Water & Drought

Folsom Lake now being drained more slowly

An aerial view of Folsom Lake at Granite Bay looking toward the northeast in late June shows how far down the lake has been drawn.
An aerial view of Folsom Lake at Granite Bay looking toward the northeast in late June shows how far down the lake has been drawn. apayne@sacbee.com

Water regulators are easing off on plans to draw down Folsom Lake, responding to concerns from Sacramento-area water agencies about the availability of supply, officials said Tuesday.

The lake still will be drawn down to historically low levels this summer as part of a complicated plan to rescue the endangered winter-run Chinook salmon. However, the reservoir is being drained more slowly for the time being “to provide peace of mind to everybody who’s watching this,” said Les Grober, assistant deputy director of the State Water Resources Control Board. “Everybody’s very concerned about Folsom.”

Grober said additional water is being pulled out of Lake Oroville to compensate for the abatement of flows out of Folsom. Oroville, which is part of the State Water Project, is considerably larger than Folsom, one of the key reservoirs in the federal government’s Central Valley Project.

Fears about Folsom Lake levels have spiked in recent weeks because of the four-year drought and water-temperature problems on the Sacramento River. To prevent a repeat of last year, when 95 percent of the juvenile salmon run was wiped out by warm water, federal and state officials have tentatively agreed to restrict flows out of Lake Shasta throughout the summer. That’s designed to keep more cold water in the lake until late summer and early fall, the peak of the spawning season.

The temperature-control plan is expected to be finalized this week, but keeping more water in Shasta creates a slew of other problems. It’s depriving farmers of more than 200,000 acre-feet of water during the height of the growing season. It also has led to more water being drained out of Oroville and Folsom to prevent salt water from intruding on the environmentally sensitive Sacramento-San Joaquin Delta, the hub through which billions of gallons of water are pumped to the San Joaquin Valley and Southern California.

Officials have said Folsom Lake levels likely will fall to 120,000 acre-feet by the end of September. That’s well below last year’s record low of 150,000 acre-feet. An acre-foot is almost 326,000 gallons.

In the Sacramento region, more than 200,000 people rely on water drawn from Folsom Lake, including residents in Folsom, Roseville and portions of Granite Bay, Fair Oaks, Citrus Heights and Orangevale. Officials in the region have expressed fears that a draw-down to 120,000 acre-feet would cut into the margin of error, bringing the lake below levels at which the valves that deliver that water would work.

“Folsom’s going to be a true symbol of ‘we’re all in this together,’ ” said water board Chairwoman Felicia Marcus at a board meeting Tuesday.

Grober said the plan still calls for Folsom to be lowered to 120,000 acre-feet, but for the time being the reservoir is being drained more slowly. The water board also expects to issue an order later this week ensuring that 120,000 acre-feet represents a “hard stop” rather than a goal. That means the lake would not fall below that level.

Sacramento water officials said the revised approach is somewhat reassuring, but they will continue to watch the lake closely. Bringing the lake down to 120,000 acre-feet “is still worrisome, because we haven’t experienced anything like that before,” said Tom Gohring of the Sacramento Water Forum, an alliance of environmentalists and water agencies. “There are still a lot of uncertainties in the system.”

As the drought worsens, managing California’s dwindling water supply is requiring almost constant tinkering. At the same time officials are fine-tuning the temperature-control plan for the Sacramento River, the water board agreed last Friday to temporarily reduce the flow of water out of the Delta and into the ocean. While that could damage Delta smelt and other threatened species in the short term, the board said it leaves more water in upstream reservoirs, alleviating some of the pressure on Folsom and Oroville. Some of that water can be released later to help farmers as well as fish, the board said.

Reducing Delta outflows has proved controversial, however. Environmental groups have sued state and federal officials this year, saying the Delta’s ecosystem is being sacrificed to bring more water to farms and cities that buy water from the Central Valley Project and State Water Project.

Dale Kasler: 916-321-1066, @dakasler

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