The Edwards Aquifer Research and Data Center (EARDC) was established in 1979 by special funding for Southwest Texas State University to provide a public service in the study, understanding and use of the Edwards Aquifer. The Aquifer is a unique, world-renowned karst aquifer which is made up of porous, permeable limestone. Springs from the Aquifer feed the Comal and San Marcos Rivers which provide base flow in the Guadalupe River system and support the habitat for at least four endangered species. EARDC takes an active role in water quality monitoring and education issues. We conduct basic and applied research related to the Aquifer in the area of aquatic biology, geochemistry, and hydrogeology.