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Flooding problems beginning

by Jim Mann
| May 17, 2011 2:00 AM

High water has started to cause some problems at the outset of a flood season that is expected to last for weeks.

The Montana Department of Transportation put machinery to work Monday removing downed trees from the Stillwater River to prevent damage to a bridge crossing on Twin Bridges Road west of Whitefish.

“It was a debris removal just to prevent them from obstructing the bridge,” department spokeswoman Lori Ryan said Monday afternoon. 

The Stillwater River that flows through Kalispell nearly reached its 7-foot action stage Monday, just shy of its 7.5-foot flood stage.

To the south, high water in the Woods Bay area restricted motorists to 35 mph from mile marker 21 to mile marker 22.5. There was about an inch of water over the highway at mile marker 22.5 on Monday morning.

The Flathead County Sheriff’s Office dispatched deputies to Star Meadow west of Whitefish to assist a woman who was apparently stranded on high ground by high water. Parts of the meadow tend to swamp out when Logan Creek exceeds its banks.

Sheriff Chuck Curry said the woman was not imminently threatened.

“Certainly a lot of the creeks are up right now,” Curry said. “Some of the low-lying stuff around them, that is starting to flood.”

Trumbull Creek often leaves its banks south of U.S. 2 west of Columbia Falls, and it’s starting to do so again, spilling into a field.

“There are some homes that eventually may get some water around, but again, they are usually the first to get wet,” Curry said.

The National Weather Service is expecting most Northwest Montana rivers to level off this week with the arrival of cooler weather. However, rivers and streams are expected to resume their rise with the return of any warm weather or significant precipitation.

“I believe what we’re seeing is the start of a pretty long flood season,” said hydrologist Ray Nickless with the Weather Service.

“There’s still lots of snow left to melt,” he said. “That’s why we’ll see rivers continue to stay high through May and into June.”

The Thompson River at Thompson Falls exceeded its flood stage of 7 feet Monday and was projected to rise to nearly 8 feet by today, then recede somewhat over the next few days.

The Yaak River at Troy exceeded its 8-foot flood stage Monday and was similarly expected to recede somewhat in the next few days.

The Fisher River near Libby was expected to exceed its 7.5-foot flood stage today and then decline.

Nickless noted that those rivers could have more peaks that are higher in the future.

That has been a concern for the U.S. Army Corps of Engineers and residents in Bonners Ferry, Idaho, which can be impacted by high flows on the Yaak, Fisher and other Kootenai River tributaries.

Libby Dam Superintendent Mick Shea said the Corps is forecasting that the Kootenai River could reach its flood stage elevation of 1,764 feet and could rise to 1,765 feet.

“We think we are going to be at or near flood stage for four to eight weeks” at Bonners Ferry, he said.

Boundary County, Idaho, officials are alarmed because Bonners Ferry agriculture starts to get damaged when the river reaches a 1,758-foot elevation. The Bonners Ferry Herald recently reported that in 2002, when the river rose to 1,758 feet, farmers endured about $2 million in crop damage and those flows only lasted a few days.

The Herald reported that the concern this year is about the duration of the high flows.

“This is extremely bad news for the community and that amount of water for that length of time will affect our farms like we have never seen before,” one official said at a recent meeting.

Libby Dam has been operated to put Lake Koocanusa at about 121 feet below full pool as of May 11, a reservoir low that hasn’t been seen since the severe winter of 1996-97.

Since May 11, the reservoir has started to refill, even with the dam discharging at powerhouse capacity of 20,000 cubic feet per second.

As the Kootenai River rises at Bonners Ferry, Libby Dam discharges will be scaled back and Lake Koocanusa will begin a more rapid refill.

Reporter Jim Mann may be reached at 758-4407 or by email at jmann@dailyinterlake.com.

Tracking high water online

U.S. Geological Survey streamflow and lake-level data:

http://waterdata.usgs.gov/mt/nwis

Hydrology charts for area rivers:

www.wrh.noaa.gov/mso/hydrology/composites.php

Area snowpack and snow water content:

www.wrds.uwyo.edu/wrds/nrcs/updatesur/update-mt.html

National Weather Service (Missoula office):

www.wrh.noaa.gov/mso