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USGS - science for a changing world


Elise Watson


San Diego Field Station, WERC

Office Phone: 619-225-6426
Fax: 619-225-6436

San Diego State University
4165 Spruance Road, Suite 200
San Diego , CA 92101

Supervisor: Tyler D Johnson
The California Groundwater Ambient Monitoring and Assessment Program (GAMA) is a statewide, comprehensive assessment of groundwater quality designed to help better understand and identify risks to groundwater resources. GAMA is being implemented by the California State Water Resources Control Board. The USGS is the technical lead for the Priority Basin Project (PBP), one of the components of the GAMA Program. The initial focus of the GAMA Priority Basin Project in 2004 to 2012 was on assessment of water-quality in groundwater resources used for public drinking water supply (Belitz and others, 2003; 2015). Groundwater basins and sub-basins (472 in total) were prioritized based upon a number of factors (Belitz and...
The USGS is working in partnership with California and federal agencies to answer the following questions about oil and gas development and groundwater resources: Where are protected groundwater resources? How close are oil and gas operations and protected groundwater, and what geologic materials separate them? Where is there evidence of fluids from oil and gas sources in protected groundwater? Where does evidence indicate no connections? When fluids from oil and gas sources are present in protected groundwater, what pathways or processes are responsible for observed transport? Have oil and gas operations as a whole contributed to water-quality changes in groundwater basins?
The U.S. Geological Survey (USGS) previously identified 62 Principal Aquifers (PAs) in the U.S., with 57 located in the conterminous states. The USGS characterized areas outside of PAs as “other rocks;” other rocks account for about 40% of the area of the conterminous states. This paper subdivides the large area identified as other rocks into Secondary Hydrogeologic Regions (SHRs). SHRs are defined as areas of other rock within which the rocks are of comparable geologic age, lithology, and relationship to the presence or absence of underling PAs or overlying glacial deposits. A total of 69 SHRs were identified. SHRs were identified in two phases. In the first phase, Other Rock Regions (ORRs) were defined as regions...
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