The U.S. Army Corps of Engineers and the Idaho Water Resource Board have signed two partnering agreements to conduct geological and operational studies of Idaho’s Weiser River as part of an effort of possibly creating additional water storage in southwest Idaho.
The Weiser River watershed encompasses a large area in southwestern Idaho. The headwaters for the Weiser River, a tributary to the Snake River, originate in the southern end of the Seven Devils Mountain Range and the west central mountains of Idaho.
Creating additional storage of water on the major tributaries of the Snake River in southwest Idaho, including the Weiser River, has been the subject of studies by private, state and federal parties for more than 50 years – for benefits resulting from flood risk management, water supply for irrigated agriculture, system and site hydropower production, ecosystem restoration, flow augmentation for fish and recreation.
For more information on these efforts see story CBB, August 5, 2011 “Idaho Plans Study Of Building Dam/Reservoir On Weiser River; Cites Salmon Recovery Benefits” http://www.cbbulletin.com/411337.aspx
The Corps comprehensively studied the Weiser River basin from 1987 through 1994. In March 2011, the Corps’ Walla Walla District completed a gap analysis study in partnership with the Idaho Water Resource Board – the “Weiser-Galloway Gap Analysis, Economic Evaluation and Risk-Based Cost Analysis Project.”
The 2011 gap analysis identified two critical gaps that must be resolved before IWRB can decide to move forward with comprehensive new feasibility, environmental and engineering studies.
The partnering agreements will team up IWRB with the Corps to conduct two new technical studies that will address those critical gaps:
1) The Snake River Operational Analysis Project will study a range of potential river-operating scenarios that seek to optimize system operations with incremental volumes of new water storage on the Weiser River, including flood control, irrigation, hydropower production, storage, recreation and flow augmentation requirements while maximizing economic benefits.
2) The Weiser River Geologic Investigation and Analysis Project will study the safety, suitability and integrity of the geologic structures at the proposed dam and reservoir site. Study activities will include mapping, core-sampling and analysis to identify or rule out potential structural weaknesses or seepage potential of a proposed dam and reservoir at this location.
These two technical studies are being conducted under a cost-sharing agreement authorized by Section 22 of the Water Resources Development Act of 1974, as amended, which provides authority for the Corps to provide planning assistance to states and tribes. The Planning Assistance States Program, permits the Corps to use its technical planning expertise to supplement and support state and Indian tribe efforts to undertake broad, statewide, comprehensive water resources planning. This program is cost shared on a 50 percent federal and 50 percent non-federal basis.
“We just completed one of the most successful projects ever done between the Corps and the Idaho Water Resource Board,” said Jack Peterson, senior adviser to the Idaho Water Resource Board. “Our extraordinary partnership with the Corps in Walla Walla during the past two years working on the gap analysis is the reason we want to partner with them again on these new studies that are vital to future of Idaho’s water resources.”
“We’re excited to be working with the State of Idaho again on the Weiser-Galloway studies,” said Rebecca Kalamasz, chief of Planning Branch for the Corps’ Walla Walla District. “The technical analysis to be conducted during these two studies is essential to help Idaho make future water-planning decisions.”
The Corps and IWRB will work together to develop two project management plans to more specifically develop the scope and schedule of the studies to be conducted.