Arizona, Nevada, and California
Comments on Geologic Parameters
Porosity values for the shallow Tertiary basin-and-range sands are not mapped regionally but are presumed to be very high owing to their unconsolidated nature. In contrast, porosity values for the deep carbonates are typically low because they are heavily dolomitized. However, hydraulic conductivity in these carbonates is as much as 940 ft/d (Thomas and others, 1996), where it is greatly enhanced by fracturing.
Thomas, J. M., Welch, A. H., and Dettinger, M. D., 1996, Geochemistry and isotope hydrology of representative aquifers in the Great Basin region of Nevada, Utah, and adjacent states: U.S. Geological Survey Professional Paper 1409-C, p. C1-C100.