Technical Reports Document Library

Note:  This document is included for its historical value and may have been replaced by more recent studies.

The study area of north Bexar County measures approximately 290 square miles and is bounded on the west, north and east by the county line and by the down-dip limit of the Edwards Aquifer Recharge zone on the south. It is located in the south central region of Texas as shown in Figure 1. The study area is located within the Balcones fault zone, a region of faulted and fractured limestone. Due to the amount of fractures and faults, most streams in the area are intermittent and flow only during and immediately after rain events. Consequently, water is supplied to the study area population almost exclusively from groundwater by the Edwards and Trinity aquifers.

In 1990, the population of north Bexar County numbered approximately 27,900 with an average historical growth rate since 1960 of approximately 80 percent per decade. With limited water resources in the area, growing demand upon the Trinity aquifer is becoming a concern. This study, developed in response to the increasing demand, consists of two main portions which are presented in separate volumes.

Volume 1 was prepared by William F. Guyton Associates, Inc. It discusses ground-water conditions and the dependability, quality, and quantity of ground water that is being used within the study area for domestic, stock, public supply, industry, and irrigation purposes. A water balance for the Trinity group aquifer is presented and areas favorable for artificial recharge and/or aquifer storage and recovery projects are identified.

Volume 2 was prepared by W.E. Simpson Company, Inc. It compares the growing demand for water in the study area with the limited groundwater supply. Volume 2 estimates future demands, establishes corresponding target supply quantities and investigates alternative water resources and their abilities to provide target supply quantities. Water quantity, quality, and the cost of resource development are considered in the evaluation. Several alternative resources are ranked accordingly and recommendations are made for further study.

The reader should note the preliminary nature of the study. All figures, except for actual test results, are estimates for helping to determine future courses of study and should not be considered as actual designs, costs, or quantities.