Valley’s emergency water situation murky
Pipeline, wells at risk in a major earthquake or other disaster
Sonoma Water maintains a system of pipelines to deliver Russian River water to over 600,000 customers.
Most people who have lived in Northern California – or anywhere else in the state – have been told or read at some point that they need to keep a three-day supply of water on hand in case the Big One hits. To the non-initiated, that means a 7.0 or better earthquake, as measured on the Richter scale; a big enough shake to cause severe damage over many counties, causing a loss of power, water and almost all the major services that make modern living so comfortable. They can all be gone in an instant.
And water is the most essential of all to life. The average person needs one gallon of water per day to get by; half a gallon for drinking and half a gallon for cooking and cleaning, according to Calwater guidelines. Calwater is the state water agency.
While Oakmont is on Santa Rosa City water, Kenwood has a private company which supplies water to Village residents from two wells and can tap the Sonoma Aqueduct in emergencies. Almost everyone one else in Kenwood has a private well. A few businesses close to Highway 12 draw water directly from the Sonoma Aqueduct. That major pipeline carries water directly from the Russian River through Sonoma Valley to the City of Sonoma and surrounding communities, serving over 23,700 people. It is the single largest source of potable water for the City of Sonoma and the dense unincorporated areas surrounding it, collectively known as the Springs.
Glen Ellen is partially served by the Valley of the Moon Water District, which relies heavily on the Russian River water that comes through the aqueduct. The District spends $2 million or more on water every year to serve its customers, according to Chris Petlock, Administration and Finance Manager for the VOMWD.
Sonoma County’s 2019 Grand Jury took a hard look at the current notion that it will take three days to restore water services, an assumption that county emergency plans incorporate, and came up with a very different conclusion of what would really be the case in the event of a 7.0 or even smaller quake.
“How significant the impacts of a major earthquake are to our water supply depends on how rapidly the water systems can be repaired,” the Grand Jury’s report concluded. “In the event of a major earthquake, some or all of the people in Sonoma County could be faced with poor water quality and with water shortages ranging from brief interruptions and rationing, to complete curtailment for extended periods.”
The grand jury report noted that there might not be enough spare parts on hand to fix all potential damage, and perhaps not enough skilled people available to do heavy engineering work. Fixing broken wells and pumps could be more problematic. There are only half a dozen well drilling companies in the county.
The Grand Jury’s findings, last year’s shutdown of the Sonoma Developmental Center’s (SDC) water filtration plant, and the intense wildfires of the last three years, set off alarms for VOMWDs General Manager, Alan Gardner.
“We had SDC as a backup authorized by state water in 2002 and it was there until last September,” Gardner said. The SDC was closed by the state a year ago and all of its disabled residents have been dispersed to neighborhood residences throughout Northern California. “It was the only source of emergency water available in the valley.”
Gardner is concerned that without sufficient back up supplies, VOMWD will not be able to supply enough water to get through a major emergency. While there are several million-gallon-plus water tanks throughout the Valley, without being refilled, they will run dry quickly.
Keep in mind that this article is about potable drinking water. Water is also crucial for coping with sewer and sanitary safety.
Sonoma County’s water comes from open flowing water and ground water. While most of the flowing water distributed by the Sonoma County Water Agency, now known as Sonoma Water, comes from the Russian River (either directly or from water stored in man-made lakes and storage tanks during good water years), the county and its nine cities also have large, deep wells pumping groundwater to augment the river water, especially in dry years and months, when the flow drops.
Thousands of rural residents, and even some urban homes, have private wells pumping groundwater for their own use.
Both public and private wells are vulnerable to a big earthquake, making them suspect as a source of supplemental emergency water. Wells also depend on electricity, though a big benefit to well owners is that they have large storage tanks that can be easily tapped. Not everyone has large storage tanks, however.
Groundwater has only recently come into full focus as a major element in California’s water supplies. As the population has grown exponentially in the past 70 years, so has water demand. Today, immense stretches of California’s Central Valley have noticeably subsided due to overdrawing of the groundwater supplies for intense agriculture.
Southern Sonoma County groundwater is experiencing an influx of salt water from San Pablo Bay as both agriculture and human demands have increased.
Just about everything involved with engineering modern water supplies is expensive, too. Gardner says building a million-gallon or more reserve tank that Glen Ellen needs could cost up to $2 million for land, construction and access rights. “I think that’s money well spent,” he added.
Sonoma Water’s five-year Capital Improvement Plan contemplates reinforcing the Sonoma Aqueduct’s weak points, mostly around bridges where wet soils amplify earthquake effects through a process seismologists call liquefaction.
Sonoma Water’s Chief Engineer Jay Jaspers acknowledged that there could be difficulties restoring water services within the three-day preferred timeline, but says his agency is working on it constantly.
“You can never eliminate risk,” Jaspers said. “You can reduce it and you can always conjure up a scenario with major devastation. Our part is to balance more realistic risks and significant impacts versus other risks too, like climate, wildfire, floods and droughts. We juggle all of that and hope that doing our projects, like we do in Sonoma Valley, will improve the system’s resiliency.”
Some of those projects include installing isolation valves to prevent water waste – 16 are already in place throughout the county with the help of Federal Emergency Management Agency (FEMA) funds.
“We also stiffened the pipe over the Rogers Creek Fault to withstand better than a 7.0 shake,” Jaspers noted. “We also got funding to install a booster station near Spring Lake that will help push water down the Valley.”
The Rodgers Creek Fault lies east of the San Andreas Fault. It is the main strand of the North American-Pacific Plate boundary north of San Francisco Bay, according to U.S. Geological Survey information on the fault. They estimate that there is a 33 percent chance of a magnitude 6.7 or greater over a 30-year period from 2014 to 2043. The fault runs right through Sonoma County, with recently identified parts of the fault zone extending toward the Bennett Valley-Mayacama fault system to the east.
A complete seismological survey of the county water system in 2000 revealed a number of weaknesses, Jaspers said. That survey was updated in 2008 and again in 2013 and Jaspers is pushing to bring those same people back to apply a decade’s worth of new technology and methodology to the county’s needs. The original study showed that some of the pipes crossing creeks could be broken and the ends displaced up to three feet, laterally.
Like roads, housing, mental health and about any other issue on the government’s table, funding is always an issue. “There are other risks,” Jaspers said, “and only so much money.”
There are five major projects identified to reinforce the pipeline through Sonoma Valley. The repair estimates of $2 to $5 million each have been identified, and work slated over the next five years, although recent actions of the Sonoma Water Board seem to have cut back on funding.
Jaspers said the county is working with contractors to improve future emergency plans and set up communication lines before the next major emergency, earthquake or fire.
Both Jaspers and Gardner lobby local, state and federal agencies as much as they can to find more funding.