Like most densely populated urban areas today, the Bay Area is vulnerable to numerous natural and technological breakdowns, from earthquakes on down. Fortunately, when it comes to our water supply San Francisco and the Peninsula are blessed with at least one potential safeguard in the event of a prolonged drought or a breakdown of the aging Hetch Hetchy water system.
However, this natural backup is extremely fragile and must be utilized with great care. The Westside Groundwater Basin Aquifer is a huge underground lake extending from the southwestern tip of San Francisco down below Daly City, South San Francisco and San Bruno. This aquifer can be accurately described as still making a successful recovery from a near-death experience.
Now the San Francisco Public Utilities Commission is preparing to drill 10 new wells into the Westside Aquifer to create a ready supply of water for emergency shortages. This $39 million project seems like a sensible backup plan to prevent the region from running dry in a typical seven-year drought period or a destructive earthquake that shuts down part of Hetch Hetchy.
The concern about these new aquifer wells is that Westside Aquifer water must be saved for true emergencies. The pumps must never be turned on for mere convenience or simply to provide cheaper water for participating cities.
SFPUC project manager Greg Bartow insisted this would not happen because the plan intends to treat the aquifer as a “savings account” that must be replenished as fully as possible so 7 million gallons a day could be available during dire circumstances.
The aquifer’s health can be observed in an easily visible thermometer. San Francisco’s Lake Merced was drying up in plain view a few years ago and the aquifer was in danger of letting in seawater contamination. Reversing this destruction required a rare cooperation among San Francisco and San Mateo counties and the three northern Peninsula cities, plus a determined push by a coalition of environmentalist groups such as the Friends of Lake Merced.
A wastewater recycling plant was built so that the cluster of golf courses in Daly City could turn off their private aquifer wells and still irrigate their greens. The Peninsula cities agreed to a three-year test of not pumping the aquifer for any of their drinking water, in exchange for discounts on costlier Hetch Hetchy water.
As a result, Lake Merced water levels rose five feet since 2002 and the aquifer is now 4 billion gallons fuller. The SFPUC estimates that some 20 percent of the Westside Groundwater Basin’s available storage space is now refilled.
Daly City last week entered into a long-term agreement not to draw from the aquifer during normal water years in return for advantageous SFPUC rates. Similar negotiations are now underway with South San Francisco and San Bruno. Such arrangements are necessary in order to truly enable the Westside Groundwater Basin to become the Bay Area’s “savings account” for dependable emergency water.