Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fingerprinting erosion

03.09.2015

Solving the mystery of erosion in the south Tobacco Creek watershed

You may have noticed that after a heavy rainstorm, creeks and rivers often turn the color of chocolate milk. That cloudy brown color is caused by sediments--weathered rock material ranging in size from tiny granules of mud to stones. As it courses along, water sweeps up sediments in the well-known process of erosion. Eventually, the sediments find a home, sometimes in a place where it isn't wanted. And, it's not just mud and sand that gets carried to water sources. Contaminants often catch a ride to waterways by clinging to sediments.


Soil experts David Lobb and Dr. Sheng Li check sediment collection traps. The sediment is collected annually to track the origin and pattern of soil migration.

Photo credit Landice Yestrau

Soil scientist David Lobb investigates the origin of these nomadic sediments. His work is in the Tobacco Creek Watershed, a collection of streams that flow into the Red River and ultimately dump into Lake Winnipeg, Canada. Lake Winnipeg is the final resting place of three major rivers, making it the second largest watershed in Canada. It feels the effects of activity taking place upstream.

"We are all being challenged to look at the watershed as a whole, not just at the water that flows out a watershed," says Lobb.

Watershed health and water quality issues are a growing concern. A variety of human activities can negatively impact watersheds.

Fertilizers used to bolster crop yields, sewage pollution from treatment facilities, and refuse from livestock can leach an excess of nutrients. The nutrients, especially phosphorus, enter large bodies of water like Lake Winnipeg. Algae feeds on this influx of phosphorus and goes into a frenzy of growth, which can lead to the choking out other species and throwing off the function of the entire ecosystem. Sediments are often blamed for carrying this nutrient runoff from topsoil sources like farm fields and livestock production areas.

In the context of these issues, Lobb and his team were keen to examine the sediments traveling downstream toward Lake Winnipeg. In order to better understand where sediments are coming from, Lobb and his colleagues from the University of Manitoba and the University of Northern British Columbia use a technique called color fingerprinting. The color of a particular sediment is key to identifying the specific origin of the erosion. "It's not as particular as fingerprinting in a crime scene investigation," says Lobb, "but we have the tools to get a sophisticated identification of the sources of sediments."

At first glance, the color fingerprinting technique is fairly intuitive. It's also cheap and quick. "In the most simple case, black sediment is from surface sources and light sediment is from subsurface," says Lobb, "That's an oversimplification of a very precise process backed up by statistical models."

The distinction between surface and subsurface sediment sources is important. Subsurface sediment, or subsoil, is usually pulled by the water from the sides or bottoms of streams. Surface sediment, or topsoil, is more than likely coming from farm fields, riparian areas, or forest floors.

South Tobacco Creek revealed some facts that complicate the picture of erosion, and the human role in the process of sedimentation.

"We found that nature is more often to blame for a lot of the sediments we see in our streams," says Lobb, "Humans may not have as much of an effect on the amount of sediment flowing out of a watershed as we've been taught," says Lobb, "but we do have a profound effect on hydrology, and that can contribute to the erosion and sediment produced downstream."

Most of the sediment found in the South Tobacco Creek is from subsurface sources. It's coming from the stream banks and the huge rock walls that borders the creek as it cuts through a 600-foot escarpment. "Most people assumed sedimentation is caused by erosion in farm fields," says Lobb. "But one of the biggest culprits is the natural channel erosion that is constantly taking place."

The color coding technique makes it simple to find the geographic origin of sediment. "What to do with these answers is not as simple," say Lobb, "but precise color fingerprinting allows technology to open up to new directions. We are now looking at managing runoff from farm fields as being as important as managing erosion and sediment losses from farm fields. And, we are looking at managing runoff and erosion from the farm field scale to the watershed scale."

One of the complications is scale. Watersheds are dynamic. The health of one section of stream or river affects another section. To address issues at the watershed level requires looking at the area as a whole. In the case of Lake Winnipeg, the watershed spans an area 40 times the size of the lake itself.

"The public is demanding actions and impacts on a watershed scale," says Lobb. "Therefore, practices and processes have to reflect that larger regional scale."

###

Read the results of the study in the Journal of Environmental Quality.

Susan Fisk | EurekAlert!

Further reports about: Agronomy Canada downstream fingerprinting nutrients phosphorus sedimentation

More articles from Agricultural and Forestry Science:

nachricht Plasma-zapping process could yield trans fat-free soybean oil product
02.12.2016 | Purdue University

nachricht New findings about the deformed wing virus, a major factor in honey bee colony mortality
11.11.2016 | Veterinärmedizinische Universität Wien

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>