Assessing Groundwater Withdrawal Sustainability in the Mexican Portion of the Transboundary Santa Cruz River Aquifer

Abstract

The impact of climate uncertainties is already evident in the border communities of the United States and Mexico. This semi-arid to arid border region has faced increased vulnerability to water scarcity, propelled by droughts, warming atmosphere, population growth, ecosystem sensitivity, and institutional asymmetries between the two countries. In this study, we assessed the annual water withdrawal, which is essential for maintaining long-term sustainable conditions in the Santa Cruz River Aquifer in Mexico, which is part of the U.S.–Mexico Transboundary Santa Cruz Aquifer. For this assessment, we developed a water balance model that accounts for the water fluxes into and out of the aquifer’s basin. A central component of this model is a hydrologic model that uses precipitation and evapotranspiration demand as input to simulate the streamflow into and out of the basin, natural recharge, soil moisture, and actual evapotranspiration. Based on the precipitation record for the period 1954–2020, we found that the amount of groundwater withdrawal that maintains sustainable conditions is 23.3 MCM/year. However, the record is clearly divided into two periods: a wet period, 1965–1993, in which the cumulative surplus in the basin reached ~380 MCM by 1993, and a dry period, 1994–2020, in which the cumulative surplus had been completely depleted. Looking at a balanced annual groundwater withdrawal for a moving average of 20-year intervals, we found the sustainable groundwater withdrawal to decline from a maximum of 36.4 MCM/year in 1993 to less than 8 MCM/year in 2020. This study underscores the urgency for adjusted water resources management that considers the large inter-annual climate variability in the region.

Advances in Transboundary Aquifer Assessment

“…These projected trends are important considerations in the development of strategies for sustainable water resources management of the Santa Cruz River aquifer. The findings of Shamir et al are supported by the paper "Assessing groundwater withdrawal sustainability in the Mexican portion of the transboundary Santa Cruz River aquifer" [11]. Tapia-Villaseñor et al develop a waterbudget model for the Mexican portion of the Santa Cruz River aquifer to assess annual water withdrawal.…”

Evaluation of the Hydrochemical and Water Quality Characteristics of an Aquifer Located in an Urbanized Area

“…Groundwater is one of the most important natural resources and plays an important role in ecosystems [1]. It is widely used for domestic, industrial, and agricultural activities; hence, its demand is constantly increasing [2][3][4][5]. Population growth, accidental spills, surface leaching, runoff, and the extensive use of fertilizers in irrigated areas are considered the main causes of groundwater alteration [6,7].…”