Is the basin the wrong scale to look at Colorado River (or Rio Grande) system groundwater losses?

I think the answer to my rhetorical question in this post’s headline is obviously “no”. I think this is enormously useful data. But I’m still puzzling over who beyond clickbaiting bloggers like myself might use it, and how.

In his coverage of the GRACE Colorado Basin groundwater depeletion, Brett Walton at Circle of Blue included an interesting comment from Arizona’s Chuck Collum:

Chuck Cullom, Colorado River manager at the Central Arizona Project, which delivers more than half of Arizona’s Colorado River allocation, said the study was helpful.

“The study is useful in using GRACE to verify at a coarse scale what water managers in the Basin know,” Cullom told Circle of Blue.

I’ve been thinking about that because the new GRACE study triggered (yet again) a discussion among some of the local water nerds about the need for such a study on the Rio Grande, something I’ve told Jay Famiglietti and Stephanie Castle that I’d be really appreciative if they’d do. In the past, I’ve used some of their data in my newspaper work, but only in a very general way:

Groundwater across the entire state, especially on New Mexico’s east side, is dwindling, according to research by the University of California’s Jay Famiglietti, who uses satellites to measure changes in the aquifer, the fresh water underground that is pumped up for use on farms and in cities.

“The trend is pretty significant,” Famiglietti said.

I’d really love to have more detail, a Rio Grande Basin study like the one just completed on the Colorado, but Cullom’s comment got me thinking about who might actually use data at the basin scale. If management of groundwater is done at a state and local scale, and if Cullom is right that water managers at that scale already know what’s going on with their own groundwater, then what is a basin-wide number telling us that might be used in policy implementation that is different than the data local-level water managers already have?

One Comment

  1. Cullom, being in Arizona, may have robust information on groundwater extraction. However, California managers do not live in a world where groundwater use is monitored, let alone regulated. The drought and the resulting spike in pumping has gotten the California legislature to look closely at regulatory changes–but have we become addicted to a rate of pumping that is always in overdraft? GRACE data have been useful in highlighting the problem–and the data cannot be fudged nor can a water agency refuse to participate in its collection.

Comments are closed.