Along the coastline of the western U.S. and Mexico, officials have pursued desalination as a means of addressing water-scarcity issues.  In California, Baja California, Baja California Sur, and Sonora, desalination plants are “being planned, under construction, or in operation”; even inland states in the southwestern U.S. are looking towards the glistening Pacific for their own supply of freshwater.  Across the American West and southwards into Mexico, building plans and climactic changes point to the invariable expansion of the desalination market.

Currently, Mexico’s desalination market is smaller than that of California’s—but the Mexican government was one of the early adopters of desalination and has invested further in the technology over the past couple of years.  The largest coastal plant is now located in Cabo San Lucas, and others are planned, in construction, or under study in La Paz, Ensenada, and Guaymas-San Carlos. Additionally, with the adoption of updated public-private-partnership law, the private sector has turned its attention to seawater desalination, and in particular, to “the possibility of exporting desalted water to the United States.”  A recent project to consider such an arrangement is the Rosarito SWRO, a 189,000 m3/d desalination plant being developed by NSC Agua. Depending on future demand for the product water in both Mexico and the US, as well as the status of a Presidential border water permit, the project may consider selling a portion of its product water to the Otay Water District in California.

With a view towards this ecological and market development, a recent study assesses the social, environmental, and political impacts of building “binational desalination systems” across the US-Mexico border region.”^[1]  The study defines this international system of water-exchange as the process in which “desalted water is produced in one country and delivered or exchanged with another country”; and it uses a “water-security framework” to assess the future of possible US-Mexico desalination systems.  The notion of “water security” refers to the presence of “a sufficient quantity of water supply to meet current and future needs”; and this security depends on a process that may be called “adaptive management.”  Adaptive management refers to:

water infrastructure (technology) and water management (institutions) that deal with uncertainty through governance systems that are flexible and dynamic, reflecting key characteristics such as trust and sustained iterative relationships, knowledge-sharing, transparency and accountability, and representation (participation and equity) among the decision-makers, the scientific community, and policy networks that comprise most water governance systems.^[2]

^{Desalination plants in the western US-Mexico Border[3]}

The authors of the paper identify four areas of concern in the potential development of US-Mexico binational desalination systems: economic considerations and energy requirements (with the latter forming the largest cost variable for desalination plants); environmental impacts on aquatic ecosystems (which may be diminished through certain measures); and the need for social and political relations to ensure the delivery of “safe, clean and affordable water” across national borders.

The study then applies these metrics to a case study of the proposed Puerto Peñasco desalination plant in Sonora, Mexico and offers “three salient conclusions to consider as desalination technology and planning moves forward in the Arizona-Sonora region.”  First, the authors argue that desalination “should be employed as an alternative to augment water supply only when other options have been carefully considered”; and explain that the success of any project will depend on efficient “water management institutions…(e.g., for registering, metering, billing and collecting water fees…Without tackling such structural problems, more water could amplify these inefficiencies and promote unsustainable growth.”

Secondly, the study explains that a sustainable, binational desalination system requires attention to “non-technological attributes of desalination systems (environmental, financial, social, institutional, legal, political).”  For instance, even if “technological, financial, and environmental matters were addressed, there may still be social, institutional, legal and political obstacles.” 

Thirdly, the study addresses the unsteady history of “transboundary-water management” along the U.S.-Mexico border region.  In the 1930s, a period characterized by “mistrust,” the U.S. government built the All-American Canal, a 130-kilometre long aqueduct in southeastern California.  The canal transported water from the Colorado River into the Imperial Valley, and replaced the Alamo Canal that was located primarily in Mexico.  In contrast, more recent international water projects known as Minute 319 and the June 2014 Arizona-Mexico cooperation have been the result of harmonious U.S.-Mexico collaborations.  Ultimately, practical experience shows that any project development will require “sustained positive relations and robust binational institutions.”