#Drought/#Runoff news

Prior to 1921 this section of the Colorado River at Dead Horse Point near Moab, Utah was known as the Grand River. Mike Nielsen – Dead Horse Point State Park

From The Associated Press via Colorado Public Radio:

Rivers are drying up, popular mountain recreation spots are closing and water restrictions are in full swing as a persistent drought intensifies its grip on pockets of the American Southwest.

Climatologists and other experts are scheduled Wednesday to provide an update on the situation in the Four Corners region — where Arizona, New Mexico, Colorado and Utah meet.

The area is dealing with exceptional drought — the worst category. That has left farmers, ranchers and water planners bracing for a much different situation than just a year ago when only a fraction of the region was experiencing low levels of dryness.

US Drought Monitor May 15, 2018.

“We face an overwhelming risk on the system, and the time for action is now,” Bureau of Reclamation Commissioner Brenda Burman said Tuesday. She spoke before the Imperial Irrigation District in Southern California, one of the biggest single users of the Colorado River.

The drought has hit the Colorado River hard. Forecasters say the river will carry only about 43 percent of its average amount of water this year into Lake Powell, one of two big reservoirs on the system.

There’s a 52 percent chance that Mexico and the U.S. states of Arizona and Nevada will take a mandatory cut in their share of water in 2020 under the agreements governing the river, forecasters have said.

In New Mexico, stretches of the Rio Grande — another of North America’s longest rivers — have already gone dry as federal biologists have been forced to scoop up as many endangered Rio Grande silvery minnows as possible so they can be moved upstream.

The river this summer is expected to dry as far north as Albuquerque, New Mexico’s most populous city. The area saw its first major dose of rain Tuesday, bringing an end to a 54-day dry spell. It wasn’t enough to make up for months without meaningful precipitation.

From the New Mexico Political Report (Laura Paskus):

On Sunday, New Mexico entered into Article VII restrictions as storage in Elephant Butte and Caballo reservoirs dropped below 400,000 acre-feet. Under Article VII of the Rio Grande Compact, that means Colorado and New Mexico can’t store water in any upstream reservoirs built after 1929.

In the Rio Grande watershed, reservoirs capture and store native Rio Grande water and water piped from northwestern New Mexico via the San Juan-Chama Project. Each drop is earmarked for particular users and managed under the legal strictures of the compact. Elephant Butte and Caballo reservoirs, for example, hold Rio Grande Project water for users in southern New Mexico and Texas. Heron, El Vado and Abiquiu reservoirs on the Chama River store water for cities like Albuquerque and Santa Fe, farmers and the six Middle Rio Grande pueblos. Cochiti Reservoir stores some San Juan-Chama water, but was built for recreation and flood control purposes.

Entering into Article VII restrictions wasn’t a surprise. U.S. Bureau of Reclamation officials have been warning since earlier this year that it would happen, due to the low snowpack and low spring runoff.

“Article VII restrictions are aimed at protecting the water supply of the Rio Grande Project,” explained Reclamation spokeswoman Mary Carlson. “However, with little to no runoff remaining upstream and the most optimistic [National Resources Conservation Service] forecast predicting zero inflow into Elephant Butte Reservoir, conditions on the project are unlikely to change much even with these restrictions.”

The issue merits a close eye given the state’s drought conditions and an interstate lawsuit over the waters of the Rio Grande. Currently, New Mexico is being sued in the U.S. Supreme Court by Texas and the federal government. The two parties allege that by allowing farmers in southern New Mexico to pump groundwater from near the Rio Grande, New Mexico failed for decades to send its legal share of water downstream.

Monsoon storms might provide some relief on the Rio Grande, but water from just one storm, or even several, can’t come close to making up the deficit. Speaking at a water conference last week, Bruce Thomson explained that flows in the Rio Grande are dominated by snowpack and receive little benefit from monsoons.

“Summer precipitation is very nice, but in terms of actual runoff, there is very little actual contribution,” said Thomson, professor emeritus and research professor at the University of New Mexico’s Department of Civil Engineering.

Pulse of water

By the time New Mexico entered into Article VII restrictions on May 20, about 20 miles were already dry through the Bosque del Apache National Wildlife Refuge, extending upstream through San Antonio and toward Socorro. Drying began in early April, months earlier than in typical years.

Carlson said water managers and biologists from Reclamation, the U.S. Army Corps of Engineers, the Middle Rio Grande Conservancy District, the six Middle Rio Grande pueblos and the U.S. Fish and Wildlife Service coordinate daily on river flows.

“We are working closely with our partners who have already created two small operational pulses to help the Rio Grande silvery minnow to spawn,” she said. “The most recent appears to have been successful based on early egg detection in the Middle Rio Grande.” She added that the federal government continues efforts to lease all available San Juan-Chama Project water to supplement Rio Grande flows, as well.

Combined with a planned release of water at the Isleta Diversion Dam, she said, water from Monday’s storm created a pulse that will help silvery minnows spawn. Crews collect the eggs, then bring them to hatcheries, where the fish are raised and eventually released back into the river.

As for farmers in the Middle Rio Grande, hydrologist David Gensler says the storage restrictions shouldn’t affect deliveries. Gensler works for the Middle Rio Grande Conservancy District, which delivers water to farmers from Cochiti to south of Socorro.

Article VII will prevent them from storing water, he said, but it’s a “moot point.”

“Mainstem flows out of Colorado have been so low that we have been releasing from storage for the last 3 weeks just to meet [Middle Rio Grande] demand,” he wrote in an email prior to the official Article VII designation. “The runoff has come and gone, and there isn’t enough to store.”

The restrictions could affect the district later in the summer.

“Should we have a wet summer, and flows at La Puente do come up, then we will be unable to store excess water,” he said. La Puente is on the Chama River, above El Vado Dam. “That would be disappointing, but for the most part storing water in the summer is rare anyway.”

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