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Transboundary water management: A transboundary Aquifers Pilot Program
The Allende–Piedras Negras Transboundary Aquifer (APN-TBA) is located between the states of Texas (United States) and Coahuila (Mexico).
The Rio Grande crosses the aquifer, serving as both a natural and political divide between the two countries.
However, it remains unclear whether the APN-TBA qualifies as a true transboundary aquifer flow system, which would require transboundary water management through joint or coordinated efforts by the two different administrative jurisdictions.
Objective of the TAPP
To develop a framework of transboundary cooperation to address transboundary water management issues along the US/Mexico border issues. The resulting framework will serve as a model and can be applied in other transboundary water basins and shared aquifers.
Specific Objectives of the TAPP
- To develop scientifically-based knowledge on assessment and management of transboundary aquifers specifically applied on the APN TBA between Coahuila and Texas.
- To develop specific feasible recommendations on water management strategies and short-term initiatives based on social and economic priorities and current and future water availability scenarios.
- Use this knowledge to support long-term sustainable economic development with social responsibility through inclusive decision-making process, transparency, stakeholder involvement and shared governance schemes.
- To develop strategies aligned to current ESG requirements and goals.
- To develop communication strategies to socialize and translate scientific findings into useful and executable information for different types of audiences and users.
- To build social capital and trust among involved institutions/stakeholders.
- Develop scientific binational publications on technical journals.
- To evaluate the feasibility to develop and maintain a groundwater monitoring network (public and accessible) for groundwater levels and water quality.
TAPP: Transboundary Aquifers Pilot Program: Knowledge, development and management of shared aquifers
The 21st century sees the U.S.-Mexico borderlands facing an emerging array of water- resources management challenges.
These challenges range from the increasing demand of water due to urbanization, industrialization, and agricultural expansion, to more drought prominent conditions.
This growing demand strains the capacity of limited water supplies to deal with a broad spectrum of social, legal, and environmental issues threatening surface and groundwater quality and border security.
Droughts conditions across the border region, already decades-long, are likely to continue and intensify, and constrain even further the ability of the parties to meet water delivery obligations in the Colorado and Rio Grande rivers (Coronado et al. 2021, Renteria et al. 2022).
A required collaboration on transboundary waters
The need to regulate groundwater between Mexico and the United States requires information and research. The Transboundary Aquifer Pilot Program of the Allende-Piedras Negras aquifer offers an alternative and an opportunity to improve our shared aquifers.
Up to 72 hydrogeological units have been identified along the very long border strip (ca 3,200 km) between Mexico and the United States; at least 28 are considered aquifers shared by the two countries (Sanchez et al., 2018; Sanchez & Rodriguez, 2021)
For some 80 years, the distribution and management of surface waters in the major basins they share – those of the Colorado, Grande/Bravo, and Tijuana Rivers – have been regulated by international treaties.
However, in the area of groundwater, only one agreement has been concluded (Minute 242, IBWC, 1973), which limits groundwater extraction in the shared Yuma/Mexicali-area aquifers, and establishes obligations of mutual consultation if one of them intends to carry out actions that could have harmful effects on the other side of the border.
Shared waters, shared issues
In basins and aquifers that are shared by two or more countries, the unsustainable use of surface and groundwater on one side, can generate negative effects on water quantity and/or quality in the neighboring country, which in turn can cause harmful environmental and socioeconomic effects. These effects were shown in a global study of TBAs with aquifer stress indicators using groundwater abstraction, groundwater recharge, and groundwater contribution to environment flow, (Wada and Heinrich, 2013).
The Allende-Piedras Negras aquifer is an invaluable water source for both Mexico and the U.S., providing essential water for human consumption, agriculture, and industry. To ensure its sustainability, it must be responsibly managed through a collaborative approach.
The Permanent Forum of Binational Waters is working on strategies for the sustainable use and conservation of this aquifer. With the Shared Aquifers Knowledge, Development, and Management Pilot Program, we can recognize and quantify its true value.
As the demand for water increases with economic development and population growth, competition for the vital resource becomes greater. It has been reported that competition for water, i.e., for shared sources, can lead to serious conflicts both at domestic and international scale. Though at the same time, this same condition offers the opportunity of bringing stakeholders to the negotiation table as water becomes a strategic and national security resource (Subramanian & Wolf 2012; Wolf 1999). Within this context, transboundary aquifers (TBAs) raise questions about their sustainable management, the fair distribution of water, and transboundary effects among the countries that share them, and at the same time, becomes a tool to promote cooperation and peace.
In addition, limited knowledge of TBAs in most regions of the world poses a problem of planning and developing shared groundwater resources. A lack of adequate, long-term groundwater monitoring is also a common obstacle to the comprehensive assessment of TBAs (Rivera et al., 2022). With limited knowledge, threats on groundwater security are perceived (sometimes wrongly), including its unsustainable use, decreased recharge rates, and even conflicts. Thus, reaching conflict-free joint governance of a TBA, to bring about equitable and sustainable use of the resource, requires a three-pillar framework, including the physical assessment of the TBA, cooperation and collaboration mechanisms, and shared management (Rivera et al., 2022).
The current water condition along the MX-U.S. border
Continued drought conditions are generating internal and bilateral tensions as competing water users in Mexico and the United States struggle to meet their needs. More frequent flooding events result in threats to critical border water infrastructure, heightened sanitation and public health issues, as well as greater contamination of transboundary water bodies.
Tension over the use of shared transboundary groundwater is increasingly apparent as the lack of clear guidelines over its management collides with a greater demand for this resource. Recent tension over the allocation of water resources (Mumme, 2021) is a harbinger of a future where competition over unreliable water supplies will intensify (Figure 1.2 shows two of the most important TBA’s cases along the border). Meeting these challenges requires innovative and strategic thinking, recognizing the complex and dynamic interaction between coupled environmental forces and socio-economic systems in the border region.
Integrated studies required for transboundary aquifers (TBAs)
TBAs are of vital importance for Mexico and the USA because, for at least twelve sister cities, they are the main source of water for domestic use, for the ‘maquiladoras’ industry as well as for the agricultural sector. Both countries have carried out studies of their share of few of these aquifers. On an intermittent basis, exchange of basic isolated information and the results of a couple of studies (San Pedro and Santa Cruz, Mesilla and Hueco Bolson) has been carried out in order to identify existing or potential transboundary effects, to mitigate or prevent them, but not much on the design of potential joint management plans. The results have been exchanged intermittently, but have not yet been integrated, reconciled, or translated into formal binational management agreements, data sharing, or sustainability plans.
From all the above, the necessity of jointly undertaking, or accelerating, integrated studies of TBAs along the US/Mexico border is clear (Rivera and Hanson, 2022). These studies shall have a solid technical basis to support strategies for sustainable binational management of priority aquifers and, eventually, to result in an agreement (formal) or set of arrangements (informal), or on a case-by-case basis scheme, which could be reconciled through interpretations or additions (i.e., Minutes) to the existing 1944 treaty on the waters of the Colorado, Tijuana, and Grande/Bravo Rivers.
Pilot Project: A Solution to the Transboundary Hydrological Enigma
The Allende–Piedras Negras Transboundary Aquifer (APN-TBA) is the pilot project and potential model for other transboundary aquifers (TBA) along the US-Mexico Border. Because of its location on the political border, the APN-TBA has a strategic value to binational relationships since it provides 85% of the total water needs in the region. From this percentage of groundwater use, approximately 70% is used by agriculture, 16% by industry, 5% by public supply, and the remaining 9% is used by rural households (Rodriguez et al., 2020).
The knowledge acquired with this pilot project will be used to frame a vision of long-term sustainable development with social responsibility, including open communication, visibility, stakeholders’ involvement, and shared governance; all these supported with scientific tools.
Download all the deliverables available of the project
These resources provide an overview of transboundary surface and groundwater conditions, focusing on socio-economic factors, governance structures, and research gaps in the region.
The documents are foundational for advancing through the next phases of this project aimed at sustainable water management.
Public hearings on shared groundwater
Public hearings on shared groundwater
Public hearings on shared groundwater
Graphic for the presentation
Users of the Allende Piedras Negras – Maverick aquifer, between Mexico and the United States of America, participate in public hearings held on April 9, 2024.
Graphic for summary
Summary of the first public hearing on the TBA aquifer Allende Piedras Negras – Maverick. Download the brief document of the session held on April 9, 2024.
Synthesis of the current situation
Synthesis of the current situation
Synthesis of the current situation
General graphic
As part of the first phase of the Allende-Piedras Negras Transboundary Aquifer Pilot Program, several key documents have been published.
Annex A - Technical Report
A detailed synthesis of data gaps, research needs, and the physical state of the aquifer system.
Annex B - References
A compilation of scientific studies on geology, groundwater, and environmental conditions in the region.
Annex C - Collected Data
All collected data, including geology, hydrology, and environmental information for the region.
Synthesis report on water supply and demand. Knowledge of the physical conditions of groundwater and aquifers in the study area
Read the mayor findings and key recommendations.
Why Water Security Matters for the Border
Water security at the Mexico-U.S. border is critical for the health and economic prosperity of millions of people who rely on these shared resources. Ensuring a reliable supply of clean water supports agricultural productivity, industrial activities, and domestic use, while also protecting biodiversity and maintaining ecosystem health.
Without a coordinated approach to managing these resources, both countries could face significant social, economic, and environmental challenges.By supporting initiatives focused on water security along the Mexico-U.S. border, your organization can help safeguard these vital resources for future generations.