Sources of Water and Salts for the Zuni Salt Lake in West-Central New Mexico

Scientific Investigations Report 2025-5057
Prepared in cooperation with the Bureau of Reclamation
By: , and 

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Abstract

The Zuni Salt Lake is located in a maar in west-central New Mexico and contains hypersaline water that has long been used by Native Americans for religious purposes and the collection of salt. There have been several investigations suggesting different sources for the water and salt to the lake. Springs, seeps, and ephemeral streamflow have all been observed to contribute freshwater to the lake, and brackish to hypersaline seeps have been documented along the banks of the lake. This report summarizes the findings of a study that characterizes the lake’s hydrology, its water and salinity sources, and the hydrogeologic conceptual model. Regional groundwater levels indicate that each of the aquifers in the area have the potential to discharge groundwater to the lake. There is also evidence of vertical groundwater flow pathways at the maar that were likely created by the igneous intrusion that fractured the intersecting aquifers. A detailed water budget was constructed from continuous lake stage, precipitation, and evaporation data to estimate the groundwater inflow to the Zuni Salt Lake. It was determined that groundwater inflow to the lake is 441 ±94 acre-feet per year, which composes as much as 77 percent of the total inflows. The high sodium and chloride concentrations measured in two hypersaline samples collected near the lake indicate that the majority of the dissolved solids entering the lake are from a hypersaline groundwater source. The geochemical and isotopic compositions measured in the lake and surrounding features support the interpretation that hypersaline groundwater is the primary source of salts to the lake, which is likely sourced from the older (and deeper) Permian units. The hypersaline groundwater samples collected during this investigation have a unique aqueous chemistry relative to each of the mapped aquifers, and variability in groundwater compositions is interpreted to result from differences in minerology and residence time.

Suggested Citation

Robertson, A.J., Pepin, J.D., Gray, E.L., Collison, J.W., Brown, J., Ritchie, A., and Ball, G., 2025, Sources of water and salts for the Zuni Salt Lake in west-central New Mexico: U.S. Geological Survey Scientific Investigations Report 2025–5057, 40 p., https://doi.org/10.3133/sir20255057.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Methods
  • Results
  • Discussion
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Sources of water and salts for the Zuni Salt Lake in west-central New Mexico
Series title Scientific Investigations Report
Series number 2025-5057
DOI 10.3133/sir20255057
Publication Date September 17, 2025
Year Published 2025
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) New Mexico Water Science Center
Description Report: viii, 40 p.; Data Release; 2 Datasets
Country United States
State New Mexico
Other Geospatial Zuni Salt Lake
Online Only (Y/N) Y
Additional publication details