Arizona's water system faces a 47% cut after designers' warnings were ignored

The Colorado River supports nearly 40 million people, yet withdrawals now exceed the water it can provide. This fall, a new federal plan to cut back water use triggered legal action from Nevada, Arizona, and the Central Arizona Project, or CAP, the massive canal system that delivers river water to the Phoenix area.

The CAP is a 336-mile network of canals, pipelines, and pumping plants that transports water across the desert. Rich Weissinger, who spent nearly 30 years working for the organization that operates the canal, described the system as an engineering marvel. He noted that the facility's moving parts are held in massive casings of riveted metal. "We have lots of people, lots of industry, lots of municipalities that depend on a stable water source," Weissinger said.

Policymakers have failed to agree on a regionwide compromise to rein in demand. As a result, the nation's two-largest reservoirs have shrunk to record lows. The new federal plans could reduce the amount of water allocated to the CAP by 47%.

The designers of the CAP warned in the 1960s that the system would not work forever without extra help. Floyd Dominy, then commissioner of the Bureau of Reclamation, forecasted that available supplies would be more than halved between 1990 and 2030. He attributed these declines to growing use in upstream states such as Colorado, New Mexico, Utah, and Wyoming. Congressmen Mo Udall and Stewart Udall also testified that the project required augmentation, or the addition of outside water supplies.

The 1960s proposals included connecting the Colorado River system to the Columbia River in the Pacific Northwest or building massive desalination facilities on the Pacific Coast. Senators from the Pacific Northwest added language to the legislation authorizing the CAP to protect the Columbia River from such transfers. Despite these plans, no major infusion of desalinated water or a pipeline to the Pacific Northwest was ever built.

Tom McCann, a former deputy general manager for the CAP, said there was no willingness to spend money on a future problem that had not yet arrived. "The warning that had been issued before, if you want to think of it that way, was largely forgotten," McCann said. He explained that cost and political hurdles prevented the implementation of the proposed solutions.

Brad Udall, a senior water and climate research scientist at Colorado State University and the son of Mo Udall, said his father and uncle deserved some forgiveness. He argued that the optimism of the mid-1960s, following World War II victory and the construction of the interstate highway system, colored their thinking. "The 1968 idea was we could build our way out of anything," Brad Udall said. He added that proponents wanted to finish the massive project and hoped to solve the remaining issues later.

Chuck Podolak, former director of the Water Infrastructure Finance Authority of Arizona, suggested that promising augmentation allowed policymakers to avoid difficult political choices. Farms and ranches account for roughly three quarters of all Colorado River water use. Podolak said that buying water from farms would be more affordable than building huge new infrastructure, but augmentation helped avoid the reality that Phoenix growth would come at the expense of agriculture.