A draft report on water storage options for the Yakima River Basin in Washington declines to choose a preferred alternative but notes the Black Rock Alternative, including two hydropower plants, would generate more than $3 million annually in net revenues.
The Bureau of Reclamation and Washington’s Department of Ecology identified seven alternatives in their Yakima River Basin Water Storage Feasibility Study Draft Planning Report/Environmental Impact Statement, released Jan. 25.
The storage study evaluates alternatives that could create additional water storage in the Yakima River Basin and assesses their potential to improve anadromous fish habitat, improve the reliability of the Yakima Project irrigation water supply during dry years, and provide water to meet future demand for municipal water supply.
The $4.5 billion Black Rock Alternative is the only alternative that would provide hydropower benefits. (HNN 9/21/07) It would include construction of the Black Rock and Sunnyside hydropower plants.
Hydro units at Black Rock and Sunnyside would be expected to generate about 196,751 MWh annually, with combined monthly generation ranging from about 14,508 MWh to 35,637 MWh. Total generation under the alternative is valued at about $7.1 million annually.
However, the report said, pumping water to the proposed Black Rock Reservoir from the Columbia River would divert some flows from Grant County Public Utility District’s 907-MW Priest Rapids Dam, reducing generation at Priest Rapids Dam and other hydro facilities. Lost generation at Priest Rapids and other dams is estimated to total $4 million annually. Combining the gains and losses in hydropower values results in a net positive hydropower benefit of about $3.1 million annually, the report said.
The report does not identify the generating capacity of the new plants, but says Black Rock and Sunnyside would be expected to generate 71,671 MWh and 125,080 MWh annually. A previous report described the Black Rock Alternative as including two or three hydropower facilities, two Black Rock plants of 23 MW and 38 MW and a 15- to 29.5-MW Sunnyside power plant.
BuRec has concluded the Black Rock Alternative is technically viable, including the ability to withstand expected seismic activity. The dam design has been selected to absorb any anticipated ground shaking and maintain the ability to contain the reservoir behind it.
BuRec previously found that construction of Black Rock Reservoir could result in seepage and groundwater migration toward the federal government’s 586-square-mile Hanford Nuclear Reservation to the east. The U.S. Department of Energy is analyzing the effects of seepage. Additionally, BuRec estimated total seepage and is analyzing measures for reducing flows toward the site. Results of the analyses will be included in the final EIS.
Public review and comment of the draft EIS is scheduled until March 31. The report is available on the Internet at www.usbr.gov/pn/programs/storage_study.