ALBUQUERQUE, N.M. (AP) — For the first time its four-decade history, the San Juan-Chama Project has fallen short on the amount of water it has delivered from the mountains of southwest Colorado to central New Mexico.
Water managers say the effect on Rio Grande Valley water operations was small, but the implications are significant. They say it demonstrates that a supply once seen as dependable backup to a faltering Rio Grande might not be as reliable as once thought.
"It's one of those things that was always a theoretical possibility, but nobody thought it would come to pass," David Gensler, water manager for the Middle Rio Grande Conservancy District, told the Albuquerque Journal (http://bit.ly/1HW03Qu).
This year's shortage amounted to 10,000 acre-feet. One acre-foot is about enough to serve two average households for a year.
The first-ever shortfall comes after three consecutive years of bad snowpack. Federal officials had warned last year that shortages might be possible and that climate change would mean less reliable supplies from the project as temperatures throughout the region warm.
The San Juan-Chama Project, completed during the early 1970s, was designed to allow New Mexico to use more of its share of water from the Colorado River. Under a 1922 compact, the river is shared by Colorado, California, New Mexico, Wyoming, Utah, Arizona and Nevada.
The water funneled into New Mexico depends on winter snow that falls in the San Juan Mountains of southern Colorado. A series of small diversion dams capture the water, and it's diverted under the Continental Divide through tunnels and into a tributary of the Rio Chama and eventually the Rio Grande.
Albuquerque, the biggest user of San Juan-Chama water, had plenty of extra water in storage to make up for the shortfall. The primary effect is on the Albuquerque Bernalillo County Water Utility Authority's ability to share with other users, said John Stomp, the utility's chief operating officer.
With significant water conservation reducing demand in the metro area, Albuquerque's stockpile of water in upstream reservoirs has become the go-to source for others in need. That's especially true for the U.S. Bureau of Reclamation, which has been buying some of the surplus water to support the endangered Rio Grande silvery minnow.
For the Middle Rio Grande Conservancy District, the shortfall is a reminder that carry-over storage for farmers in the valley is exhausted.
"We've drained all of our savings," Gensler said.
With most of its farm water coming from the Rio Grande rather than the San Juan-Chama Project, the effect this year was minimal, about 1 percent of overall supply, Gensler said. But during dry years, San Juan-Chama water can provide a critical surge of late-season water for farmers.
The Bureau of Reclamation study that highlighted the risks to the San Juan-Chama Project posed by climate change concluded that by the 2020s, the project could see a shortfall on average once every six years.
Information from: Albuquerque Journal, http://www.abqjournal.com