The Metropolitan Water District of Southern California voted Tuesday to shoulder most of the cost of revamping the system that delivers water from the Sacramento-San Joaquin delta to the Southland, committing nearly $11 billion to building two massive tunnels.
The first thing to remember about precipitation in California is that it’s unpredictable, as the past several winters have once again shown us. Several years of severe drought ended in the 2016-17 winter with near-record rain and snow storms that filled the state’s badly depleted reservoirs. The 2017-18 “water year,” as hydrologists call it, began with what seemed to be a return to drought but then, in March, the state experienced a steady stream of storms that added to the Sierra snowpack upon which Californians are so dependent.
Despite a dismal start to the rainy season, recent storms have helped to ease fears of water shortages across California during the upcoming drier months. The extended fire season and unusually dry start to the winter may have worried many residents about the state’s water supply for the dry season. California has a distinct wet and dry season. After the wet season typically peaks between December and March, the state relies on reservoirs and melting snow from the mountains for its water supply in the drier months that span late spring to the fall.
Two tunnels, one or none? The question continues to swirl around plans to perform major surgery on the sickly heart of California’s water system. Confronted with a shortage of funding, state officials announced last month that they would move ahead with the construction of one giant water tunnel under the Sacramento-San Joaquin Delta rather than two. But the announcement did little to settle the fate of the project, which Gov. Jerry Brown’s administration considers vital to sustaining water deliveries to one of the country’s richest agricultural regions and the urban sprawl of Southern California.
A series of supercharged storms that blasted the Sierra in March has bolstered the snowpack that was alarmingly low before the start of the month. The National Weather Service (NWS) in Sacramento tweeted Saturday that the water content of the snowpack has more than tripled in the past month. On Feb. 22, an average of 4.6 inches was measured and on March 23 an average of 15.5 inches was recorded, going from 16 percent to 56 percent of the April 1 average.
The Trump administration is pushing for a $1.3 billion expansion of the 602-foot Shasta Dam in Northern California even though state officials are dead set against it, according to the Los Angeles Times. Plans include a vertical expansion the equivalent of two stories, although California state law prohibits an increase to the dam’s current height. The dam is on federal land, but similar projects in the past have deferred to state law in the permitting and construction processes.
The State Water Board is updating the water quality plan for the Sacramento–San Joaquin Delta. This plan sets flow and water quality standards for the Delta and its watershed, affecting water supply to more than 25 million Californians and millions of acres of Central Valley farmland. Parties that would be affected by this plan – water suppliers, fish and wildlife managers, environmental nonprofits – are negotiating voluntary agreements to present to the board for consideration.
A fierce atmospheric river blasted the northern and central Sierra overnight, dumping several feet of snow to elevations above 8,000 feet and bringing a slushy mix of rain and snow to lower elevations. On State Route 88 over the Carson Spur, Caltrans snow ploughs faced drifts that rose well above the top of their trucks. As of 11:30 a.m., the road still wasn’t clear. In the mountains, ski resorts shuttered lifts due to the high volume of snow. Squaw Valley and Alpine Ski resorts ceased operations at 3 p.m. due to high avalanche conditions.
The flows have been shut off through the Hyatt Powerhouse at the base of Oroville Dam, and the lake is beginning to rise. And that’s all by design, according to the state Department of Water Resources. The flows were shut down about 10 p.m. Wednesday and hadn’t resumed as of Thursday afternoon. But hours-long cutoffs have been occurring since March 8. Since March 15, water has been released for a few hours in the morning and a few hours in the evening but the penstocks in the powerhouse have been closed off for the rest of the day.
Heavy rain in the Sierra foothills pushed a small dam within San Francisco’s Hetch Hetchy water system to the brink of failure Thursday, sending a brief scare through the rural region where roads were closed and a few dozen residents were forced to evacuate. Officials at the San Francisco Public Utilities Commission said the danger in the area, west of Yosemite National Park, had diminished by nightfall as the storm gave way. There was no interruption to water service for the agency’s 2.7 million Bay Area customers.
