Hells Canyon undergoes flow reduction

Jul. 22—The Snake River in Hells Canyon is expected to get a bit bony in coming days, the result of a flow reduction planned by Idaho Power Company.

Because of below-normal stream flows entering the company's three-dam Hells Canyon Complex, it plans to drop the minimum flows exiting Hells Canyon Dam from 8,500 cubic feet per second to 6,500 cfs.

The complex is made up of Brownlee, Oxbow and Hells Canyon dams. The complex is the company's workhorse, producing 70 percent of the power it sells to customers, mostly in southern Idaho.

Under the plan, flows will fluctuate between 18,000 and 6,500 cfs, with higher flows coming when the company is running water through hydroelectric turbines. The company's license to operate the dams requires it to release enough water at the southern end of the canyon to maintain flows at 13,000 cfs at Lime Point in the canyon's northern end. However, the company is not required to release more water from Brownlee Reservoir than what naturally flows into it, even if it means flows at Lime Point fall below the 13,000 cfs threshold.

Brad Bowlin, a spokesperson for the company, said baseline flows coming into the three-dam complex are dropping and below seasonal averages. Flows in the Salmon River, which joins the Snake River in Hells Canyon, are also dropping and below long-term averages.

"If you sort of do the math, if we are passing what we are getting through the Hells Canyon Complex and that plus what is coming in from Salmon doesn't total 13,000 cfs," Bowlin said.

Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273. Follow him on Twitter @ezebarker.