19-020 Corps, Reclamation set to reduce Boise River flows to 1,400 cfs on Monday

The U.S. Army Corps of Engineers and the Bureau of Reclamation plan to reduce Boise River flows through the City of Boise on Monday morning, March 18, 2019, from approximately 1,900 to 1,400 cubic feet per second (cfs), as measured at the Glenwood Bridge gauge.

This decrease in flows from Lucky Peak Dam and Lake is in response to drier conditions forecasted by the National Weather Service.  Seasonal snowpack in the Boise River basin as of March 15 was 127 percent of median, according to the Natural Resources Conservation Service. Precipitation totals for March 1 through March 14 were 32 percent 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.

Additional adjustments in water releases from Lucky Peak Dam and Lake are possible during the coming weeks, depending upon weather conditions. Flows could also fluctuate depending upon water diversions for irrigation use through the New York Canal, as determined by Idaho Water District Number 63.

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 54 percent 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.