BOISE, Idaho — Record or near-record snowpack in Snake River drainages above Brownlee Reservoir is prompting increased flood-control operations there. Idaho Power has been lowering the reservoir to accommodate higher-than-normal inflows and to make room for anticipated large runoff over the coming weeks.
This means developed boat ramps will be unavailable until May due to low reservoir elevations.
The maximum water level in Brownlee is based on requirements from the U.S. Army Corps of Engineers, which coordinates Columbia Basin flood control efforts. To maintain operational flexibility and system reliability, Idaho Power also considers upstream and downstream conditions and scheduled releases from other reservoirs. Weather and streamflow forecasts are also used to establish reservoir elevation targets.
Inflow to Brownlee Reservoir has been higher than normal during February and early March. Inflow in February averaged 27,000 cubic feet per second (cfs) and peaked in mid-February at over 50,000 cfs. Inflows in March have continued to average nearly 27,000 cfs. Current weather forecasts anticipate additional snow and rain in southwest Idaho and southeastern Oregon over the next week. Inflow to Brownlee Reservoir will increase over the next few days and will likely stay high through the spring as snowmelt boosts flows in rivers and headwater streams.
The reservoir has been drafted approximately three feet per day for the last eight days and was at an elevation of 2,024 feet above sea level as of March 9. Brownlee Reservoir will likely be drafted below an elevation of 2,020 feet for most of March and April. By comparison, that’s more than 50 feet — roughly the height of a five-story building — below the reservoir’s full mark at 2,077 feet.
All boat ramps will be unavailable and boaters should expect the reservoir to remain at these low levels until at least the first week of May, when refill operations may begin. Visit our Water Information page for current reservoir elevation information.
Idaho Power recognizes the impact these operations may have on recreationists and others in the area. The company’s goal is to keep the reservoir elevation at levels that maximize hydroelectric generation and maintain recreational access. However, flood-control operations take precedence over those considerations.
Once flood-control restrictions are lifted and inflows begin to decline, Idaho Power will allow the reservoir to refill as quickly as possible while maintaining our hydro operations and required downstream flows.
In addition, Idaho Power will continue work on the Moonshine Mine Boat Launch near Richland. The low reservoir elevation has allowed for significant progress on the project and construction will proceed as long as conditions allow. This will allow boater access to the reservoir at much lower elevations than are currently available on the Oregon side of the reservoir.
About Idaho Power:
Idaho Power, headquartered in Boise, Idaho, and locally operated since 1916, is an electric utility that employs more than 2,000 people who serve approximately 535,000 customers throughout a 24,000-square-mile area in southern Idaho and eastern Oregon. With 17 low-cost hydroelectric projects as the core of its diverse generation portfolio, Idaho Power’s residential, business and agricultural customers pay among the nation’s lowest rates for electricity. IDACORP, Inc. (NYSE: IDA), Idaho Power’s independent publicly traded parent company, is also headquartered in Boise, Idaho. To learn more, visit idahopower.com or idacorpinc.com.
Contact: Brad Bowlin