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Drought: earthquake risk forces Silicon Valley to reduce water consumption


California is known for its history of natural disasters, and in Silicon Valley, two potential calamities – drought and earthquake risk – converge to dry up the water supply in the center of the country’s technological economy. State.

In a meeting Wednesday, Santa Clara Valley Water District board members voted unanimously to declare a water shortage emergency – in part because a key county reservoir had to be emptied to reduce earthquake risks highlighted by federal regulators.

County officials warned last year that drainage from Anderson Reservoir would put the area in a perilous position, but were forced to drain the lake anyway as the reservoir and dam sits atop the fault. Calaveras, which could trigger a large-scale earthquake.

To preserve supplies, the district is calling for a mandatory 33% reduction in water use from 2013 and plans to rely almost entirely on groundwater, said Tony Estremera, chairman of the District Administration Board of the valley water. But if too much groundwater is tapped, the ground risks sinking, he said, questioning the structural integrity of roads, bridges and buildings.

“It’s really not acceptable in a place where we have some of the biggest companies in the world,” Estremera said, referring to tech giants Apple and Google, which have campuses in Silicon Valley.

To prevent land subsidence, the Water District wants local governments to put restrictions in place, including reducing watering of lawns to three days a week, banning the filling of swimming pools and ending the watering of lawns. the use of potable water for washing buildings.

It will hurt some homeowners and businesses, but David Gurrola, a landscaper in East Palo Alto, says it could help his. He expects some customers to start removing sod and replacing it with cacti, succulents, bark and gravel, and adding high-efficiency drip irrigation systems.

“That’s what they did in the last drought,” said the owner of E&D Landscaping, referring to the dry years between 2012 and 2016. “No reason to abandon your yard or your garden.

While Southern California has so far avoided emergency drought restrictions, Santa Clara County – which includes San Jose, the state’s third largest city – is scrambling, and the rest the bay area is not far behind.

The US Drought Monitor reported Thursday that four of the six counties in the San Francisco Bay Area had entered an “exceptional” drought – the most severe category of drought, reflecting the potential for widespread loss of crops and pastures, as well as the potential for water emergencies.

San Mateo and Santa Clara counties remain in “extreme” drought.

The dry conditions are the result of two years of low rainfall and unusually high temperatures across the region, including the wine region and Marin County, which declared a drought emergency in May. While San Francisco and East Bay maintain reservoirs in the High Sierra that can help them get through the summer, they cannot rely on these supplies if the winters to come are also dry.

Water experts note that the Bay Area has experience with water shortages, which will help it adjust to its current challenge.

“Drought is not unusual,” said Ellen Hanak, vice president and director of the Water Policy Center at the Public Policy Institute of California. “The water districts know how to prepare.

Jonas Minton, senior water policy adviser for the Planning and Conservation League, agreed, noting that only two of the six counties have imposed restrictions.

Still, Hanak and Minton said water managers must contend with the changes that have left the state with more precipitation in the form of rain instead of snow. Additionally, rising temperatures evaporate much of the remaining snowfall and runoff, leaving less for downstream reservoirs.

“California has relied on a rapidly disappearing water storage system,” Hanak said. “It’s snow. ”

Unlike Southern California, the Bay Area does not have a dominant water agency that provides supplies to multiple counties. In Santa Clara, the Valley Water District serves 15 towns and around 2 million people, relying on a “solid water portfolio” of reservoirs, groundwater supplies and contracts with projects. state and federal water sources, said Minton, former deputy director of the Department of Water Resources.

As of last year, however, the district has lost much of that portfolio.

In February 2020, the Federal Energy Regulatory Commission ordered an immediate seismic modernization of the dam, which was built over sand and gravel in 1950, making it vulnerable to strong tremors. If the dam were to collapse in an earthquake, scientists say the floodwaters could destroy parts of the town of Morgan Hill and even San José downstream.

This has forced the district to empty its largest reservoir, which when full contains just over 91,000 acre-feet of water, and embark on a rebuilding program that is expected to take at least until 2034, a declared Estremera.

An aerial view shows the drought-stricken Stevens Creek Reservoir at 18% capacity in Cupertino, Calif., May 20.

(Josh Edelson / Associated Press)

Some of the district’s other watersheds are also low, including the Stevens Creek Reservoir, which had fallen to 18% of capacity in May.

Adding to the pain that month, the federal government announced it was cutting urban water allocations for the Central Valley project in half. About a quarter of the Santa Clara Valley Water District’s supply comes from the Federal Water Supply Project, which is supplied largely by runoff from the Sierra snowpack. As of April 1, this snowpack was 59% of normal.

Estremera said the district is investing heavily in recycling and conserving water, as well as planning for new reservoirs, such as the potential $ 2.5 billion Pacheco Reservoir, which would contain 140,000 acre-feet of water. water, half the volume of the Anderson Reservoir. While the mayor of San José, Sam Liccardo, announced his opposition to the reservoir, saying it was too expensive, Estremera said the region needed all options.

“You cannot create more water,” he said. “You have to conserve, preserve and recycle. “

Lessons learned from the 2012-2016 drought should also help the region overcome the current emergency, said Adrian Covent, vice president of public policy for the Bay Area Council, a regional industry group.

“Around this time, companies started doing things like changing the sod in favor of drought tolerant plants and improving water efficiency,” he said, calling the Bay Area “most water efficient region in California”.

The biggest concern of his group is Marin County – the only other Bay Area county with water restrictions.

Unlike other counties, Marin is 75% dependent on supplies from local watersheds, which have not been adequately replenished for over two years, and 25% from the County Water Agency. Sonoma, which has been declared a state of emergency by the government. Gavin Newsom in April.

“Lack of drought tolerant supplies could lead to a moratorium on new connections and housing construction,” he said, noting the housing shortage in the Bay Area and the need for new affordable housing .

The state’s water planners and engineers will need to design and build new infrastructure to adapt to climate change, while preparing for the unpredictable, Hanak said.

Forest fires, she noted, can wreak havoc on water supply systems – reducing water quality in surface reservoirs, destroying infrastructure and contaminating water supplies. This is especially true in the Bay Area, with its Byzantine network of water agencies.

“California is a state of extremes,” Hanak said. “We’re never going to make these problems go away. What we need to do is find strategies for resilience and realize that there is no one size fits all. “





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