EL PASO, Texas – Locals gathered this week at La Llorona Park in Las Cruces, New Mexico for the annual arrival of the Rio Grande, watching the flow of water push downstream, clearing debris from the bed of the river dried up in its path – once again a flowing river.
Also known as Río Bravo in Mexico, it is one of the longest river systems in North America, stretching nearly 1,900 miles from Colorado to the Gulf of Mexico.
But in recent years, the river’s path through southern New Mexico has been dry for more months than it is wet.
From Colorado, the river flows through the US states of New Mexico and Texas, then the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas towards the Gulf.
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In southern New Mexico, however, the river bed is dry for months of the year, until the river is actually lit from a reservoir south of Truth or Consequences.
Capture a river
That’s because the river is effectively captured by a 301-foot concrete dam at Elephant Butte in Sierra County, which is part of the Rio Grande project overseen by the US Bureau of Reclamation, to replenish the world’s largest reservoir. state water.
The dam, completed in 1916, is located approximately 120 miles north of El Paso, Texas.
As the river crosses New Mexico from Colorado, the volume measured at the Otowi gauge between Santa Fe and Española indicates the amount of water that will be distributed from the lower Rio Grande.
Earlier this year, the Bureau of Reclamation estimated the throughput would be as low as 255,000 acre-feet.
From the reservoir, water is distributed to the Elephant Butte Irrigation District, El Paso Water Improvement District No. 1, and Mexico under a 1906 treaty, through d ‘a system of diversion dams and 139 miles of canals.
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One of these dams, the American Diversion Dam built in 1938, is located northwest of El Paso and diverts water to the El Paso Valley. El Paso Water’s electricity company supplies drinking water from the Rio Grande as well as groundwater from the Mesilla Bolson and Hueco Bolson aquifers.
From Elephant Butte – named after a volcanic formation on an island near the dam, which would resemble a sleeping elephant – water moves south and west for nearly 20 miles to the reservoir and dam of Caballo.
While most of the land receiving water is in New Mexico, the project also supplies farms in West Texas, as well as approximately 25,000 acres of irrigated land in Mexico’s Juárez Valley.
Gary Esslinger, Treasurer / Manager of EBID, explained that water allocations to each district are determined between January and March. The prolonged drought has made these allocations more difficult over the past decade.
“It’s a dice game every year to determine: did we get the snowpack we needed in the watershed to get to Elephant Butte so that we could allocate an allowance to our farmers,” he said. he declares.
The reservoir started in 2021 below 10 percent of its capacity, which has led to low water allocations to farmers of around 4 inches. Esslinger said that instead of getting its 60,000 acre-foot treaty spending, Mexico would only see 10,000.
Meanwhile, farmers in the area are predicting a shorter growing season, which could mean reduced production or a reliance on pumped groundwater, damaging some crops.
It also means that the appearance of the river in the Mesilla Valley will be fleeting in 2021. EBID did not release the river from the Caballo reservoir until May 31 and it will likely be gone by August as it heads towards the gulf.
“The river was opened and closed like a tap”
The arrival of the lower Rio Grande in southern New Mexico has long been an annual celebration. However, these flows decreased and the river was visible for a shorter time.
In 2020, Las Cruces only saw the river in March. In 2021, not before June.
“The river has been turned on and off like a tap, and now the tap is almost out of water,” said Kevin Bixby, director of the Southwest Environmental Center.
This is because in dry years there is less water to be released and the dry river bed absorbs water like a sponge.
Based on instruments monitoring the flow, Esslinger estimated that 350 cubic feet of released water had been lost between Caballo and the Leasburg Diversion Dam.
A prolonged drought exacerbated by climate change has reduced the annual snowpack that replenishes the river, and with warmer temperatures more water is lost through evaporation or through the dried-up river bed.
Agriculture in a Changing Climate
“Climate change may have doomed the Rio Grande,” Bixby said, “but I don’t think agriculture, as it’s practiced today in southern New Mexico, is sustainable.”
Bixby noted that Project Rio Grande interventions have ‘manipulated’ river systems and caused ecological damage: ‘All species and fauna, fish, birds and plants that depend on a healthy river – they all suffered and many of them disappeared. “
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Additionally, some lucrative crops harvested in the Mesilla Valley for generations require more water, putting agriculture on a future collision course with municipal and recreational uses, he argued.
“I think it’s only a matter of time until people understand that growing pecans in the desert is not sustainable,” Bixby said. “Water is a resource of public trust, which means that the government has a duty as an administrator to manage this resource for the benefit of all, including future generations.
The Rio Grande project also provides water for a hydroelectric power station and for flood and sediment control; and Sierra County has developed a tourism industry around the recreational use of Elephant Butte Lake; but its main objective, historically, has been to support agriculture in the region.
Still, “tub rings” on the rocks facing the lake indicate drainage, and by 2021 the water level was expected to drop an additional 50 feet, forcing marinas to relocate and endangering fish and other wildlife. .
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“At the end of the day, it’s irrigation water,” Bureau spokesperson Margaret Carlson said. “We are bound by (congressional) permissions for the reservoir and by law, and if the beneficiaries of the project – who are the farmers – ask for their water, we will release it.”
How Monsoons Can Help
Late-summer thunderstorms in the region, known as the “monsoons,” may provide a much needed boost, Esslinger said, but they are difficult to predict.
Weather stations measure precipitation and if EBID determines that a 2-3 inch rain is coming, the district can shut off the valves in Caballo and capture the storm water to “determine how we can best use that flood water and take advantage of it: irrigate with or put in drains and recharge the aquifer.
If the monsoons bring enough rain upstream – from Socorro to Albuquerque and Santa Fe – he said this could effectively extend the irrigation season if it arrives early enough; otherwise, it helps replenish the reservoir, which is in deficit from previous storage levels.
“It is a crisis that we are facing right now because of the drought we have been in,” he said. “We try to respond as fast as possible to any kind of moisture we can get, anything that gets wet, and we use it.”
Follow Algernon D’Ammassa on Twitter: @AlgernonWrites.
Read the story of the US Bureau of Reclamation’s Rio Grande Project here: