Another year, another growing season that will need summer monsoon rains to avoid water shortages.
After a promising snowy start in late December, weather turned drier as expected under La Niña, with regional snowpack and precipitation falling to levels below a year ago and the 30-year median, according to a recently released federal report on March conditions.
Lower temperatures this year have been a double-edged sword, causing more powder snowfall with less water content. But the sometimes frigid conditions have also prevented the snowpack from melting too soon — as it has in recent years — so the runoff flows when New Mexico farmers need it for their spring planting.
Water managers say March offers the first accurate forecast of upcoming runoff because that’s when the greatest snowfall occurs.
The snow cover this year would be sufficient if there were not the tanks being low, because the state owes Texas a large amount of water. There’s also this problem, experts say: climate change is increasing temperatures and increasing evaporation.
Spring runoff should be enough to get irrigators through July, but after that they’ll need heavy summer rains to boost water supplies for the rest of the growing season, Jason said. Casuga, interim CEO and chief engineer of the Middle Rio Grande Conservancy. District.
“I expect it to be tough in the warm months,” Casuga said. “Without end-of-season storage, if we don’t get rain in the monsoon season, it will be very difficult in the second half of the irrigation season.”
It’s a similar situation to 2021, also in the throes of La Niña, a weather pattern in the Pacific Ocean that pushes precipitation north and causes drier-than-normal conditions in southwestern states.
Almost all of New Mexico is plunged into drought conditions ranging from severe to exceptional, with Santa Fe County struggling with extreme drought. While much better than a year ago when half the state was mired in exceptional drought, this is a marked downturn from January’s more favorable picture after the steep drops in snow.
Last year, much-needed summer rainstorms arrived, replenishing water supplies enough for most farmers to irrigate well into the fall, in stark contrast to 2020, when almost no rain fell. during the summer, leading to severe water shortages in September.
‘Difficult situation’ Data shows snowpack in the upper Rio Grande basin is 90% of ‘long-term normal’ and down 18% from a year ago, technician Jaz Ammon said. hydrology to the US Natural Resource Conservation Service, which helped compile the report. This basin is the closest study area to Santa Fe, with data collected at weather stations in Taos, Ski Santa Fe and other locations in the region, Ammon said.
Rainfall in the basin between October and April was 79% of long-term normal, down from 90% last year, Ammon said.
The long-term, or normal, median covers the period from 1991 to the present, he said.
State Engineer Mike Hamman said the agency recently moved the start time by a decade, removing the wettest period of the 1980s, which created a drier scale that made the years of drought less arid.
“The bar is lower,” Hamman said.
A recent study published in the journal Natural climate change says the West is experiencing the driest 22-year period since AD 800, plunging the region, which includes New Mexico, into a mega-drought.
Human-caused climate change is worsening the severity of the drought and extending its duration, researchers say, estimating it could drag on to the 30-year mark before finally passing.
Previous mega-droughts predated the Industrial Revolution, when heat-trapping greenhouse gases began to be released en masse into the atmosphere, showing that the West can experience severe natural droughts independent of climate change, have said the study authors.
However, cumulative greenhouse gas emissions over the past two centuries have clearly worsened the current drought in the West, they said.
Climate change has increased average temperatures by about 2 degrees since the 1990s and reduced rainfall, leading to what scientists call aridification.
It intensified evaporation and dried out the soil, causing it to absorb water like a sponge. This in turn reduced the amount of runoff entering the Rio Grande and flowing downstream to farmers and Elephant Butte Reservoir, the main hub of Texas water passage to pay debt and meet the obligations of a multi-state water sharing pact.
Meanwhile, consecutive La Niña patterns further deplete water sources.
Rolf Schmidt-Petersen, director of the Interstate Stream Commission, said the overall picture the federal report paints is bleak — unless the region gets a good monsoon.
“It points to a tough situation ahead,” Schmidt-Petersen said. “I see a year as difficult as last year with less stored water available.”
No backup power
Water storage will be drastically reduced this year as the renovation of the El Vado dam will begin by summer.
The work will remove the main reservoir to conserve “native” or natural water from the Rio Grande, as opposed to Colorado River water that flows through the dams and tunnels of the San Juan-Chama federal system into the Rio Big.
For now, the loss of the reservoir means there is no place to store native water for irrigation, leaving the Conservation District no buffer to supply farmers in the latter part of the season. , said Casuga. The absence of emergency water during a dry season can be problematic, he added.
State officials want to store additional native water in Lake Abiquiú but must overcome some obstacles. The Army Corps of Engineers, which oversees the Abiquiú Dam, must approve it, and all Rio Grande Compact commissioners must approve it.
Texas has opposed storage expansion in New Mexico until it pays off its water debt to the Lone Star State of about 127,000 acre-feet, or 41 billion gallons. One acre-foot is enough to submerge a football field in one foot of water.
Hamman, the state engineer, said he wrote a letter to the Army Corps of Engineers asking to store 20,000 acre-feet, or 6.5 billion gallons, in Abiquiú to meet the water needs of the pueblos. He is confident that the body will agree.
Additionally, the state wants to store 45,000 acre-feet, or 14.6 billion gallons, at the reservoir to help cover irritation needs.
Hamman thinks he can break the stalemate with Texas.
“We will continue to discuss with the State of Texas to see if there are other scenarios that could benefit the entire basin,” he said.
Meanwhile, the irrigation district has staggered water deliveries to various areas since March, so growers are getting supplies early rather than late, as they did last year, Casuga said, adding that a quick distribution is important as they face another tough season.
“We wanted to make sure we were more above that and were more efficient than we were last year,” Casuga said.
Ammon said the only way to really solve drought-induced problems is to have two or three consecutive above-average wet years.
Robust snowpacks and rainfall would be needed for all those years, he said.
“Either isn’t enough to cut it,” Ammon said.