The USGS San Diego Hydrogeology Project


The USGS project I volunteer on got a nice write up in the newspaper on

Sunday.  Here's the thank you from the guy I volunteer for and the article:
> All,
> Thanks for your hard work on the San Diego project. We got a nice  writeup
> in the San Diego Union Tribune editorial on Sunday, Sept. 2.  Pretty hard
> to get an editorial, much less a good one. So this we  will want to savor.
> Not sure we "oversee" anything, but we definitely  are playing a
> critically important role.
> The article focused on defining the San Diego Formation, use of  brackish
> ground-water, and in particular the monitoring wells we  installed to
> tattle on the gw system in case there is over pumpage.
> These positives coming from 3rd parties (Sweetwater Authority, and a
> possibly skeptical UT editorial board) were possible because of the  trust
> we have established, by listening to the cooperator, and  telling them
> what they want to hear, and what they don't, often, and  in different
> ways.
> So thank you for helping create a banner PR day for the USGS.
> --wes
> ************

. . . hold the salt

> Sweetwater quietly taps brackish water pool
> September 2, 2007
> Below the surface, there is good news in this time of drought. Some  800
> feet below the surface, it turns out.
> Sweetwater Authority, a district that supplies 180,000 residents in
> National City, Bonita and western Chula Vista, has been quietly going
> about a water success story since 1999. Sweetwater pumps brackish  water
> out of a huge aquifer known as the San Diego Formation and  desalinates
> it.
> San Diego is at the end of the line for imported water, both
> geographically and in water rights hierarchy. It helps everyone that  the
> district now gets 20 percent of its supply, some 4 million  gallons a day,
> as brackish water right out of the ground. Dennis  Borstad, general
> manager, said a decision to double that production  may come by fall of
> 2008.
> Sweetwater understands that desalinated water is drought-proof. The
> supply is already here, not subject to aqueduct failure hundreds of  miles
> away or to competing claims for imported water. The district  has signed
> up to purchase water from a proposed ocean water  desalination plant in
> Carlsbad. It is also in exploratory talks with  Otay Water District for a
> brackish water plant along that watershed.
> Within a few years, Borstad estimates, a small district in a near- desert
> could be getting as much as 60 percent of its supply from
> drought-resistant sources: fresh and brackish water wells and the ocean.
> Sweetwater has several advantages as it taps this source. Until 10  years
> ago, the brackish water below the flat land of South County was  untapped,
> too salty to treat economically. Little was known about the  aquifer's
> size or how fast it could naturally recharge itself.
> But improving technology lowered treatment costs even as the price of
> imported water soared. Sweetwater had an economical way to dispose of  the
> brine byproduct, into the man-made Sweetwater channel along state  Route
> 54. No need to build an expensive outfall pipe far into the  ocean.
> Tapping into the aquifer, said district engineering manager  Michael
> Garrod, is like sinking a straw into a sponge.
> Some of the deeper brackish water is actually subterranean runoff  from
> San Diego's mountains, the result of the last ice age 16,000  years ago.
> Sweetwater has moved cautiously, knowing that overpumping in other
> regions has caused the land to subside and ocean water to intrude.  The
> U.S. Geological Survey is involved in overseeing the water  pumping, the
> San Diego Regional Water Quality Control Board the brine  disposal.
> Ten innocuous wells, their above-ground apparatus no bigger than a  hall
> closet, pump the brackish water. Fourteen monitoring wells also  have been
> sunk, their only function to tattle on what is happening  hundreds of feet
> below the surface.
> So far, no apparent problems. The aquifer is much wider, its ability  to
> recharge must faster than originally thought. Energy costs are  much lower
> to treat brackish water than ocean water. A convenient  disposal outlet
> helps as well.
> Desalination's promise beckons, along the shore at Carlsbad and below  the
> coastal plain of South County.

return to publications and events