Study looked at Raccoon River watershed in Iowa
Just as a leaky roof can make a house cooler and wetter when it’s raining as well as hotter and dryer when it’s sunny, changes in land use can affect river flow in both rainy and dry times, say two University of Iowa researchers.
While it may be obvious that changes in river water discharge across the U.S. Midwest can be related to changes in rainfall and agricultural land use, it is important to learn how these two factors interact in order to get a better understanding of what the future may look like, says Gabriele Villarini, UI assistant professor of civil and environmental engineering, assistant research engineer at IIHR—Hydroscience & Engineering and lead author of a published research paper on the subject.
“We wanted to know what the relative impacts of precipitation and agricultural practices played in shaping the discharge record that we see today,” he says. “Is it an either/or answer or a much more nuanced one?
“By understanding our past we are better positioned in making meaningful statements about our future,” he says.
The potential benefits of understanding river flow are especially great in the central United States, particularly Iowa, where spring and summer floods have hit the area in 1993, 2008, 2013 and 2014, interrupted by the drought of 2012. Large economic damage and even loss of life have resulted, says co-author Aaron Strong, UI assistant professor in the Department of Urban and Regional Planning and with the Environmental Policy Program at the UI Public Policy Center.
“What is interesting to note,” says Strong, “is that the impacts, in terms of flooding, have been exacerbated. At the same time, the impacts of drought, for in-stream flow, have been mitigated with the changes in land use composition that we have seen over the last century.”
In order to study the effect of changes in agricultural practices on Midwest river discharge, the researchers focused on Iowa’s Raccoon River at Van Meter, Iowa. The 9,000-square-kilometer watershed has the advantage of having had its water discharge levels measured and recorded daily for most of the 20th century right on up to the present day. (The study focused on the period 1927-2012). During that period, the number of acres used for corn and soybean production greatly increased, roughly doubling over the course of the 20th century.
Not surprisingly, they found that variability in rainfall is responsible for most of the changes in water discharge volumes.
However, the water discharge rates also varied with changes in agricultural practices, as defined by soybean and corn harvested acreage in the Raccoon River watershed. In times of flood and in times of drought, water flow rates were exacerbated by more or less agriculture, respectively. The authors suggest that although flood conditions may be exacerbated by increases in agricultural production, this concern “must all be balanced by the private concerns of increased revenue from agricultural production through increased cultivation.”
“Our results suggest that changes in agricultural practices over this watershed—with increasing acreage planted in corn and soybeans over time—translated into a seven-fold increase in rainfall contribution to the average annual maximum discharge when we compare the present to the 1930s,” Villarini says.
The UI research paper, “Roles of climate and agricultural practices in discharge changes in an agricultural watershed in Iowa,” can be found in the April 15 online edition of Agriculture, Ecosystems & Environment.
Gary Galluzzo | newswise
Raiding the rape field
23.05.2018 | Julius-Maximilians-Universität Würzburg
New technique reveals details of forest fire recovery
17.05.2018 | DOE/Brookhaven National Laboratory
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences