Abstract

The history of the San Antonio region has been closely associated with water. Early settlements were located in the San Antonio River valley because of the excellent supply of water.

San Antonio is the largest city in the United States which depends entirely upon ground water for its water supply. One of the region’s major aquifers, the Edwards and associated limestones, is the only source of water for approximately 1,000,000 people in the region. The geology of the Edwards and associated limestones is presently the subject of an intensive, multi-agency study.

The ground water supply for the southern portions of the San Antonio region is derived from several aquifers, the major aquifer being the Carrizo-Wilcox aquifer. The Carrizo-Wilcox aquifer has been intensively developed for agriculture purposes during the past two decades.

At the present time, there are no surface water supplies for domestic and industrial demands in the San Antonio region. Medina Lake is a privately owned (Bexar, Medina, Atascosa Water District) irrigation water reservoir, while Canyon Lake is primarily a flood retardation, conservation reservoir which supplies some downstream users by releases to the stream.

The Edwards and associated limestones aquifer and Carrizo-Wilcox aquifer, with proper development and protection, can supply the majority of the water demands in the region for the near future. However, with ever increasing demands for water in the region, alternative sources of water must be developed in the immediate future. These alternative sources include sewage recycling, reuse, recharge and the development of surface water resources in the San Antonio region.