Friday, August 14, 2020
Aug. 14, 2020

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PacifiCorp spilling water at all three Lewis River dams

By , Columbian Outdoors Reporter
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PacifiCorp is spilling about 10,000 cubic feet per second at Swift Dam today as big flows come down the North Fork of the Lewis River.
PacifiCorp is spilling about 10,000 cubic feet per second at Swift Dam today as big flows come down the North Fork of the Lewis River. (ALLEN THOMAS/The Columbian) Photo Gallery

ARIEL — PacifiCorp was spilling large amounts of water at Merwin, Yale and Swift dams Thursday as it copes with the stream flow from the wettest place in Southwest Washington — the upper watershed of the North Fork of the Lewis River.

“It’s swung completely in the other direction,’’ said Frank Shrier, principal scientist for PacifiCorp, recalling the dry winter, spring and summer of 2015 in the Lewis River system.

The utility is spilling 19,000 cubic feet per second at Merwin Dam, 20,000 at Yale Dam and 10,000 cubic feet per second at Swift Dam, Shrier told the Lewis River Aquatic Coordination Committee on Thursday morning.

The committee is a monthly meeting of Pacifi­Corp, state and federal fishery agencies, the Forest Service, Cowlitz PUD, Indian tribes and others involved in Lewis River management under the utility’s 2008 federal license to operate Merwin, Yale and Swift dams.

Inflows at Swift were 45,000 cubic feet per second on Wednesday and 90,000 cfs at Merwin, he said.

Only 700 cubic feet per second were flowing into Swift in July.

“It rivals 2006, but it’s not the same because there’s not that much snowpack,’’ Shrier said.

At June Lake, elevation 3,440 feet, on the south flank of Mount St. Helens, there have been 16.7 inches of rain since Sunday, he said.

The huge inflows into Swift Reservoir has resulted in “several acres’’ of floating wood in the 4,500-acre impoundment, he said. A portion of the plastic pipe at Eagle Cliff Bridge used to release adult salmon and steelhead for reintroduction has been lost.

A log boom to keep floating wood at the upper end of the reservoir has failed. The boom is important because floating debris can damage the $60 million juvenile fish collector anchored at Swift Dam.

The collector puts out a flow that attracts young salmon and steelhead, which are then trucked to Woodland and released into the lower Lewis River.

“Our main issue is getting the log boom at Swift,’’ Shrier said.

The three reservoirs had 34 feet of combined storage passage as of Thursday.

Shrier said another 6 inches of rain is forecast to fall in the upper North Lewis in the next five days.

Increased spilling at the dams is not anticipated, he added.

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