Imagine a salmon, in the fall of 1893, swimming up the Tuolumne River and bumping into the brand new La Grange Dam.
The question of whether these fish used to spawn above that spot dominated a meeting Monday on the future of the reservoir, owned by the Modesto and Turlock irrigation districts. They store most of their water in the far larger Don Pedro Reservoir, about 2 miles upstream, but they could face costly improvements at La Grange to make life better for salmon.
How costly? Perhaps as much as $60 million, if the Federal Energy Regulatory Commission requires an elaborate system for transporting fish past the two reservoirs and into an upstream river stretch. The amount is a long way from being decided.
FERC, which oversees reservoirs with hydroelectric plants, ruled in 2012 that La Grange needs a license and the conditions that come with it to enhance the environment. MID and TID built the dam decades before such approval was required.
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The districts have appealed the ruling but still have to go through the licensing process. They also are in the midst of renewing the 1966 license for Don Pedro.
Monday’s meeting, which drew about 50 people to the MID office, dealt with what studies FERC should require on fish and other concerns as part of the La Grange process. Representatives of several environmental groups and fishery agencies asked for a look at trucking or otherwise moving salmon past the 110-foot dam.
“It’s just common sense that we’ve lost a lot of habitat,” said Larry Thompson, a fishery biologist with the National Marine Fisheries Service office in Sacramento. He noted that the upper watershed includes several tributaries to the Tuolumne and has forest cover that could help provide the cool water needed by spawning fish each fall.
Salmon hatch in rivers up and down the Central Valley, then spend two to five years in the Pacific Ocean before returning to reproduce and die. They have struggled in recent decades for reasons that are much debated: blocked spawning grounds, river diversions to farms and cities, water pollution, predation by other fish and more.
The parties asking for fish-passage studies said they could cost $1 million to $2 million. TID would bear about two-thirds of the expense and MID the rest, based on their shares of the Tuolumne supply. They would do the same with physical changes aimed at helping salmon.
The costs ultimately fall on the districts’ customers, said Cecil Russell, chief executive officer of the Modesto Chamber of Commerce. “It’s not money that falls out of the sky,” he said. “It’s money that has to be recovered from ratepayers.”
The Turlock district already has proposed a 5 percent electricity rate increase for 2015, in part because of the licensing costs for La Grange and Don Pedro. MID will be looking at power rates soon. Licensing costs also are borne by the districts’ water users.
FERC could decide in February what studies will be needed for the La Grange license, said John Devine of HDR Inc., a consulting engineer for MID and TID. The fish-passage study would be a two-year look at how many salmon spawn close to the dam and whether they might benefit from being transported several miles between this area and the river above Don Pedro.
Devine said the study could find that few salmon get as far up the river as La Grange Dam, so a fish passage costing tens of millions of dollars would not make sense.
The studies FERC orders could include the habitat conditions in the Tuolumne stretch above Don Pedro, such as spawning gravels, tree cover and flows. The Rim fire burned across most of it last year, but the damage was generally light along the riverbed compared with upper canyon slopes. The water levels fluctuate with releases from the Hetch Hetchy Water and Power System, operated upstream by San Francisco.
The key issue with the Don Pedro relicensing is how much water should be released into the lower Tuolumne, through La Grange, to benefit salmon. Farming advocates say large amounts would reduce the irrigation water that has helped agriculture thrive in and near Stanislaus County for more than a century.
MID board member Larry Byrd, who used to help manage river releases as a district employee, said salmon are suffering mainly from striped bass and other predators that have become too numerous. “The eggs are getting eaten even before they hatch,” he said.
Predation studies are part of the Don Pedro relicensing.