Location:
Crooked River, Culver, Oregon
Client:
Deschutes Valley Water District
Services Provided:
Geotechnical Engineering
Sitework Monitoring
Special Inspection
Construction Materials Testing
Project Overview:
In 2018, Deschutes Valley Water District, ODFW, ODOT, BLM, Trout Unlimited, Deschutes Partnership, Energy Trust of Oregon, OWEB and PGE joined forces to break ground on a fish passage project to remove a major barrier to salmon and steelhead at the Opal Springs Dam on the Crooked River. The project objectives were to increase generating capacity and make upstream habitat more accessible and to reintroduce anadromous fish in the Deschutes Basin.
Scope of Work:
The project included raising the existing 175-foot concrete division dam by two feet and constructing an approximate 300-foot-long, concrete cast-in-place fish ladder that required both temporary shoring and engineered excavations. The 30-cubic-feet/second (cfs) vertical slot fish ladder provides downstream passage for smolts through pneumatic crest gates and “smooth” chutes. The 4.3 MW Opal Springs hydroelectric project was originally commissioned in 1985 to generate power for Deschutes Valley Water District’s 4,200 customers in Jefferson County. Raising the water level significantly increased the generating capacity of the dam.
As part of the Opal Springs construction team, Wallace Group provided geotechnical engineering, earthwork, dam crest monitoring, construction materials testing, and special inspection services.
Challenges:
Technical and job-site safety challenges addressed by Wallace Group engineers and geologists included mitigating rock-fall, talus seepage, and slope stability for temporary excavation and H-pile and lagging shoring. The Opal Springs Fish Passage project began reintroducing anadromous fish to the Upper Crooked River Basin in 2019.
