One of the important concepts we have agreed on, regarding the building of the Auburn Dam, is that having the extra cold water the dam would store would be able to provide help to the salmon during times of low water, and this study validates that.
Dams are necessary for the development of land for human communities, providing flood protection and water supply, and they are also necessary for the stabilization of animal communities, such as the salmon, as they allow us the capacity to control the environment for their benefit when necessary.
Long-time residents of the Sacramento region will remember that before Folsom Dam was built, there were years when no salmon could spawn due to the almost dry conditions of the American River, and what water was in it was too warm and was flowing too slow for the salmon.
Study: Dams Could Benefit Salmon
Cold Water Stored In Reservoirs May Help Fish
POSTED: 6:58 am PDT May 1, 2008
UPDATED: 8:10 am PDT May 1, 2008
SACRAMENTO, Calif. -- California's vast network of reservoirs -- which destroyed more than 5,000 miles of salmon habitat when their dams were erected decades ago -- could turn out to be a savior for a species on the brink of collapse, according to a new study.
Those dams store cold water, which the study says will be vital to the salmon's survival as climate change is expected to warm California's rivers.
"Paradoxically, the very thing that is constraining fish now, we could use those to our advantage," said study author David Yates, a project scientist at the National Center for Atmospheric Research in Boulder, Colo.
The peer-reviewed paper will appear in a future issue of the Journal of Climatic Change. Yates and the journal agreed to release the study's findings early to The Associated Press.
It comes at a time when the number of salmon returning to spawn in the Central Valley rivers, which are crucial to the West Coast stocks, are at historic lows.
Earlier this month, federal fisheries regulators recommended that fishing along California's coast and most of Oregon be suspended for the year. It was the first time the Pacific Fishery Management Council had taken such a drastic step, one that is jeopardizing the $150 million West Coast salmon industry.
Unfavorable ocean conditions, habitat destruction, dam operations, agricultural pollution and climate change are among the potential causes.
Historically, 1 million to 3 million chinook salmon spawned annually in the streams that tumbled out of the western Sierra Nevada. This year, just 50,000 are expected to return to the Central Valley river systems.
Yates' research projects that an increase in air temperature of 3.6 degrees to 7.2 degrees Fahrenheit could be lethal for the young winter-run and spring-run salmon in the Sacramento River. The increase in water temperatures would vary depending on the depth and flows of the river.
Studies have shown that high water temperatures have wide-ranging and potentially fatal consequences for salmon, who generally need water temperatures lower than 68 degrees when they return to fresh water. It reduces their swimming ability, increases their vulnerability to disease and leads to lower growth rates. Spawning females require even colder water of 57 degrees for their eggs to live and juvenile salmon migrate back to the ocean more successfully when the river is no more than 64 degrees.
Higher water temperatures can be offset if federal water managers preserved the cold water stored behind Shasta Dam, near the head of the Sacramento River, and released it when the salmon head upriver. Salmon that once headed far upstream to cooler, mountain streams are now forced to spawn in valley waters because the dam blocks their path.
It's a management option not available on rivers that aren't dammed.
