Public invited to hear about groundwater study

At Modesto meeting, scientists to discuss initial results of testing of raw well water in Merced and Stanislaus counties

Scientists from the U.S. Geological Survey (USGS) will discuss their initial findings from a comprehensive study of untreated well water in Merced and Stanislaus counties at a meeting Wednesday, May 23, in Modesto, Calif.

The meeting, conducted by the State Water Resources Control Board and the USGS, is set for 10 a.m. to 12 p.m. at the Modesto Irrigation District, 1231 11th St., Modesto. A map, agenda and other information are available at the State Water Board’s Web site at http://www.waterboards.ca.gov/gama/.

The State Water Board’s Groundwater Ambient Monitoring and Assessment (GAMA) Program is partnering with the USGS and Lawrence Livermore National Laboratories (LLNL) to sample drinking water wells in 35 groundwater basin “study units” throughout California. The USGS is the project lead for the GAMA Statewide Basin Assessments.

As part of the Statewide Assessment, samples were collected from 78 wells in the Central-Eastside San Joaquin Valley study unit, including the Modesto, Turlock, and Merced ground-water basins, during March-May 2006. The sampling included collection from 58 wells, mostly utilized for public supply; the wells were randomly selected in grid cells within the 1,695 square mile study area. Samples also were collected from 20 monitoring, domestic and irrigation wells.

At the meeting, USGS scientists will give an overview of the preliminary results. A full report on the sampling data is expected to be published later this year.

The GAMA Statewide Basin Assessment Project is designed to characterize water quality in groundwater basins. GAMA does not evaluate the quality of water delivered to consumers. After withdrawal from the ground, water is typically treated or mixed to maintain water quality before consumers receive it.

With the cooperation of local water agencies, the non-regulatory GAMA program is testing well water in every major groundwater basin in California over a 10-year period. The goal of GAMA is to improve statewide groundwater monitoring and facilitate the availability of information about groundwater quality to the public.

USGS scientists from the California Water Science Center are conducting the majority of the testing. The center, based in Sacramento, has more than 130 scientists who bring a broad range of scientific disciplines to the study of modern water management issues. More information on the GAMA program is available at: http://www.waterboards.ca.gov/gama/ and http://ca.water.usgs.gov/gama/.

USGS provides science for a changing world. For more information, visit www.usgs.gov.

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