Facing a shrinking share of Colorado River water, Arizona is studying a proposal to fund a $5 billion-plus seawater desalination plant on Mexico’s Sea of Cortez, paired with a pipeline stretching roughly 200 miles across the border to a reservoir west of Phoenix. The plan is one of several binational “paper water” exchanges the state’s Water Infrastructure Finance Authority (WIFA) has been evaluating as Arizona confronts long-term cuts to its primary water source.
How the exchange would work
Under the arrangement, Mexico would keep the physical desalinated water produced at the plant; Arizona’s investment in building the facility would instead entitle the state to draw a larger share of Colorado River water in exchange, a structure similar to the water swap San Diego’s county water authority has pursued around its Carlsbad desalination plant. Multiple project teams have pitched competing versions of the concept, including Israel-based IDE Technologies, which has proposed a plant and 200-mile pipeline to a reservoir west of Phoenix, and a consortium of EPCOR Water Innovation Partners with Spanish firms Sacyr and Acciona, which has floated an even larger facility near San Felipe or closer to the border.
The stakes behind the push are significant: a report from the Arizona governor’s office this year projected that a meaningful share of the Phoenix metro area’s long-term groundwater supply would go unmet without new sources, prompting the state legislature to set aside roughly $1 billion for water augmentation projects, desalination among them.
Environmental and political friction
The proposals have drawn pointed criticism. Sierra Club’s Arizona chapter has argued desalination “is just not sustainable” given its high energy demands, and environmental groups have raised alarms about the specific geography of the Sea of Cortez’s upper reaches: its elongated, bay-like shape means brine discharged from a large plant could concentrate in the water, threatening endangered species such as the vaquita porpoise and the totoaba fish. A proposed pipeline route would also cross Organ Pipe Cactus National Monument, a UNESCO biosphere reserve already disturbed by border wall construction.
Beyond the environmental questions, any deal requires sign-off from both the US and Mexican governments, adding a diplomatic layer on top of the technical and financial review WIFA’s board has only recently begun conducting in public, after previously citing procurement confidentiality rules to keep project details under wraps.
Source: The Arizona Republic / azcentral.com