A group of Dartmouth researchers trying to assess the impact of Tropical Storm Irene on streams hopes that their results will help policymakers improve regulations for future storms, research group co-leader and geography professor Frank Magilligan said.
The research team, which was headed by Magilligan and earth science professor Carl Renshaw, received a three-year, $345,000 grant from the National Science Foundation for the study, following an initial $45,000 grant to conduct a damage assessment immediately after the August 2011 storm, Magilligan said.
Irene provided an opportunity to gain insight into how natural systems respond to and recover from disturbances.
"Irene was a really great example of an unprecedented flood in New England and that led to lots of geomorphic change things like hill slope erosion, landslides, overbank flooding and overbank deposition of material," he said.
Magilligan's research also has implications for the effectiveness of "hard engineering," or human interference in order to produce faster stream recovery, he said. This technique, which may be used to provide short-term relief, may not have long-term benefits.
"A lot of state agencies were very proactive in trying to stabilize river systems right after Irene," Magilligan said. "There was a lot of initial effort at just bringing in heavy equipment which potentially made it worse. We're already seeing the effects of this in terms of declining fish populations and the like."
The team's research on Irene provides information useful for policymaking, but does not supply solutions to the geomorphic change that major storms bring, Magilligan said.
Abby Franklin '13, a geograhy major who is writing her senior thesis on the research, said she hopes that governments will more closely examine their response to tropical storms and hurricanes while recognizing the resulting threat of future floods.
"For me it's a learning experience just to get out and understand some of the results of a flood this size," she said. "For the larger community, it's a wake-up call."
People often dismiss the idea of a natural disaster affecting them in their lifetime, even though Irene and Hurricane Sandy hit within two years of each other, Franklin said.
Many scientists believe that events like Sandy and Irene are going to become more intense and common in the future, according to Magilligan.
"Sandy and Irene revealed some of the risks that society faces," he said. "We've had a billion dollar natural disaster every year for the past ten years. Whether it was Irene or Sandy or wildfires in the America West, or draughts in the America Southwest, essentially, these are becoming progressively more frequent occurrences having enormous effects on the economy."
Climate change may have an effect on the increasing threats of storms, Franklin said.
"On a scale beyond hurricanes, there is global warming which tends to be an intensification of extremes," Franklin said. "Wetter areas get wetter. Drier areas get drier. And New England is a very wet part of the country."
Geography major Matt Pierce '14, who assisted in surveying rivers for the project, said that the possibility of increased storm frequency will cause people to think more seriously about the risks these storms pose. Research and numbers do not convey the same sense of reality as personal experience does, he said.
"Overall, people don't really think about these types of events unless it happens to them or their neighbor, or their own barn or house is wiped out by a river," Pierce said. "Locally, people who've experienced the power of a stream they can relate to it but otherwise people may find it hard to fully understand."
He said he hopes that this attention will increase the number of researchers studying these types of storms and their consequences.
Renshaw could not be reached for comment by press time.
