USGS Makes New Information on Arizona’s Ground Water Available on the Web

Where in Arizona are ground-water levels falling? Where are they stable or rising? How much has the water table changed since large-scale pumping has occurred? A new online system developed by the U.S. Geological Survey (USGS) is designed to answer these and other questions for the most developed ground-water areas in the State. The system uses water-level measurements from wells, collected over the past 75 years by USGS and the Arizona Department of Water Resources. Visit the new online system, called “Arizona Ground-Water Conditions Interactive Map Service.”

The new site provides basic information on the system, a link to the just-released Open-File Report explaining how the data layers were created, and a button to launch the interactive map. The map initially shows the entire state and selected features including boundaries of ground-water areas. Users can select specific types of ground-water information to display in a menu on the right. For example, “Trends in recent water levels” show where ground-water levels are generally declining, are nearly stable, or have been rising over the past 10 years. Tools are available to zoom in to specific areas of interest and to view well observation records. Some interesting results that can be seen on the map are:

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In much of the Tucson area, ground-water levels in the last 10 years are declining, but there are areas in north-central and southern Tucson along I-19 where water levels are rising
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In much of Avra Valley (west of Tucson), water levels are rising
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In the Prescott Active Management area, trends in water levels are nearly all declining with a few showing stable readings.

Other layers of information available on the map include the locations of wells that have experienced water-level declines of at least 75 feet or rises of at least 50 feet. Also shown are wells that have long-term records, providing users with information on the changes recorded water levels over several decades.

Fred Tillman of USGS, developer of the new internet site, commented, “the status of ground-water conditions is often challenging to display. We took the approach of providing different layers of information, applicable to different questions about the ground-water systems. Arizona is very dependent upon ground water and it is important to provide accessible information to policymakers, water managers and the general public on the status of this valuable, shared resource.”