Minidoka South Gated Spillway Erosion Repair and Prevention Project

Reclamation’s purpose and need for the proposed action is to conduct ongoing repairs and reinforce bedrock at multiple damaged sites beneath and immediately downstream of the spillway apron below the south spillway gates, which would allow all spillway gates to be returned to regular service and would prevent further erosion.

The rate and extent of erosion that has already occurred indicates that further use of gates 5, 6, 7, and 8 without first reinforcing the bedrock areas that are subjected to high hydraulic stress is likely to result in further erosive deterioration of the bedrock; this could compromise the structural stability of the spillway. It is anticipated that ongoing use of the spillway may continue to create conditions that necessitate spot maintenance and repair activities of this nature, the need for which would be identified during future periodic inspections.

08/2022 Minidoka SGS Erosion Repair and Prevention Project EA and FONSI PDF 4.75 mb


Amy Goodrich
Natural Resource Specialist
(208) 383-2250

Bureau of Reclamation
230 Collins Road
Boise, ID 83702

Last Updated: 4/19/23