The Edwards Aquifer (Balcones Fault Zone) forms a narrow belt extending through nine counties, including Travis County. A groundwater divide in Hays County hydrologically separates the aquifer into the San Antonio and Austin regions. Water in the aquifer occurs in fractures, voids, and solution channels in the Edwards and associated limestone formations. Over the last three decades, our understanding of the hydrogeology of the Edwards as well as our other aquifers has increased dramatically.

Auquifer graph2

In Travis County, many of our springs flow from the Edwards Aquifer, down gradient from the Edwards Aquifer Recharge Zone (EARZ). Pumping and groundwater management is not established by a district in northern Travis County. However, the segment of the EARZ south of the Colorado River is managed by the Barton Springs/Edwards Aquifer Conservation District (BSEACD). In the recharge zone, the Edwards limestone outcrops on the surface of the land and is directly recharged from rainfall and stream channels above it. Upstream from the EARZ, the Edwards Aquifer Contributing Zone (EACZ) provides indirect recharge because surface streams flow towards the EARZ. Landowners in Travis County who own or reside on property over the EARZ or EACZ should contact the BSEACD and the TCEQ’s Edwards Aquifer Protection Program to implement practices that ensure that land use activities do not result in polluting of the aquifer.

The aquifer is extremely susceptible to pollution. Research shows that little substantive attenuation of some pollutants occurs before reaching the aquifer. The vulnerability of the Edwards Aquifer, the high usage of the aquifer as a drinking water supply, and the presence of endangered species led the State of Texas to formulate a regulatory structure to address development proposals in the EARZ and EACZ to ensure aquifer water quality does not significantly degrade.