The water situation in Arizona is changing so quickly that planning is impossible
The role of the Central Arizona Groundwater Replenishment District in future growth is much more unclear today than it was a decade ago.
Laura Grignano explains the types of water supplies in the Phoenix metropolitan area
Laura Grignano, manager of the Central Arizona Groundwater Replenishment District, explains the valley’s water resources and the CAGRD’s role in managing them.
Nick Oza, The Republic | azcentral.com
Once a decade, the Central Arizona Groundwater Replenishment District must decide how much water it needs to return to the aquifer to balance the groundwater extracted by its members.
According to state law, this operating plan must also explain how the district intends to obtain the water, where it intends to store it underground and how it intends to finance it all.
There is a lot at stake in getting this baseline amount of water – the so-called “recharge obligation” – right, because the district has a long-term responsibility for refilling this pumping capacity from existing development.
Overestimating may result in more supplies being purchased than necessary – and that isn’t cheap – driving up costs for thousands of homeowners.
But underestimating needs – particularly given the difficulty of finding the renewable water sources needed to supplement this pumping capacity – can easily result in non-compliance with commitments.
And that could mean big problems for communities on the outskirts of the Phoenix metropolitan area, Pinal County and Tucson, which rely on the county to “pay back” much of the water they pump.
Groundwater plan marked with a giant asterisk
After months of work — and several pauses to see how the proposed changes to the Groundwater Act would play out — the district, known to most as CAGRD for short, has submitted a draft plan with a draft number.
If all goes as expected, the district expects to be able to recharge 64,100 acre-feet of water annually by 2044.
That’s 18,900 acre-feet less per year than originally projected for that period. (One acre-foot is roughly enough to supply water to three Arizona homes for a year, though admittedly that’s not an exact figure.)
However, there is a big problem associated with this replenishment requirement.
The district expects four water providers – Buckeye, Queen Creek, EPCOR and Arizona Water Co. in Apache Junction – to take an alternative path to obtain assured water supply certification.
The number already needs to be revised
This proposed designation would allow providers to resume groundwater extraction to fuel their growth, but reduce that allocation over time, essentially buying time to help them transition to renewable sources such as leased river water or reclaimed wastewater.
This would also require these suppliers to meet the water needs of users that they do not currently meet – which would include a significant portion of the CAGRD’s refill obligation.
However, this assumes that the rule-making process for creating the designation proceeds as expected and without major changes.
The state water management agency recently made changes that are expected to increase the CAGRD’s replenishment obligation, but by exactly how much is unclear.
CAGRD expects that the number will be revised soon.
These are big surprises, even for CAGRD
If that sounds like a lot of uncertainty, that’s true.
Even for CAGRD, which has a long tradition of adapting to the unexpected.
The lawmakers who created the district in the 1990s assumed that participation would be limited and that they could simply use excess water from the Colorado River to meet their obligations.
They never imagined that entire communities would become dependent on the CAGRD for their growth (which is indeed the case) or that the surplus water would one day disappear (which it did).
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These unexpected surprises have made the district extremely popular with developers but extremely unpopular with groundwater fanatics.
However, its role for future growth is now far less clear than it was when the last action plan was adopted.
Even bigger changes could come soon
As deeper cuts are expected along the Colorado River after 2026, it will become increasingly difficult to find renewable resources to supplement this pumping capacity.
Arizona’s water security program has also changed significantly.
A decision by the state to no longer allow groundwater-based development growth effectively ended all new CAGRD filings in the Phoenix metropolitan area and Pinal County, but there could be some resumption depending on how the alternative designation process turns out.
Meanwhile, a spate of proposed legislation – including one to support the conversion of farmland to housing in the Phoenix metropolitan area and Pinal County – could further alter the program and its impact on CAGRD.
This uncertainty makes planning difficult, and the district must revise its projections in the second and eighth years when unexpected increases in obligations or reductions in water supplies occur.
And then there is the mandatory review in the fifth year to make sure everything is going as planned.
The more opportunities there are to make quick course corrections, the better.
You can reach Allhands at [email protected]. On X, formerly Twitter: @joannaallhands.
