According to tucson.com, the state agency that operates the multibillion-dollar Central Arizona Project warns that water shortages could hit Tucson and Phoenix as soon as five years from now.
Chances are expected to rise in the next few years due to drought, growing water demand and declining water levels in Lake Mead at the Nevada border.
Over a 10-year period ending in 2026, the likelihood of urban CAP shortages is 17 to 29 percent in a given year depending on weather, particularly the impacts of climate change, CAP says.
Such shortages would occur if Lake Mead, now about 1,085 feet elevation, drops below 1,000 feet. Then the lake becomes what CAP calls a “dead pool” in which operations are sharply curtailed.
If that happens, the consequences could be dire, including:
- Diversions from the Colorado River into the CAP’s 336-mile-long concrete canal for urban and Indian users would likely — if not almost certainly — be cut and could be eliminated, although CAP officials say that’s unlikely. Agricultural users by then would most likely have their CAP supplies reduced sharply.
- Hoover Dam’s electric power, which is generated by the lake and serves cities and farms in three states, would be cut by nearly half or possibly much more. Arizona urban and farming users buy nearly 19 percent of the dam’s power at subsidized rates. Southern California users buy more than 50 percent. Nevada users buy the rest.
- Las Vegas, which gets more than 90 percent of its water from the Colorado, would be unable to withdraw any. A new pump station would be needed to bring the water up, at a cost of $250 million to $300 million.
- The U.S. Interior Secretary could intervene in advance to hold down states’ water diversions. CAP could receive 950,000 acre-feet just to meet Arizona’s core municipal needs and fulfill the feds’ obligations to Indian tribes. Nevada would get enough to meet health and safety needs. Farms’ water would be reduced drastically, and Mexico would get less water than it’s already agreed to take in times of shortage, leading to increased international tension.
- In that case, the Interior Secretary’s discretion would replace the historic “Law of the River,” a series of laws, court rulings and regulations that have governed the Colorado’s operations for a century.
That could trigger controversy and potential litigation. CAP officials say states and the federal government need to take action soon to prevent that from happening.
The New York Times States “Arizona could be forced to cut water deliveries to its two largest cities unless states that tap the dwindling Colorado River find ways to reduce water consumption and deal with a crippling drought…”
The federal Bureau of Reclamation forecasts that Lake Mead, a Colorado River reservoir that is the network’s sole water source, will fall to a level not seen since the lake was first filled in 1938.
If Phoenix and Tucson do not reduce consumption, “the cuts could be necessary by as early as 2019, according to an analysis by the water project, and officials said that depending on drought conditions, the chances of water cutbacks by 2026 could be as high as 29 percent,” states the New York Times.
In related news, tucson.com states that the worst drought in 1000 years is coming to the Southwestern U.S. after 2050, according to a new study written by scientists at Columbia and Cornell universities and released Thursday.