Mountain streams with rhythm?

May 24, 2002

COLLEGE STATION - Turns out that picturesque mountain stream you've always admired doesn't just burble randomly down the hillside: It marches to the measured cadence of its own drummer. Geographer Anne Chin has discovered that like their flatland cousins, mountain streams meander too. It's just that they meander vertically, dropping from pool to pool at a rhythmic, periodic rate.

Chin, a professor in the College of Geosciences at Texas A&M University, will publish an article on her research, titled "The Periodic Nature of Step-Pool Mountain Streams," this summer in The American Journal of Science.

"Mountains cover a sizable portion of the earth's surface, and as urbanization encroaches on mountain ecosystems, the streams there assume greater importance," Chin said. "Both policy-makers and the public are becoming concerned with how to manage mountain habitats and protect them from damage by human activities.

"The problem is that scientists don't fully understand the energetics and form-process interactions of high-gradient mountain streams," she continued. "Since most of these streams are located in steep, rugged terrain, access to them has been limited, and hydrologists and geomorphologists have tended to ignore them. Now, however, we realize that the theories about how lowland streams interact with the environment may not explain what's happening in the mountains."

Chin is the first scientist to advance the idea that mountain streams are organized in a regular, periodic pattern. Focusing on the pools and rocky drop-downs such streams create in their beds as they move downhill, she applied spectral analysis to the problem and discovered mountain stream step-pool sequences proceed in a rhythmic, staircase-like pattern.

"Mountain streams are more complex than those in the flatlands," Chin said. "Mountain streams work to accomplish different tasks, moving rocks from pebbles to heavy boulders. Such streams change more slowly, over a longer time scale, so their adjustment to environmental change takes longer. Thus their responses to both natural and anthropogenic disturbances are more difficult to understand.

"Mountain streams are confined by narrow valleys and can't move laterally," she observed. "They can only move vertically, for the most part, and this takes away a degree of freedom in their ability to adjust to energy conditions in the stream system. At the same time, the steepness of the stream's course gives them a high level of energy, which they must regulate. Lowland streams manage their energy more uniformly and efficiency through meandering over the face of the landscape, but mountain streams can only adjust vertically, so they create step-pool sequences to dissipate energy."

Chin, whose research interests center on fluvial geomorphology and hydrology, is conducting projects in the arid and semi-arid basins around Arizona's McDowell Mountains and the Santa Monica Mountains in California. She's also studying the impacts of roads and trails on stream channel dynamics in the Ouachita National Forest in Arkansas, collaborating with the U.S. Department of Agriculture Forest Service.

"The idea that mountain streams' vertical adjustment takes place in a periodic fashion is a new one, and that's exciting," Chin said. "No one has ever said this before."
-end-
Contact: Judith White, 979-845-4664, jw@univrel.tamu.edu;
Anne Chin, 979-845-7155, a-chin@tamu.edu.

Texas A&M University

Related Energy Articles from Brightsurf:

Energy System 2050: solutions for the energy transition
To contribute to global climate protection, Germany has to rapidly and comprehensively minimize the use of fossil energy sources and to transform the energy system accordingly.

Cellular energy audit reveals energy producers and consumers
Researchers at Gladstone Institutes have performed a massive and detailed cellular energy audit; they analyzed every gene in the human genome to identify those that drive energy production or energy consumption.

First measurement of electron energy distributions, could enable sustainable energy technologies
To answer a question crucial to technologies such as energy conversion, a team of researchers at the University of Michigan, Purdue University and the University of Liverpool in the UK have figured out a way to measure how many 'hot charge carriers' -- for example, electrons with extra energy -- are present in a metal nanostructure.

Mandatory building energy audits alone do not overcome barriers to energy efficiency
A pioneering law may be insufficient to incentivize significant energy use reductions in residential and office buildings, a new study finds.

Scientists: Estonia has the most energy efficient new nearly zero energy buildings
A recent study carried out by an international group of building scientists showed that Estonia is among the countries with the most energy efficient buildings in Europe.

Mapping the energy transport mechanism of chalcogenide perovskite for solar energy use
Researchers from Lehigh University have, for the first time, revealed first-hand knowledge about the fundamental energy carrier properties of chalcogenide perovskite CaZrSe3, important for potential solar energy use.

Harvesting energy from walking human body Lightweight smart materials-based energy harvester develop
A research team led by Professor Wei-Hsin Liao from the Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong (CUHK) has developed a lightweight smart materials-based energy harvester for scavenging energy from human motion, generating inexhaustible and sustainable power supply just from walking.

How much energy do we really need?
Two fundamental goals of humanity are to eradicate poverty and reduce climate change, and it is critical that the world knows whether achieving these goals will involve trade-offs.

New discipline proposed: Macro-energy systems -- the science of the energy transition
In a perspective published in Joule on Aug. 14, a group of researchers led by Stanford University propose a new academic discipline, 'macro-energy systems,' as the science of the energy transition.

How much energy storage costs must fall to reach renewable energy's full potential
The cost of energy storage will be critical in determining how much renewable energy can contribute to the decarbonization of electricity.

Read More: Energy News and Energy Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.