Open-file Report - 618
Hydrogeology and water resources of the Salt Basin, New Mexico and Texas

INTRODUCTION

The Salt Basin is a hydrologically closed, semiarid basin shared across the southern region of New Mexico and westernmost Texas (Figure TS-1). Water resources in the southwestern United States are limited, and they are becoming further strained due to increasing aridity and rising temperatures in the face of climate change. Even with significant changes to current water use and robust conservation, exploration of new or alternative water resources may be necessary as water shortages occur in the Southwest. Historically, in New Mexico water resource exploration efforts have occurred in basins with limited groundwater pumping or population. The Salt Basin has been one such region of exploratory interest for several decades.

The process of determining a firm water budget in this region has long eluded and challenged researchers and consultants. Data density in some areas is too sparse to draw reliable conclusions, especially with regard to the subsurface. One of the biggest obstacles to fully quantifying the water resources in the region is simply its remoteness and isolation, in addition to limited data availability and groundwater access.

PURPOSE AND SCOPE OF THIS PROJECT

Beginning in 2019, the New Mexico Bureau of Geology and Mineral Resources (NMBGMR) and the New Mexico Institute of Mining and Technology (NMT) initiated research to assess the water resources of the Salt Basin region of southern New Mexico and westernmost Texas. This project was funded by the U.S. Bureau of Reclamation and was conducted in coordination with two graduate students at NMT, the U.S. Geological Survey (USGS), the New Mexico Interstate Stream Commission (NMISC), and consultants with the NMISC. The current study was initiated as a result of NMISC considering potential groundwater export from the New Mexico portion of the basin to other regions of New Mexico, particularly during times of reduced surface water availability.

The purpose of this project was to assess the water resources and evaluate the sustainability of pumping 100,000 acre-ft/yr in the Salt Basin region. In particular, the project’s scope addressed the Salt Basin regional water availability by (1) identifying and attempting to address data gaps where there is currently little or no information about the groundwater system; (2) refining estimates of the regional water budget, including groundwater recharge, storage, evapotranspiration, and pumping; (3) building and updating the hydrogeologic framework and numerical hydrologic model; and (4) running specific pumping scenarios in the revised model. These efforts focus attention on the region’s capacity to sustain current groundwater withdrawals in the Salt Basin and implications for future development in New Mexico. Additional techniques applied in this study included electromagnetic geophysical measurements to better characterize the subsurface of the Salt Basin and to evaluate use of these methods in identifying saline or brackish aquifers.

In the first year of this study, the research team compiled previous data and reports to build the data release report NMBGMR Open File Report 608 (Kelley et al., 2020). Kelley et al. (2020) included an overview of the Salt Basin geology, a description of the geophysical and geochemical studies completed by others, a review of the previous estimates for recharge, and discussion of the existing hydrologic models of the region. From this data summary, in the second year of this study, data gaps were identified and efforts were taken to fill them. The research team collected 13 new water chemistry samples, inventoried 20 wells in New Mexico, conducted geophysical surveys, and applied new recharge estimations, along with estimating groundwater storage and water use. Two student master’s theses were completed on portions of this research. This report is the final summary and synthesis of the work completed.

CD or DVD-ROM format

Download

Most open-file reports are PDF files and require the free Adobe Acrobat Reader software to view. These reports may also contain GIS data or other file types, and some are collections of files that are intended to run from a CD-ROM or local hard drive.