Contamination Of An Aquifer by Salt Water Injection
CALVIN WOODS, Professor
Department of Civil Engineering
Texas A & M University
College Station, Texas
INTRODUCTION
This paper describes an investigation of the salt water contamination of a fresh water
aquifer in North-Central Texas. The aquifer, the Seymour Formation, is the smallest major
aquifer in the State of Texas and its general location is shown in Figure 1. This investigation
was limited to the Seymour Formation located in Haskell and Knox Counties, Texas.
Figure 1 — Location of Seymour Formation in State of Texas.
The groundwater resources of Haskell and Knox Counties, Texas, are contained in the
Seymour Formation which is a shallow surface deposit of fine silt, sand, and gravel ranging
in thickness from 0 to 85 feet. The Seymour Formation is the surface formation in nearly
fifty percent of Haskell and Knox Counties, occupying the high divides between the major
stream valleys. This formation consists of coarse-grained sand and gravel, fine-grained sand
and silt, red and gray clay, claiche, and some volcanic ash. The Seymour overlies the red
Permian clays. The water in the Seymour is generally of fair quality while the Permian beds
are generally a tighter formation containing brackish to salty water.
In 1913, Gordon (1) reported that there was water in the base of the Seymour, but
generally the Seymour was not filled with water. In 1962, Ogilbee and Osborn (2) reported
that the Seymour had filled with water sometime between 1900 and 1935. Both geologic
studies indicated that the Seymour was primarily recharged by precipitation directly on the
aquifer and that there was very little exchange of water between the Seymour and the
underlying Permian formation. Water is stored in the Seymour, and losses from the
Seymour consist of evapotranspiration losses and flow from the Seymour into the major
streams. Geologic cross sections indicate that there is no possibility of significant recharge
of the Seymour by the major streams because the Seymour lies above the flood plains at the
major streams.
Ogilbee and Osborne felt that the filling of the Seymour with water was due to above
average precipitation during the 1900 to 1935 period, and the fact that a large part of the
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