Geology and Ground -Water Resources of Comal County,Texas
- Permanent Link:
- Geology and Ground -Water Resources of Comal County,Texas
- Series Title:
- O. George, William
- Publication Date:
- Subjects / Keywords:
- Geology ( local )
Ground-Water ( local )
Comal County ( local )
Central Texas ( local )
Waters Supply ( local )
- serial ( sobekcm )
- The purpose of this report on the geology and ground-water resources of Comal
County in central Texas is to determine the sources of the waters that supply
Comal Springs, the largest springs in the Southwest, and other springs and wells.
Comal County has an area of about 559 square miles and in 1950 had a population of 16,325. Comal Springs discharge within the city limits of New Braunfels,
the county seat of Comal County.
With the exception of a small outcrop of basaltic rock near the western boundary of the county, all the rocks in the county are sedimentary in origin and range
in age from Cretaceous to Recent. The main water-bearing formations, the
Edwards and Glen Rose limestones, are a part of the Comanche series which
has a maximum thickness of about 1,900 feet in Comal County. The Gulf series
which is about 500 feet thick yields very little water. The Uvalde gravel of
Pliocene (?) age is found only on hilltops and is too thin to retain water. Small
yields for domestic and stock use are obtained from the Leona formation of
Pleistocene age, which occurs as terraces along the main streams and has a maximum thickness of about 50 feet. Extensive faulting has exposed almost all the
Cretaceous rocks. Seven main faults which are a part of the Balcones fault zone
in central Texas cross the county in a northeasterly direction. They are normal
faults with the downthrow to the south or southeast, are roughly parallel, and
have a combined displacement of about 1,500 feet. The direction of movement
of ground water is largely controlled by these faults.
Studies of hydraulic gradients; chemical analyses; correlation among water
levels, rainfall, and discharge measurements of Comal Springs; and relative runoff of streams within the county prove rather conclusively that more than half
of the water discharged by Comal Springs is supplied by a large underground
reservoir which also supplies many artesian wells in the San Antonio area. The
data show that a relatively large proportion of the water comes from recharge
- Original Version:
- USGS, Vol. 1138 (1952-01-01).
- 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.
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