Boise River floodwater backing up on Glenwood Street
Snowmelt runoff into Boise River reservoirs has risen with the recent above-normal temperatures, but water managers say they are holding Lucky Peak reservoir’s discharge steady.
And the river’s flow downstream of Lucky Peak has actually declined with increased irrigation demand, the Bureau of Reclamation and Army Corps of Engineers say.
Reservoirs stand at roughly 85 percent of capacity, the two agencies said in a joint release Wednesday. The flow at Glenwood Bridge was expected to fall near 8,400 cubic feet per second this week and, in fact, was just below that level about 5 p.m. Thursday. This puts the river back to levels seen at the start of May.
Current weather forecasts, irrigation demand and remaining reservoir storage capacity allow for managers to hold Lucky Peak’s outflow steady for now. As always, future weather and snowmelt conditions could change that plan, the agencies cautioned, and flooding will continue to be a concern. Official flood stage at the Glenwood Bridge is 7,000 cfs.
The Corps of Engineers and Bureau of Reclamation operate Lucky Peak, Arrowrock and Anderson Ranch dams on the Boise River to manage flood control and storage needs.