“You want the tree to extract the maximum amount of water that it is capable of extracting and putting it to beneficial use,” Daviet said as he stood in the shade of the orchard of still-leafless trees.
While chile farmers in the Hatch Valley struggle their way through drought by pumping saline water from shallow aquifers, the pecan farmers in the broad Mesilla Valley face very different problems. Like their Hatch Valley colleagues to the north, they depend on Rio Grande irrigation water from the Elephant Butte Irrigation District. When it’s not there, in drought years like we’ve seen recently, they pump groundwater.
Compared to the Hatch Valley, the groundwater in the Mesilla Valley beneath Las Cruces and the cities around it looks luxuriously deep.
“In the Mesilla Valley, we’ve got an abundant groundwater source,” Daviet said. Where the aquifer in the Hatch Valley can be as shallow as 80 to 100 feet deep, the Mesilla aquifer extends hundreds of feet down, in some places thousands.
Its depth means it can act like a savings bank, Daviet said. In wet years, when there’s plenty of water from the Rio Grande, surface water is spread across the pecan orchards, with some of it soaking down and refilling the aquifer.
Evidence of the effect can be found in a ditch running down the western edge of Daviet’s farm – a drain dug to remove rising groundwater as a result of extensive valley irrigation during the first part of the 20th century.
“We’ve applied water to that groundwater source in these years of plenty,” Daviet said.
When Daviet took over the family farm in the mid-1990s, Elephant Butte Reservoir was full, surface water was plentiful and the aquifer was rising as farmers spread river water across their fields.
Pumping Mesilla Valley groundwater in years of drought is more expensive, but Daviet views it as drawing down a water savings bank.
But hovering over that practice is a lawsuit filed earlier this year by the state of Texas, which has a different view of the situation. The lawsuit charges that groundwater pumping in New Mexico, by lowering the water table during drought years, has effectively reduced what flow there is in the Rio Grande. The result, it charges, is less water available to farms and cities across the border in Texas.
The fear in the Mesilla Valley is that the Texas lawsuit could force farmers to curtail their groundwater pumping, leaving pecan orchards vulnerable to drought.
Texas has asked the United States Supreme Court to step in and resolve the dispute. New Mexico, in a response filed this month, asked the court to throw out the case. A decision on whether the suit can proceed is not expected until later this year. If the court allows the case to proceed, sorting out the water conflict is expected to take years.
For ongoing coverage, story archive and resources, visit: Drought in New Mexico
— This article appeared on page A8 of the Albuquerque Journal