California Communities Are Bracing for Drought
Does This Mean We Should Panic in the Bay Area?
Listening to news about the current drought, one might wonder how long we have before we run out of water. Fortunately, for those of us who live in San Francisco and other communities served by Hetch Hetchy, we can rest a little easier than just about anyone else.
The SFPUC, which manages our water supply, has a lot of reservoir storage capacity. Hetch Hetchy makes up only a quarter of it, and at full storage, the SFPUC has enough water to last six years. Right now they’re sitting on enough water to last four-and-a-half years. That’s like driving with your gas tank three-quarters full – hardly time to panic.
The SFPUC also has a long history of inflating demand projections. Just a few months ago they got caught trying to cook the books in their Urban Water Management Plan. When forced to use actual demand projections, potential rationing decreased by 27%.”
Despite being in an enviable position, the SFPUC wants you to believe our water security is far from certain. They want you to support their lawsuits against the State Water Board. The Board is in the process of requiring more water to be left in the Tuolumne River – the source of Hetch Hetchy – to help restore the San Francisco Bay-Delta and rivers that feed it.
In an average year, the SFPUC is entitled to three times as much water as is needed, so if next year is close to average, all of their reservoirs will fill. The drought will be over, at least for San Francisco.
The reason the SFPUC has so much storage is because their Regional Water System was designed for demand that is twice what it is today. As a result of increased water use efficiency driven by greater awareness of the value of water and a tripling of its cost over the past decade, we’re using 30% less water today then we were 35 years ago, despite population growth.
85% of San Francisco’s water supply comes from the Tuolumne, a 149-mile-long river that begins 13,000 feet above sea level in Yosemite National Park. Water from the Tuolumne irrigates over 200,000 acres of agricultural farmland in Stanislaus County, feeding people all over the world. It also provides drinking water for 2.7 million people in the San Francisco Bay Area.
Where more than 100,000 salmon once spawned, barely 1,000 returned to the Tuolumne last year, impacting everything from insects that feed on their carcasses to orcas in the Pacific Ocean and the fishing community at Fisherman’s Wharf. It’s a disgrace the river that provides us with so much is worse off than any other in the Central Valley.
The SFPUC could do so much more to restore the Tuolumne, but Instead has produced a gloom and doom scenario that if more water is left in the river, we could face severe rationing. They inflate demand projections, assume hardly any recycled water will be brought online, and plan for an extremely conservative drought that is much worse than any over the past 1,100 years, based on tree-ring data.
It’s a disgrace the river that provides us with so much is worse off than any other in the Central Valley.”
In reality, rationing figures could be almost anything, depending on policy decisions. For example, at current demand the SFPUC could manage the worst drought on record (1987-92), with higher flows in the Tuolumne, without requiring any rationing or developing any new water supplies. By implementing reasonable rationing requirements and producing recycled water, we could extend our supply by another year or two.
In contrast, the SFPUC has manufactured a very different scenario. The “Design Drought” they use for planning purposes arbitrarily combines the 1987-92 drought with the driest two-year period on record (1976/77) to create an artificial 8.5-year mega-drought. To accommodate this scenario, rationing in the later years must be shifted into the earlier years, unnecessarily increasing rationing figures.
The SFPUC also has a long history of inflating demand projections. Just a few months ago they got caught trying to cook the books in their Urban Water Management Plan. When forced to use actual demand projections, potential rationing decreased by 27%.
The graph below demonstrates how SFPUC policies harm the Tuolumne. Any time there’s a drought, they starve the river, hoarding water behind dams just in case we were to experience the Design Drought. Between 2012 and 2016, only 12% of the Tuolumne’s natural flow was left in the river. When precipitation returned in 2016/17, their reservoirs filled quickly, and all the water we conserved during the drought had to be “dumped.” The Tuolumne experienced one good year at the expense of five terrible years. This pattern has repeated for decades.
Balancing our water needs with those of the environment is not rocket science. Here’s what needs to happen.
1) The SFPUC should conduct a science-based probability analysis to determine how long of a drought they should plan for (adding a buffer to accommodate uncertainties).
2) They should identify what went wrong with past demand projections (their numbers have been off by an average of 22% over the past two decades), and correct the problems so they’re working with realistic projections.
3) Once they have a better understanding of how much water might be available for human consumption, the SFPUC should determine how much alternative supply (such as recycled water) needs to be developed to fill the potential deficit.
The possibility of running out of water is small. The likelihood of California’s Central Valley salmon going extinct is high if we continue to divert unsustainable amounts of water from our rivers. It’s time for the SFPUC to abandon their lawsuits and become a leader in river stewardship.
Peter Drekmeier is the Policy Director of Tuolumne River Trust