Great Basin Carbonate and Alluvial Aquifer System (GBCAAS)

Science Center Objects

The Great Basin Carbonate and Alluvial Aquifer System (GBCAAS) was part of the federally-funded USGS Water Availability Program. Specific objectives of the study included quantifying current ground-water resources, evaluating how those resources have changed over time, and developing tools to assess system responses to stresses from future human uses and climate variability. The GBCAAS study covered an area of more than 100,000 mi2 encompassing most of the Great Basin regional aquifer system. The area is characterized by numerous arid to semi-arid basins with unconsolidated alluvial aquifers separated by mountain ranges often comprised of carbonate aquifers. Population is concentrated within 100 miles of Salt Lake City and in the Las Vegas area and is growing rapidly. In the less populated areas, ranching and irrigated farming are the main economies. The area includes two national parks and numerous national wildlife refuges.

Basemap showing Great Basin and model study area

Basemap showing Great Basin and model study area.  

The primary objectives of this five-year study (2007-2011) were to

  1. compile and interpret hydrogeologic information to develop an updated conceptual model of the aquifer system, and
  2. develop a numerical groundwater flow model for testing the conceptual model, and for providing additional insight on groundwater quantities and flow directions.

Data compiled for this study generally included information from 1940 through 2006, as data prior to the 1940s was scarce.