Devastating flooding, such as Iowa's Flood of 2008, motivated a team of researchers from the University of Iowa and Iowa Flood Center to analyze a hydrologic model with the potential to predict the extent of flooding based on predicted rain patterns
Devastating floodwaters such as those experienced during Iowa's Flood of 2008 -- which swamped many Iowa communities, along with ten square miles of Cedar Rapids -- are notoriously difficult to predict.
So a team of University of Iowa mathematicians and hydrologists collaborating with the Iowa Flood Center set out to gain a better understanding of flood genesis and the factors impacting it. They were able to do this by zeroing in on the impacts of certain rainfall patterns at the smallest unit of a river basin: the hillslope scale.
This week in the journal Chaos, from AIP Publishing, the team describes how they analyzed the nonlinear dynamics of a recently proposed hydrological model at the hillslope-scale under fluctuating precipitation. The study appears as one of a special collection of related articles in the March issue of the journal, which is focused on "Nonlinear Dynamics for Planet Earth." See http://tinyurl.com/kl28r53
The proposed hydrological model that is the subject of the new study "describes a mass balance among volumes of water at the hillslope scale," said Rodica Curtu, an associate professor in the Department of Mathematics at the University of Iowa, working on the project with Morgan Fonley, a graduate student. "Some of these volumes are easily observed, such as ponded water and streamflow, while others such as water in unsaturated areas and saturated zones of soil are more difficult to observe."
When this model is brought to equilibrium, it exhibits a natural tendency to amplify some oscillations but dampen others. "The deciding factor about this behavior is the frequency at which the oscillations are applied to the model via precipitation patterns," she pointed out.
If the hillslope system "experiences a certain frequency of rainfall, the soil becomes the least likely to take in water -- and instead puts it all in the nearest river so the streamflow exhibits large spikes of water," Curtu said. The mathematics involved tap into methods from the theory of nonlinear dynamical systems.
The key significance of this work? Mechanistic description and mathematical investigation of physical processes "can be more enlightening than model calibration, when studying nonlinear phenomena," Curtu said. This is because, she explained, mechanistic, physics-based equations “may not only simulate processes under investigation, but also uncover some of their underlying properties."
"In this case, by using physical parameters to describe a realistic hillslope, we found a pattern of precipitation that yields the greatest -- most amplified -- runoff coefficient, which determines the manner and how fast water will reach the river link."
The team's research sets up a framework by which future hillslope-soil models can be analyzed to predict the worst possible rain pattern that could lead the hillslope to flood, Curtu noted. This can be used to predict the extent of flooding possibilities based on predicted rain patterns.
Next up, the researchers will consider the effects of these streamflow oscillations once they reach the river network. Because the oscillations are occurring separately at each river link, "streamflows interact in ways that can amplify or destroy the oscillations as they combine in the river network," said Curtu.
Since this is a framework for soil models, Curtu and colleagues offer further improvements to the soil model to create a more accurate representation of water in the soil. "Using this framework, we can potentially find other factors that impact the extent of flooding both at the small hillslope scale and at the larger river catchment scale," she added. "Our work will continue in this direction with our Iowa Flood Center collaborators -- Witold Krajewski, Ricardo Mantilla and Scott Small."
The article, "Nonlinear response in runoff magnitude to fluctuating rain patterns," by Rodica Curtu and Morgan Fonley will be published in the journal CHAOS on March 10, 2015 (DOI: 10.1063/1.4913758). After that date it can be accessed at: http://scitation.aip.org/content/aip/journal/chaos/25/3/10.1063/1.4913758
This work received funding from the National Science Foundation (Award Number DMS-1025483).
ABOUT THE JOURNAL
Chaos: An Interdisciplinary Journal of Nonlinear Science is devoted to increasing the understanding of nonlinear phenomena and describing the manifestations in a manner comprehensible to researchers from a broad spectrum of disciplines. See: http://chaos.aip.org
Jason Socrates Bardi, AIP
Jason Socrates Bardi, AIP | newswise
Modeling magma to find copper
13.01.2017 | Université de Genève
What makes erionite carcinogenic?
13.01.2017 | Friedrich-Schiller-Universität Jena
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Trade Fair News
16.01.2017 | Automotive Engineering
16.01.2017 | Life Sciences