ALLENDE - PIEDRAS NEGRAS TRANSBOUNDARY AQUIFER: AN INITIAL MODELING ASSESSMENT
Recently, a total of 36 potential transboundary aquifers have been identified in the Mexican-U.S border. Sixteen aquifers were identified and characterized as transboundary with enough level of confidence; however, only 11 aquifers have been recognized officially as transboundary by Mexico and the United States. The Allende-Piedras Negras aquifer between Texas and the state of Coahuila, Mexico, has been identified as transboundary with reasonable level of confidence; however, it has not been recognized officially by both countries or at international level (ISARM). The purpose of this work is to demonstrate the hydrogeological linkages of this aquifer at transboundary level as well to offer a better understanding of the system with the objective to offer new information that could support its identification and recognition at international levels.
In order to accomplish this objective, a simulation tool will be developed and tested using available well data from prevous studies in the region using primarily historical piezometric levels. The capacities of a modeling tool (MODFLOW) will be tested to verify the hydraulic connectivity of the transboundary aquifer system. After confirmimg the connection of the transboundary flow, and due to limited water well data in the Mexican side, extraction scenarios will be tested to offer potential consequences of the system in both sides of the border, if excessive water extraction occurs. Some of the hydraulic properties will be taken from hydrological studies and previous pumping tests if availabe to start the modeling process; if there is missing informaion, it would be taken from calibration or available data from closer areas, such as hydrulic conductivity or permeability values.
The methodology followed to perform this project will also include the collection of geological information to homogenize and correlate the geological units in both sides of the border. This process would provide more refined information of the aquifers already identified and laking of information. The expected results will offer both the grounds for future simulation models in the poorly studied aquifers in the border between Texas and Coahuila and provide the first assessments for potential groundwater management in the region.