EARDC Pictures

EARDC Building

EARDC Building

EARDC Building

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About EARDC

The Edwards Aquifer Research and Data Center (EARDC) was established in 1979 by special funding for Texas State University to provide a public service in the study, understanding and use of the very fragile natural resource, the Edwards Aquifer. The Aquifer is a unique, world-renowned karst aquifer which is made up of porous, permeable limestone. It supplies water of exceptional quality to 1.5 million people in the San Antonio area and neighboring cities. Springs from the Aquifer feed the Comal and San Marcos Rivers which provide base flow in the Guadalupe River system. The Aquifer and it's associated spring support the habitat for nine species that are listed as endangered or threatened by the federal government. EARDC takes an active role in water education issues and works daily with public schools as well as institutions of higher education. Annually since 1989, our Center has given some 40 tours to more than 1,000 elementary and secondary school students as part of their science field trips. Seminars and Workshops are held frequently that promote water education and water conservation. The Center also provides laboratory analysis of 4,000 water samples a year to more than 100 customers. EARDC operations are organized around four major areas: The Data Center, operating both statewide and nationally, collects, maintains, and makes available information on the Edwards Aquifer. The information is stored in six major categories:

  1. Base Data: maps, aerial photography, and related media.
  2. Meteorological Resources: Data from the national Weather Service and Texas Natural Resources Information System (TNRIS) are available, including information on precipitation, evaporation, humidity, solar radiation, wind speed and direction.
  3. Biological Resources: Information about species composition, distribution, and dynamics.
  4. Water Resources: The Texas Water Oriented Data Bank in Austin, accessed via our computer, provides available surface and groundwater data. Much of the data in the local area are available in our own files.
  5. Geologic and Land Resources: Data obtained from the Bureau of Economic Geology, U. S. Soil Conservation Service, and U. S. Geological Survey include geologic and soil data.
  6. Socio-economic Resources: Census data organized by the standard metropolitan statistical area (SMSA) are available.

The Technical Services Center offers a variety of technical services to the public and various government offices. Most prominent at the present are the Laboratory Services for water analyses. The laboratory uses a rigorous quality assurance program including split samples with 17 other laboratories and blind samples provided by the U. S. Environmental Protection Agency. In addition, the Texas Department of Health certified our Laboratory to perform bacteriological testing of water. The specialized water analyses available include standard chemical analyses for anions, cations, and metals; pesticides and other organic carbons; bacteriological analyses; and bio-monitoring. The Education Center seeks to improve public understanding of the Edwards Aquifer through the development and the dissemination of educational materials and through development and implementation of educational programs. Examples include curriculum development for public schools, in-service training for science teachers, and material for local units of government. Materials and services provided through the EARDC Education Center include:


The Research Center conducts basic and applied research related to the Aquifer in the area of aquatic biology, geochemistry, and hydrogeology. Previous subjects of environmental research included: