Even in a good year, much of the Rio Grande
is diverted for irrigation. But it’s only May,
and the river is already turning to sand.
LEMITAR, N.M. — Mario Rosales, who farms 365 acres along the Rio Grande, knows the river is in bad shape this year. It has already dried to a dusty ribbon of sand in some parts, and most of the water that does flow is diverted to irrigate crops, including Mr. Rosales’s fields of wheat, oats, alfalfa and New Mexico’s beloved chiles.
Because last winter’s mountain snowpack was the second-lowest on record, even that irrigation water may run out at the end of July, three months earlier than usual. But Mr. Rosales isn’t worried. He is sure that the summer thunderstorms, known here as the monsoon, will come.
“Sooner or later, we’ll get the water,” he said.
The monsoon rains he is counting on are notoriously unpredictable, however. So he and many of the other farmers who work 62,000 acres along 140 miles of the Rio Grande in central New Mexico may get by — or they may not.
“Nobody’s got a whole lot of water,” said David Gensler, the hydrologist for the Middle Rio Grande Conservancy District, whose job is to manage the river water that is delivered to Mr. Rosales and the others through diversion dams, canals and ditches. “If we use it up early in the season and don’t get any rain further on, the whole thing’s going to crash.”
Parts of the state got some much-needed rain this week, which may help Mr. Gensler extend his irrigation water a bit. But whatever happens this spring and summer, the long-term outlook for the river is clouded by climate change.
As the river dries, crews rescue endangered minnows from remaining pools of water.
Drainage ditches carry water that has seeped out of the riverbed.
The Rio Grande is a classic “feast or famine” river, with a dry year or two typically followed by a couple of wet years that allow for recovery. If warming temperatures brought on by greenhouse gas emissions make wet years less wet and dry years even drier, as scientists anticipate, year-to-year recovery will become more difficult.
“The effect of long-term warming is to make it harder to count on snowmelt runoff in wet times,” said David S. Gutzler, a climate scientist at the University of New Mexico. “And it makes the dry times much harder than they used to be.”
With spring runoff about one-sixth of average and more than 90 percent of New Mexico in severe to exceptional drought, conditions here are extreme. Even in wetter years long stretches of the riverbed eventually dry as water is diverted to farmers, but this year the drying began a couple of months earlier than usual. Some people are concerned that it may dry as far as Albuquerque, 75 miles north.