Water-Spills Over Dams Increased to Aid Salmonby Associated Press
Post Register, April 17, 2000
KENNEWICK, Wash. - Operators of some Columbia and Snake river dams have begun spilling extra water over the structures to see how many juvenile salmon can be kept away from often-lethal dam turbines.
The increased spill will reduce the amount of electricity generated by the turbines. But the loss is expected to be negligible because the high spring runoff will meet seasonal power demand.
"We believe the tests will show the benefits ... more than outweigh the costs," said spokesman Perry Gruber of the Bonneville Power Administration, the federal agency that markets power from the dams.
The BPA is conducting the program at the direction of National Marine Fisheries Service, which oversees recovery efforts for federally protected salmon and steelhead.
Young salmon typically begin their journey to the Pacific Ocean in early spring. Some are taken around the dams by barge to the mouth of the Columbia. Others make their own way downstream, trying to avoid natural predators as well as turbines.
The increased spills are intended to help the fish avoid the turbines and propel themselves over spillways.
Dam managers for the U.S. Army Corps of Engineers have been told to be cautious and not spill too much water. Spilling water into pools below the dams releases dissolved atmospheric gases into the river. If concentrations are too high, fish can contract an often-fatal disease similar to the bends in humans.
Friday was the first full day of the spill tests.
At Bonneville Dam - about 35 miles east of Portland, Ore., on the Columbia - spills will be increased to see which level suits fish best. At the Snake River's Lower Monumental Dam, 30 miles northeast of the Tri-Cities, the full spill has been increased from 12 hours a day to 24 hours a day.
The plan is to increase fish passage a little at each dam.
Results of the tests will provide more information to federal officials considering salmon-restoration options including modifying dams to make them more fish-friendly or breaching four lower Snake River dams.
"This is one more small step to improve salmon survival," said Brian Brown, hydro operations director for NMFS.
"The more difficult issues of potential dam breaching - increased spring and summer flows, improving water quality and the definition of the performance standards to recover threatened and endangered salmon - are still ahead," he said.
learn more on topics covered in the film
see the video
read the script
learn the songs