the film
forum
library
tutorial
contact
Commentaries and editorials

Judge, Court of Appeals
Ignored Fish Facts

by John McKern
Walla Walla Union-Bulletin, April 8, 2018

A judge's ruling mandates more water be spilled over Snake and Columbia river dams

Little Goose Dam on the Lower Snake River dam. I am writing about the front-page article, “Court Oks boosting spill to aid fish” published April 3.

Terry Flores, executive director of Northwest RiverPartners, is correct that Judge Michael Simon, the Court of Appeals and the plaintiffs made this wrong decision based on ignorance of the facts.

In brief, seven of the eight U.S. Army Corps of Engineers dams are equipped with one or two overflow spillways that do speed up and safely bypass fish past each dam. The Lower Snake River dams have seven or nine undershot spill gates, and the lower Columbia River dams have 16 to 20.

The overflow spillways function like a stream exiting from a lake, and fish are attracted to the flow and pass quickly. The undershot spillways discharge water from a depth of 40 to 50 feet at about 35 miles per hour with an instantaneous pressure release that would give a human diver the bends.

The rapid expansion entrains air that becomes supersaturated in the water and persists to the next dam where spill can again increase the supersaturation.

In a series of reservoirs where high supersaturation levels persist from dam to dam, and down river below Bonneville, the last dam, juvenile fish are subjected to increased gas in their blood, rapid decompression, disorientation, injury and greater susceptibility to predation by birds and fish.

Also, adult fish are exposed to gas supersaturation from the estuary all the way to Idaho or Eastern Washington. They can become intoxicated by the gas in their blood, and hit weirs in the fish ladders, or be “scalped” as they fall back under the undershot spill gates.

While the overflow weirs do provide a more natural way past the dam, and fish do delay while resisting passage through the very unnatural slots 40 to 50 feet below the surface, more spill does not speed up the travel of the water moving downstream. Whether the water passes through turbines or the spillway, the travel time of water through each reservoir is the same.

Therefore, maximizing spill as ordered by Judge Simon is more harmful to both juvenile and adult salmon and steelhead than the judicious use of spill and generation that was envisioned when the overflow spillway weirs were developed.

This information and much more was provided in a declaration the Columbia and Snake Rivers irrigators asked me to write last year. Judge Simon totally ignored these facts, and, apparently, so did the 9th U.S. Circuit Court of Appeals.


John McKern, Walla Walla
Judge, Court of Appeals Ignored Fish Facts
Walla Walla Union-Bulletin, April 8, 2018

See what you can learn

learn more on topics covered in the film
see the video
read the script
learn the songs
discussion forum
salmon animation