed under the Endangered Species Act.