Ground Water Canada

Heli study to map flows under mountain watershed in Colorado

September 26, 2017  By Ground Water Canada

Crested Butte, CO – Residents in and around Crested Butte, Colo., may see a safe, low-flying helicopter towing a hula-hoop-shaped object beginning in early October and lasting for approximately two weeks.

The airborne device, contracted by the U.S. Geological Survey through Geotech, will be collecting critical geophysical data in support of interdisciplinary geologic and hydrogeologic studies, and fly about 200 feet above the ground surface, the USGS said in a news release.

The USGS and partners are conducting the survey to map the uppermost part of Earth’s crust – often termed the Critical Zone – within the East River and adjacent areas near Crested Butte.


The helicopter and hoop will collect data along pre-planned flight grids within the East River and surrounding areas. A sensor that resembles a large hula-hoop will be towed beneath the helicopter to measure tiny voltages that can be used to map Earth’s subsurface. The USGS will analyze these data to characterize subsurface sediment and rock properties.

“Detailed information about subsurface geology is critically important for understanding how ground water is transported through a watershed and how its path can impact the chemistry of streams and rivers,” said Dr. Burke Minsley, a USGS research geophysicist. “However, this type of subsurface data is difficult to obtain, especially in remote and rugged environments. This survey will provide invaluable new underground insights to depths of up to 500 feet that will contribute to an improved understanding of this region, with foundational new data at the critical watershed scale, which cannot be readily obtained by any other means.”

These data are critically important to understand where ground water flows. This knowledge contributes to a greater regional understanding of the quality and quantity of water available throughout the headwaters of the Gunnison Basin. 

This survey is being conducted in close coordination with a related U.S. Department of Energy grant awarded to the USGS. The work is being carried out in cooperation with the Rocky Mountain Biological Laboratory, the Lawrence Berkeley National Laboratory’s Watershed Function Scientific Focus Area and affiliated DOE funded projects that focus on developing new understanding of mountain headwater systems.

The airborne geophysical survey data and models will be released to the public following completion of the survey.

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