KUNM

Rio Grande Hydrologists Worried After July Heat

Aug 3, 2016

During the irrigation season in New Mexico, the Rio Grande is allowed to go completely dry in some stretches. Even Saturday’s intense thunderstorm in Albuquerque hasn’t sustained flows in some regions of the river south of the city.

Independent journalist Laura Paskus reports on climate change for New Mexico In DepthAt The Precipice: New Mexico’s Changing Climate.

Paskus says July’s hot weather has hydrologists worried they’ll run out of irrigation water for some users before Labor Day. She spoke with KUNM’s Elaine Baumgartel. 

KUNM: What a storm we had Saturday night here in Albuquerque—thunder, lightning, flooding—it was a big deal. How did that storm impact the Rio Grande?

Paskus: The Rio Grande starting in mid-July had started going dry in stretches south of Albuquerque down towards San Antonio and the Bosque del Apache National Wildlife Refuge. And there were about 17 or so miles dry and that storm helped push some water downstream. We saw a big bump in the gages close to Albuquerque. But as you go further south the water dissipates. The ground is absorbing water. The plants are absorbing water. So we still have about 10 miles dry near San Antonio.

KUNM: We’ve had so many recent years of drought and pretty severe drought—a one time event like this doesn’t make up for it but how much impact does this rain have on levels in reservoirs for example?

Paskus: On the Rio Grande reservoir system it doesn’t have a huge impact. Over in the eastern part of the state, in the Pecos, those big storms can have a good impact on those reservoirs. But on the Rio Grande, those reservoirs really need some big snows over a few years and some good strong snowmelt at the right time of year to fill those back up.

KUNM: What does this dryness on the Rio Grande mean for water users downstream of Albuquerque?

Paskus: The Middle Rio Grande Conservancy District, which supplies water to farmers, they are doing full deliveries, as I understand it, to farmers so far this year. I think they are a little bit worried about how they’re going to get through the whole season, but their hydrologist is a self-proclaimed optimist and he thinks they’re going to get through the season just fine. But it does mean that people need to be paying attention to how much water they’re using and thinking about that. I know for me, just trying to grow sunflowers and amaranth in my yard, I was really happy to see that rain because I wasn’t out there with a watering bucket.

KUNM: What does the dryness on the Rio Grande tell us about the impacts of climate change on water resources in New Mexico?

Paskus: As the region continues warming, we’re going to see increased evaporation off the reservoirs. We’re going to see potentially less snowpack and earlier spring runoff of that snowpack, more sublimation, which is the water ends up in the air instead of in the soils and the streams. So we are going to see, likely, constrained surface water supplies.

KUNM: It’s not just farmers and cities who are depending on the water in the Rio Grande, there’s also a range of endangered species that live in this middle Rio Grande stretch, the Rio Grande silvery minnow, various species of endangered birds. How are these species affected and what are we seeing there?

Paskus: The drying does affect the slivery minnow. Every spring, when and if the river dries, biologists go out there and scoop the endangered minnows out of puddles and bring them to a flowing stretch of the river. But this year what they’ve seen is really high numbers of the silvery minnow, they’re finding in the puddles which means, hopefully they were elsewhere is well. And that is a result of these big spring flows that we had this year and so the minnows were able to spawn, their numbers were a lot higher than they have been in the past. So, hopefully the population will be able to survive the drying a little bit better.