Technical Reports Document Library

Note:  This report is included for its historical value; results may have been superseded by more recent studies.

A program to resample observation wells tapping a zone of transition between water of good quality- and saline water in the Edwards and associated limestones was begun in 1959. The chemical analyses of the resampling program are being used to detect possible encroachment

of saline water into the fresh-water areas as the head in the aquifer changes. Those analyses compiled through 1963 were published by the Edwards Underground Water District (Garza, 1962, 1964), and this report presents the chemical analyses compiled during 1964.

This program is part of a more extensive hydrologic investigation carried on by the U.S. Geological Survey in cooperation with the Edwards Underground Water District, the Texas Water Commission, and the city of San Antonio.

Listed in this report are chemical analyses from 80 wells which usually are sampled twice a year, but some of the wells are sampled only once throughout the year because their use is limited.

The water samples were analyzed in the laboratory of the U.S. Geological Survey in Austin, Tex., for specific conductance, pH, chloride, sulfate, bicarbonate, and hardness. A more complete analysis was made for one or the samples from each well, and these analyses are on file in the offices of the Geological Survey in Austin and San Antonio. Locations o£ wells and other data pertaining to the resampling program may be found in tables in the report.