This story previously reported incorrect information about Grant County PUD's dam license requirement. The error has been corrected in this version.

WENATCHEE — A state mandate to increase water supplies in the Columbia Basin could lead to a higher water level behind Rocky Reach Dam and projects to pump Columbia River water into dammed mountain canyons around the region.

Chelan County PUD commissioners Monday expressed interest in a proposal to work with the state Department of Ecology to identify water-storage sites around the county that could also generate electricity.

Ecology has a state mandate to increase the water supply in Eastern Washington by storing more Columbia River water for irrigation, city water supplies and to supplement streamflows for fish during times of drought, Ecology official Derek Sandison told commissioners Monday.

Sandison directs the agency’s Columbia Basin water-supply effort.

Commissioners plan to vote at their next meeting, Nov. 9, on an agreement to work with Ecology officials.

Gregg Carrington, the utility’s director of energy resources, said the agreement would be the first step in a potentially five-year process to explore water-storage potential and new sources of power generation in Chelan County.

The exploratory process would include ample opportunity for public comment, he said.

Carrington said water storage in Chelan County could happen by:

• Raising the level of the Rocky Reach Dam reservoir — called Lake Entiat — by 1 to 3 feet and releasing it during low-flow periods of late summer and fall.

• Pumping water from the river during periods of high flow to mountain reservoirs that could be built by damming dry canyons. The water would be released, as needed, to flow downhill back to the river.

Ecology would pay for studies into either alternative using part of the $200 million bonding authorization granted by the state Legislature in 2006 to increase water storage.

If research shows building mountain reservoirs is feasible, Carrington said PUD officials would urge Ecology to consider adding turbines that could generate electricity when the reservoir water is released and flows back to the river, Carrington said.

This system for generating electricity is called “pumped storage.”

Some 40 pumped-storage projects already operate around the country, and another 40 are in the permitting stage, including four in Washington, according to a study funded by the National Hydropower Association, an industry lobby group.

Carrington and PUD General Manager Rich Riazzi said pumped-storage projects are a cleaner alternative to natural gas-fired plants for producing electricity on demand at times when intermittent power sources, like wind farms, aren’t generating.

They also take advantage of surplus by using the electric pumps to fill the reservoir at times when power is plentiful, but other demand is low.

At a potential construction price of $1 billion a pumped-storage project would be a multi-agency effort that could include the region’s PUDs, the Bonneville Power Administration and Bureau of Reclamation, Carrington said.

The Chelan PUD would only pursue this option if state laws were changed to allow pumped-storage generation to count toward state quotas for renewable energy, Carrington said.

Private investors are exploring some of the state’s potential sites, Carrington said.

“We want to be the ones who are filing for permits for sites in our own back yards,” he said.

Commissioner Randy Smith described the PUD’s joint efforts with Ecology as “intriguing.” Commissioner Dennis Bolz said it has “tremendous potential.”

The PUD considered building a pumped-storage project at Antilon Lake, northeast of Manson, in the 1970s to provide supplemental power for the then growing nuclear energy, Carrington said.

A proposal in the 1990s to increase the Rocky Reach reservoir for power generation was rejected by federal regulators because of its then-unmeasurable impact on migratory fish — a problem that has since been resolved through modern fish-study technology, Carrington said.

Christine Pratt: 665-1173

pratt@wenatcheeworld.com