Delineation of the Pahute Mesa–Oasis Valley groundwater basin, Nevada

Scientific Investigations Report 2015-5175
Prepared in cooperation with the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, Office of Environmental Management, under Interagency Agreement, DE-NA0001654
By: , and 

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Abstract

This report delineates the Pahute Mesa–Oasis Valley (PMOV) groundwater basin, where recharge occurs, moves downgradient, and discharges to Oasis Valley, Nevada. About 5,900 acre-feet of water discharges annually from Oasis Valley, an area of springs and seeps near the town of Beatty in southern Nevada. Radionuclides in groundwater beneath Pahute Mesa, an area of historical underground nuclear testing at the Nevada National Security Site, are believed to be migrating toward Oasis Valley. Delineating the boundary of the PMOV groundwater basin is necessary to adequately assess the potential for transport of radionuclides from Pahute Mesa to Oasis Valley.

The PMOV contributing area is defined based on regional water-level contours, geologic controls, and knowledge of adjacent flow systems. The viability of this area as the contributing area to Oasis Valley and the absence of significant interbasin flow between the PMOV groundwater basin and adjacent basins are shown regionally and locally. Regional constraints on the location of the contributing area boundary and on the absence of interbasin groundwater flow are shown by balancing groundwater discharges in the PMOV groundwater basin and adjacent basins against available water from precipitation. Internal consistency for the delineated contributing area is shown by matching measured water levels, groundwater discharges, and transmissivities with simulated results from a single-layer, steady-state, groundwater-flow model. An alternative basin boundary extending farther north than the final boundary was rejected based on a poor chloride mass balance and a large imbalance in the northern area between preferred and simulated recharge.

Suggested Citation

Fenelon, J.M., Halford, K.J., and Moreo, M.T., 2016, Delineation of the Pahute Mesa–Oasis Valley groundwater basin, Nevada (ver. 1.1, May 2016): U.S. Geological Survey Scientific Investigations Report 2015–5175, 40 p., http://dx.doi.org/10.3133/sir20155175.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Delineation of the Pahute Mesa–Oasis Valley Groundwater Basin
  • Conclusions
  • References Cited
  • Appendix A. Revised Groundwater Discharge Estimates for Death Valley and Sarcobatus Flat, Nevada and California
  • Appendix B. Regional Analysis to Balance Recharge and Discharge in Pahute Mesa–Oasis Valley and Surrounding Groundwater Basins, Nevada and California

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Delineation of the Pahute Mesa–Oasis Valley groundwater basin, Nevada
Series title Scientific Investigations Report
Series number 2015-5175
DOI 10.3133/sir20155175
Edition Version 1: Originally posted January 22, 2016; Version 1.1: May 12, 2016
Year Published 2016
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Nevada Water Science Center
Description Report: vi, 40 p.; Plate: 21.08 x 32.62 inches; Appendix B; Model Archive
Country United States
State California, Nevada
Online Only (Y/N) Y
Additional Online Files (Y/N) Y