Snake River drawdown could be boating hazard

LEWISTON – Fluctuations in flows of the Snake River in Hells Canyon to meet power demands could lower the river to a level the U.S. Army Corps of Engineers considers unsafe for navigation.

Idaho Power Co. plans to lower the river level to 6,500 cubic feet per second Sunday at Johnson Bar, located about 88 miles upriver of Clarkston, said Dennis Lopez, an Idaho Power spokesman.

“We are making this drawdown during the light load periods – midnight to 6 a.m.,” Lopez said.

Lopez said that when demand for power is highest – during the hottest part of the day – flows could increase to 23,000 cfs.

Flows below 8,500 cfs above the mouth of the Salmon River are unsafe for navigation, said Ed Kim, a hydrologist with the corps at Walla Walla, Wash.

“Boaters have to exercise extreme caution out there,” said Kim. “If you don’t have to go above the mouth of the Salmon, don’t.”

When the river is flowing below 8,500 cfs, rocks that are normally submerged appear above the water and can damage boats. Also, new currents appear that can make navigating the river more challenging.