Fish passage waiver denied at Bowman Dam
On October 9th, the Oregon Fish & Wildlife Commission denied a fish passage waiver request at Bowman Dam near Prineville. Had the requesting Crook County stakeholders offered more mitigation measures, including streamflow restoration in the Crooked River below Bowman Dam, the waiver application might have been approved.
Hindsight is 20/20
The Upper Crooked River Basin comprises a significant portion of the total steelhead habitat found in the Deschutes Basin – particularly Mid-Columbia Steelhead, Chinook Salmon, and Bull Trout. After its construction in 1961, nearly 500 miles of stream habitat were blocked by Bowman Dam. Regrettably, we now know just how devastating the dam has been for the Crooked River aquatic ecosystem and its iconic fish species. In 2006, Mid-Columbia Steelhead were included on the federal Endangered Species Act.
Google image of Bowman Dam
Today, Bowman Dam has a new opportunity to provide agricultural water and flood control, while generating green energy and reconnecting the river for fish and wildlife.
Unfortunately, Ochoco Irrigation District, the City of Prineville, and Crook County have decided to take a different course. Instead of proposing to install a hydroelectric facility at Bowman Dam with a fish passage, they requested a waiver and offered insufficient mitigation.
They can do better.
Restoring flows in the Lower Crooked River to levels needed to meet the life cycle requirements of migrating fish would be a valuable mitigation option and priority for the fishery.
In 2011, ODFW’s Tim Hardin studied a set of enhanced flows designed to meet the needs of both irrigators and fish:
1. Hardin calculated that providing a minimum flow of 140 cubic feet per second (CFS) year-round for Steelhead in the Lower Crooked River is optimal but would use about 41,600 acre-feet more stored water than is used under present operations in a median year.
2. Reducing flows below 140 CFS in certain months could maintain 90% or better fish habitat and use about 20,000 acre-feet less storage compared to the constant flow of 140 CFS.
3. These recommended “balanced” monthly flows vary between 80 and 140 CFS to meet fish’s life cycle needs.
Bowman Dam
Last year, hydrologist Greg Kamman determined their impact in normal years and dry years on irrigation district water supply after modeling the balanced flows using historical data. In both of these scenarios (normal and dry), sufficient water was available to provide the recommended flows for fish and meet the agricultural needs of Ochoco Irrigation District and North Unit Irrigation District. Only in years of severe drought would water supplies be insufficient, and in these years the shortages could be shared by fish and farms.
By establishing mitigation flows for both normal years and drought years, fish and irrigators could be adequately served in most years in a manner that is feasible for the waiver applicants to implement.