First came the tremor in Pinal County.
In 2019, state water officials found that, looking out over 100 years, there will be a shortfall of available groundwater for new developments dependent on it.
Then came the earthquake in the Phoenix area. On June 1, the Arizona Department of Water Resources announced, similarly, that their model shows large unmet demand for water in the Phoenix area, forcing limits on groundwater-based development in outlying areas.
Tucson could be the aftershock. In the next year or two, the state is expected to complete a similar model of groundwater in the Tucson Active Management Area. Will the model show we’ll also have unmet demand for water over the next century?
As it turns out, probably not.
Signs are that Tucson will find itself in a different position than Pinal County or the Phoenix Active Management Area, because of differences in our local history, culture and economy.
While that may provoke a sigh of relief, it’s not really good news. As the earthquake in Phoenix shakes out, we can see we may need the leverage of a projected shortfall to achieve the conservation we really need in the long run.
Now, the Tucson area has been a leader in conservation. That’s one of the reasons a variety of experts told me that the active management area here is unlikely to be found in shortfall.
“Tucson has always been a different sort of community — a desert city that understood conservation and living within our means and embracing the desert city concept,” said Val Little, founder of the Water Conservation Alliance of Southern Arizona.
That ethic goes back at least to the 1970s, when Tucson Water first started charging block rates — higher prices for greater levels of consumption. That’s also when Pete the Beak, the Tucson Water mascot, appeared and encouraged people to conserve water, with success.
We were early and enthusiastic adopters of xeriscape, water harvesting, and low-flow appliances. Even as population rose in Tucson, water use declined.
Water outlook likely sufficient
Beyond conservation, another reason we’ll likely be found to have sufficient water is that for more than two decades we’ve been banking Colorado River water funneled here by the Central Arizona Project.
“The relative demand compared to relative supply puts us in a better place,” said Kathy Jacobs, director of the Center for Climate Adaptation Science and Solutions at the University of Arizona. “It isn’t just happenstance. It’s because we have a very large CAP allocation.”
Then there’s the fact we have little agricultural land compared to the Phoenix area and especially compared to Pinal County.
Overall, the outlook for the Tucson area leaves David Godlewski, president of the Southern Arizona Home Builders Association, pretty confident.
“We shouldn’t be in the same position (as Phoenix) because we have taken better care of our water resources,” he said. “We are optimistic that as a region we’re in a much better position that we’ll be able to grow and conserve water at the same time.”
They are all probably right about the outcome of the Arizona Department of Water Resources study. Tucson is the only active management area of the five in Arizona that has actually achieved safe yield in recent years — a balance between water inflows and outflows.
But if we’re not careful, that success could ultimately harm conservation efforts in the long run.
Demand and supply big factors
Consider the reaction of Godlewski’s colleagues in the Phoenix area, the Home Builders Association of Central Arizona, to the shortfall announcement there, plus a couple of other key factors.
As my colleague Tony Davis reported, the vice president of that association, Spencer Kamps, pushed back hard against the model’s finding at the first meeting of the governor’s Assured Water Supply Committee on June 27.
“When you are in the process of selling homes to customers, and then this home will be shut down, the impacts will be substantial,” Kamps complained. “People will lose money. And the demand for housing is not going away.”
In fact, the director of the Arizona Department of Water Resources, Tom Buschatzke, was already showing that his department’s findings might not be so firm as previously thought.
He announced two alternative ways far-flung developments that should be shut down under his department’s finding might actually be able to get the water certificates they need. Buschatzke also expressed openness to tinkering with the model that made the massive shortfall finding.
In other words, the water model’s findings, which seemed inflexible when announced, actually became flexible when powerful economic forces applied pressure.
And that’s dangerous, because the model doesn’t even take into account one key factor: Likely cuts to the supply of Colorado River water.
In other words, Tucson’s active management area could be found to have a sufficient supply for groundwater-dependent housing developments. But then the CAP supply that helps justify that finding could be slashed by as much as half as the warming climate dries up the river.
In addition, rules allowing water to be pumped in one area and recharged in another area mean that deep holes in the water table can develop even under permitted conditions. Fissures and land subsidence can result.
Leverage for conservation
A 2022 report by the Bureau of Reclamation, University of Arizona and other institutions found that the Tucson area has four high-risk areas due to population growth and groundwater decline:
The area north of Oro Valley from Catalina to Saddlebrooke
A portion of the Tanque Verde valley not far from Sabino Canyon
The far southeast side of Tucson
The Green Valley area
A benefit of a shortfall finding would be that it would incentivize further infill development. That saves outlying land from sprawl and is more environmentally beneficial in terms of water and energy use, among other factors.
Kathleen Ferris, an author of the state’s 1980 groundwater law and member of the assured water-supply committee, said there’s a risk of postponing the inevitable.
“The more growth on groundwater that occurs, the more likely the model will eventually show unmet demand,” she said.
Even if the state finds a sufficient 100-year supply, she said, “that doesn’t mean the pumping and use of that groundwater is sustainable.”
It isn’t, clearly, especially in a warming climate with population growth and a declining Colorado River.
We need tools to deal with this reality. And, it turns out, a model that shows we don’t have a sufficient groundwater supply for 100 years of growth is just that — not a dictate but a tool. The Phoenix experience shows that.
A model finding a shortfall for the Tucson area could offer the needed leverage to force the conservation measures we’ll eventually need.
Wide array of proposals submitted to alter Arizona groundwater rules
