Permanent Link:

https://digital.lib.usf.edu/SFS0069901/00001

Material Information

Title:

GEOLOGIC FRAMEWORK AND HYDROGEOLOGIC CHARACTERISTICS OF THE EDWARDS AQUIFER RECHARGE ZONE, BEXAR COUNTY, TEXAS

Series Title:

USGS Water-Resources Investigations

Creator:

G. Stein, William
B. Ozuna George

Publication Date:

1995-01-01

Language:

English

Subjects

Subjects / Keywords:

Bexar County ( local )
Edwards Aquifer ( local )
Fault Zone ( local )

Genre:

serial ( sobekcm )

Notes

Abstract:

In Bexar County, residential and commercial development on the Edwards aquifer recharge zone is increasing. The aquifer possibly can be contaminated by spills, leakage of hazardous materials, or runoff from the rapidly developing urban areas that surround, or are built on, the intensely faulted and fractured, karstic limestone outcrops characteristic of the recharge zone. Furthermore, some of the hydrogeologic subdivisions that compose the Edwards aquifer have greater effective porosity than others. The areas where the most porous subdivisions crop out might provide efficient avenues for contaminants to enter the aquifer. The Edwards aquifer recharge zone has relatively large permeability resulting, in part, from the development or redistribution of secondary porosity. Lithology, stratigraphy, diagenesis, and karstification account for the effective porosity and permeability in the Edwards aquifer outcrop. Karst features that greatly enhance effective porosity in the outcrop area include sinkholes and caves. Hydrogeologic subdivision VI, the Kirschberg evaporite member, appears to be the most porous and permeable subdivision within the Kainer Formation. Hydrogeologic subdivision HI, the leached and collapsed members, undivided, is the most porous and permeable subdivision within the Person Formation. Hydrogeologic subdivision II, the cyclic and marine members, undivided, is moderately permeable, with both fabric- and notfabric-selective porosity. The faults in northern Bexar County are part of the Balcones fault zone. Although most of the faults in this area trend northeast, a smaller set of cross-faults trend northwest. Generally, the faults are en echelon and normal, with the downthrown blocks typically toward the coast.

Original Version:

USGS Water-Resources Investigations, Vol. 95-4030 (1995-01-01).

Record Information

Source Institution:

University of South Florida Library

Holding Location:

University of South Florida

Rights Management:

This object is protected by copyright, and is made available here for research and educational purposes. Permission to reuse, publish, or reproduce the object beyond the bounds of Fair Use or other exemptions to copyright law must be obtained from the copyright holder.

USFLDC Membership

Aggregations:

University of South Florida
Karst Information Portal

Postcard Information

Format:

serial