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N.M. Water Year: Too Little Under the Bridge

Happy New Water Year!

I’ve been unable to confirm whether any of New Mexico’s water managers were out drinking Sept. 30, the last night of the 2011-12 “water year.” But it wouldn’t surprise me. The year just completed was an atrocious water year that with few exceptions left New Mexico’s irrigation ditches near dry by late summer and the state’s reservoirs near empty.

“It was a miserable year for sure,” said Phil King, a professor at New Mexico State University and adviser to the Elephant Butte Irrigation District, one of the hardest hit of the state’s water users.

Water managers usually measure their years from Oct. 1 through Sept. 30. That “water year” matches the way they manage their supplies, with snowpack accumulating in the fall and winter, and farmers and cities using the melting runoff to meet their needs during the following spring and summer. While some irrigation water continues to flow after Oct. 1, most farmers are winding down their season by now.

That makes early October a good time to take stock, looking back at the water year just completed and thinking about the forecast for the snow season to come.

Coming on top of a lousy 2010-11, the water year just completed worked hard to earn its description as “miserable.” After teasing us with a wet start, things dried out in the spring. Much of what seemed a promising winter snowpack blew away in the dry spring winds rather than making it to New Mexico’s rivers. Summer rains provided little relief.

Flows of native water on the Rio Grande this year past Otowi (a key measurement point down the hill from Los Alamos) were just a hair under 50 percent of the long-term average (for numbers nerds, the mean dating back to 1940). Elephant Butte Reservoir, the Rio Grande’s largest storage reservoir, held 113,234 acre feet of water, just 5 percent of capacity.

“Native water” here includes water that naturally flowed down the river from points north, and does not include imported San Juan-Chama water, which is tunneled beneath the Continental Divide from the headwaters of the San Juan River. Without that bonus supply of imported water, the Rio Grande would be completely dry through Albuquerque right now, water managers say.

The dwindling river is not a new problem. Native flows on the Rio Grande have been below the long-term average in 10 of the 12 years since the turn of the century.

If the Rio Grande seems bad, things were even worse on the Pecos River in the past water year. With another dry year and even less big-water storage on the river that dribbles down New Mexico’s eastern plains, farmers in the Carlsbad Irrigation District got less than a third of a normal irrigation allotment this year, according to district manager Dudley Jones.

But next water year will be better, right? That’s what New Year’s is all about. Out with the old and in with the new?

A round of calls over the last week to some of the state’s savviest water managers yielded surprisingly glum outlooks.

It would take “a storm of biblical proportions” to make up for the ground we’ve lost during the drought, Jones told me.

New Mexico faces three problems in the new water year.

The first problem is the winter forecast itself. There were signs of an El Niño forming, a climate pattern driven by warm water in the equatorial Pacific ocean that tips the odds toward wetter winters in New Mexico. El Niño is no guarantee, but it improves our chances of extra storms to make up some of the long-term drought shortfall.

But this year’s El Niño has been slow and weak, not offering a very hopeful forecast as a result.

Second, after two consecutive drought years, the state’s watersheds are like a dry sponge right now, King said. A big chunk of whatever snow we get this winter will simply soak into dry ground before runoff can start reaching streams and rivers. “The watershed will take its bite first,” he explained.

The third problem may be the most vexing.

In recent years, for a given size snowpack, water managers have seen substantially less water actually making it into New Mexico’s rivers, King noted.

Scientists at both New Mexico State University and the University of New Mexico are looking closely at the puzzle in search of answers. While the reason behind the runoff drop-off remains a mystery, it is consistent with what you would expect as New Mexico’s temperatures rise, noted UNM professor David Gutzler, one of the scientists looking at the issue.

That combination of factors means it will take an above-average winter snowpack this year just to get average flows in New Mexico’s rivers, King said. King already has warned Elephant Butte Irrigation District farmers to expect another sub-par irrigation allotment in 2013.

But Jones, down in Carlsbad, sees a silver lining. At least La Niña, which brought us our last two dry winters, is gone!

UpFront is a daily front-page opinion column. Comment directly to John Fleck at 823-3916 or jfleck@abqjournal.com. Go to www. ABQjournal.com/letters/new to submit a letter to the editor.
— This article appeared on page A1 of the Albuquerque Journal

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