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Report Warns Of Arizona’s Diminishing Groundwater Supplies

A recent report from Arizona State University warns the state is mining groundwater faster than it can be replaced. The report focuses on five areas around the state including Prescott and Phoenix that fall under the rules of the 1980 Groundwater Management Act. KNAU’s Melissa Sevigny spoke with water expert Sarah Porter about the report’s conclusions. 

Describe to me the 1980 Groundwater Management Act, what was it meant to do?

At the time… people began to realize that groundwater was being over drafted, and that Arizona was growing on groundwater…. and the intent of the Groundwater Management Act was to slow the overdraft of groundwater, and in the places, in the Active Management Areas that have a safe yield goal, clearly the intent was to turn around the overdraft. Safe yield means to basically strike a balance over the long term between the amount of water that is withdrawn and the amount that is replenished. It can be replenished by nature through rain or it can be replenished by human recharge.

So safe yield, it’s like a bank account, the idea is you’re not taking out more than you put in.

Yeah…. In my family when my husband and I want to tap into long term savings, we have a chat, and that’s the kind of importance that Arizona was placing on groundwater. That was the long-term savings, for those times of great need.

It’s forty years later, how are we doing with getting to safe yield?

There are still some issues that getting in the way of getting to safe yield. I guess the reality is that, the Groundwater Management Act was quite innovative and momentous and it took a huge spirit of compromise to make it happen… and among those included permitting current pumpers at the time the Groundwater Management Act was passed to continue to pump. And so a big conclusion of our report is that we have residual pumping that is going to keep us from getting into safe yield and staying into safe yield. The kinds of programs that would over time eliminate residual pumping or reduce it haven’t really been supported or invested in. That’s a very big limitation.

What’s the work that needs to be done in the future, how do we get to this vision of sustainable water use?

We have specific recommendations in our report about different possibilities… I think the bigger thing is the commitment to the idea that we grow on renewable water supplies and not on finite water supplies. That’s really step number one.

Is that possible?

I think so…. You know, today, the amount of water a house uses in Phoenix is probably, I’m betting its below what anyone would have envisioned in 1980. We are able to do so much more with so less water, all of the cities in the Active Management Areas are. How did we get there? We got there with a lot of rigor around growing on renewable supplies and reducing dependence on groundwater, and generally moving toward more efficient use of water… Again, it goes back to this philosophical position. I have adult children and I urge them to think about how they can create long term savings, that’s what a good parent would do and what a prudent water manager would do, is create long term savings of water for the future. If we don’t, we’re just more vulnerable.

Sarah Porter, thank you so much for speaking with me.

Thanks so much.

Melissa joined KNAU's team in 2015 to report on science, health, and the environment. Her work has appeared nationally on NPR and been featured on Science Friday. She grew up in Tucson, Arizona, where she fell in love with the ecology and geology of the Sonoran desert.
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