possible new groundwater resources http://ca.water.usgs.gov/sandiego http://ca.water.usgs.gov/sandiego possible new groundwater resources http://ca.water.usgs.gov/sandiego possible new groundwater resources USGS San Diego Hydrogeology Project USGS San Diego Hydrogeology groundwater resources USGS San Diego Hydrogeology http://ca.water.usgs.gov/sandiego/