The Central Arizona Project, or CAP, canal cuts like a mirage through central Arizona, zigzagging through bleak desert scrub for more than 300 miles. Its stairstep journey begins at Lake Havasu near the town of Parker, where the first of 14 pumping stations lift the water 800 feet from the Colorado River into the Buckskin Mountain Tunnel, a waterfall moving backward. The canal ends on the San Xavier District of the Tohono O’odham Nation, an elevation lift of 2,900 feet.
The CAP has deep roots in Arizona history. When the 1922 Colorado River Compact and ensuing negotiations and litigation promised 2.8 million acre-feet of water to Arizona, the water buffaloes of the era envisioned a canal to bring that water to farms in the central part of the state. The CAP soon became seen as a rescue mission to Phoenix and Tucson, whose growing populations were over-reliant on fossil aquifers filled up during the Pleistocene.
That was the CAP’s historic role in Arizona: water transportation. “Over time it became apparent to our leadership that we needed to engage in activities to protect the resource that we deliver,” explained Chuck Cullom, Colorado River Program Manager. Today, the Central Arizona Water Conservation District, or CAWCD, which operates the CAP, is Arizona’s primary voice for water issues, along with the Arizona Department of Water Resources, or ADWR.
This shift in perspective came about partly because of Arizona’s junior priority right to the Colorado River. In times of shortage, California can draw its full allotment before Arizona receives a drop. Arizona can reduce the risk of shortage by improving the efficiency of water management throughout the river basin. To that end, CAWCD has engaged in discussions with Mexico about water management for more than a decade, and more recently began collaborating with conservationists on adjustments to the Law of the River that acknowledge environmental needs. Along with its counterpart agencies in California and Nevada, CAWCD helped develop an agreement called Minute 319.
How does water for the environment fit into this ongoing discussion? That’s an open question, especially as persistent drought squeezes the Southwest’s water infrastructure to the breaking point. Will Worthington, a retired CAP engineer who began working on the project in the 1970s and saw it through to completion in 1992, said that recognition of environmental concerns is a relatively new outlook for CAWCD and other municipal water agencies.
“As I look back on it, I don’t recall that there was any acknowledgment of what would happen to the river once we began pumping the flow,” Worthington said. “Certainly for us planners it was not a matter of concern that our project would dry up the river—in a sense, the last straw.”
For Worthington, that changed a decade ago when he joined LightHawk, a volunteer group that donates flights for conservation, as a pilot and took his first flight over the Colorado River Delta. “I really did not know that this had happened to our river, and that our project, along with many others, had caused it to happen,” he said.
For CAP, Minute 319 provides greater security with the shortage-and-surplus sharing agreement between the United States and Mexico. For conservationists, it’s a step toward securing water for ecosystems. Minute 319 is a powerful experiment in collaboration. Despite the widely differing perspectives and values of the people at the negotiation table, and the challenge of working over an international border, nearly everyone involved has reason to work for a renewal of Minute 319—whether it’s environmental health or long-term water supply in their minds.
“We have built new relationships that allow for the U.S. and Mexico to operate the Colorado River system in a more efficient and collaborative fashion than we have in the past,” Cullom said. “As the system is stressed by drought and imbalance between supply and demand, having that relationship and openness will help us avoid unnecessary conflict and misunderstanding.”
Western history places water at the center of conflict—indeed, the creation of CAP is a story of lawsuits and political bargaining that left a bitter legacy in Arizona. Collaboration over water may be a better way forward in a future of scarcity, particularly if ecosystems such as the Colorado River Delta can find a voice at the negotiation table alongside of cities and farms. Worthington put it this way: “It’s a bit ironic that I spent a good part of my career taking water out of the Colorado, and now I’m trying to see what I can do to put it back.” ✜
Melissa Sevigny is a science writer from Tucson. She writes more about western water politics and river restoration in Mythical River, forthcoming from the University of Iowa Press.