NM drought worsening despite recent rainfall
Silvery minnows gain most from storms; reservoirs getting low
Never mind this week’s rain. It didn’t help much — unless you happen to be a silvery minnow.
“A few rainfall incidents does not end a six-month drought,” said Royce Fontenot, senior hydrologist in the Albuquerque office of the National Weather Service. “We got a big drink of water (this week), but we need to keep getting those big drinks. That’s the story of this drought. It gives you a lot of water and then turns it off.”
A map released Thursday by the U.S. Department of Agriculture’s drought monitor shows that more than 20 percent of New Mexico — scattered areas in the northern part of the state — is in exceptional drought, the most serious category, and more than 99 percent of the state is in some kind of drought. And the dropping of water levels in the Elephant Butte and Caballo
reservoirs forced a restriction on storing additional water in northern New Mexico reservoirs.
To make things grimmer, Fontenot said Thursday that the outlook for the next eight to 14 days is hot and dry.
There is a silvery lining, however. David Gensler, water operations manager for the Middle Rio Grande Conservancy District, said the sudden increase in Rio Grande flows caused by the rain this week stimulated spawning among the endangered silvery minnow, as indicated by the number of minnow eggs collected in surveys.
“The rain made lots of silvery minnow babies,” Gensler said. “A sudden increase in river flow is like candlelight and violins to them.”
“Twenty percent of the state in exceptional drought is pretty high,” Fontenot said. He said New Mexico has not had that degree of exceptional drought since August 2013. But it has been even worse in the past. In a drought that lasted from May 2011 to May 2012, as much as 49 percent of New Mexico was in that category.
Some parts of New Mexico got a lot of rain from a system that moved into the state Monday and lingered into Thursday. A thunderstorm Monday broke a 54-day streak without measurable precipitation in Albuquerque. Albuquerque got 0.12 inch that day, Clayton 0.46, Roswell 0.51, Tucumcari 1.10 inches and Clovis 1.21.
Some areas got more rain in the succeeding days. Fontenot said that on Wednesday up to 6 inches of rain fell within six hours along U.S. 84 in San Miguel and Guadalupe counties.
“But the moisture we got (this week) is only going to go so far,” Fontenot said. “We need that robust (summer) monsoon. Now things look good for that. I’m cautiously optimistic, but we have to wait and see.”
This week’s rain, as vigorous as it was in some areas, did not stop the water levels in the Elephant Butte Reservoir, five miles north of Truth and Consequences, and Caballo Reservoir, 16 miles south of TorC, from dropping low enough to trigger a Rio Grande Compact provision prohibiting the storage of additional water in upstream reservoirs.
The Rio Grande Compact governs the distribution of water among Colorado, New Mexico and Texas. According to Article VII of the compact, New Mexico cannot store water in northern reservoirs such as El Vado, Abiquiu and Heron when the combined waters at Elephant Butte and Caballo recede to less than 400,000 acre-feet. Water from Elephant Butte and Caballo is used to irrigate lands in southern New Mexico and West Texas, provide water for industrial and municipal use in El Paso and supply water to Mexico.
The Conservancy District’s Gensler said the total water in Elephant Butte and Caballo dropped below 400,000 acre-feet Sunday, putting the Article VII restriction into effect for the first time since early this year. An acre-foot is the amount of water necessary to cover an acre to a depth of 1 foot.
On Thursday, combined water in the two reservoirs was at about 394,000 acre-feet, Gensler said.
“If we talk for a while it might be down to 393,000 acre-feet,” Gensler told the Journal on Thursday. “It’s dropping pretty fast.”
OK for now
Gensler said the Article VII restriction would probably not change much for the irrigators on the 70,000 acres of cropland served by the Conservancy District.
“Opportunities for storage are pretty rare during the summertime anyway,” he said. And he noted that even though Article VII restricts the storage of additional water, it does not prohibit the release of water that had already been in storage. He said that adds up to 107,000 acre-feet in El Vado, Heron and Abiquiu.
“That’s what we’ve got to get us through the summer,” he said. “And any little shot of moisture we get will help. This week’s rain saved us 1,500 acre-feet or so, allowed us to charge up our canals, reduce storage release slightly and got a few more people some water.”
Gensler said, however, that things could get really bad if the state is still under the Article VII restriction next spring.
“That’s when it will really hurt us,” he said. “Assuming we have a nice snowpack next spring, it would be nice for us to replenish our reservoirs, and Article VII would stop us from doing that in 2019.
“Whether we get through this (irrigation) season or not, whatever happens, we are going to use up much of our storage. We could have a lot of empty lakes by the end of the year.”