Will Outcry Over New Dams Doom Endangered Salmon?
Environmental objections to new dam construction in California may be a primary reason why endangered winter-run Chinook salmon and other threatened fish go extinct.
When Shasta Dam finished construction in 1945, fisheries experts at the federal government expected it to precipitate the sure extinction of Sacramento River’s migratory Chinook salmon and steelhead that spawned in tributary streams and rivers located above the dam.
In a remarkable tale of survival, these salmon and steelhead still exist because of an unexpected benefit the dam provided: a reliable steady supply of very cold water to be released each year during the summer and autumn months when the fish migrate to new spawning grounds in gravels below Shasta Dam.
This year, for example, Shasta Dam is releasing about 10,000 cubic feet of water per second to keep the Sacramento River cool for salmon, as well as to generate hydropower and provide water for downstream users and other environmental purposes. Other major dams are contributing, too.
Despite their proven benefits, environmental groups that say they want to save the Sacramento River’s salmon are becoming very vocal in opposing raising Shasta Dam or a new reservoir in Colusa and Glenn counties. The new storage would increase the cold-water pool at Shasta Lake, making more water available to protect the endangered fish from sure extinction.
Because one of the dams’ primary reasons for existence is flood control, the U.S. Bureau of Reclamation (USBR) operates them to allow a sufficient margin of safety in case of heavy river flows. One result of adding more depth to Shasta and new storage at Sites Reservoir would be to allow USBR managers to store more cold water than they do today, permitting them to increase the volume of cold-water flows they release later in the year.
How much more water could they store to protect the endangered winter-run Chinook salmon? USBR estimates that they would be able to store as much as 1.1 million acre-feet more water in Sites, Shasta, Trinity, Oroville and Folsom reservoirs. Instead of the 3.0 million acre-feet they had in November 2014, they would have had 4.1 million acre-feet, or 23% more in the total North-of-the-Delta storage pool.
Lack of cold water to protect the salmon in 2014 and 2015 caused catastrophic losses of 95–98 percent of all the migrating winter-run Chinook salmon in the Sacramento River. The same conservation groups and activists that are blocking new dams are asking for higher flows out of Shasta for salmon and less to other uses, including urban, food-production and even water for wildlife refuges essential to the survival of other endangered species of animals, fish, amphibians and birds.
The failure of fish to survive in 2014 and 2015 is documentary proof that the current structure and operating policy used by USBR are insufficient to protect these highly endangered fish in times of extreme drought. If they can’t be afforded protection then, when conditions are extreme, their numbers will dwindle and they will become extinct.
Had Sites Reservoir been built and Shasta Dam been raised, it’s virtually certain that the lethal water temperatures fish experienced the last two years would have been avoided and far more migrating fish would have survived.
Obstruction of new water storage projects by environmental, tribal, sports-fishing, and commercial-fishing groups may be dooming the Sacramento’s winter-run Chinook salmon to extinction. The fish are caught between the perceived evil of more dams inundating river valleys and streams and the reality that the fish will continue to die because USBR hasn’t enough space to store cold water and release it from their existing network of dams.
In a sense, the short-sighted opposition to building water storage projects, new dams and expanding reservoirs is fulfilling today the long-ago predictions of government biologists, putting the salmon on a fast track to vanish from the face of the earth.