Wednesday, November 25, 2009

Tech Scientists, Students Discover Rio Grande Spring

By John Larson

SOCORRO – Scientists from the Bureau of Geology and Mineral Resources on the New Mexico Tech campus have discovered what is believed to be the largest spring to date that feeds into the Rio Grande.
The spring is located about 11 miles below the state line with Colorado in the upper Rio Grande.
Geologist Paul Bauer and hydrogeologist Peggy Johnson have been working on a study designed to inventory and classify all springs on the upper Rio Grande.
“It’s about 80 miles of river, from the state line down to the stream gauge at Embudo,” Bauer said. “Our primary task was to determine where, how, and why this ground water reaches the river.”
“This spring is the single largest spring that we have found on our survey between the state line and Embudo gage,” Bauer said.
He said the gage (a system of measuring river flow) at the village of Embudo was the first river gage in the United States.
“John Wesley Powell of the U.S. Geological Survey set that up in 1898,” Bauer said. “He then sent all his young engineers out to other rivers in the country to with that system.”
Bauer said the single spring, in a crater at least 12 feet deep, shoots out 6,000 gallons a minute, accounting for about 10 percent of the entire river accretion - gain from springs and seeps - that occurs along that 80 mile stretch.
“Our best guess for the origin of the spring is that ground water is flowing through a collapsed lava tube,” Bauer said. “At higher river levels the spring disappears from view.”
The study by Bauer and Johnson is a continuation of their ongoing work on the geology and hydrogeology of the Taos County region.
“Last fall while working in the Ute Mountain stretch in inflatable kayaks, we floated over an amazing submerged spring, however, the river was too high to evaluate the spring,” he said. “This year we returned at very low water to check it out.”
Finding and surveying springs is challenging work in the Rio Grande gorge, as there are few roads down to the river and the trails are steep and many are primitive, he said.
“Where possible, we used inflatable kayaks to survey springs, and where that wasn’t possible due to the [turbulent] rapids, we carried our gear into the gorge and surveyed on foot,” Bauer said.
Team members Matt Martinez and Kristoph Kinzli were integral in measuring the depth and flow of the river in the spring area.
“To date, we have cataloged about 170 springs and seeps in the gorge. Most of them are small, although some are quite large, flowing at rates of several thousand gallons per minute,” Bauer said.
“One of the most surprising findings has been the large number of springs, and the variety of geologic settings that host the springs.”
Bauer is a Principal Geologist and Associate Director at the New Mexico Bureau of Geology and Mineral Resources.
Peggy Johnson is Senior Hydrogeologist and Associate Director for Hydrogeologic Programs.

Photo: New Mexico Tech graduate student Kristoph Kinzli uses specialized equipment to measure the flow of water coming from the spring.

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