Cities, growers to get similar San Juan River quota this year
Water managers are hoping for wet monsoon to make up difference
Facing another summer of diminished river flows, New Mexico farmers along the Rio Grande feel besieged by the relentless drought and will get only modest relief from this year’s supply of water diverted from the San Juan River basin.
Cities and growers will receive an estimated 60 percent of their full allocations from the San Juan this summer, about the same as last year and not enough to offset the depleted Rio Grande if the monsoon is weak.
The U.S. Bureau of Reclamation dispenses San Juan water that naturally would flow into the Colorado River but is instead diverted to the Rio Grande via the Rio Chama through a complex system of dams and tunnels called the San Juan-Chama Project.
The dip in the San Juan-Chama supply reflects a larger problem: A La Niña weather pattern, which causes drier conditions in the Southwest, is combining with climate change to reduce river flows.
Water managers find themselves in the familiar position of hoping for rain — and plenty of it.
“We are at the mercy of nature,” said Rolf Schmidt-Petersen, director of the New Mexico Interstate Stream Commission. “I think we’re going to experience shortages with our northern acequias sooner rather than later, and then that will translate all the way down through our system if we don’t get rain relatively quickly.”
Forecasts show no precipitation on the horizon, which means the Rio Chama is likely to dip below 60 percent of its historically normal levels by summer, Schmidt-Petersen said.
Lack of water storage adds to the challenges. Most reservoirs are severely depleted, and El Vado Lake, a storage site on the Rio Chama that’s key to creating a backup supply, is unavailable this summer while its dam undergoes renovations.
Federal officials will divide the allocations into
monthly installments through the summer rather delivering them all at once.
Theoretically, flows could continue into the fall if there is adequate runoff, but more likely they’ll end well before that, given the area’s current hydrology, said Carolyn Donnelly, water operations supervisor for the Bureau of Reclamation.
“July or August is most likely going to be the last one,” Donnelly said of the releases.
About 14,000 acre-feet of water, or 4.6 billion gallons, will go to the Middle Rio Grande Conservancy District for irrigation.
Santa Fe will receive
3,400 acre-feet, or 1.1 billion gallons.
Albuquerque, the biggest user, will get 31,000 acre-feet, or about 10.1 billion gallons.
Both cities have groundwater systems to augment river water when necessary. Water officials have said the multiple sources will enable the cities to avoid serious shortages amid the changing climate in the coming decade.
Jesse Roach, the city of Santa Fe’s Water Division director, said the city has a year’s worth of stored water it can tap, and the federal allocation will be a helpful supplement.
But, he said, the city will head into the fall with some of its reserve depleted, driving home the need for improving overall supply through a return-flow system.
“If there’s going to be less San Juan-Chama water available, we need to use it more efficiently or, as would say, consume it more fully,” Roach said.
For farmers, who rely mostly on the Rio Grande for their livelihoods, the increasingly arid climate, with warming temperatures and higher evaporation, is troublesome.
By putting back some of the San Juan-Chama water pulled from the Rio Grande — even as treated e±uent — the local government would receive returnflow credits allowing it to divert more of the water, he said.
He was speaking of plans for a 17-mile pipeline stretching from the wastewater treatment plant southwest of the city to the Buckman Direct Diversion on the Rio Grande, which lies at the end of Old Buckman Road a few miles northwest of the Diablo Canyon Trailhead.
The estimated $20 million project also would enable the city to build a backup water supply that would be vital in the coming years as a changing climate is predicted to strain supplies throughout the region.
“Without the return-flow project or without doing anything, we think we would start to see shortages in the next 10 to 20 [or] 30 years,” Roach said.
For farmers, who rely mostly on the Rio Grande for their livelihoods, the increasingly arid climate, with warming temperatures and higher evaporation, is troublesome.
They mainly irrigate with water that flows naturally into the Rio Grande, known as native water.
The San-Juan Chama water is a finite supplement to help get them into July, when the monsoon typically starts, said Jason Casuga, CEO and chief engineer of the Middle Rio Grande Conservancy District.
Still, he would have liked to have seen a larger amount of San-Juan Chama water coming this summer, as the spring runoff looks slimmer.
“If native drops so low and we