BOISE — The U.S. Bureau of Reclamation is expected to ask the Idaho Water Resource Board this month to provide matching funding for a proposed study that would seek ways to store more water on the Boise River system.
The study would cost $5.6 million and would require a 50 percent match from non-federal partners, such as the IWRB and irrigation districts.
IWRB Chairman Roger Chase told Capital Press that finding ways to store more water in the Boise River drainage is a board priority.
“We’re working with the Bureau of Reclamation to see if there is ... any way we can find some additional storage on the system,” he said. “We can certainly use some more water if we can capture it.”
Creating more storage capacity is also a top priority for farmers and other irrigators in the region, said Roger Batt, executive director of the Treasure Valley Water Users Association.
He said only about 25 percent of the water that passes through the Boise River is able to be stored in the system’s three major reservoirs, which have a combined storage capacity of just under 1 million acre-feet.
About 1.8 million acre-feet of water was sent down river this year to prevent flooding in the Boise area.
“That’s water we’ll never see again,” Batt said. “We would have liked to have been able to capture at least some of that.”
The population of the Treasure Valley area in southwestern Idaho is projected to grow from about 650,000 now to more than 1 million people in the next 25 years.
“We’ll always be advocates for additional storage capacity,” said Clinton Pline, president of the TVWUA’s board of directors and a farmer. “We may not need it today but we’re going to need it tomorrow.”
U.S. Army Corps of Engineers officials told water board members last year that the benefits of raising Arrowrock Dam by up to 70 feet was the best option for solving water supply and flood risk problems in the Boise River system.
But they also said the benefits of the project didn’t equal the cost and that $3.5 million study has been discontinued.
The Bureau of Reclamation has proposed conducting a study that would look at the possibility of raising Arrowrock, Anderson and Lucky Peak dams by several feet each, which would add 60,000 acre-feet of combined storage capacity.
“The water board and reclamation are now looking at whether to move forward with a feasibility study of these smaller raises,” said Cynthia Bridge Clark, the Idaho Department of Water Resources’ water project section manager.
Will Patterson, chairman of the Nampa & Meridian Irrigation District’s board of directors, said the district is working closely with the bureau to try to find ways to store more water.
“We think it’s very critical to find additional storage capacity on the Boise River” system, he said.
He said NMID is willing to contribute a portion of the non-federal match that is required for a project to proceed.