Triple digit temps dry the Rio Grande

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The Middle Rio Grande was dry near San Antonio in July.

Laura Paskus/NMID

The Middle Rio Grande was dry near San Antonio in July.

IMG_5305Despite spring runoff that ripped down the Rio Grande in early June, consistently high temperatures in July are contributing to drying in the Rio Grande, the state’s largest river.

Under a 2003 plan from the US Fish and Wildlife Service, the river is legally allowed to dry south of Albuquerque during irrigation season.

The river began drying in mid-July as managers allow water to flow into irrigation channels. Currently, there are about 17 miles dry south of Albuquerque, between San Antonio and the southern boundary of Bosque del Apache National Wildlife Refuge.

July has been tough on everyone, says David Gensler, hydrologist with the Middle Rio Grande Conservancy District, which delivers irrigation water to farmers between Cochiti and Elephant Butte. “After a pretty easy spring, the high temps have done a number on us,” he says. “Every farmer from Cochiti to Socorro needs water, and needs it yesterday.”

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The district has already released 24,000 acre feet of water out of storage in El Vado Reservoir. There’s a chance, he says, that the district could run out of water before Labor Day, but he’s hoping it lasts a week or two longer.

But at heart, Gensler is an optimist: he thinks cooler temperatures and monsoon rains will come – and allow farmers a full irrigation season despite the troubles right now.

Salvaging the silvery minnow

Spring runoff is crucial to the survival of the Rio Grande silvery minnow, an endangered species that needs that spike to spawn.

Water managers try to keep certain stretches of the river wet for the fish during irrigation season – and biologists conduct “salvage” when the river starts to dry. They look for the endangered silvery minnows in puddles, then scoop them up and transport them to a part of the river that’s still flowing.

Upstream 380

“It’s amazing how a month of extreme heat and little to no rain can change the situation on the river,” says Mary Carlson, public affairs specialist with the US Bureau of Reclamation in Albuquerque. “I watch those clouds roll in each evening, but the rain hasn’t come.”

The USBR has released more than 6,000 acre feet of water from storage this year to supplement flows on the river for the silvery minnow. One acre foot equals 325,851 gallons.

So far this year, biologists have found about 6,000 minnows. That’s almost six times what they found last year – and a huge number compared to the previous very dry years. In 2012, they found 84 fish; 2013, 9; and 2014, 28.

In early June, the Middle Rio Grande.

Laura Paskus/NMID

In early June, the Middle Rio Grande was flowing high with runoff.

“You get an idea of how important that spring runoff is,” says Thomas Archdeacon, with the US Fish and Wildlife Service.

Earlier this year, Archdeacon’s study of the effects of river drying on the rare fish was published in the peer-reviewed journal, Transactions of the American Fisheries Society.

Meanwhile, on the eastern side of the state, water managers have been releasing water out of reservoir storage to keep the Pecos River wet for another rare fish, the Pecos Bluntnose shiner. Reservoir levels on the Pecos are more secure than they are on the Rio Grande. Elephant Butte Reservoir, for instance, is currently at 23 percent of average.

“Flash drought”

The hot temperatures aren’t unique to New Mexico.

This month, NASA reported that June 2016 was 1.62 degrees Fahrenheit above the 20th century average. That breaks last year’s record for the warmest June on record. So far this year, the average global temperature is 1.89 degrees above the 20th century average. That shatters last year’s record of 0.36 degrees higher than average.

At a meeting of New Mexico’s Drought Monitoring Work Group on Tuesday, experts noted how quickly the state has dried out in the past month, particularly in the east. “It’s shaping up to be almost a ‘flash drought’ in the east,” said Senior Service Hydrologist Royce Fontenot of the National Weather Service in Albuquerque.

During that meeting, forecasters and experts, including state climatologist David DuBois, discussed making changes to the state’s drought monitoring map. Based on things like precipitation, temperature, and soil moisture, the group can determine an area’s level of drought, ranging from “abnormally dry” to “exceptional drought.”

Today, they released the new map, expanding “abnormally dry” conditions through northeastern New Mexico and identifying the southeast as being in “moderate drought.” The map also reflects slightly improved conditions in the southwest.

Currently, 96 percent of the state is classified as “abnormally dry” – up from 76 percent last week and 50 percent a year ago. About 16 percent of the state is experiencing moderate drought.

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Current New Mexico Drought Monitor map. From http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?NM

Monsoon rains picked up in the past week, and while two more months remain of monsoon season, forecasters are already seeing the conditions in place for La Niña. For the southwestern United States, those conditions usually mean drier weather.

During the rest of the monsoon season, forecasters are anticipating that Arizona and western New Mexico will see normal to above normal precipitation levels. Fontenot anticipates that fall will be normal, too. But going into winter, precipitation levels are predicted to drop.

That could mean bad news for next year’s spring runoff in the Rio Grande.

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