Rivers and a Warming Planet

Last week Merrill Lynch Research released a “Climate Change Primer” outlining the challenges and potential investment opportunities climate change provides.  Of course, climate change impacts our fisheries as well.  The Merrill Lynch report begins with the statement that climate change is the top global risk we face. 

“Extreme weather is recognized as the #1 global risk today, with climate change acting as the ultimate risk multiplier, compounding societal stresses including economic disparity, human migration, and interstate conflict. The 16 warmest years on record have occurred in the 21st century and 2017 is on track to be the 41st consecutive year where global temperatures are above the 20th century average. Extreme weather now covers 10-12% of the globe vs. 0.2% during 1951-1980, with the frequency and severity of heat waves, hurricanes, floods, and droughts intensifying.”

One of the primary controversies for local anglers over the past few years has been lower Deschutes River temperatures.  Some believe that river temperatures in the lower most stretches have recently risen due to the operation of PGE/CTWS’s Selective Water Withdrawal tower.  What has been lacking is consideration that the operation of the SWW has coincided with climate change.  Over the past 7 years of SWW operation air temperatures have consistently set records and a drought has occurred.

This is especially relevant given ODFW’s insistence that releases from the Pelton Round Butte complex have little if any influence on river temperatures by the time the water reaches Sherars Falls below Maupin.  The lower Deschutes River below Pelton Round Butte is broad and shallow, averaging only 6 feet deep.  Per ODFW, air temperature and sun exposure are the overwhelming determinants of river temperature in the bottom section of the river, the area where most of the complaints about elevated temperature have been made.