Water & Drought

Sacramento water coalition works to avoid feared ‘dead pool’ at Folsom Dam

Folsom Dam is seen from the shoreline at Beal's Point on Wednesday in Folsom. A half-million Sacramento water users nearly lost their main water source last year when Folsom Lake dropped close to the “dead pool” level, which is below the dam’s water intakes. That alarmed water officials. Now, water managers say they have a plan to reduce the chance that Folsom Lake water will become inaccessible in future droughts.
Folsom Dam is seen from the shoreline at Beal's Point on Wednesday in Folsom. A half-million Sacramento water users nearly lost their main water source last year when Folsom Lake dropped close to the “dead pool” level, which is below the dam’s water intakes. That alarmed water officials. Now, water managers say they have a plan to reduce the chance that Folsom Lake water will become inaccessible in future droughts. rpench@sacbee.com

It happened last February, in year three of what state officials are now calling California’s millennial drought. Visitors to Folsom Lake found levels so low they could hike for miles on dry lakebed and explore remnants of a previously inundated Gold Rush village.

At the same time, Sacramento water managers – the people responsible for transporting water from the reservoir to half a million household taps – were hunched over their computers, alarmed by what they saw.

The lake was within months of becoming a “dead pool.”

For water officials, that’s as ominous as it sounds. The condition occurs when reservoir levels fall below the intake pipes near the base of the dam that funnel water to residents in Folsom, Granite Bay, Roseville and other communities in Sacramento, Placer and El Dorado counties, as well as Folsom Prison.

It had never happened in the nearly 60-year history of Folsom reservoir. Many people hadn’t thought it possible.

“It freaked us out,” said Tom Gohring, executive director of the Water Forum, a coalition of Sacramento-area cities, water districts, environmental groups and businesses that focuses on water supply.

The federal Bureau of Reclamation, which operates Folsom Dam, considered floating a barge on the reservoir with a pump to push water up to the intake portal on the back wall of the dam. Suburban water agencies scrambled to secure access to groundwater. Some, like Roseville, considered rationing.

The crisis was averted when an unexpected burst of late-winter rain hit, offering last-minute reservoir replenishment. This spring, the reservoir level is notably higher after a better, although still below-average, rainfall season.

But 2014 served as a wake-up call.

Faced with the prospect of drier winters ahead, Sacramento officials are proposing changing the way the dam is operated to keep more water behind its wall each year as drought insurance. They want the federal government to alter monthly releases from the dam so that an extra cushion of water remains stored each December to guard against a “dead pool” scenario come summer and fall.

Gohring said his group is fine-tuning a proposal that would give local water districts the buffer they want, without running afoul of the water needs and rights of other agencies and downstream users.

“We are at a point where we’re convinced it is doable,” Gohring said.

He and other forum members, including several dozen Sacramento-area water agencies, say their proposal is not envisioned as a way for the region’s residents and businesses to avoid long-term conservation.

Efforts to cut water use are underway throughout the state, and more stringent conservation regulations are on the way. Citing unprecedented drought conditions, Gov. Jerry Brown last month ordered urban water agencies statewide to cut usage 25 percent by February, on average, compared with 2013, with the biggest per-capita users taking the biggest cuts.

The State Water Control Board’s draft framework for carrying out that order divides the state’s 411 urban water agencies into nine tiers, based on their per capita water use between July and September last year. As proposed, nearly half of the Sacramento region’s 23 water districts would need to cut water use by 36 percent this year – the highest rung in the framework. All but two Sacramento-area communities would have to cut usage by at least 28 percent.

The order mandating the cutbacks ends in February. But state water officials plan to launch discussions later this year on regulations for more permanent conservation goals.

This year’s cutbacks should give Folsom reservoir some room to recover from several years of below-normal precipitation. But state officials say California faces warmer winters and more frequent droughts because of climate change. Even with bold conservation efforts, water demand in Sacramento is expected to increase as the region grows, putting more stress on the reservoir to deliver.

A recent state Department of Water Resources analysis of tributaries that feed into the Sacramento-San Joaquin Delta suggests a “dead pool” at Folsom, once unthinkable, eventually could happen once every decade.

That analysis, and last February’s scare, prompted Water Forum leaders to look for ways to “improve” reservoir management. The forum, founded in the 1990s by the city and county of Sacramento, has worked to improve water availability and water quality, with a focus on the reservoir and lower American River.

Despite their proximity to Folsom Dam and the rivers that feed it, local water agencies have no assurance their proposal will get traction. Folsom Lake is part of a much larger system of dams and reservoirs that make up the state and federal water projects that pipe fresh water to cities and farms statewide, and provide the flows needed for fish and wildlife in the sensitive Delta estuary.

Changing dam operations would require buy-in from state and federal officials, as well as other water agencies with water rights in the reservoir and a stake in the timing and size of downstream flows. Reservoir operations are based on a series of sometimes hard-fought agreements among stakeholders across the state, including water agencies, farms, fisheries, electric utilities and environmental regulators.

In addition, the dam’s priority function is to keep Sacramento from flooding. The Bureau of Reclamation operates based on long-standing flood-control rules that require reservoir levels to remain low enough throughout the rainy season to ensure that outflows into the lower American River in a heavy storm would not overwhelm levees. This causes dam operators to release large pulses of rainfall in winter.

Gohring of the Water Forum said the proposal is being fashioned with all those priorities in mind. A formal proposal likely will be ready for publication by early summer.

It will call for dam operators to maintain between 285,000 and 365,000 acre-feet of water behind the dam every year in December. Holding more water in the dam in winter also would mean that releases throughout the year draw on colder water, which is beneficial to fish.

The proposal sets a new minimum standard for flows on the American River: 500 cubic feet per second. Currently, flows rarely drop below 800 cfs, but the bureau has the authority to release less than 500 cfs in extremely dry conditions, according to Gohring.

In many years, maintaining those storage levels would be easy. Despite the ongoing drought, the lake held 574,800 acre-feet last week. The reservoir’s maximum storage is 977,000 acre-feet. Last year, however, the dam held only 150,000 acre-feet in February. Dead-pool level is just under 100,000 acre-feet.

Bureau of Reclamation officials were guarded in their response to the proposal, but said they are open to discussing changes.

“Reclamation is always interested in ideas that improve fishery protection and project operations,” bureau spokeswoman Erin Curtis said in an email. “We are aware that the Water Forum has been preparing a proposal, but we do not have much information yet on the specifics.”

The concept has broad local support among water agencies that would benefit. Officials in Roseville and Folsom, communities heavily reliant on Folsom reservoir, are assisting, as is the Regional Water Authority, an association of 23 local agencies.

Ron Stork, of the environmental group Friends of the River, also is involved. He said the proposal would help American River fish, because it assures minimal flows and releases of cooler water.

“It’s a long time in coming and needs to happen,” Stork said.

Lester Snow, director of the California Water Foundation, a Sacramento-based nonprofit that advocates for sustainable water management, cautioned that the proposal goes only so far. He said, in the long-term, the region needs robust water-conservation efforts and judicious management of its groundwater, an assessment that many regional water officials say they agree with.

“There is not a single silver bullet,” Snow said.

Call The Bee’s Tony Bizjak, (916) 321-1059.

Related stories from Sacramento Bee