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Could the Kootenai or Moyie Rivers flood
this season?
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May 5, 2014 |
Do you have river plans for the summer?
Innertubing on the Moyie, perhaps? Rafting on
the Kootenai? Fishing? Swimming at Big Rock?
Or maybe you have farmland in the Kootenai
Valley.
We're going to talk rivers here, including Moyie
and Kootenai river levels, and the current
outlook for flooding on those rivers.
Currently Near Flood Stage
Interestingly, a glance at the latest National
Weather Service map of 144 river observation
gauges scattered throughout northern Idaho, all
of Washington, and northern Oregon, shows only
two areas currently designated as "Near Flood
Stage." Those areas are the Naches River near
Cliffdell in Washington, and the Kootenai River
at Bonners Ferry.
As of Sunday, May 4, the Kootenai River was
hovering at a level about five and one half feet
below flood stage (or more accurately, its
"Minor Flood Stage"), possibly rising another
1/2 foot on Monday, May 5, according to the
National Weather Service.
For those who thrive on seeing the actual data
points, minor flooding of the Kootenai River
occurs when the water level in the river rises
to an elevation of 1,764 feet above sea level.
Currently, the Kootenai water level is at
approximately 1,758.5 - 1,759 feet
elevation--around five feet below minor flood
stage. The river would have to rise an
additional 6 feet beyond its Minor Flood Stage,
to an elevation of 1,770 feet, to be at the
"Moderate Flood Stage," and another eight feet
above that to be at its "Major Flood Stage."
What Happens With Flooding?
What exactly happens when the Kootenai River
hits its Minor Flood Stage? At Minor Flood Stage
of the Kootenai River (water level of 1,764
feet), minor flooding begins along the farmland
of the Kootenai Valley, much of that due to
seepage as the water table rises. Low level
roads near the dikes and levees of the river
banks may also have seepage flooding.
Were the river level to rise another two feet
(still within the Minor Flood Stage), water
would begin to lap onto the lawn of the Kootenai
River Inn, the lowest point in the downtown
Bonners Ferry area.
This actually happened in June 2006, as the
Kootenai River crested at 2.67 feet above its
flood stage. Many may recall that on June 25,
2006 calls went out for community volunteers to
assemble at the Kootenai River Inn, where crews
put in several hours sandbagging the river bank
there. By the way, a short video of that 2006
sandbagging operation is available for viewing
at our companion website,
boundarycountylive.com. Maybe you were one of
those volunteers who turned out to help sandbag
and prevent further flooding.
The Kootenai River has crossed the level for
"Major Flooding" on four occasions in the time
records have been consistently kept dating back
to 1927. On those occasions (1948, 1954, 1956,
and 1961), before the days of the Libby Dam,
flooding would occur in the downtown area of
Bonners Ferry.
The highest recorded level of the Kootenai River
since 1927 occurred in 1961, when the river
level reached 1,780.13 feet above sea level,
more than 2 feet above its Major Flood Stage.
The Moyie River
The Moyie River, measured at its gauge at
Eastport, reaches minor flooding when its water
levels attain an elevation of 2,629.06 feet.
River level data of the Moyie have been kept
consistently since 1929. Its highest recorded
level in that time period was in May of 1954,
when it crested about a foot and a half higher
than its Minor Flood Stage.
Where does the Moyie River stand right now?
Currently, it is flowing at approximately 2 feet
below its Minor Flood level.
For your Moyie River plans, such as innertubing,
swimming, and fishing, it might help to know
that the river has hit its highest crest level
68 times during the month of May over the past
84 years. The Moyie crested in the month of June
eight times in the past 84 years--May and June
are generally when the Moyie is at its highest
levels. Of course, you don't really need
scientific data to know that; people around here
would know that May and June are usually the
high water months, just from looking at the
river. But its nice to know that science is
backing us up on this observation.
Flooding Predictions for this Season
So what are the predictions on whether we will
actually cross the flood stage at the Kootenai
River this year? The National Weather Service's
Northwest River Forecast Center in Portland,
Oregon does sophisticated modeling of
streamflows on the Kootenai and other rivers.
Their modeling takes into account many factors,
including snowpacks, soil moisture levels in the
basins, historical precipitation and temperature
sequences, and other data. Their modeling has
generated 53 different potential streamflow
"traces" for the Kootenai River this summer.
These traces show streamflows we might expect on
the Kootenai River if weather and precipitation
patterns are similar to patterns of past years.
As of the first of May, at least 95% of their
predicted streamflow traces are falling below
the Kootenai River flood stage. That is an
optimistic picture, and if the weather holds to
past patterns, we should be OK and look forward
to no flooding. However, should unexpected or
unusual changes in this season's weather
patterns occur, such as more rain or warmer
temperatures than expected, those optimistic
models would have to be discarded and
re-calculated, and the predictions for possible
flooding might have to change.
We are hoping that doesn't happen.
So, get your innertubes patched and ready to go,
get your rafting gear together, and dig out your
swimsuit. We are hopefully aiming for a great
summer on the Kootenai and Moyie Rivers of
Boundary County.
Copyright 2014, newsbf.com |
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