06/08/2026
We have a Libby Dam flow update for you!
The June Water Supply Forecast (WSF) for the April through August inflow period for Koocanusa Reservoir, is 7.064 million acre-feet (116% of average).
The WSF has been well above average through the winter, driven by above normal snowpack at elevation in the upper Kootenay River watershed (https://www.nwrfc.noaa.gov/snow/index.html?version=20201207v1), and Koocanusa Reservoir has been drafted accordingly through the winter and spring. Please see attaches in the comment section.
Current Koocanusa Reservoir elevation is ~ 2,420’ after having reached a low pool elevation of ~ 2,369’ (90’ from full pool and 85’ from target refill elevation).
Current Koocanusa Reservoir inflow is ~ 45,000 cfs after having peaked at ~ 68,000 cfs on May 31.
Current Libby Dam discharge is 25,000 cfs.
Current Bonners Ferry stage is ~ 1,756.5’ (flood stage is 1,764’) after having peaked ~1,757’ on May 30/31.
Koocanusa Reservoir elevation is projected to reach ~2,454’ (full pool elevation for reservoir management purposes) by late July / early August and remain over 2,450’ through most of September.
Libby Dam has been discharging full powerhouse capacity (25,000 cubic feet per second – cfs) since May 26 for Kootenai River white sturgeon spawning in the lower Kootenai River.
Discharge will be reduced to 22,500 cfs late Sunday evening and then reduced to 20,000 cfs on June 11.
Further flow decreases will occur through the end of June, and we expect river flows during July and August to be above the minimum bull trout flow of 9,000 cfs for this year before reducing discharge to the bull trout minimum flow in late August / early September.
More detailed flow updates will be provided as they are coordinated to occur, as described above.
Details are also available via the links below.
US Army Corps of Engineers Libby Dam Water Management Data:
https://water.usace.army.mil/overview/nws/locations/lib
Short term forecasts for Libby Dam elevations and inflow:
http://www.nwrfc.noaa.gov/river/station/flowplot/flowplot.cgi?lid=LYDM8
Short term forecasts for Libby Dam outflow:
http://www.nwrfc.noaa.gov/river/station/flowplot/flowplot.cgi?lid=KBDM8
