Catahoula Water Chemistry Network

Science Center Objects

In 2009, large volume groundwater users began the exploration of the Catahoula Sandstone as an alternate water source in Montgomery County. Little to no information exists on the water quality of the Catahoula Sandstone in Montgomery County. To assess the viability of the Catahoula Sandstone as a potential source of groundwater, the USGS Texas Water Science Center is collecting water-quality data to assess the general water-quality characteristics as well as the age of the water in the sandstone.

The Catahoula Sandstone is the basal hydrogeologic unit of the Gulf Coast aquifer system in Montgomery County. The Gulf Coast aquifer system includes the Chicot, Evangeline, Jasper aquifers, Burkeville confining unit and the Catahoula Sandstone. The Chicot aquifer in Montgomery County is relatively thin and many instances not viable as a major groundwater producer beyond southern Montgomery County.  

Groundwater quality sampling

Groundwater quality sampling from the Catahoula aquifer.

As populations have increased over the last 30 years, groundwater has become an important resource for public-water supply and industry in the area of Montgomery County.  Groundwater availability and quality from the Gulf Coast aquifer system is a primary concern for water managers and community planners in Montgomery County. Primary withdrawal for public- and industrial-supply is from the Evangeline and Jasper Aquifers. The USGS, in cooperation with many agencies, have worked together to monitor and
appraise the Gulf Coast Aquifer system by conducting yearly synoptic water-level measurements, historical water-level trend analysis, ground-water modeling simulation and evaluation, and continuous real-time water level data within the region, inclusive of Montgomery county. Water-levels in the Chicot, Evangeline, and Jasper aquifers have shown an overall decline in Montgomery County since 2001 (Johnson and others, 2011). As part of the consideration for any alternate water sources in the Montgomery County area, the Catahoula Sandstone is currently being investigated as an alternative option.

This study will obtain an initial geochemical fingerprint of the water from multiple wells screened in the Catahoula Sandstone, as well as potentially determine the source of the water as connate or meteoric. Up to six wells screened in the Catahoula Sandstone will be sampled each year to assess the quality of the water. The results from this analysis, although limited, will provide insight to the water’s chemical signature and quality as well as the potential viability in this area of the Catahoula Sandstone as a water resource. 

Overall quality of the water will be determined by field parameters, major ions, trace metals, nutrients, total dissolved solids, and dissolved organic compounds. Geochemical fingerprint, age, and potential source may be better understood through isotopes, dissolved gasses, and noble gasses.