Odessa Subarea Special Study

The U.S. Bureau of Reclamation and Ecology are investigating continued phased development of the Columbia Basin Project. The investigation, known as the Odessa Subarea Special Study, focuses on project development for the purpose of replacing groundwater currently used for irrigation in the Odessa Ground Water Management Subarea with surface water. The five year study began in 2006, and will conclude with a planning report and the appropriate National Environmental Policy Act (NEPA) documents. While this is not a storage study, alternatives include provisions for storage.

Odessa Area (USBR image from 9/2006 Special Study)

On April 1, 2008, Reclamation released an appraisal-level engineering investigation of four water delivery alternatives and six water supply options.

The four water delivery alternatives proposed possible infrastructure (canals, pumping plants and
laterals) and configurations to deliver replacement surface water to existing groundwater irrigated lands in the Study area. Reclamation selected Alternative B for further study.

Alternative A - Construct a new East High Canal system north and south of Interstate 90.

Alternative B – Construct a new East High Canal system north of Interstate 90; enlarge the
capacity of the existing East Low Canal south of Interstate 90 and construct a 2.3 mile
extension.

Alternative C - Enlarge the capacity of the existing East Low Canal south of Interstate 90.

Alternative D – Use current East Low Canal configuration north of Interstate 90.

http://www.usbr.gov/pn/programs/ucao_misc/odessa/update-feb2008.pdf

Increased diversions will be required from the Columbia River above current Columbia Basin Project diversions to provide the replacement water supply. Reclamation examined water supply options that would not affect Columbia River flow objectives identified for fish listed under the Endangered Species Act (ESA). These water supply options included:


▪ Modifying operations at existing Columbia Basin Project storage facilities
	- Banks Lake Drawdown: Draw down Banks Lake to elevations ranging from 4 to 16 feet lower than current operations
	- Banks Lake Operational Raise: Raise reservoir water surface elevation 2 feet
	- Potholes Reservoir Reoperation: Adjust water storage timing in the reservoir


▪ Constructing new storage facilities that would be filled in September and October to provide water to Odessa Subarea lands in March through August. Three sites were examined -- Dry Coulee, Rocky Coulee and Lower Crab Creek. After examining these options, Reclamation decided to continue to study operational modifications at Banks Lake and Potholes Reservoir and the possible construction of Rocky Coulee Dam and reservoir as potential options to provide the replacement water supply.

http://www.usbr.gov/pn/programs/ucao_misc/odessa/update-feb2008.pdf

Public Participation

The study was submitted to the public for comment in October 2007. Reclamation received 81 written comments from State agencies, environmental, conservation and non-governmental organizations, State residents, and representatives for agriculture and recreation interests. The majority of comments were from Washington State residents. Those expressing support for the Study predominately advocated Alternatives A and B, with some support for Alternative C. Many noted that Alternative D, which would rely on the existing canal system, could not deliver a replacement water supply to sufficient acres to address the issues associated with the declining aquifer and would not be able to deliver water to lands south of Interstate 90, an area where significant aquifer decline is occurring.

To see more detailed information about the study please visit the U.S. Bureau of Reclamations website.

Download the Odessa Subarea Special Study, Appraisal-level Investigations, Summary of Findings Report.