Improvements to the Chewuch Canal will help reduce effects of irrigation withdrawals on the Chewuch River. Photo by Laurelle Walsh

Improvements to the Chewuch Canal will help reduce effects of irrigation withdrawals on the Chewuch River. Photos courtesy of Trout Unlimited

By Laurelle Walsh

Two years after reaching a permanent late-season Diversion Reduction Agreement, the Washington Water Project of Trout Unlimited and the Chewuch Canal Company (CCC) are ready to begin infrastructure improvements on the Chewuch Canal, soon after the ditch is turned off Oct. 1, according to Trout Unlimited’s Lisa Pelly.

“Multiple crews will be working simultaneously on multiple parts of the ditch,” Pelly said of the construction project. At the end of Pearrygin Lake near Silverline Resort, work will include installation of a new intake structure at the lake, which acts as a reservoir for the irrigation canal. That intake structure will supply water to the new Lake Creek Pipe, to be buried in the hillside above Lake Creek between Pearrygin and the existing “bubbler” debris screen at the start of the pressurized pipe.

Work will also resume on piping the open ditch along the base of Studhorse Mountain between Heckendorn and Bear Creek.

The construction project was awarded last week to Selland Construction of Wenatchee, with a project bid just over $1.5 million, said Pelly.

Trout Unlimited’s initial estimate had been around $700,000 when the project was first put up for bid in fall 2012, but after bids came in higher than expected – in part because the cost of pipe suddenly went up – project planners realized they would have to “concentrate efforts on raising more money,” said Pelly.

Pelly estimates it will cost around $2 million to complete the project.

Project funders include the state Salmon Recovery Funding Board, tributary grants from the PUDs of Chelan and Grant counties, the Yakama Nation and the Bonneville Power Administration.

Irrigation canal infrastructure improvements are but one aspect of the multi-part Diversion Reduction Agreement signed by the CCC and Trout Unlimited in October 2011. It will go into effect at the start of the next irrigation season, on May 1, 2014.

Chewuch River

Chewuch River

With the ultimate goal of reducing the effects of irrigation withdrawals on the lower Chewuch River, the CCC agreed to limit its diversions when the river’s base flows drop below 100 cubic feet per second (cfs) during the irrigation season – May 1 to Oct. 1.

A new reservoir permit also switches the time when the CCC can fill its reservoir in Pearrygin Lake from late fall and winter when river flows are generally low, to spring and early summer when flows are high.

The CCC also adopted a drought management plan which will go into effect in years when river flows drop below 100 cfs during the irrigation season and when it appears that its reserve in Lake Pearrygin – the top five feet of water – wouldn’t be enough to supply shareholders for the rest of the season.

“These efficiency improvements will allow the CCC to deliver water to their users despite the reduced diversions and improve system function and management, while improving flows during critical low periods for fish,” a Trout Unlimited press release said.

“We’re excited for this project to get under way,” said CCC president Roger Rowatt. “I would like to thank Chewuch Canal Company board of directors and shareholders for their time and patience in helping to bring this project to its final phase. This has been a long time coming.”