The Doña Ana Soil and Water Conservation District is hosting a Watershed Conservation Educational Webinar Series through mid-July. John Pearson, who worked at the White Sands Test Facility before retiring, has been on the DASWCD board since February. His recent webinar was about factors influencing groundwater recharge, which he talked about with Scott Brocato.
Scott Brocato:
You recently hosted one of an ongoing series of webinars. The one that you hosted was titled “Factors Influencing Groundwater Recharge”. First of all, explain groundwater, and groundwater recharge versus an aquifer recharge.
John Pearson:
Yes. The groundwater comes out of the aquifer. The aquifer is more or less a storage facility for the water, and so what I wanted to talk about was pretty much spurred by questions I had received over the decades from people in the area on where our water comes from. If it's not coming from the river--and it certainly isn't right now, because the river is not flowing. But we do depend on the river lot for irrigation.
But where does our drinking water come from? And we have two main aquifers in this area, in the Las Cruces area: the Jornada del Muerto Basin and the Mesilla Basin. And then across the mountain, of course, there's the Tularosa Basin, which is overlaid by White Sands. And then we have the Hueco Bolson over in El Paso. (Bolson) comes from the Spanish meaning “a purse”. So it's an area that's bound geologically and where sediments have collected, and there's a sufficient thickness of those sediments to collect water over the years. And so it's a holding area for water.
Scott Brocato:
Your webinar also gave an overview of the regional hydrogeology. What is hydrogeology, and what are some of the unique factors to our region?
John Pearson:
Well, you know, geology is essentially the study of the Earth and looking at the rock types and the history. Hydrogeology is how water interacts with the various layers in the ground with the alluvial layers and rock layers, and it's essentially a study of how fluid flows through porous media.
Scott Brocato:
What were some questions and concerns that people who were part of your recent webinar have?
John Pearson:
Well, they're wondering what the supply of water is, how the water table is dropping. When the river isn't running, the farmers in the valley have to rely on groundwater to irrigate their fields. And so when they pump water out of the ground, the water table will drop. Now, if the river was flowing, there's a very...a much interconnectedness between the surface water and the groundwater. But since it hasn't been flowing or it flows episodically, we've seen a continuous drop in the groundwater table. If you've lived here long enough, you remember Burn Lake. It was very nice to go out there and get chased by the geese if you had bread in your hand. But that was essentially the groundwater table, and it's dropped below that level now. So it's dry.
Scott Brocato:
What are your own concerns about our region’s hydrogeology?
John Pearson:
Well, I'm very much concerned that we're mining the groundwater at a rate that's going to make it expensive to maintain the level of use that we have. Now, by mining, I mean we're taking it out and it's not being replaced at the same rate. So we're essentially drawing upon our bank account and not really putting back into it,, and so it's depleting. And when the easy water is gone—the fresh water that's shallow and easy to pump out—when it's gone, we're going to have to turn to other methods, such as desalination, which is very expensive; or bringing water in from other places. And so that's a very large concern. And the way to address this, one way is through conservation. And then—I'm very ignorant when it comes to farming and crop types and everything—but we might need to look at what the crops are using ,and maybe adjust some crop types to use less water. And I'm just speculating on that.
Scott Brocato:
Where can folks reach out to to find more information about these topics?
John Pearson:
When I was working out at the NASA site, people would ask me questions. They’d say, “I've got a well on my property and the water levels dropped below this level. Is it going to come back?” Or “the neighbor put in a well, and now my well is dry.” And I explain as best I could, given that information, what's going on. And they are always thankful to learn more about what's going on below them and the water they depend on.
