Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study Findings Have Impact Up and Down Stream

02.08.2010
A University of Arkansas researcher and her colleagues examined streams in urban, agricultural and forested settings and determined that the differences they found may affect how cities try to restore urban streams.

Geosciences researcher Stephanie Shepherd, geosciences professors John C. Dixon and Ralph K. Davis, and graduate student Rose Feinstein report their findings in River Research and Applications.

Shepherd’s work examined the shape of headwater streams, as well as the materials found in them, in cities, on farmland and in forested areas in the Illinois River watershed in northwest Arkansas. She found that the material in streams shifted from gravel in the forested streams to a high percentage of bedrock in the urban streams. Scientists know that urban streams run deeper and faster than forested streams, but until now the reasons haven’t been completely clear.

“The research shows one way that change is occurring in these streams,” Shepherd said. “It also suggests that just making an urban stream look like a forested stream will probably fail.”

To arrive at this conclusion, Shepherd looked at floodplains, measured depths and counted pebbles in streams at several sites in each land use category as determined by land use surveys – urban, agricultural and forest. Forested sites had more sinuous streams than the agricultural or urban sites. The forested streams had meander bends with gravel bars, which were absent in the urban and agricultural streams. Urban streams also ran significantly wider and deeper than those found on farmland and in forests.

The biggest difference between streams occurred in the materials found in the different settings. Urban streams had a lot of exposed bedrock, while agricultural streams had less than 1 percent exposed bedrock and forested streams had no exposed bedrock.

The exposed bedrock in urban streams occurs when cities harden the banks of a stream, create drainage channels or pave and reinforce the landscape surrounding it. This decreases new input into the urban stream. It also forces water into the stream that, in a forested setting, would be absorbed into the ground. This forced water produces high-speed flow, which then moves material such as stones and pebbles through quickly, sometimes scouring the bottom of the stream all the way to the bedrock.

“Streams are not static – materials are moving through them at different velocities all the time,” Shepherd said. “If there are not new gravel inputs in urban streams, we have to think of them as a different system.” Many of the physical characteristics surrounding forested streams, such as large areas of undisturbed soil, cannot be reproduced in an urban setting, she said, so scientists should explore new ways besides simple restoration to mitigate urban streams.

Shepherd and her colleagues work in the department of geosciences in the J. William Fulbright College of Arts and Sciences at the University of Arkansas.

CONTACTS:
Stephanie Shepherd, researcher, geosciences
J. William Fulbright College of Arts and Sciences
479-575-3355, slsheph@uark.edu
Melissa Lutz Blouin, director of science and research communications
University Relations
479-575-5555, blouin@uark.edu

Melissa Blouin | Newswise Science News
Further information:
http://www.uark.edu

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>