BOISE, Idaho -- The U.S. Army Corps of Engineers and the Bureau of Reclamation will increase flows through the City of Boise by 500 cubic feet per second (cfs) on Tuesday, April 23. Currently, Boise River flows through town are approximately 5,300 cfs, as measured at the Glenwood Bridge gauge. Flows will reach approximately 5,800 cfs by mid-morning on Tuesday.
The increase in flows from Lucky Peak Dam and Lake is in response to above average precipitation the Boise River System has received so far in April. As of April 22, the Boise River basin has received 197% of normal month-to-date precipitation, and the snowpack in the basin is 126% of normal according to the Natural Resources Conservation Service. These increases from Lucky Peak Dam and Lake are necessary to help reduce the risk of flooding later in the spring, which can happen with rapidly melting snow and seasonal precipitation.
Additional adjustments in water releases from Lucky Peak Dam and Lake are likely during the coming days, depending on weather conditions and resulting inflows. Flows also could fluctuate depending on water diversions for irrigation use, as determined by Idaho Water District 63.
When river flows exceed 4,000 cfs at the Glenwood Bridge gauge, water is likely to begin seeping onto low spots on the Greenbelt path next to the river, especially near bridge underpasses. The Greenbelt serves as a flowage easement area, intentionally designed to provide space for higher flows occurring in the Boise River.
Officials advise the public to be aware of risks associated with flood season. The water is deep, cold and fast. Extreme caution should be used near the river banks. A flow rate of 7,000 cfs, or about 10 feet in water depth, at the Glenwood Bridge gauge, is considered flood-stage level on the Boise River.
Currently, the Boise River reservoirs are at 75% of capacity. A full supply of irrigation water is anticipated this summer.
For real-time Boise River flows at Reclamation facilities in the Pacific Northwest Region, visit http://www.usbr.gov/pn/hydromet/rtindex/boise.html.
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Reclamation is the largest wholesale water supplier in the United States, and the nation’s second largest producer of hydroelectric power. Its facilities also provide substantial flood control, recreation, and fish and wildlife benefits. Visit our website at https://www.usbr.gov and follow us on Twitter @USBR.
The Corps of Engineers and the Bureau of Reclamation operate three dams on the Boise River as a system to manage flood control and irrigation storage needs — Lucky Peak Dam, Arrowrock Dam and Anderson Ranch Dam. Storage capacity provided by Reclamation’s Arrowrock and Anderson Ranch dams, and the Corps’ Lucky Peak Dam, combined with well-planned water releases, help manage Boise River flows through the City of Boise.