The San Francisco Public Utilities Commission’s (SFPUC) Regional Water System delivers Sierra Nevada water from the Hetch Hetchy Reservoir, and runoff from protected local reservoirs, to our customers. However, this system crosses three major seismically active earthquake faults – the Hayward, Calaveras,and San Andreas – before reaching customers taps, leaving us vulnerable in the case of a major earthquake or other emergency. To supplement our primary supplies and ensure reliable, high quality drinking water in the event of a major earthquake, drought, or decline in the snowpack, the SFPUC is planning to diversify San Francisco’s water supplies and increase the use of available local groundwater sources.
Groundwater - Also known as well water is a naturally occurring, renewable source of water found beneath the ground surface. As surface water (such as rain/precipitation) seeps into the ground, it passes between soil particles and collects in aquifers. An aquifer is an underground geological reservoir made up of permeable materials that can readily yield water to springs or wells.
The 45-square mile Westside Basin, a series of aquifers extending from Golden Gate Park in San Francisco southward through San Bruno, is a vital local resource for San Francisco and neighboring communities in San Mateo County. For more information on local groundwater basins read here.
Groundwater is also an important water supply source for other communities throughout the world. In California alone, it provides approximately 40 percent of the state’s drinking water.
The SFPUC Groundwater Program currently includes the following three proposed projects plus a Groundwater Stewardship and Management Program and ongoing monitoring activities:
| San Francisco Groundwater Supply Project: This project would provide a local source of water to improve reliability during drought or maintenance conditions, as well as ensuring that a reliable, high-quality source of water is available in case of an earthquake or other emergency. The project proposes the construction of up to six wells and associated facilities in the western part of San Francisco to extract up to 4 million gallons per day of water from the Westside Groundwater Basin. The extracted groundwater, which would be used for both regular and emergency water supply, would be disinfected and blended in small quantities with imported surface water before entering the municipal drinking water system. |
|
|
|
Regional Groundwater Storage and Recovery Project: This project proposes to balance the use of both groundwater and surface water to increase water supply reliability during dry years or in emergencies. The project is located within San Mateo County and is sponsored by the SFPUC in coordination with its partner agencies, the California Water Service Company (Cal Water), the City of Daly City, and the City of San Bruno. The project proposes to install 16 new wells to pump stored groundwater during a drought. During years of normal or heavy precipitation, the proposed project would provide surface water to the partner agencies in order to reduce the amount of groundwater pumped. |
| Lake Merced Water Level Restoration Project:
The goal of the Lake Merced Water Level Restoration Project is to protect and balance the benficial uses of Lake Merced by providing a more stable water level regime using sustainable water sources. Currently, this project is undergoing re-evaluation and revision. We will post updated information as soon as it is available. |
 |
Need more information?
Contact: Michele Liapes at (415) 554-3211 or mliapes@sfwater.com
