In the ongoing effort to have Arizona communities use less water — specifically, less Colorado River water — people in charge of managing the state’s water supply have a new objective.
In a speech given last Thursday to a law school conference in Colorado, Tanya Trujillo, the U.S. Interior Department’s assistant secretary for water and science, said her agency is seeking emergency cuts to reduce the risks of Lake Mead and Lake Powell, the country’s two largest reservoirs, declining to dangerously low levels next year.
Doug MacEachern, communications director for the Arizona Department of Water Resources, said it’s an ultimatum put to the Colorado River Basin states.
“Basically, states have until August to come up with a plan to cut between 2 million and 4 million acre-feet of water used per year, or the federal government will determine how much water each state gets cut,” MacEachern said.
Arizona, California and Nevada are considered lower basin states, drawing water from the Colorado River from Lake Mead and Lake Havasu. Utah, Colorado, New Mexico and Wyoming make up the upper basin states.
MacEachern said under a variety of current plans and strategies, Arizona is on a path to reduce its use of Colorado River water by more than 800,000 acre-feet in 2022.
MacEachern says his boss, ADWR Director Tom Buschatzke, will speak and negotiate with the other six Colorado River states on behalf of Gov. Doug Ducey.
“These states have a long history of working together,” MacEachern said. “The river states will decide how to divvy up these extraordinary cuts.”
ADWR works with out-of-state and federal water agencies in determining how much water flows into the driest parts of Arizona, through “wholesalers” and on to local providers such as EPCOR.
“The biggest job ADWR will have, in these next two months, will be to find out what level of cuts we can live with,” MacEachern said.
The immediate problem with Colorado River water supplies, MacEachern explained, is that lakes Mead and Powell are at such low levels, both are close to not providing enough water to have some flow through Hoover Dam. If either of those two northern Arizona lakes become “dead pools,” where the river would end, they would provide no water to Arizona and California communities that take water from the river south of Hoover Dam.
Previous efforts to mitigate drought, global warming and population expansion haven’t worked, MacEachern said. ADWR’s main focus during the next two months will be inventorying and determining how much of a cutback the state can endure, even with cuts that affect businesses and residences.
Municipalities have begun planning to receive less Colorado River water. Earlier this month, the city of Surprise discussed a plan that anticipates ADWR will declare a Tier 2a shortage on the Colorado River in August, to take effect in 2023.
ADWR is already calling for a Tier 1 designation on the Colorado River this year, meaning Arizona will receive less water from the lakes fed by the river.
Since the beginning of 2022, Arizona has been in a “Tier 1” shortage condition that required the state to leave 512,000 acre-feet of its annual 2.8 million acre-foot allocation in Lake Mead.
Should surface levels at Lake Mead descend to below 1,060 feet by the beginning of 2023, the amount Arizona might have to leave in the reservoir may increase to 592,000 acre feet.
A Tier 3 shortage, according to Surprise officials, would lead to the city experiencing a cut of about 400 acre-feet of water from the Central Arizona Project, which is supplier of Colorado River water through the central part of the state.
The Buckeye City Council also recently approved an updated drought management plan. The detailed plan recognizes the levels, the authority of ADWR to change levels and advisories at any time, and authorizes the city manager to put restrictions in place as levels change.
MacEachern said Arizona’s system of priority means different parts of Pima and Maricopa counties will be affected in different ways by the cuts. One thing is clear, however: small and large water authorities all need to be thinking about places to get water that aren’t tied to the Colorado River.
“There’s been talk, in the Legislature, about establishing an authority that’s only charged with finding new sources of water,” he said.
MacEachern said, upon hearing a couple of ideas or frequently mentioned concepts, that it won’t be easy to come up with practical, affordable solutions.
“For example, when someone suggests, ‘drill deeper into the ground,’ we’ve done that already,” he said. “We’re predisposed to not using up all our groundwater and not drilling lower than 1,100 feet underground. That’s not what we want. So some solutions are going to have to be really creative.”
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