Studying groundwater in San Diego
Posted by George J Janczyn on August 16, 2010
Drilling at Balboa Park well site
Groundwater news in San Diego doesn’t stop you cold like, say, a news report on IPR drinking water that asks “What’s the difference between the sewage used now for irrigation and the recycled sewage project the City Council approved?” (Voice of San Diego), but groundwater is an important part of San Diego’s strategy to decrease reliance on imports that are becoming less reliable & more expensive.
Presently, a comprehensive geologic and hydrologic study of the San Diego area is being done by the U.S. Geological Survey, although that work doesn’t typically lead to sensationalized news reports.
News does pop up occasionally, such as the recent revelation about what were thought to be two separate aquifers under Balboa Park and National City now seen as possibly connected — thanks to the Easter Quake in northern Baja. Or desirable groundwater in Mission Valley contaminated by MTBEs from the fuel tank farm near Qualcomm Stadium. And the Helix Water District planning to augment groundwater resources with an IPR project in El Monte Valley near El Capitan Reservoir.
Otherwise, it has been awhile since I’ve heard anything about work going on in gathering and analyzing groundwater data throughout the county, so I touched bases with Wes Danskin, the Project Chief for the USGS San Diego Hydrogeology Project to ask what’s up. Here’s what he reported:
1. We have a comprehensive data report in colleague review. It summarizes all the sw, gw, and water quality data collected as part of the study from 2001-09.
2. We will be drilling a multiple-depth well in San Pasqual in September.
3. We’d like to drill another well in the South Bay area to complete our monitoring network, and possible a well in the Chollas Creek area to close the data gaps in that area as well.
4. We are making progress on a 3-D geologic framework model of the south coastal SD County area.
5. We are synthesizing the vast amount of water quality data with the goal of understanding gw flow paths.
6. We are estimating where and how much direct recharge from precipitation has occurred over the past century over much of the county. Pretty schematic, but we hope it will be helpful in determining the major gw flow paths.
Among the possibilities raised by USGS’s studies, if we’re lucky it could turn out there’s enough groundwater beneath Balboa Park to take care of its irrigation needs and save the 1.5 million gallons per day of potable water now being consumed by the park.
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Burt Freeman said
Thank you, George, for the interesting info re San Diego ground water and the report from the USGS program (How much does the USGS program cost; does that add to our cost of water? Not directly)!
Your implicit question: Does ground water constitute a significant source of San Diego water supply? Conventional wisdom has us with few aquifers (in contrast to LA basin). Specifically, does it help Balboa Park?
Seems like there are several additional quantitative questions to be answered to make that final judgement. How much is there? What is the water quality and how much treatment would be required? How much would it cost ($/AF) to add to our potable supply? How long would it last (questions of withdrawl and natural recharge rates)? Could the aquifers be used for water storage? Etc.
Belinda Smith said
Thanks for the update, George!
If ground water becomes even a small part of our portfolio, we’d be smart to implement legislation that makes all new surfaces permeable so rainwater can run into the ground, and recharge local aquifers.