Primary Mexico-United States treaties for transboundary waters
A series of treaties between the United States and Mexico serve as the basis for cooperation over shared water resources in the border region. See Figure 3.3 for a timeline of these agreements.
The earliest treaty was signed shortly after the Mexican-American War: the 1848 Treaty of Peace, Friendship, Limits, and Settlements
Figure 3.3 Timeline of relevant treaties identified by the authors.
between the US and Mexico.14 This agreement established the physical boundaries between the two countries and designates the Colorado and Rio Grande rivers to become international basins. The agreement was followed by five lesser, but still significant conventions, through which the two countries cooperated on a range of issues: placement of boundary monuments; boundary disputes related to meandering rivers; establishment of the International Boundary Commission (IBC); allocation of water in a segment of the Rio Grande; and construction of the commission’s first joint infrastructure project, the Rio Grande Rectification Project.
In 1944, the two countries entered a new treaty that continues to guide and influence water management and allocation decisions in the border region today. The Treaty for the Utilization of Waters of the Colorado and Tijuana Rivers and of the Rio Grande (1944 Water Treaty) authorized the joint construction and operation of two dams along the lower basin of the Rio Grande, expansion of the IBC’s jurisdiction to include water and, thereby, creation of the IBWC, and distribution of the waters of the major cross border watersheds: the Colorado River, Tijuana River, and Rio Grande.15 It also tasked the IBWC by addressing border sanitation issues with a transboundary impact.
In the Colorado River, under Article 10 of the 1944 Water Treaty, the United States is required to ensure Mexico receives 1,850,234,000 cubic meters of water annually. In the Rio Grande, the treaty recognizes the bifurcation of the river as two separate basins and allocates only the waters of the lower basin amongst the two countries in specific terms. Under Article 1 of the 1906 Convention between the United States and Mexico “Equitable Distribution of the Waters of the Rio Grande,” the United States is required to deliver 74,008,800 cubic meters annually of water to Mexico from the upper basin. Article 4 of the 1944 Water Treaty allocates to Mexico two-thirds and to the United States one-third of the waters of six Mexican tributaries (Conchos,
San Diego, San Rodrigo, Escondido, and Salado rivers, and the Las Vacas Arroyo), which collectively must amount to at least 431,721,000 cubic meters per year averaged over a five-year cycle.16 The 1944 Water Treaty also apportions to Mexico the entire flow of two Mexican tributaries, the San Juan and Alamo rivers, while the United States is allotted the entire flow of seven US tributaries: the Pecos and Devil’s rivers, the Alamito, Terlingua, San Felipe, and Pinto creeks, and Goodenough Spring. The remaining waters in the lower Rio Grande basin are shared equally under the treaty.17
A distinctive element of the 1944 Water Treaty is the linkage embedded into the agreement that includes the distribution of waters from two rivers in two geographically different regions along the border serving different basins. Itay Fischhendler et.al. argue that this arrangement has constrained the ability of the two nations to adapt management regimes in response to the unique environmental stresses of each river.18 Yet, Minutes 318, 319, and 323—which responded to reduced flows in the Colorado and environmental degradation in the Colorado delta, and created a mechanism for Mexico to store its water allocations within the US—suggest such concerns can be addressed through the IBWC’s unique minute system for interpreting and implementing the 1944 Water Treaty. Fischhendler et.al. also highlight that while Mexico receives water from, but does not contribute to, the Colorado River’s volume, the United States receives more water from the entire Rio Grande than it contributes to that river.19 To some extent, it appears that in developing the 1944 Water Treaty, the parties traded water from one watershed in exchange for water from another, an option that would not have been readily available had they negotiated separate agreements for each river.
While, on balance, this arrangement may appear fair to some and unfair to others, it was the product of more than 20 years of negotiations involving issues beyond the mere allocation of water, including population pressures, sanitation, droughts and floods, economic development, and border security.20 Such pressures may have contributed to the two nations expanding the scope of the treaty to the three rivers in order to have more options for negotiating their respective priorities. Moreover, there may be an advantage to having only one institution with responsibility for all three rivers as the delivery and use of water across borders often involves multiple diverse stakeholders with broadly different interests. If ever the treaty was opened for renegotiations, the consolidated approach could allow the two nations to fully consider all the diverse interests and priorities, as well as the implications for all of the encompassed river basins.21
More recently, the United States and Mexico entered into two additional agreements that expanded their transboundary interests beyond water, but have proven to be critically important for water management because of the actors brought into the conversation. On 14 August 1983, the United States and Mexico signed the Agreement on Cooperation for the Protection and Improvement of the Environment in the Border Area (La Paz Agreement), which serves as the basis for bilateral cooperation on environmental protection in the border zone, defined as 100 km north and south of the international line.22 The agreement stipulates obligations related to consultation, information sharing, review of environmental concerns, annual meetings, and formal reporting.23 It also designates the respective federal environmental agencies as the coordinators, thereby tasking the EPA and Mexico’s Secretariat of Environment and Natural Resources (SE-MARNAT) with protecting human health and the environment and obligating them to monitor and measure pollution levels related to water and air. Moreover, it obligates them to consult with state and municipal governments, nongovernmental organizations, and others on cooperative measures.24
Initially, the La Paz Agreement was used as a diplomatic instrument between the two governments through its respective environmental agencies to establish goals and objectives primarily related to water, air, and land issues. More recently, it has become a mechanism to provide joint funding. Binational initiatives include the Integrated Border Environmental Plan (1992-1994), Border XXI (1995-2000), Border 2012 (2001-2012), and Border 2020 (2013-2020).25 The latter’s goal of access to clean and safe water includes objectives on increasing household water and sewer connections for the communities along the border, assisting utilities to build capacity, watershed protection through reduction of surface water contaminants, and sharing of water quality data for transboundary watersheds by both federal governments.26 It also calls for additional investment in water resource management. Under the auspices of the La Paz Agreement, these programs serve as an institutional framework for cooperation between the two governments, raise awareness of environmental issues along the border, and provide a certain level of legitimacy that further strengthens engagement among the various government agencies, most notably the IBWC, which has authority over transboundary water issues.27
Development of the goals and objectives of the La Paz Agreement is based on stakeholder engagement and a system of five taskforces geographically distributed along the border.28 Taskforce members include representatives from state and local governments, tribal groups.
Water diplomacy and shared resources 79 academia, and nongovernmental organizations. This grassroots approach, managed binationally by EPA and SEMARNAT, follows a process of engagement through conferences with experts on water, air, and land issues, a yearly national conference, and various public comment opportunities. To some extent, this participatory approach has provided legitimacy to the goals and objectives set under the framework of the La Paz Agreement with each successive program building on the previous one.
During the early 1990s when NAFTA was being negotiated, environmentalists expressed their growing dissatisfaction with the results of the La Paz Agreement.29 They had expected more attention and resources from the two federal governments and highlighted worsening environmental conditions in the border region where some of the poorest communities were located. During this time, many communities along the border did not have wastewater treatment, and pollution of transboundary rivers was an issue. Broadening support for NAFTA presented an opportunity to raise awareness of these conditions on the coattails of that agreement’s authorization process, and to link the border’s environmental health to trade.
As a result, the two countries were pressed by environmental stakeholder groups to sign an agreement within the framework of the negotiations of NAFTA, known formally as the Agreement between the Government of the United States of America and the Government of the United Mexican States Concerning the Establishment of a Border Environment Cooperation Commission and a North American Development Bank (NADB Agreement).30 It created the NADB, which diverged in structure and process from the IBWC and included water pollution, wastewater treatment, and other priorities within its mandate. Moreover, the NADB is truly a binational institution equally funded by both governments. Over the past 170 years, the implementation and evolution of these agreements along the United States-Mexico border have created a unique governance structure for cooperation.