WEISER, Idaho — A significant step has been taken in the state’s effort to determine whether it’s feasible to build a dam on the Weiser River with a reservoir that could hold up to 750,000 acre-feet of water.
The Idaho Water Resource Board recently filed an application for a preliminary permit with the Federal Energy Regulatory Commission to study the possibility of building a 40- to 60-megawatt hydropower plant at the dam site.
The hydropower plant would play a critical role in financing the project, which is estimated to cost about $500 million.
Cynthia Bridge Clark, a staff engineer in the Idaho Department of Water Resources’ water planning section, said the FERC application is not a determination of the feasibility of the project and “there is still quite a bit of work to be done.”
However, she added, “There’s definitely a lot of interest … in vetting the project and understanding what its potential is.”
IWRB Chairman Roger Chase said the proposed project is high on the board’s priority list.
“The water board thinks it’s a pretty important project,” Chase said. “So far, the preliminary work that has been done says we can build a dam there. It’s one of the last really good sites in Idaho, in my opinion, for building a reservoir and dam.”
Rep. Gayle Batt, R-Wilder, said the reservoir would provide a huge benefit to farmers and other water users in southern Idaho, especially those in the fast-growing Treasure Valley area.
“There is going to be increasing demand for water in this valley and I’d rather get it from new storage facilities than by forcing farmers to give it up or having a war between rural and urban areas,” she said.
The proposed dam is officially called the Weiser-Galloway Project, but is commonly referred to as the Galloway project. It would be built on the Weiser River near its confluence with the Snake River, about 13.5 miles from the city of Weiser.
The Boise, Payette and upper Snake river systems are required to release 40,000, 160,000 and 200,000 acre-feet of water respectively each year to provide river flow augmentation for salmon recovery purposes.
If the proposed reservoir could provide 220,000 acre-feet of flow augmentation water, that would free up a lot of water for irrigation purposes in those basins, Clark said.
The proposed dam has been studied off and on since 1954 but the idea picked up steam in 2008 when the Idaho Legislature directed the IWRB to instigate storage projects, including the Galloway site. The legislature this year approved $2 million to fund environmental compliance and land acquisition studies associated with the dam.
“We’re not going to create any more water in Idaho but we can store more of the water that now leaves the state,” Chase said. “The Galloway site is one of the best sites in the state to do that.”