Most of California’s largest urban water systems have invested in groundwater recharge programs in rural regions. Restore Hetch Hetchy’s Yosemite’s Opportunity provides a list of some of these programs totaling up to 1,875,000 acre-feet of water storage – or more than 5 times the size of Hetch Hetchy Reservoir’s 360,000 acre-feet. Many of these cooperative programs involve agricultural lands near the California Aqueduct in Kern County where it is convenient for water agencies to exchange supplies.
The California Department of Water Resources is conducting studies in each of the principal San Joaquin Valley watersheds to show how cooperative management can improve water supplies and groundwater levels while reducing flood. Restore Hetch Hetchy has been critical of San Francisco for declining to participate. Might the SFPUC change its mind?
Restore Hetch Hetchy has been sharply critical of the San Francisco Public Utilities Commission for not pursuing similar programs in Stanislaus County, where the Turlock and Modesto Irrigation Districts share the Tuolumne River and Don Pedro Reservoir and where there are ample opportunities to recharge groundwater that could provide widespread benefits. (We do give San Francisco credit for its groundwater banking program in San Mateo County – see below)
Our goal, of course, is to encourage San Francisco to improve its system so that Hetch Hetchy Valley can be restored! Others would like San Francisco to be less stingy with releases to sustain salmon populations in the lower Tuolumne River and downstream through the Delta and into the ocean. Businesses and residents in San Francisco and neighboring counties might prefer simply to have an increased buffer against drought. While these policy objectives differ, no reasonably informed person can deny that recharging groundwater in wet years has the potential to add cost-effective water supply.
Restore Hetch Hetchy has been particularly critical of the SFPUC for declining to even take part in the “Managed Aquifer Recharge” (aka Flood-MAR) studies being conducted by the California Department of Water Resources. We have made this point directly to the SFPUC and included it in our Fall Newsletter.
So we were pleased that the SFPUC did include DWR’s Flood-MAR studies in a meeting with the Bay Area Water Stewards last week. DWR staff presented their methodology and results of their initial study of the Merced River watershed. DWR will be extending its work to other Sierra watersheds, and we are hopeful it will produce useful results suggesting how flood waters from all rivers, including the Tuolumne, could be better managed.
The Flood-MAR studies are just studies (and be forewarned they are not designed for the casual reader) . They provide information and do not require any action. But that information can demonstrate how water agencies can better work together to manage water more effectively. So kudos to DWR for undertaking this effort. We hope San Francisco will join other water agencies throughout the state and learn what benefits might be achieved through restoration.
The SFPUC does deserve credit for working with cities in San Mateo County to recharge about 60,000 acre-feet of groundwater capacity. Essentially the cities will use surface water in wet years, allowing the aquifer to recharge (“in-lieu”). If and when a drought occurs, the SFPUC can extract these stored supplies for all customers.