Climate Change, The Columbia River, and Ridgefield

The above graphic shows Columbia river predicted flows in the 2050s.  The time of peak flows from spring snow melt is earlier  and summer flows are much less (source UW)

The Columbia River responds to the Pacific Ocean tides all the way to  the Bonneville Dam.  At Ridgefield at midnight Monday night, the high tide is expected to bring the river to 6.56 feet and at 3 AM the low tide is expected to be 3.84 feet.  Its not a great difference but it is enough to reverse flows of Lake River into Vancouver Lake and even Gee Creek into the pond/wetland complex upstream.  In addition to tides, the Columbia is greatly effected by the flow of water coming down the Columbia River.  Last winter and spring, the flows from the heavy rains brought the Columbia River here to  a peak of about 16 feet (flood stage is 17 feet).

The latest climate assessment released Friday by the Trump Administration showed a sea level rise of 1.6 to as much as 8 feet by 2100. NOAA has an interactive site to show the impact of sea level rises for different areas.  To show how it will impact Ridgefield, Lake River, and the refuge click this:  Columbia river sea rise

The site is interactive and set  for 3 feet but it can be changed from none to six feet.  You can also zoom in and out and change location.  At three feet there is a real change is the level of water in both the Carty and River S Units. The Columbia River will rise to 6 feet and more with time.  The only question  is how soon.  Sea level rise will continue for hundreds of years no matter what.  That is because the carbon dioxide already released will  stay with us a very long time.

The Columbia River reverses flow from the ocean to as much as 53 river  miles upstream  and salt water intrusion  is about 23 river miles upstream.  With sea level rise, the flow reversal will increase  carrying  salt water further upstream as well.   The difference between high and low tides will likely increase.  With the loss of snow and ice in the Columbia Mountains and Rockies, the summer flows are projected to decrease by as much as  50 % by the  2050’s .  With lower flows and higher river levels the resident time for water to travel from Bonneville Dam to the ocean will increase.  This may mean a warmer  slower river and could create serious problems such as having  less oxygen and encouraging invasive species.   Having the peak flows as much as a month or more earlier would put the annual crest into the rainy season and thus an increased risk of flooding.  This would certainly be exacerbated by having this on a river higher from sea level rise. It will likely mean that the height of a 100 or a 500 year flood will have to change.   Building in areas above a flood zone may find those zones rising.

The material for this article was gleaned from many different sources.  The impacts of a river higher from sea level rise with changes in seasonal flows will have profound impacts for both communities and natural areas.   What really seems to be missing is a more comprehensive study that better quantifies and qualifies the predicted changes.

 

 

 

 

 

 

About Paul Snoey

I have a degree in Biology and Environmental Science from WSU Vancouver
I am very fond of Gee Creek and Allen Canyon Creek and do a lot of volunteer work to restore these creeks.

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