19-062 Boise River flows to decrease to 3,300 cfs on Friday

Published May 23, 2019

The U.S. Army Corps of Engineers plans to reduce flows through the City of Boise to approximately 3,300 cubic feet per second (cfs) by late-morning on Friday, May 24. Currently, Boise River flows through town are approximately 3,800 cfs, as measured at the Glenwood Bridge gauge.

The decrease in flows from Lucky Peak Dam and Lake is in response to recently reduced inflows. The flow decrease is necessary to help balance reservoir-refill goals with the continued risk of flooding later during the spring, which can happen with rapidly melting snow and seasonal precipitation.

Additional adjustments in water releases from Lucky Peak Dam and Lake may occur 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.

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. 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.

Residents of flood-prone areas in and near the greater Boise area are encouraged to keep informed of changing river, stream, and weather conditions on the National Weather Service, Boise Office website at https://www.weather.gov/boi/. The site offers flow data, weather forecasts, and flood alerts. Follow flood-response instructions issued by your local emergency management agency https://adacounty.id.gov/emergencymanagement/, and tune-in to local radio and television news stations.

Currently, the Boise River reservoirs are at about 86% of capacity. As of May 22, the Boise River system of reservoirs has about 130,456 acre-feet of available storage space. A full supply of irrigation water is anticipated this summer.

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. For real-time Boise River flows at Reclamation facilities in the Pacific Northwest Region, visit https://www.usbr.gov/pn/hydromet/rtindex/boise.html.

Public Affairs Office

Release no. 19-062