BOISE, Idaho — The U.S. Army Corps of Engineers plan to reduce river flows by 1,500 cubic feet per second (cfs) by Monday, May 20. Flows are currently around 5,800 cfs, as measured at the Glenwood Bridge gauge.
Flows will decrease by 500 cfs each morning Thursday, May 16 through Monday, May 20, reaching around 4,300 cfs by late morning Monday.
The decrease in flows from Lucky Peak Dam and Lake is in response to recent weather conditions and resulting inflows. The flow decrease is necessary to balance reservoir-refill goals with the continued risk of flooding during spring. That can happen with melting snow and seasonal precipitation.
Additional adjustments in water releases are likely in the coming days depending on weather conditions. Flows could also fluctuate depending on water diversions for irrigation use, as determined by Idaho Water District 63.
At 4,000 cfs, or about 7.4 feet in depth, river water may seep into low spots on the greenbelt path next to the river, especially near bridge underpasses. The Greenbelt is designed to be a flowage easement area, to provide space for higher flows occurring in the Boise River. 7,000 cfs, or about 10 feet in water depth, at the Glenwood Bridge gauge, is considered flood-stage on the Boise River.
Currently, the Boise River reservoirs are at about 82% of capacity. As of May 14, the Boise River system of reservoirs has about 174,915 acre-feet of available storage space. A full supply of irrigation water is anticipated this summer.