Libby Dam and Koocanusa Reservoir update

Submitted by

Gregory Hoffman

Current Koocanusa Reservoir elevation: 2429.9 feet (Full Pool is 2459 feet)
Current Koocanusa Reservoir inflow: ~39 kcfs
Current Libby Dam outflow: 15 kcfs
Current Kootenai River elevation at Bonners Ferry: 1755.6 feet (Flood Stage is 1764 feet)

Libby Dam outflow decreased last night (Monday, June 19) from 15 kcfs to 14 kcfs. This decrease begins the transition from the sturgeon pulse to the summer operation of targeting an elevation of 2449 ft in Lake Koocanusa  by September 30th.  Flows may be reduced later this week after evaluating summer inflow volumes and the refill operation.

Sturgeon flow augmentation began Monday May 15, as local Kootenai River tributaries downstream of Libby Dam were forecasted to peak.  Outflows were decreased from powerhouse capacity to 18.0 kcfs May 21.  A second pulse of up to powerhouse capacity flows started on June 02 and began ramping down on June 11.

The current water supply forecast for the April -Aug inflow volume for June is 7594 (129% of average).  Additionally, the May forecast set the Bull Trout minimum after the sturgeon pulse to 9 kcfs, and the sturgeon volume for this year to 1.2 MAF, which is a Tier 5 year.