Koocanusa high leads to floodplain changes for RDEK

Record high on Koocanusa reservoir in July has forced the regional district to change its construction rules

The Sweetwater development beside Koocanusa

The Sweetwater development beside Koocanusa

The regional district has been forced to change its rules for homes built near Koocanusa.

For the first time ever, the reservoir south of Jaffray was allowed to go past full in July to prevent flooding downstream.

Koocanusa holds water from the Kootenay and Elk Rivers before it flows through Libby Dam in Montana, down the Kootenai River through Bonners Ferry, Idaho, and back into Canada into Kootenay Lake.

In late June, during a record snowmelt and weeks of pounding rain, an unprecedented agreement between Canada and the U.S. gave the dam’s operators permission to let the reservoir go two feet past full, in order to prevent more serious flooding in Idaho and the West Kootenay.

But that meant that the regional district’s guidelines for homes beside Koocanusa, specifically the Sweetwater development, were no longer accurate.

“As a result of the extraordinary conditions this spring and summer the reservoir actually experienced a “surcharge” where additional water was held back behind the Libby Dam, raising the elevation of the reservoir 60 centimetres (two feet),” said Andrew McLeod, manager of planning and development services.

“The primary effect of the changes to the … bylaw that are being considered by the board is to adjust the future siting of buildings on some of the lakefront lots to move them back from, and above, the potential surcharge elevation of the water in the reservoir.”

The bylaw amendment was given first and second reading by the Regional District of East Kootenay board of directors on Friday, September 7.