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Agencies, Farmers Mull Aquifer Options by Matthew Weaver Capital Press, October 28, 2010

Study looks at using Columbia water to irrigate 102,000 acres

MOSES LAKE, Wash. -- The U.S. Bureau of Reclamation and Washington State Department of Ecology will decide next summer how best to expand the state's largest irrigation system to replace groundwater from the region's declining aquifers.

The agencies on Oct. 26 released a study examining several options for using Columbia River water to irrigate as much as 102,000 acres. Irrigation water there is currently pumped from deep wells in the Odessa Subarea, where the aquifer has declined by 200 feet or more during the past 30 years.

The agencies released their Odessa Subarea Special Study Draft Environmental Impact Statement at the Columbia Basin Development League's annual meeting in Moses Lake, Wash.

The public comment period ends Dec. 31. The agencies will then prepare a final report and environmental impact statement that will be released next summer.

The options the agencies will consider include:

• Four alternatives covering partial replacement of ground water with surface water on 57,000 acres. They would use the existing East Low Canal with a 2.1-mile extension south of Interstate 90 and bring in 138,000 acre-feet of water. Estimated cost: A minimum of $728 million.
• Four alternatives to replace all of the ground water used with surface water on 102,600 acres north and south of Interstate 90. They would involve construction of a new East High canal and bring in 273,000 additional acre-feet of water. Estimated cost: As much as $3.3 billion.
• A no-action alternative.

The proposals would bring surface water to land that is now irrigated using wells, said bureau technical services project manager Chuck Carnohan.

Derek Sandison, director of the Department of Ecology Office of the Columbia River, said cost-share partnerships would be key in making the alternatives financially feasible.

Sandison said that taking no action would have significant economic consequences.

Carnohan said the partial replacement option has fewer environmental impacts, as it mainly uses existing infrastructure. There are concerns about construction of a new canal system disturbing wildlife habitat, Carnohan said.

Both sets of alternatives also carry concerns about disturbing nesting grebes or affecting summer recreational activities on Banks Lake.

The water would come from Banks Lake or Lake Roosevelt, which are reservoirs created by Grand Coulee Dam or the $300 million Rocky-Coulee Reservoir, also under consideration, which would mitigate the drawdown of the other two lakes.

Carnohan indicated that cost-benefit ratio calculations leaned in favor of the partial replacement options.

Related Sites:
Columbia Basin Development League
Odessa Subarea Special Study Draft Planning Report
Odessa Subarea Special Study Detailed Map