Could the Kootenai or Moyie Rivers flood this season? |
| May 5, 2014 |
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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 |