The environmental impact statement, which was released jointly by the state Department of Ecology and the U.S. Bureau of Reclamation, included eight alternatives for either partially or fully replacing groundwater with surface water from Columbia River reservoirs for irrigation, as well as a no-action alternative. The agencies did not select a preferred alternative.
The federal agency manages the Columbia Basin Project.
Congress authorized eastern Washington's Columbia Basin Project in 1943 to irrigate more than 1 million acres of arid land. The project was to have been completed over some 70 years but was never finished.
To date, about 671,000 acres of land in the project have been developed as farmland and irrigated. Key crops in the area include wheat, alfalfa, onions and potatoes for some of the nation's largest processors of frozen french fries and other products for the world market.
Washington state issued temporary permits in the 1960s and 1970s for groundwater wells in areas of the project that were unfinished, with the expectation that the federal government would complete the project. Groundwater levels have since declined in the Odessa aquifer, located between Moses Lake and Spokane.
Four of the eight alternatives released Tuesday would supply surface water to about 57,000 acres currently irrigated by groundwater south of Interstate 90. The other four proposals would replace groundwater with surface water for 102,600 acres, both north and south of the interstate.
All would be achieved by drawing from Banks Lake or Lake Roosevelt, which are reservoirs created by Grand Coulee Dam, by drawing water from a new reservoir northeast of Moses Lake, or by a combination of the three. Excluding the no-action alternative, the costs range from $728 million to $3.3 billion.
The two alternatives that only partially replace water and don't include construction of a new reservoir offer the best cost-benefit ratio, acknowledged Bill Gray, the Reclamation's Columbia-Cascades area manager. Those alternatives largely use existing infrastructure to deliver water.
The proposed reservoir would hold about 117,000 acre-feet of water, at a construction cost of about $300 million. An acre-foot is the amount of water needed to cover an acre of land with one foot of water.
Addressing the problem of declining groundwater levels is of tremendous importance to the region and the state as a whole, said Derek Sandison, director of the state Department of Ecology's Office of the Columbia River.
"We need to move the process of finding solutions to this problems forward as rapidly as possible to provide people in the region some certainty about their economic future," Sandison said in a statement.
Similar water studies are being conducted in central Washington's Yakima Valley and in the Walla Walla River basin, areas of eastern Washington that are heavily agricultural and susceptive to drought.
"We have no shortages of water problems in eastern Washington," Sandison said. "All of these projects cost money, but the problems that we're facing are significant and in some cases, like Odessa and Yakima, there's significant economic peril in not doing anything."
A 2005 study by Washington State University concluded that the loss of the potato crop alone on land irrigated by groundwater and the related processing plans would cost the region about $630 million per year and 3,600 jobs. The Washington State Potato Commission commissioned the study.
Public comment on the impact statement will be accepted through the end of the year. Public meetings also will be held Nov. 17 in Coulee Dam and Nov. 18 in Moses Lake.
Gray said he expects public comments to include suggestions that have been included or may not have been considered. All would be expensive, and times are tough, he said.
"I don't think any basin can expect the federal government to come in and foot the bill," he said. "That will probably be part of the decision process, as to who steps up to the plate to share costs."
-- The Associated Press