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Commentaries and editorials

Salmon and River Temperature

by Michael Howard
Idaho Statesman, October 26, 2017

Graphic: Maximum scroll cast temperatures at Bonneville Dam in June and July 1950 to 2015, with a break point at 1977 showing increased temperature coincident witht eh completion of the four Lower Snake River Dams Rocky Barker concludes (Oct. 8 front page salmon article) that the Snake/Columbia hydroelectric dams act as "giant solar collectors" that helped cause river temps to reach 73 degrees (lethal for salmon) in 2015. He also mentions that the lower Salmon (without dams) rose to 76 degrees that year. Hmm…

Dam pools create a "thermocline effect" in which water temperatures on the bottom are much colder than surface temperatures. The S.F. Boise River below Anderson Ranch Dam (as delighted fly fisherman can affirm) remains frigid throughout the hottest summers because it's fed from the bottom of the dam pool. Ditto the Owyhee River (below Owyhee reservoir). Both are renowned "tail-race" trout fisheries with miles of year-round ice-cold flows.

Any scientific model that compares Snake/Columbia river temperatures with/without dams must accurately calculate the cumulative thermocline effect on all dams on every river that feeds the Columbia ... otherwise the algorithm is flawed. In other words, removing dams to offset rising river temps associated with climate change may not be the panacea we're betting on. Once the dams are removed, we lose billions in annual "salmon survival mitigation funds" that power companies currently pony up -- along with the gargantuan loss in cheap, carbon-free hydroelectricity.

Related Pages:
Acidic Oceans and Warm Rivers that Kill Idaho's Salmon Might be Norm in 50 Years by Rocky Barker, Idaho Statesman, 10/7/17
Salmon by Rocky Barker, Idaho Statesman, 9/10/17
Everything We're Doing to Replace Vanishing Salmon Might be Killing Them Off Faster by Rocky Barker, Idaho Statesman, 9/7/17
A Changing Electrical Grid May Make Snake River Dams Expendable by Rocky Barker, Idaho Statesman, 8/6/17
With Shipping Down on Snake River, Farmers Worry About Dams' Future by Rocky Barker, Bellingham Herald, 8/7/17
Northwest Salmon, the Stuff of Legends, Still Struggle to Survive by Rocky Barker, Idaho Statesman, 7/8/17
Nature Again Turns Against Returning Fish that Already Face Long Odds by Rocky Barker, Idaho Statesman, 5/20/17
Is Snake River Shipping Worth Enough to Keep Dams that Harm Salmon? by Rocky Barker, Idaho Statesman, 8/6/17
Fate of Pacific Northwest Orcas Tied to Having Enough Columbia River Salmon by Barker & Peterson, Idaho Statesman, 7/9/17

Michael Howard, Boise
Salmon and River Temperature
Idaho Statesman, October 26, 2017

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