Rains boost reservoir but more needed
Water in key Southern N.M. reservoir surpasses projections but is not enough to offset drought
Much-hoped-for summer rains have put four times more water into a key reservoir in Southern New Mexico than federal officials had forecast earlier this year.
Monsoons have dropped enough rain to fill Elephant Butte Reservoir to 4 percent of its capacity, which is still quite low but far better than the 1 percent predicted for the end of August.
The bad news is that far more precipitation will be needed to pull the state out of its severe water shortage — years more, in fact.
While a few months of rain offers a welcome reprieve to a prolonged drought, it will take several strong snowpacks and robust monsoon seasons in a row to sufficiently replenish Elephant Butte and other record-low reservoirs, federal water managers say. A weather analyst agreed. “It’s going to take a long time for that [water storage] to become anywhere near normal, if it ever does again,” said Brian Guyer, a National Weather Service meteorologist in Albuquerque. “We can hardly manage to get more than one above-normal snowfall in a decade, let alone have two in a row.”
As of this week, Elephant Butte had 102,000 acre feet of water. An acre foot is roughly 326,000 gallons, enough to cover a football field with a foot of water.
Caballo Reservoir, about 27 miles farther south, was expected to end August with less than 15,000 acre feet.
It would be ideal for the two reservoirs to reach a combined 400,000 acre feet, enabling New Mexico to store water again under its 70-year-old pact with Texas and Colorado, said Mary Carlson, spokeswoman for the Bureau of Reclamation, which oversees water resources and dams.
Right now, New Mexico must funnel whatever Rio Grande water it doesn’t use for irrigation to Texas to meet the obligations under the agreement.
The agency would like to end the year with Elephant Butte filled to 20 percent to 30 percent capacity, providing a solid cushion for next year’s supply, Carlson said.
“But we are glad to at least be in a better position,” Carlson said.
In a statement, an agency official said they made conservative estimates of reservoir levels based partly on the meager spring runoff from the mountains and also because monsoons are tough to predict.
“However, it started raining in late June and the storms continued steadily through July and into August,” said Jennifer Faler, the
agency’s area office manager in Albuquerque. “They’ve proved to be a big help with water levels this summer.”
The winter snowpack was actually decent, but the ground, which had grown arid from years of drought, soaked up much of the melting snow, resulting in little runoff flowing into waterways, Guyer said.
Last winter’s snowfall was reduced by La Niña, Guyer said, referring to a Pacific Ocean-cooling event that pushes storms northward as they approach the continent, making the Southwest drier.
Another La Niña is expected this winter, although it will be weaker than last year’s, Guyer said. That still doesn’t bode well, given how the state urgently needs heavy snowfall, he said.
Summer rainstorms weren’t enough to prevent the Middle Rio Grande Conservancy District from ending the irrigation season on Oct. 1, a month early, just as it did last year. The shortened season will again cause hardship for farmers who grow winter crops, but it couldn’t be avoided, said Mike Hamman, the district’s CEO and chief engineer.
Supply was bordering on the threshold that would trigger restrictions allowing only pueblos to receive water, so district officials decided to impose the October cutoff, Hamman said.
Hamman hopes the rains will help the district to end 2021 with roughly the same water debt of 97,000 acre feet that it owed Texas at the start of the year. Breaking even would be a blessing as the valley struggles with persistent drought, he said.
“We’re hoping that we can get really close to somewhere around zero for the year — in other words, not any more debt,” Hamman said. “And it’s looking really possible.”