This is something I did not know the history of—that there once was a fish ladder—so this article from the Auburn Journal is very informative.
A recent news article states “San Francisco (Nov. 10, 2015) – Environmental groups filed a request yesterday to supplement their complaint against the U.S. Bureau of Reclamation and growers who flood irrigate rice in the Sacramento Valley for mismanaging water supplies that should have been used to protect California’s once-booming salmon runs and fishing industry.”
The suit was filed by the Natural Resources Defense Council against the bureau and the Rice Growers Association, alleging that the bureau unlawfully diverted limited water supplies from behind Shasta Dam for the use of corporate agriculture, instead of using the water to keep Chinook salmon alive below the dam. Chinook salmon especially — threatened winter and spring runs — are on the verge of extinction.
These headlines are almost daily occurrences in California newspapers with little being accomplished to save our anadromous fishes.
Californians must get salmon and steelhead over rim dams in order to prevent extinction.
According to NOAA records, Folsom Dam originally had a fish ladder installed, but it was washed out by a flood in 1949 and sadly was never rebuilt. The builders knew fish passage over the dam would be necessary to preserve salmon and steelhead, but the need has been buried and ignored for over half a century.
Fish ladders or some counterparts like fish elevators or fish pipelines over Folsom Dam and the North Fork Dam on the North Fork of American River would help reopen the dams now blocking natural passage for the fish.
Such changes would allow fish to spawn naturally in their natural habitat, which once extended to the crest of the Sierra. So doing will be a natural adjutant to the current management method of artificially spawning the fish at the Nimbus Fish Hatchery, which is manually squeezing out the eggs from females and milt from the males and hand mixing the fertilizing agents in a bucket.
Salmon are consummate natural creatures, and when this fish passage project is completed, they will only benefit.
The public is not yet ready to dismiss fish hatcheries, which have extended the lives of a weakened salmon species. But people well know fish hatcheries were advertised as a means of circumventing opposition to the rampant dam building of the last century.
People now know that the common mixing of milk and eggs does not strengthen the species like precocious males fertilizing eggs in a process of natural selection in the wild (see spawning video at www.sarsas.org).
When salmon and steelhead are able to get over these two dams, they will have a minimum of 125 miles of prime salmon spawning gravels in North Fork and its several tributaries, now all blocked. Passage must be installed in place of a system of “Catch and Haul” by trucking fish upstream.
Trucking the fish will cost hundreds of millions of dollars each year whereas the fish passage is a one-time expense for fixing the problem permanently.
Many very knowledgeable fish scientists have summarily dismissed the possibility of fish passage over California’s rim dams and have stopped planning and experimenting with possibilities.
Folsom Dam is 340 feet to the top of the dam and 275 feet to its hydraulic height, the natural operating depth of the dam.
The fish ladder must be incremental with resting pools for fish to negotiate the dam’s height. When the fish return, an underwater funneling system could be used near the dam to shoot the fish back through an opening very close to the dam, freefalling the fish back into the river where they’re ready to make their return to the Pacific.