Army Corps flood fighters continue work in
Idaho
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| May 22, 2011 |
SEATTLE – The Army Corps of Engineers’ Seattle
District has flood fight teams out in three
river basins, and the Corps' Emergency
Operations Center is under 24-hour operation as
rivers remain high.
In Kootenai County a flood team is assisting
county efforts to prevent Hayden Lake Dam from
failing by strengthening the existing structure,
which was actively eroding. Construction began
May 15 and is expected to continue through
Friday.
In the Yakima basin, at the request of Yakima
County, teams have completed work to shore up a
weakened portion of the Nile levee, which was
constructed during the 2009 Nile landslide on
the Naches River to protect Highway 410. Teams
have also completed work on an area of the
federally constructed levee on the Yakima River
near Terrace Heights and the levee protecting
the sewage treatment plant. The team also raised
the City of Naches levee and provided assistance
on the previously damaged Rock Creek Levee on
the Naches River.
A team is on the St. Joe River to provide
technical assistance to St. Maries as the St.
Joe River remains high.
The Corps finished assisting Lincoln County with
work at Bay Horse Dam on Miller Lake. When Corps
and Lincoln County team members arrived on site
May 13, the dam was overtopping by 3 to 6 inches
at each of the abutments and at the center, and
two other low spots. A swift water search and
rescue team had deployed to open the 40 inch
outlet pipe out of the structure, which had
become plugged – there was very little water
flowing out, and there was failure occurring
around the outlet structure. Only about half
could be opened to flow, with additional debris
threatening to plug the outlet on the upstream
side. The overtopping was causing erosion of the
face of the dam when the Corps arrived on site.
The team worked until midnight to place 1-2 rows
of sandbags across the top of the dam and built
an overtopping spillway using sandbags and
plastic sheeting. The outlet was cleared and is
now flowing and working well, and the level of
water behind the dam continues to drop.
The Corps has distributed 291,000 sandbags to
date in western Montana and northern Idaho, and
provided a pump to the town of Cataldo, Idaho,
which faces flooding from the Coeur d’Alene
River, and another pump is on stand-by for the
Pend Oreille. On Monday the Corps began reducing
outflows from Libby Dam from 20,000 cubic feet
per second to 16,000 cfs. The Libby Dam outflow
reduction should help to keep the stage below
1,764 feet at Bonners Ferry while the local
inflows remain high.
This morning flows into Lake Pend Oreille were
100,000 cubic feet per second and the Albeni
Falls Dam was passing 70,000 cfs in free flow
operation. Flood stage at Newport is 100,000
cfs, a stage elevation of about 2,046 feet. The
lake elevation is above 2,058 feet and rising.
Flood stage on the lake is 2,063.5 feet.
Public meetings to discuss Pend Oreille flood
risk are being held May 18 in Sandpoint, Idaho,
and May 19 in Cusick, Wash.
Additional flood teams for eastern Washington,
western Montana and northern Idaho are on alert.
Current flow information for many of the river
basins in the Northwest may be found here:
http://www.nwd-wc.usace.army.mil/nws/hh/index-j.html. |
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