In Northern California, earthquakes have the potential to disrupt more than buildings. Water supply and infrastructure has also been significantly damaged in the past when major quakes have struck.
(TNS) — In the aftermath of the Loma Prieta 6.9 temblor and its aftershocks in Northern California, hundreds of underground utility pipes began “bleeding” out the region’s water supply.
Most customers affected were asked to conserve for a few days, maybe told to boil their tap water to be safe. Others, especially in the mountain communities, waited for about a week for water service to resume as district employees raced to repair ruptured pipes and refill emptied holding tanks. San Lorenzo Valley Water District, then serving 5,400 homes in the Boulder Creek area, needed some $1 million worth of infrastructure repairs for 80 main breaks and other problems, former District Manager Jim Mueller told the Sentinel in 1989 and 2009.
Rick Rogers, then district director of operations, was standing in a windowless office talking to his boss, Mueller at the time the quake struck and the lights went out at 5:04 p.m. on Oct. 17, 1989. Now, Rogers himself serves as the district’s manager. After making his way out of the building and checking on his bed-confined 90-year-old mother, Rogers on Wednesday recalled that he quickly got down to work.
“We started shutting down the reservoirs and doing assessments of the water system and we realized that we had major damage,” Rogers said. “A lot of our wood reservoirs ratcheted, catastrophically failed and were just empty.”
While the smaller redwood reservoirs sprayed out water until they had emptied, one aftershock lifted a large steel reservoir tank off its foundation, Rogers said. All communications were down, nearly the entire water system supply had been drained and backup generators needed to be brought in by police escort through numerous closed byways.
Were an earthquake of Loma Prieta’s magnitude to strike again, Rogers said, the district’s seismic-standard reservoirs and pipelines would stand a better chance of weathering the storm. Soquel Creek Water District Chief Engineer Taj Dufour described modern industry improvements such as the ability to lock water pipes to each other, real-time leak detection technology, flexible pipe couplings, redundant pipelines and continued use of Federal Communications Commission-licensed radios for worker communications when cell towers are down.
“We have a lot more generators, we have a lot more storage, a lot more sources of supply. We’d be in a lot better shape,” Rogers said, echoing comments heard in recent interviews with water district leaders across the county.
Since 1989, however, the mountain water district has grown, consolidating with the former Citizens Utilities of Felton and Lompico Water District — which respectively faced 40 main breaks and the loss of half its storage tanks plus dozens of burst water mains. Rogers said plans are in progress to make significant capital improvements in the Lompico area, such as replacing facilities, installing more generators and moving a majority of its water storage to higher elevations so as to more heavily use gravity, rather than electricity, to reach customers.
Last week’s scheduled Pacific Gas & Electric Co. power outage, affecting some customers in San Lorenzo Valley Water District for as long as 50 hours, served as the latest emergency test run for many agencies countywide, officials said. Efforts to warn customers to cut back on water use during disasters paid off during the outage, Rogers said, with a 50% customer water use reduction. Similarly, Scotts Valley Water District saw water usage drop Thursday and in Soquel Creek Water District, water production decreased by 40% Thursday, officials said.
“Living in the San Lorenzo Valley, you’re used to power outages, you’re used to the earthquakes, you’re used to flooding. We already had a pretty good operational plan,” Rogers said. “But we took extra precautions with PG&E’s warning because it was going to be districtwide.”
Scotts Valley Water District fared better than most of its county peers, with one main break and minor damage to one tank, about a $17,400 repair bill. Even so, said General Manager Piret Harmon, Santa Cruz County, Calif., water agencies have learned much in the intervening decades.
“As you know, we are on our own,” Harmon said. “We get zero state and federal imported water, so whatever is local is local and the more we can work together across jurisdictional boundaries, the better off we are and are going to be.”
To that end, water pipeline interties between water districts have been built so that agencies can offer each other mutual aid in times of need. Most recently, Scotts Valley connected to San Lorenzo Valley Water District, and last year Soquel Creek Water District and the City of Santa Cruz began actively transferring water for a pilot program and in times of emergency. Soquel Creek also has one-way ties to supply small districts Trout Gulch and Pure Source with water as needed. Scotts Valley and Soquel Creek are investigating developing recycled drinking water plants and Scotts Valley already does so for irrigation purposes. Santa Cruz is in the midst of testing efforts to inject water into underground aquifers in hopes of retrieving the supply later, as needed.
©2019 the Santa Cruz Sentinel (Scotts Valley, Calif.). Distributed by Tribune Content Agency, LLC.