Karst Aquifers: Edwards-Trinity Plateau Aquifer

Science Center Objects

The Edwards-Trinity aquifer, located in the Trans-Pecos and the Edwards Plateau areas, is composed of relatively flat-lying rocks that are generally exposed at the land surface. This aquifer is generally recharged by precipitation; water is mostly unconfined in the shallow parts of the aquifer and is confined in the deeper zones.

The rocks that compose the Edwards-Trinity aquifer are relatively flat-lying and are generally exposed at the land surface in the Trans-Pecos and the Edwards Plateau areas. The geologic formations that compose the Trinity and the Edwards aquifers generally are exposed in updip areas, but they dip eastward and southward beneath younger units and lie deep in the subsurface. The downdip boundary of each aquifer approximately coincides with the farthest updip extent of water that contains 10,000 milligrams per liter dissolved solids. The base of the aquifer slopes generally to the south and southeast. Most of the rocks that underlie the Edwards-Trinity aquifer are much less permeable than those that compose the aquifer and, thus, serve as a barrier to groundwater flow. Locally, however, the underlying rocks are permeable and are hydraulically connected to the Edwards-Trinity aquifer, thus extending the thickness of the flow system. The aquifer is generally recharged by direct precipitation on the land surface. Water is mostly unconfined in the shallow parts of the aquifer and is confined in the deeper zones.

 

Caves

Inside the Edwards-Trinity Plateau aquifer, Sonora Caverns, Sonora, Texas.

Inside the Edwards-Trinity Plateau aquifer, Sonora Caverns, Sonora, Texas. (Credit: Eve Kuniansky, USGS.)

 

Springs

 

Featured Studies and Datasets

Aquifer-scale studies and the datasets they produce are a key component to understanding how karst aquifers behave, and the quality of water within them.

  • National Water-Quality Assessment, South-Central Texas — A program to describe the status and trends in water quality of a large, representative part of the Nation's surface-water and groundwater resources.

 

Additional Information

The following websites are additional sources of information about this aquifer: