The Tuolumne River flows through Modesto. The Tuolumne has become one of the most over-drafted rivers in the state, but a new plan meant to protect fish and other wildlife would drastically cut the amount of water available for human use. Photo: Michael Macor, The Chronicle
WASHINGTON — San Francisco faces potentially drastic cutbacks in its water supply, as state regulators proposed leaving more water in three Northern California rivers Thursday to protect wildlife in the Sacramento-San Joaquin River Delta estuary, the linchpin of California’s water supply.
The draft rules by the State Water Resources Control Board would raise the amount of water into the Merced, Stanislaus and Tuolumne rivers to 30 to 50 percent of what would naturally flow in them. That means less water would be available for urban users and farmers in the northern San Joaquin Valley, compounding their need to conserve.
Current flows into those rivers dip as low as 10 percent during parts of the year, and, if the plan is made final, state officials said they would start the increase with a midpoint of 40 percent during spring flows from February through June.
“The bottom line is we’ve simply diverted too much water for fish to be able to survive,” said board Chairwoman Felicia Marcus in a telephone interview. “This should have been done earlier, but it’s a hard thing to do in the worst drought in modern history.”
The rules on river flows have not been updated since 1995, and even then they never considered the needs of wildlife in any of the three tributaries, Marcus said. In the meantime, fish populations have plummeted in all three rivers and California’s second-largest river, the San Joaquin, runs dry for long stretches. Marcus said the science clearly shows the fish need more water.
The board would have acted three years ago but delayed the plan because of California’s record drought that has forced thousands of acres of farm fields to be fallowed, required individuals to cut their water use by a quarter and driven half a dozen species of native fish, including the state’s storied salmon runs, to the brink of extinction.
Birds using the Pacific Flyway migration path through the Central Valley have also suffered a dire lack of water.
The Tuolumne has become one of the most over-drafted rivers in the state, with about 80 percent of its normal flow diverted to human uses. San Francisco draws its water from the river, which it dammed in the early 20th century in Yosemite National Park, and is one of its largest water rights holders. Even as the Tuolumne has been over-drafted, the city has aggressively defended its water rights.
In all, the river provides water to 2.6 million residents and businesses in the Bay Area and also supplies water to farmers through the Modesto and Turlock irrigation districts.
On paper, California has allocated five times more water to human uses than exists in the state’s rivers. The over-drafting becomes apparent during droughts, when it is impossible to meet every user demand and wildlife often takes the biggest hits.
As high as the proposed increases are, they fall short of the 60 percent flow that state and federal wildlife officials had recommended, both to save wildlife and to prevent saltwater from damaging the Sacramento-San Joaquin River estuary.
Still, San Francisco Public Utilities Commission spokesman Charles Sheehan said the agency has not yet seen the full draft rule, but said for Bay Area customers “this could have significant impacts in drought years and in post-drought years when you’re trying to refill your system.”
Farm groups, which often say water left in rivers is “wasted to the sea,” swiftly denounced the proposal.
California Farm Bureau President Paul Wenger said in a statement that the plan could idle as many as 240,000 acres of farmland. Farmers have made great strides in improving water efficiency, he said, and “it’s time to apply the same standards to water dedicated to environmental flows.” Efforts to protect fish by simply increasing the water available to them have not worked, he said.
But fish biologists said the state continues to shortchange fish, even with the new rule.
“There is no evidence that 40 percent is going to cut it,” said Jon Rosenfield, a salmon biologist at the Bay Institute, an environmental group. “All the fish and wildlife agencies have said that way more than 40 percent of tributary flows is necessary to protect the hardiest fish, the salmon, and that’s not counting other fish and wildlife that might require more flows.”
Less than 5 percent of San Joaquin River water now reaches the delta, he said, and what is left in the river is often a poisonous soup of farm runoff.
“The river has been mined almost out of existence,” Rosenfield said. One recent consequence is the emergence of highly toxic algae blooms in the southern delta, he added.
Peter Drekmeier of Save the Tuolomne, an environmental group, said San Francisco has cut its water use by 30 percent since 2008 and can do more. He faulted farm irrigation districts that use the river for encouraging unwise use by vastly underpricing water, selling it as cheaply as $15 an acre-foot when urban residents pay $1,500.
Marcus said the board will hear public comments until November and then issue revisions incorporating those comments with final approval expected early next year.
San Francisco is expected to challenge the rule, although how aggressively remains to be seen. “We intend to participate in that process,” said Sheehan, the utility agency spokesman.
The rules are part of a series of updates of something called the Bay Delta Water Quality Control Plan. They cover only the San Joaquin River and southern delta; the board will later take up the Sacramento River, delta outflows, Suisun Marsh and other areas.
Carolyn Lochhead is The San Francisco Chronicle’s Washington correspondent. Email: clochhead@sfchronicle.com
This article originally posted by The SF Gate.