Water & Drought

Sacramento water agencies brace for historic drop in Folsom Lake levels

Multiple local water officials say that even if Folsom Lake temporarily becomes nothing more than a river, the Sacramento region’s residents will get the water they need.
Multiple local water officials say that even if Folsom Lake temporarily becomes nothing more than a river, the Sacramento region’s residents will get the water they need. aseng@sacbee.com

Folsom Lake is losing more than a billion gallons of water each day. Lake levels will likely fall to historic lows by summer’s end, testing the reliability of a water supply that once seemed invulnerable.

The region’s top water officials say they are ready: Scared, but prepared. They have imposed significant, mandatory water-use rules on their customers. Water districts closest to the lake are connecting their systems with those that don’t depend on it for a water supply. Several have dug wells and installed pumps to improve their access to groundwater.

The districts also have an insurance policy: A planned barge that, if it works, will pump water from Folsom Lake even if lake levels fall below permanent intake valves.

Many of these precautions didn’t exist even two years ago. But the drought has created a flurry of activity around a once-unthinkable question: What if Folsom Lake dries up?

“We are very concerned,” said Richard Plecker, environmental utilities director for the city of Roseville, which normally relies on Folsom Lake. “We have it bad just like everyone else. But we’ve done some things. We’ve thought about it, planned it and funded it.”

Built by the U.S. Army Corps of Engineers in 1955, Folsom Lake is primarily designed for flood control, but it also serves as the primary source of water for hundreds of thousands of suburban Sacramento residents. It’s also a bulwark against Sacramento-San Joaquin Delta saltwater intrusion that could taint drinking water for millions of Californians, a recreational hub for the entire Sacramento region and a linchpin for maintaining the delicate ecosystem of the lower American River.

Folsom Lake drew national attention early last year as shocking images of its mostly-dry bed were seen by millions. A long-submerged mining town named Mormon Island became an unlikely attraction – disaster tourism – near Sacramento.

The lake level will likely be that low again, and soon. It’s falling by 1.4 billion gallons each day.

Folsom Lake chart 

Federal officials have set a target of 120,000 acre-feet or more of water in the lake by summer’s end. Early last year, at its driest, the lake never fell below 150,000 acre-feet.

The drought is to blame. Four years of dry, hot weather have raised lake temperatures and depleted many of the state’s reservoirs. In response, the state has cut flows from Lake Shasta to protect an endangered species of salmon and raised flows from Folsom Lake to prevent salt water from intruding into the Delta. About 25 million people use Delta-based federal and state water projects for supplies, though pumping is slight now because of the drought. Farms and Delta towns also would be hurt if the water they use for irrigation and drinking water contains too much salt.

Several local water leaders said they believe the lake will fall to the bureau’s minimum target – and they hope it doesn’t slip much lower in the fall.

“There is a lot of uncertainty in hitting 120,000 acre-feet,” said Tom Gohring, executive director of the Sacramento Water Forum. “If the salinity in the Delta starts to get too high, they’ll have to crank Folsom up higher. We could miss 120 and go lower.”

Folsom Lake map 

Even if that happens, even if Folsom Lake temporarily becomes nothing more than a river surrounded by acres of cracked soil, the Sacramento region’s residents will get the water they need, multiple local water officials said.

The groundwork for that optimism was laid about 15 years ago when local agencies, as part of the Sacramento Water Forum agreement, pledged to expand their groundwater supplies and connect to one another.

That objective took on new urgency early last year as Folsom Lake levels fell sharply. Water agencies quickly implemented a number of projects, largely funded by grants, that would enable water to be moved from places with groundwater to those that rely heavily on Folsom Lake.

Three cities and water districts serving more than 200,000 people would be most affected by a crisis at Folsom Lake: The city of Folsom, the city of Roseville and the San Juan Water District, which serves Granite Bay and sells water to Fair Oaks, Citrus Heights and Orangevale. All three agencies are working on construction projects to mitigate the threat of a dwindling Folsom Lake.

The San Juan Water District and Sacramento Suburban Water District are building pumps that will move water from Sacramento Suburban, which has ample groundwater supplies, to Granite Bay, which doesn’t. San Juan is also building a new pipeline to the Placer County Water Agency, which draws water upstream from Folsom Lake and has a significant amount of water in storage. Both projects are expected to be completed by the end of summer, officials said.

Keith Durkin, assistant general manager of the San Juan Water District, said his district’s customers used about 38 million gallons on Wednesday; they will use less during the early fall, when Folsom Lake will likely be at a low point. Once current projects are completed, he said, “We are somewhere between 30 and 35 million gallons a day if we got nothing out of Folsom.”

Next door in Roseville, officials have spent years expanding groundwater reserves. They are about “halfway” finished with that effort, Plecker said, and capable of delivering about 17 million gallons of groundwater per day. Roseville also has an agreement and connection with the Placer County Water Agency for 10 million gallons of water per day. In September, when Folsom Lake is expected to be at or near historic lows, Roseville customers will likely be using about 20 million gallons a day, Plecker said.

“We recognized years and years ago that we might have to cross this bridge,” he said. “The emotional side of me – it scares the hell out of me. But as a leader and engineer, I have to think rationally. We’ve got ... options to meet our needs.”

The city of Folsom does not have significant groundwater reserves – it sits largely on a granite cap. But City Manager Evert Palmer said Folsom has tied itself to other water agencies through recent projects. Folsom is currently improving pipes between the city and parts of Rancho Cordova served by the Golden State Water Co.

Like others, Folsom has told customers to cut water use as Folsom Lake levels drop. The city has a target of cutting water use by 32 percent during the next nine months, and preliminary figures suggest it will hit that goal, Palmer said. Less demand for water gives the city breathing room in a crisis.

“The focus has been on demand reduction. There is an obligation to do what we can in this extraordinary time.” But, he added, “I believe it is very dangerous to plan to operate Folsom Lake to the level that is being contemplated right now.”

A catastrophe at Folsom Lake also could affect water agencies downstream on the American River, including the city of Sacramento.

Sacramento pumps some of its water from the American River. As long as flows are high, its pumps work. But several local water officials said the state will quickly cut back Folsom Lake flows during autumn as the lake reaches historic lows. If American River flows are cut too much, they could fall below the level from which Sacramento historically could draw water.

John Woodling, executive director of the Sacramento Regional Water Authority, said the city of Sacramento recently installed equipment that improved its ability to pump from the American River, even when the river runs low. “Last year, they were having problems. Now, they are pretty confident,” he said.

While cities scramble for alternative water sources, the U.S. Bureau of Reclamation is building a barge with multiple pumps capable of drawing water from a nearly-depleted Folsom Lake.

Water agencies take water from Folsom Lake through huge intake valves. Those valves can, in theory, work until lake levels fall to about 85,000 acre-feet, though they may not function as well as levels draw close to that mark. If the intake valves stop working, Reclamation’s barge would pump water directly from the lake and send it over the dam to local agencies.

“I think we are on the road to install it and have it operational this year,” said Drew Lessard, manager of the Central California office of the U.S. Bureau of Reclamation. He said his department is working with “a sense of urgency.”

Woodling said local water agencies are glad that the barge will be built, but hope they do not need to rely on it. Instead, he said, agencies will look to use connections to each other and tap groundwater reserves.

“It’s going to get really low in September, then it’s going to get ... even lower unless it rains,” he said. But, he added, “We’ve been preparing for this for 15 years.”

Phillip Reese: 916-321-1137, @PhillipHReese Bee researcher Pete Basofin contributed to this article.

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