See more from this Division: Joint Sessions
See more from this Session: A Celebration of Soil Science, Solute Transport, and National-Scale Water-Quality Research: In Honor of Jacob Rubin
Abstract:
In California, the USGS is collaborating with the State Water Board to implement a comprehensive evaluation of California's ground-water quality. The overall effort is identified as the Groundwater Ambient Monitoring and Assessment Program (GAMA), and the USGS effort focuses on basins that provide water for public supply (Priority Basin Project). The design of the state-scale Priority Basin Project is based, to a large extent, on the national-scale NAWQA program.
The Priority Basin Project has been designed to balance the need for statewide consistency with the need for local relevancy. Within each basin, equal-area-grid sampling is used to provide a statistically robust assessment of ground-water quality at the basin-scale, and additional wells are sampled to address process-related issues. The samples are analyzed for an extensive suite of inorganic constituents, including age-dating, and for an extensive suite of organic constituents at very low concentrations (<1 ppb). The combination of age dating and low-level detections of organic constituents provides an opportunity to evaluate the connection of that part of the aquifer system used for public supply with potential sources of contamination. The Priority Basin Project also utilizes data collected for the purposes of regulatory compliance. Based on sampling to date, and depending on location, about 10% to 20% of the resource has concentrations of inorganic constituents above health-based benchmarks. In contrast, organic constituents are less frequently detected above benchmarks (generally less than 1%).
See more from this Division: Joint Sessions
See more from this Session: A Celebration of Soil Science, Solute Transport, and National-Scale Water-Quality Research: In Honor of Jacob Rubin