19-032 Boise River flows will increase this week

Published April 9, 2019

The U.S. Army Corps of Engineers and the Bureau of Reclamation will continue to increase flows through the City of Boise. Currently, Boise River flows through town are about 1,200 cubic-feet-per-second (cfs) and will increase by 500 cfs throughout today, Tuesday, April 9, 2019, as measured at the Glenwood Bridge gauge. Flows will increase by another 500 cfs daily, on Wednesday, April 10, Thursday, April 11, and Friday, April 12, incrementally reaching approximately 3,200 cfs by late-Friday evening.

Additional adjustments in water releases from Lucky Peak Dam and Lake are likely during the coming weeks, 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.

This increase in flows from Lucky Peak Dam and Lake is in response to recent inflows and more rainfall forecasted by the National Weather Service. Seasonal snowpack in the Boise River basin as of April 8 was 120% of median, according to the Natural Resources Conservation Service. Precipitation totals for April 1 through April 7 were 103% of normal, according to the National Weather Service. The water releases are necessary to help reduce the risk of flooding later in the spring, which can happen with rapidly melting snow and seasonal precipitation.

Officials advise the public to be aware of risks associated with flood-season Boise River flows. 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, as measured at the Glenwood Bridge gauge, is considered flood-stage level on the Boise River.

The public should be aware that river flows may frequently change during the snow-melt season as Corps and Reclamation reservoir managers balance flood-risk management with irrigation supply. Currently, the Boise River reservoirs are at 61% of capacity. A full supply of irrigation water is anticipated this summer.

For real-time Boise River flows at Corps and Reclamation facilities, visit https://www.usbr.gov/pn/hydromet/rtindex/boise.html.      

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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.

Public Affairs Office, USACE - Walla Walla District
Public Affairs Office, USBR - Pacific Northwest Region

Release no. 19-032