CAP expecting a Tier 1 shortage of the Colorado River

Arizona water officials are expecting a shortage of the state’s share of Colorado River water to be declared soon. It’s due to continuing drought conditions. We spoke with Ted Cooke, the general manager of the Central Arizona Project, about what the shortage declaration would mean for the state’s water supply.

Although the decision won’t be made until August, according to Cooke, the Colorado River will certainly have its first Tier 1 shortage. The Tier 1 shortage indicates that Lake Mead has dropped to 1075 feet above sea level, which according to Cooke, will affect agriculture.

“A Tier 1 shortage will be a reduction a little over 500,000 acres to Arizona’s supply. Arizona has a total water supply of about 7 million acre-feet per year, about 2.8 million of that is from the Colorado River. Roughly half of Arizona’s supply is diverted by the Central Arizona Project,” Cooke said. “All of that reduction, that Tier 1 reduction of half a million-acre feet will be taken by the Central Arizona Project. Those reductions will pass on to the lowest priority water users first. The largest lowest priority water user in the CAP service area is Central Arizona agricultural users.”

However, a portion of their reduction will be mitigated and restored by ground-water pumping and wet water deliveries.

With the drier conditions Arizona is experiencing, the chances of a Tier 2 shortage are increasing. A Tier 2 shortage can be expected as early as 2023, according to Cooke. The chances of a Tier 3 shortage go up in 2024.

“The responses to these shortage levels that have been identified, Tier 1, Tier 2, and Tier 3, are also defined in advance what will happen if we reach those levels in the lake. Here is what the response will be, here’s how much it’s going to be reduced, here’s who it’s going to impact, so we can plan for that in advance. We know what’s going to happen, it doesn’t make it any less painful for it to happen but at least we have some advanced knowledge of what will occur and who it’s going to impact in advance,” Cooke said.