What is GAMA-PBP?

The Groundwater Ambient Monitoring and Assessment Program-Priority Basin Project (GAMA-PBP) is a statewide, comprehensive assessment of groundwater quality designed to:

  • Describe and explain patterns in groundwater quality
  • Determine where and to what extent groundwater meets drinking water-quality benchmarks
  • Determine how groundwater quality is changing at the basin scale
  • Identify the natural and human factors affecting groundwater quality
  • Improve availability and usefulness of scientific data and information about groundwater quality

This information can be used in multiple ways, including by local communities to determine whether and what kind of treatment may be needed when groundwater is used for public water-supply systems or for projecting future changes in groundwater quality associated with reduced nutrient applications.

GAMA-PBP is a component of the California State Water Resources Control Board’s (SWRCB) Groundwater Ambient Monitoring and Assessment Program, and the USGS is the technical lead. The GAMA-PBP receives funding from the SWRCB and USGS Cooperative Matching Funds.

What We're Learning: Highlights

Public Supply Well Inorganic Constituent Data and Trends Map

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This interactive web map plots trends in groundwater quality (inorganic constituents) at public supply wells from 1974-2019 using data from USGS GAMA-PBP and monitoring data reported to the California State Water Resources Control Board Division of Drinking Water.

GAMA-PBP Groundwater Quality Assessment and Trends Data

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This interactive webmap plots and enables downloads of water-quality data from domestic and public-supply wells sampled by the USGS for GAMA-PBP. Data can be viewed and downloaded for study type, constituent groups, individual sites, and grid cells.