Rapid increase in flow predicted for Kootenai

Cooler than normal temperatures

combined with above normal rain and snow is expected to result in

above normal Kootenai River flows in the coming weeks.

“Forecasts suggest we could see

significant rapid rises in reservoir elevation, up to eight feet

per day, by mid-May through mid-July,” said Joel Fenolio, Upper

Columbia Senior Water Manager for the Army Corps of Engineers. “The

Kootenai River may be at or near flood stage for a period of time

starting mid-May. Downstream tributaries to the Kootenai which are

not controlled by Libby Dam, such as the Yaak, Moyie and Fisher

Rivers, are expected to be at or above flood stage as well.”

The U.S. Army Corps of Engineers has

created water storage space for greater than normal inflows by

drafting the Koocanusa Reservoir down to 2,354 feet in elevation,

approximately 100 feet below capacity, on the reservoir side of

Libby Dam.

Current high-elevation snowpack is 128

percent of normal and lower-elevation snowpack is 153 percent in

the Kootenai River basin. The National Oceanic and Atmospheric

Administration forecast is for cooler than normal temperatures

through June with continued higher than normal precipitation

through May.

Generally upper river runoff is

regulated by Libby Dam, while lower river runoff is mostly

unregulated since it flows into the Kootenai River below the dam.

The Corps’ flood risk management operation is to retain as much

Kootenai River flow as possible behind Libby Dam while the

downstream unregulated tributaries, which are forecasted to flood,

pass as much of their spring snowmelt and rain flows as possible.

It is likely that Kootenai River flows may be at or above flood

stage from unregulated tributary flows alone.

Residents and businesses in the river

basin should be prepared for potentially swift water rises in a

relatively short period of time once snowpack begins to melt.

The Corps is regulating Libby Dam for

flood risk management, closely monitoring weather conditions,

snowpack readings and inflows to mitigate flood risk

downstream.

The Corps is targeting a reservoir

elevation of 2,348-2,351 feet by the end of April. The reservoir

will continue to be drafted at a rate of roughly one foot per day

until the start of reservoir refill, projected for the first or

second week of May.

Two public information meetings for

Libby Dam operations are scheduled for May. The first is May 9 at

the Kootenai River Inn in Bonners Ferry, Idaho, at 7 p.m. The

second is May 12 at Libby City Hall at 7 p.m.