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Texas–Mexico Border Area

Environmental Research—Just the Beginning
Nearly a third of the Bureau’s research is directed toward environmental concerns such as the environmental impact of human activities and society’s increasing need for water resources.

In the Texas–Mexico border area Bureau scientists, together with UT/A&M border universities, recently completed a project funded by the Texas Higher Education Coordinating Board. The project produced, among other things, a transnational digital database of the border area’s geology. These types of high-quality transboundary datasets are extremely important to those concerned with responsible development and environmental protection of this region. Bureau scientists involved in Texas–Mexico research include Jay A. Raney and Thomas A. Tremblay.


Airborne Geophysical Surveys
A second Lower Rio Grande Valley project conducted by the Bureau involves the use of new airborne geophysical surveys to determine possible sources of groundwater. This work, if successful, could be easily applied to adjacent areas in Mexico.

To assist Mexican researchers in their search for resources, Bureau scientists have traveled to Mexico to deliver presentations and to hold workshops for Mexican groundwater professionals. Bureau scientists involved in airborne geophysical surveys and hydrogeologic studies include Jeffrey G. Paine and Alan R. Dutton.

Patterns evident on conductivity images at a shallow depth (30 m) north of McAllen reflect lateral and vertical changes in water quality and sediment or rock type. The concentration of wells producing relatively fresh water in the upper part of the image fall in an area of low electrical conductivity.

 

The color image of an area north of Brownsville depicts the electrical conductivity 110 m below the ground surface as measured by an airborne EM system. Cool colors indicate relatively poor conductivity and warmer colors indicate relatively high conductivity. Because water becomes more electrically conductive as its dissolved mineral content increases, the poorly conductive areas in general are better areas to explore for ground water at this depth. In addtion, shapes of conductivity anomalies can be used to infer the geologic environment. Three wells drawing water from about this depth confirm that ground-water quality is better where conductivity is lower.

 

Lower Rio Grande Riparian Corridor
Researchers at the Bureau are currently involved in a multidisciplinary study of the Lower Rio Grande riparian corridor. (The term "riparian" describes the banks surrounding bodies of water; for this study, riparian corridor refers to the banks of the Rio Grande.) Riparian zones are characterized by high plant and animal species diversity and are among the most productive ecosystems in North America. The rapid decline of riparian ecosystems in the United States, however, has made their preservation an important goal of governmental and private organizations. This study, funded by the U.S. Environmental Protection Agency, involves collecting a wide range of data to assess current corridor conditions and building a comprehensive database to help guide future assessments. Bureau scientists involved in riparian studies include Jay A. Raney, Thomas A. Tremblay, William A. White, and researchers from the UT Center for Space Research, The University of Texas-Pan American, and The University of Texas at Brownsville.

Map of Lower Rio Grande valley showing approximate location of existing ecological transects and example of riparian vegetation in the Santa Ana National Wildlife Refuge.