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Groundwater Flow Model Investigation of the Vulnerability of Water Resources at Chaco Culture National Historical Park Related to Unconventional Oil and Gas Development

Scientific Investigations Report 2023-5097
Prepared in cooperation with the National Park Service
By: , , , and 
https://doi.org/10.3133/sir20235097

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Abstract

Chaco Culture National Historical Park (CCNHP), located in northwestern New Mexico, protects the greatest concentration of Chacoan historical sites in the American Southwest. Geologically, CCNHP is located within the San Juan structural basin, which consists in part of complex Cretaceous stratigraphy and hosts a variety of energy resources. As part of a larger study to investigate the vulnerability of water resources at CCNHP related to oil and natural gas extraction activities, a MODFLOW groundwater model of the Mancos Shale and Gallup Sandstone units was created by the U.S. Geological Survey, as a part of a cooperative study with the National Park Service, to assess advective groundwater flow paths and traveltimes. The model determined that groundwater flow directions currently trend from south-southeast to north-northwest within the vicinity of CCNHP, groundwater traveltime through the Gallup Sandstone ranges from thousands to tens of thousands of years, and traveltime through the Mancos Shale may range from millions to tens of millions of years. The capture zone of the main CCNHP well (referred to as the “Chaco well”) extends to the south-southeast and ranges in width from approximately 1 to 12 miles, depending on pumping rate. Eighteen inactive hydrocarbon related wells are located within the capture zone and within 10 kilometers of the Chaco well. Given model estimates of traveltimes of groundwater in the Gallup Sandstone aquifer, advective groundwater transport to the Chaco well would take approximately 430 years from the nearest inactive hydrocarbon related wells. Differencing of historical and modern-day potentiometric surfaces of the Gallup Sandstone indicate a drop in groundwater levels between 34 and 96 feet within the CCNHP boundaries. Hydraulic fracturing, simulated as increased hydraulic conductivity zones, decreased groundwater traveltimes (from millions to thousands of years) and acted as permeable pathways from the Mancos Shale to the Gallup Sandstone.

Suggested Citation

Shephard, Z.M., Ritchie, A., Linhoff, B.S., and Lunzer, J.J., 2023, Groundwater flow model investigation of the vulnerability of water resources at Chaco Culture National Historical Park related to unconventional oil and gas development: U.S. Geological Survey Scientific Investigations Report 2023–5097, 39 p., https://doi.org/10.3133/sir20235097.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments 
  • Abstract
  • Introduction
  • Methods
  • Results
  • Discussion of Potential Chaco Well Contamination
  • Limitations and Further Model Development
  • Summary and Conclusions
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Groundwater flow model investigation of the vulnerability of water resources at Chaco Culture National Historical Park related to unconventional oil and gas development
Series title Scientific Investigations Report
Series number 2023-5097
DOI 10.3133/sir20235097
Year Published 2023
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) New Mexico Water Science Center
Description Report: viii, 39 p.; Data Release
Country United States
State Arizona, New Mexico
Other Geospatial Chaco Culture National Historical Park
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details