More water in the Rio Grande could be a hazard for southern swimmers and a boon for farmers

River visitors south of Elephant Butte have cause for caution next week, while farmers near Albuquerque may have a reason to celebrate. The reason is more water in the Rio Grande.

But the short-term influx comes as reservoir levels across the state are below historic averages.

Elephant Butte Dam is expected to drop 3 feet next week after the Bureau of Reclamation releases approximately 10,000 acre-feet, so water levels south of Elephant Butte will be much higher.

Visitors in the area between Elephant Butte Dam and Caballo Reservoir should use extreme caution, as river flows may change quickly, the Bureau of Reclamation has warned.

Reservoir levels across the state are already lower than historic averages because of a dry winter.

Southern Colorado had a below-average snowpack and the Sangre de Cristos had poor snowfall, according to Andrew Mangham, senior service hydrologist for Albuquerque’s National Weather Service office.

“A big driver for these reservoirs is the winter snowpack, and the fact of the matter is that our winters are trending drier,” Mangham said.

But rainfall is bringing some short-term moisture to New Mexico. Albuquerque residents finally saw water flowing through the Rio Grande this week after more than a month of drying, and a wet weekend could bring flooding to communities along the Pecos River.

Elephant Butte

The Bureau of Reclamation was limiting releases from Elephant Butte Dam during July, because of debris buildup in Caballo Reservoir. The releases next week, beginning Wednesday, will bring Caballo back up to normal levels.

“Because we haven’t released water from Elephant Butte since late July, it is important that members of the public accessing these areas are aware that water will be flowing again next week,” Elephant Butte Field Division Manager Benjamin Kalminson said in a statement. “Once releases begin, the rate of water flow can change rapidly. Please remain cautious and safe when in the area and do not attempt to cross the channel, even if it looks dry, during this time.”

The flows will be swift, with the potential to overcome even the strongest swimmers, he said.

Heavy rainstorms in July brought debris into Caballo from burn scars in the mountains to the west of the reservoir, Kalminson said. Debris built up in Caballo was affecting the reservoir’s intake and the agency limited water releases so workers could clear out the debris.

They removed 17 tons of debris from Caballo Reservoir in July, and another 14,000 cubic feet were removed in August with heavy machinery.

The Elephant Butte releases will last five to six days. Reclamation plans to remove a temporary dam at Rotary Park, then rebuild it after the water releases are done. This is the last big water release from Elephant Butte planned until next year’s irrigation season.

Even with limited releases, Elephant Butte is already sitting at 3.8% full, which means the water level is around 4,291 feet. That’s lower than the average elevation for August over the decades, which was 4,347 feet.

The vast majority of New Mexico reservoirs are running low, Mangham said. The reservoirs tend to be a little lower than average water levels from the last 25 to 30 years, but significantly lower than averages for the three preceding decades.

“Once the sort of mega-drought started setting in, we saw most of the reservoirs drop quite significantly and never really recover,” Mangham said.

Rio Grande drying

The Rio Grande is wet again in the Albuquerque area, ending one of the longest dry periods it’s had in decades, according to Anne Marken, water operations manager for the Middle Rio Grande Conservancy District. Areas of the Albuquerque reach have been dry over 43 days, with a maximum of close to 12 miles drying.

“I think people downstream of us are really accustomed to seeing river channel drying, and it’s new to Albuquerque,” Marken said. “But I think it’s something that could potentially happen more frequently, until we get to a place where the (Middle Rio Grande Conservancy District) can store water again.”

The Rio Grande dries regularly in areas south of Albuquerque, and historically the river dried routinely in the 1950s in the Albuquerque area. But it hadn’t dried for 40 years in the Albuquerque metro until 2022 when it dried for five days along 10 miles, she said.

The water in the river in the Albuquerque metro came from rainfall, Marken said. Some of that monsoon rain was upstream of Cochiti Dam and is moving through the reservoir headed toward Albuquerque. Without more rain, the river will likely be dry again in Albuquerque sometime next week.

The drying is in part because of a poor snowpack in Colorado and New Mexico, meaning there’s less water in the river system.

“The hydrology this year has been very, very poor,” Marken said. “The snowpack conditions were like bottom 10% of what we’ve seen. It’s not the lowest we’ve seen, but it’s very near the bottom of what we’ve seen.”

A lackluster monsoon season in the Middle Rio Grande Valley has also contributed, according to Marken. But some of the drying is connected to the way the river is managed and legal agreements about sharing Rio Grande water.

“In 2018, we had even less snow in the basin than we saw this year, but we had so much (water) storage that I don’t even think people were aware that it was a dry year,” Marken said. “The (Middle Rio Grande Conservancy) District was able to keep water flowing through the river all season.”

The Middle Rio Grande Conservancy District has very little stored water it is allowed to release at the moment, because of a legal agreement between states about how the water is divided called the Rio Grande Compact.

That means farmers have been dependent on rainfall for irrigation, and much of the rainwater running through Albuquerque is destined for farms. The MRGCD is targeting areas where farmers have not received many irrigation deliveries recently. There is not enough water in the river to do irrigation deliveries in the Corrales area.

Aside from Pueblo irrigators, who have different water rights, there have been limited irrigation deliveries for the past two months upstream and downstream of Isleta Pueblo.

“When the system’s struggling, the farmers struggle along with it,” Marken said.

Drying south of Albuquerque was also more extensive than typical. Over 40 miles dried in the San Acacia reach, a level of drying that hasn’t been seen in that area since the early 2000s, Marken said.

Flood risk

There is a heightened risk of river and stream flooding over the holiday weekend for rivers along the southern fringe and eastern side of the Sangre de Cristo Mountains. Those rivers are especially vulnerable to repeated rounds of monsoon rain causing river flooding, Mangham said.

Heavy rainfall has saturated soils in the area and the National Weather Service has reports of streams near the Mora, Sapello, Pecos and Vermejo rivers rising out of their banks.

Mora County commissioners already declared a disaster Wednesday after N.M. 434 and several county roads were damaged by flooding.

While the Pecos River is outside the burn scar area, some of its tributaries do reach into burn scars from the Calf Canyon/Hermits Peak Fire, causing higher than normal flows over the last few years in those tributaries, Mangham said.

A surge of monsoon moisture is expected over the weekend, which could mean a lot of rain around the state by Monday, Mangham said.