The Transboundary Nature of the Allende–Piedras Negras Aquifer Using a Numerical Model Approach. (28th April 2020)

• Record Type: Journal Article
• Authors: Rodriguez, Laura; Sanchez, Rosario; Zhan, Hongbin; Knappett, Peter S.K.
• Is Part Of: Journal of the American Water Resources Association. Volume 56:Number 3(2020)
• Page Start: 387
• Page End: 408
• Publication Date: 2020-04-28
• Subjects: transboundary -- Allende–Piedras Negras -- model -- groundwater -- Rio Grande; Water-supply -- Periodicals; Hydrology -- Periodicals; Water resources development -- Periodicals; Water resources development -- Environmental aspects -- Periodicals; 333.9100973
• DOI: 10.1111/1752-1688.12843
• Languages: English
• ISSNs: 1093-474X

Abstract

Abstract: The Allende–Piedras Negras (APN) aquifer is located between the states of Texas (United States [U.S.]) and Coahuila (Mexico). The Rio Grande crosses the aquifer, acting as a natural and political divide between the countries. However, it remains unclear whether the APN aquifer can be considered a truly transboundary aquifer flow system, which would potentially require joint management by two different administrative jurisdictions. The main purpose of this study was to evaluate the transboundary nature of this aquifer. This was achieved by developing a detailed hydrogeological model to analyze the direction of volumetric fluxes within the APN aquifer using Visual MODFLOW. The model simulated a spatially averaged cumulative drawdown of 0.76 m for the entire aquifer over an 18‐year modeling period (2000–2017). The flow convergence zone, previously located below the Rio Grande, has shifted to the U.S. side in most locations, driven by higher pumping rates of the wells located near the river. This shift of the convergence zone from one country to the other means that groundwater recharge from one side flows underneath the river to the other side. This qualifies the APN aquifer as a "transboundary groundwater flow system." The procedure followed in this study may be applied to other aquifers that straddle the U.S.–Mexico border and may motivate future modeling studies on other poorly studied transboundary aquifers around the world and thereby enable bi‐national aquifer management. Abstract : Research Impact Statement : More precipitation falling as rain and briefer snow cover would increase the kinetic energy of rain falling on snow‐free ground, hence may increase surface soil erosion in the Lake Tahoe Basin.