Barton Springs segment of the Edwards (Balcones Fault Zone) Aquifer, central Texas

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Publication Date

January 2019

Abstract

The Barton Springs segment of the Edwards (Balcones Fault Zone) Aquifer is a prolifi c karst aquifer system containing the fourth largest spring in Texas, Barton Springs. The Barton Springs segment of the Edwards Aquifer supplies drinking water for ~60,000 people, provides habitat for federally listed endangered salamanders, and sustains the iconic recreational Barton Springs pool. The aquifer is composed of Lower Cretaceous carbonate strata with porosity and permeability controlled by depositional facies, diagenesis, structure, and karstifi cation creating a triple permeability system (matrix, fractures, and conduits). Groundwater fl ow is rapid within an integrated network of conduits discharging at the springs. Upgradient watersheds provide runoff to the recharge zone, and the majority of recharge occurs in the streams crossing the recharge zone. The remainder is direct recharge from precipitation and other minor sources (infl ows from Trinity Group aquifers, the San Antonio segment, the bad-water zone, and anthropogenic sources). The long-term estimated mean water budget is 68 ft3 /s (1.93 m3/s). The Barton Springs/Edwards Aquifer Conservation District developed rules to preserve groundwater supplies and maximize spring fl ow rates by preserving at least 6.5 ft3 /s (0.18 m3 /s) of spring fl ow during extreme drought. A paradox of the Barton Springs segment of the Edwards Aquifer is that rapid recharge allows the Barton Springs segment of the aquifer to be sustainable long term, but the aquifer is vulnerable and limited in droughts. The karstic nature of the aquifer makes the Barton Springs segment vulnerable to a variety of natural and anthropogenic contaminants. Future challenges will include maintaining the sustainability of the aquifer, considering climate change, population growth, and related land-use changes.

Document Type

Article

Identifier

SFS0072690_00001

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