UPDATE: May 19, 2016
In its May 18 presentation to the Idaho Water Resources Board, the U.S. Army Corps of Engineers revealed its findings of a $1.5 million study regarding the Treasure Valley's water needs. And while Corps officials said indeed the flood risk remains and water needs will get only higher, it could not fully recommend the raising of the Arrowrock Dam by as much as 70 feet. The chief reason? The immense cost of such a project. Corps officials told the water board that raising the dam is definitely a solution to flood and drought concerns, but it still chooses not to be involved in such a project due to the high cost.
Corps officials concluded that the cost/benefit analysis of such raising and improving the dam - estimated to be around $1.3 billion - would be about 0.7. In other words, the cost would outweigh the benefit, according to Corps Project Manager Karen Zelch.
ORIGINAL STORY: May 17, 2016
As rising temperatures in the Treasure Valley trigger greater attention to the region's water supplies for irrigation, recreation and sustenance, two provocative presentations that surfaced this week regarding the Arrowrock and Anderson Ranch dams.
The U.S. Army Corps of Engineers was scheduled to present its findings May 18 from a recent study that offered as one of its possible alternatives raising the height of Arrowrock Dam by as much as 70 feet. The immense project would reportedly create an additional 32,000 acre-feet of water storage capacity in the Boise River reservoir system. The study was a joint project between the Corps and the Idaho Water Resource Board.
Concurrently, staff from the U.S. Bureau of Reclamation stood before the Idaho Water Resource Board this week saying the agency intends to launch its own study on the possibility of raising the Anderson Ranch Dam on the South Fork of the Boise River to provide more water supply for the Treasure Valley and areas as far away as Elmore County.
The studies come in the wake of news from the Water Resource Board in April that suggests if population growth and climate change trends hold, there will be a startling demand for water—as much as a 357 percent increase—in the next 50 years.
The study, conducted for the Water Resource Board by Boise-based SPF Water Engineering, led to a robust conversation about water conservation—or lack thereof—in Idaho. In particular, Boise Weekly learned that a number of Treasure Valley water providers, including Kuna and Star, were not metering some of their customers.
"That said, I think we'll have a good water year in southwest Idaho this summer," said Brian Patton, board chief of the Idaho Department of Water Resources.
"But keep in mind, that's just for this year," he added.