Colorado Plateau Regional Groundwater Availability

Science Center Objects

Study goals

This project seeks to quantify the status of groundwater as an integrated resource with surface water in the arid and semiarid region of the Colorado Plateau principal aquifer system. Surface-water resources that originate in this region are over allocated and serve 35 million people, 4.5 million acres of farmland, and are used to generate 12 billion kilowatt hours of electricity in the southwestern U.S. Recent studies have found that nearly half of surface-water resources in this region are supplied directly from groundwater discharge. That is, groundwater and surface water are an integrated resource. Prior USGS and other studies have mainly examined groundwater and surface water as separate systems, and there has yet to be a synthesis of groundwater availability in regional and locally-important aquifers that contribute to surface water. As a result, the potential changes to integrated groundwater and surface-water availability owing to human and natural water use and variable climate are uncertain.


  • quantify the current status of groundwater resources and how these resources have changed through time;
  • improve conceptual and numerical models of groundwater and surface-water interactions (feedbacks) in this region; and
  • project possible changes in groundwater storage and discharge to surface water caused by human and natural water use and variable climate.
Map of the Colorado Plateau, including the San Juan River pilot study area.

This illustration shows the Colorado Plateau Regional Availability Study area, which includes the San Juan River Basin pilot phase area. (Public domain.)

Pilot phase

This study is in a pilot phase during fiscal years 2017 and 2018. The purpose of the pilot phase is to identify possible technical challenges of using the USGS code GSFLOW for simulating groundwater and surface-water flow in the Colorado Plateau principal aquifer system. During the pilot phase, the project will evaluate GSFLOW in the San Juan River Basin (SJRB). The SJRB was selected because of its relatively large area compared to other basins in the Colorado Plateau, and because it exhibits complex groundwater and surface-water exchange between mountains and plateaus representative of dominant hydrologic processes throughout the Colorado Plateau.