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

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 233
Author(s):  
Elia M. Tapia-Villaseñor ◽  
Eylon Shamir ◽  
Mary-Belle Cruz-Ayala ◽  
Sharon B. Megdal

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.

Author(s):  
R.C. Phillips ◽  
Nigel Kaye ◽  
John Saylor

Quantifying evaporative loss from reservoirs plays a critical role in sound water-availability management plans and in reservoir management. Various methods are used to quantify reservoir evaporation; however, each method carries a degree of uncertainty that propagates to model predictions of available water within a reservoir or a reservoir network. Herein, we explore the impact of uncertainty in reservoir evaporation on model outputs of historical and future water availability throughout the five major reservoirs in the Savannah River Basin in South Carolina, USA, using four different evaporation methods. Variability in the total available water is evaluated using the United States Army Corps of Engineers (USACE) 2006 Drought Contingency Plan hydrologic model of the Savannah River Basin, which incorporates recent water-management plans and reservoir controls. Results indicate that, during droughts, reservoir evaporation plays a large role in water-availability predictions, and uncertainty in evaporative losses produces significant uncertainty in modeled water availability for extreme events. For example, the return period for an event in which the availability of water in Lake Hartwell was reduced to 50% of full pool capacity varied from 38.2 years to 53.4 years, depending on the choice of evaporation parameterization. This is a variation of 40% in the return period, depending on the choice of evaporation method.


2020 ◽  
Author(s):  
Elia Tapia ◽  
Eylon Shamir ◽  
Sharon Megdal

<p>The Transboundary Santa Cruz Aquifer (TSCA) is located in Northwestern Mexico and Southwestern United States (U.S.). Groundwater from the transboundary aquifer is being shared by the states of Arizona in the U.S. and Sonora in Mexico; particularly by the cities of Nogales, Arizona and Nogales, Sonora. The Arizona-Sonora border region is subject to climate uncertainties, limited water availability, and water quality issues. The objective of this study is to assess the impacts of changes in groundwater demand, effluent discharge, and climate uncertainties within the TSCA. Groundwater recharge in the TSCA is highly sensitive to climate uncertainties and physical water and wastewater transfers from both the U.S. and Mexico. Perennial flows in the area depend on the effluent discharges from both the U.S. and Mexico. Population growth and residential construction have increased groundwater demand in the area, in addition to wastewater treatment and sanitation demands. These human activities, coupled with climate uncertainties and possible reductions to effluent discharge, influence the hydrology of the area. We use a conceptual water budget model to analyze the long-term impact of the different components of potential recharge and water losses within the aquifer, including changes in projected climate that are based on three downscaled CMIP5 RCP8.5 Global Climate Models. Water budget model simulations for most effluent discharge and groundwater pumping scenarios reflected groundwater deficit. Additionally, climate projections showed variations that range from severe long-term drying to positive wetting. This research improves the understanding of the impact of climate uncertainties and water management decisions on water sustainability, with an accessible methodology that can be globally applied.</p>


2004 ◽  
Vol 61 (7) ◽  
pp. 1095-1101 ◽  
Author(s):  
Carla M Riva Rossi ◽  
Enrique P Lessa ◽  
Miguel A Pascual

Rainbow trout (Oncorhynchus mykiss) was first introduced into Argentinean Patagonia, the southernmost region of South America, from the United States in 1904 and at present constitutes the most conspicuous freshwater fish in lakes and rivers of the region. The Santa Cruz River in Southern Patagonia is the only river in the world where a self-sustained population of introduced rainbow trout is known to have developed an anadromous run. In this study, we examined mtDNA sequence variation to identify the source of Santa Cruz River rainbow trout, providing a historical framework to interpret the processes underlying phenotypic variation and structure of Patagonian populations. The Santa Cruz River may harbor distinct North American stocks of rainbow trout, widely distributed around the world during the late 19th and early 20th centuries, but today threatened after decades of habitat loss, species introduction, and introgression from alien stocks. The mtDNA sequence data revealed that the most likely origin for wild anadromous and nonanadromous fish was the McCloud River in California. Meanwhile, a local hatchery stock, representative of rainbow trout introduced from Denmark after 1950 and widely stocked ever since throughout Patagonia, most probably originated from multiple lineages from western North America, including non-Californian populations.


2013 ◽  
Vol 45 (1-2) ◽  
pp. 149-167
Author(s):  
Benita Heiskanen

During the years 2008-2012, the El Paso, Texas-Ciudad Juárez, Chihuahua border region between the United States and Mexico saw a wave of violence that occurred as a result of the so-called “drug war” between the Juárez and Sinaloa drug cartels. As the criminal organizations began recruiting local gangs for their enforcement strategies, the violence soon spiraled beyond the context of the drug trafficking industry, generating mayhem and social decay throughout Ciudad Juárez. In four years, the death toll in the city amounted to 10,882, with 3,622 bodies in 2010. This article discusses the impact of the violence in the region as experienced by border residents and in relation to policy responses by the U.S. and Mexican governments. Drawing on fieldwork and interviews conducted in January-May 2010 with members of the border community, it focuses on the interviewees’ experiences in 2010. The discussion of violence is contextualized as a global crisis, with ramifications upon urgent issues of citizenship and political and human rights across national boundaries.


2014 ◽  
Vol 84 (5-6) ◽  
pp. 244-251 ◽  
Author(s):  
Robert J. Karp ◽  
Gary Wong ◽  
Marguerite Orsi

Abstract. Introduction: Foods dense in micronutrients are generally more expensive than those with higher energy content. These cost-differentials may put low-income families at risk of diminished micronutrient intake. Objectives: We sought to determine differences in the cost for iron, folate, and choline in foods available for purchase in a low-income community when assessed for energy content and serving size. Methods: Sixty-nine foods listed in the menu plans provided by the United States Department of Agriculture (USDA) for low-income families were considered, in 10 domains. The cost and micronutrient content for-energy and per-serving of these foods were determined for the three micronutrients. Exact Kruskal-Wallis tests were used for comparisons of energy costs; Spearman rho tests for comparisons of micronutrient content. Ninety families were interviewed in a pediatric clinic to assess the impact of food cost on food selection. Results: Significant differences between domains were shown for energy density with both cost-for-energy (p < 0.001) and cost-per-serving (p < 0.05) comparisons. All three micronutrient contents were significantly correlated with cost-for-energy (p < 0.01). Both iron and choline contents were significantly correlated with cost-per-serving (p < 0.05). Of the 90 families, 38 (42 %) worried about food costs; 40 (44 %) had chosen foods of high caloric density in response to that fear, and 29 of 40 families experiencing both worry and making such food selection. Conclusion: Adjustments to USDA meal plans using cost-for-energy analysis showed differentials for both energy and micronutrients. These differentials were reduced using cost-per-serving analysis, but were not eliminated. A substantial proportion of low-income families are vulnerable to micronutrient deficiencies.


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