Columbia-Pacific Northwest Region

Anderson Ranch Dam Raise

Reclamation and the Idaho Water Resource Board finished negotiations on a federal / non-federal contract for final design and construction to raise Anderson Ranch Dam. The contract was signed on November 19, 2021.

The contract allows final design work for the dam raise to commence. It includes cost-share arrangements for the full construction of the dam raise, although those provisions will be subject to a record of decision or final decision to raise the dam thereby increasing reservoir storage space.

Reclamation and the Idaho Water Resource Board partnered to complete the Boise River Basin Feasibility Study to explore new surface water storage opportunities in the Boise River Basin. Authorized under the Water Infrastructure Improvements for the Nation Act of 2016, the study focused on a 6-foot raise of Anderson Ranch Dam in Idaho, resulting in approximately 29,000 acre-feet of new storage space. In December 2020, the Secretary of the Interior determined the Study’s recommended plan to be feasible in accordance with the WIIN Act.

Ongoing project activities include:

• Reclamation and IWRB staff continue coordinating post-feasibility study activities, including the dam raise and reservoir rim projects.