Edwards Aquifer
Aquifer systems are vital to the regions that overlie them. The Edwards Aquifer (figure 1.2) underlies the cities of San Antonio, San Marcos, and Austin in south-central Texas. San Antonio is the largest city in the United States whose water supply comes principally from groundwater, distributed throughout the city after being pumped from hundreds of wells drilled into the Edwards Aquifer. Water from these wells supports a population of more than 2 million people.