Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers advance understanding of mountain watersheds

30.10.2015

University of Wyoming geoscientists have discovered that the underground water-holding capacity of mountain watersheds may be controlled by stresses in the earth's crust. The results, which may have important ramifications for understanding streamflow and aquifer systems in upland watersheds, appears Oct. 30 in Science, one of the world's leading scientific journals.

The scientists conducted geophysical surveys to estimate the volume of open pore space in the subsurface at three sites around the country. Computer models of the state of stress at those sites showed remarkable agreement with the geophysical images.


James St. Clair, a University of Wyoming doctoral student, is the lead author on a Science paper that discovers the distribution of porosity in the subsurface of mountain watersheds can be determined by looking at the state of stress in the earth's crust.

Steve Holbrook Photo

The surprising implication, says Steve Holbrook, a UW professor in the Department of Geology and Geophysics, is that scientists may be able to predict the distribution of pore space in the subsurface of mountain watersheds by looking at the state of stress in the earth's crust. That state of stress controls where subsurface fractures are opening up -- which, in turn, creates the space for water to reside in the subsurface, he says.

"I think this paper is important because it proposes a new theoretical framework for understanding the large-scale porosity structure of watersheds, especially in areas with crystalline bedrock (such as granite or gneiss)," Holbrook says. "This has important implications for understanding runoff in streams, aquifer recharge and the long-term evolution of landscapes."

James St. Clair, a UW doctoral student, is lead author of the paper, titled "Geophysical Imaging Reveals Topographic Stress Control of Bedrock Weathering." Holbrook, Cliff Riebe, a UW associate professor of geology and geophysics; and Brad Carr, a research scientist in geology and geophysics; are co-authors of the paper.

Researchers from MIT, UCLA, the University of Hawaii, Johns Hopkins University, Duke University and the Colorado School of Mines also contributed.

Weathered bedrock and soil together make up the life-sustaining layer at Earth's surface commonly referred to as the "critical zone." Two of the three study sites were part of the national Critical Zone Observatory (CZO) network -- Gordon Gulch in Boulder Creek, Colo., and Calhoun Experimental Forest, S.C. The third study site was Pond Branch, Md., near Baltimore.

"The paper provides a new framework for understanding the distribution of permeable fractures in the critical zone (CZ). This is important because it provides a means for predicting where in the subsurface there are likely to be fractures capable of storing water and/or supporting groundwater flow," St. Clair says. "Since we cannot see into the subsurface without drilling holes or performing geophysical surveys, our results provide the means for making first order predictions about CZ structure as a function of the local topography and knowledge (or an estimate) of the regional tectonic stress conditions."

The research included a combination of geophysical imaging of the subsurface -- conducted by UW's Wyoming Center for Environmental Hydrology and Geophysics (WyCEHG) -- and numerical models of the stress distribution in the subsurface, work that was done at MIT and the University of Hawaii, Holbrook says.

The team performed seismic refraction and electrical resistivity surveys to determine the depth of bedrock at the three sites, which were chosen due to varying topography and ambient tectonic stress. At the two East Coast sites, the bedrock showed a surprising mirror-image relationship to topography; at the Rocky Mountain site, the bedrock was parallel to topography. In each case, the stress models successfully predicted the bedrock pattern.

"We found a remarkable agreement between the predictions of those stress models and the images of the porosity in the subsurface with geophysics at a large scale, at the landscape scale," Holbrook says. "It's the first time anyone's really looked at this at the landscape scale."

St. Clair says he was fortunate to work with a talented group of scientists with an extensive amount of research experience. He adds the experience improved his ability to work with a group of people with diverse backgrounds and improve his writing.

"Our results may be important to hydrologists, geomorphologists and geophysicists," St. Clair says. "Hydrologists, because it provides a means for identifying where water may be stored or where the flow rates are likely to be high; geomorphologists, because our results predict where chemical weathering rates are likely to be accelerated due to increased fluid flow along permeable fractures; and geophysicists, because it points out the potential influence of shallow stress fields on the seismic response of the CZ."

Despite the discovery, Holbrook says there is still much work to be done to test this model in different environments.

"But, now we have a theoretical framework to guide that work, as well as unique geophysical data to suggest that the hypothesis has merit," he says.

###

The work was supported by the National Science Foundation's (NSF) EPSCoR program, the U.S. Army Research Office and the NSF Critical Zone Observatory Network.

Media Contact

Steve Holbrook
steveh@uwyo.edu
307-766-2427

http://www.uwyo.edu 

Steve Holbrook | EurekAlert!

Further reports about: NSF Wyoming fractures landscape scale structure theoretical framework topography

More articles from Earth Sciences:

nachricht Impacts of mass coral die-off on Indian Ocean reefs revealed
21.02.2017 | University of Exeter

nachricht How much biomass grows in the savannah?
16.02.2017 | Friedrich-Schiller-Universität Jena

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Microhotplates for a smart gas sensor

22.02.2017 | Power and Electrical Engineering

Scientists unlock ability to generate new sensory hair cells

22.02.2017 | Life Sciences

Prediction: More gas-giants will be found orbiting Sun-like stars

22.02.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>