Central Arizona cities may soon have a new water source: Farmland west of Phoenix

Developers create master plans for communities because it helps growth occur in an orderly fashion.

But can we do the same to draw down an aquifer, minimizing problems like subsidence and fissures while pumping the most groundwater for those who buy it?

We’re about to find out.

Landowners want state's OK to pump

Harquahala Valley Landowners LLC, which represents farmers and investors who own land in the area, has applied with Queen Creek and the state Land Department to pump up to 7.6 million acre-feet over 100 years from the Harquahala Irrigation Non-expansion Area west of Phoenix.

That’s nearly enough to submerge the state of Maryland under a foot of water.

If the state water department director approves their request, that 7.6 million acre-feet would be pumped over time from more than 28,000 acres, an area larger than the city of Tempe.

Queen Creek also would gain access to 500,000 acre-feet of that water over 100 years – after which it would need separate approvals to transport that water through the nearby Central Arizona Project canal, across metro Phoenix and, eventually, to the town’s homes and businesses.

If this sounds complicated, it is.

But the outcome also is wildly consequential.

Because it could open the floodgates to a water source that many once considered too costly or difficult to tap.

Only certain basins can transfer water

Rural areas worried in the 1990s that thirsty cities would one day make a play for the water in their aquifers.

So, lawmakers passed something of a compromise, outlawing groundwater transfers from all but a handful of basins.

The rules governing who can pump this water, and how much, depend on the basin.

In the Harquahala, landowners can either pump water to transfer out of the basin at a certain rate per year or appeal to the director to pump more, if they can prove it won’t “unreasonably increase damage” to others nearby.

Which would largely be farmers, who have known for years that cities would eventually come calling for their land.

Those participating in the project have agreed to retire the land and its current water use for agriculture once others begin to pump.

But there’s a catch.

They want to 'master plan' depletion

This water can only be transferred to political subdivisions in the initial Active Management Areas – which, practically speaking, means cities in metro Phoenix, Pinal County and Tucson.

And those cities must own Harquahala land to be able to pump.

For years, folks figured cities would have to buy out thousands of acres of farmland to be able to pump enough water to make this worth their while.

But that’s where the Harquahala Valley Landowners’ proposal gets creative.

The landowners are pooling their land into one master-planned depletion project.

Goal is to maximize water, minimize ill effects

Cities would only have to buy 1 acre in a 40-acre subdivision, but they would have access to water pumped from a slew of connected wells on properties they don’t directly own.

Those wells would be drilled in phases, and on land that is best primed to produce the most water.

That matters, because placement matters. Moving a well 40 acres left or right can make a huge difference in water quantity and – as importantly – water quality.

Instead of doing this piecemeal, wells can be placed in the best spots to ensure the best water – without withdrawing too much too quickly.

Arizona's water crisis: What that means for some cities

That way, cities get the water they want without the burden of maintaining a ton of land, at a pace that should not exacerbate the giant cracks and sunken land that typically come with groundwater depletion.

Or, at least, that’s the argument before the state water director.

Additional hurdles, even if the state says yes

There are additional hurdles to overcome, even if he says yes.

Any water that moves through the nearby Central Arizona Project canal must meet certain water quality standards. Defining those has been a multiyear process.

That also means the water cities pump will likely require treatment before it enters the canals. It’s unclear what that will entail, or how much it will cost.

Queen Creek was the first to bite on the concept, in 2021, paying $30 million for its acre – and the 5,000 acre-feet of water it could transport annually, for 100 years.

Buckeye recently agreed to pay $80 million for a similar amount of water, though it hasn’t yet applied to the state for the OK to use it.

Cities need water. Watch how this plays out

But there are a ton of other cities with big question marks on their renewable supplies – particularly Central Arizona Project water.

If the state agrees with Harquahala Valley Landowners, a sizable chunk of water could soon be on the table for future transport (though it’s expected that subsequent cities would have to apply to the state water director for access to it, proving how much water is left and how their pumping would not negatively impact others).

It would be our first foray into a brave new world of transporting water from one aquifer for cities to use in another.

And one that would take a novel approach to pumping – not completely draining the basin, but essentially “master planning” the removal of its cheapest, best water to lessen the ill effects of doing so.

Keep an eye on how this plays out.

Reach Allhands at joanna.allhands@arizonarepublic.com. On Twitter: @joannaallhands.

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This article originally appeared on Arizona Republic: Arizona cities may soon have a new water source: Harquahala farmland