The sedimentary layers that make up the earth’s surface tell the story of how the top most layers have shifted and changed over the years due to transport and deposition of sediment over time. Woodruff uses this depositional record to develop probability prediction rate models for recurrence of future large weather events.
His work focuses on the mechanisms of sediment transport during extreme flooding and what that can tell us about the timing and occurrence of the weather phenomena that caused it.
Using Hurricane Sandy as an example, Woodruff notes, “We can look at how that impacted the northeast U.S. coastline and how it brought unusual sediment to areas that don’t normally experience that type of flooding and inundation. We can use this to improve interpretations of older sediments at the same location and to get a sense of how earlier events have impacted the area.”
Working in the Connecticut and Deerfield River watersheds, Woodruff studies the processes that govern sediment transport in freshwater tidal rivers. His earlier work on the Lower Hudson River estuary combined physical oceanography with marine geology and provided a backdrop for understanding the effects of spring floods on trapping sediment.
Spring floods were the original focus of his work in the Connecticut River Valley until Hurricane Irene hit in 2011. Irene provided a unique opportunity for Woodruff and his students to compare their seasonal flooding data to the extreme flooding effects Irene had on the depositional record of the Connecticut and Deerfield Rivers.
Notes Woodruff, “We have to look at how these large flood events are recorded along the flood plain of river systems. With Irene, it was not only how unique of an event it was, but also the question of how land use changes affected the imprint of this type of event along the river.”
With funding from the National Science Foundation Rapid Response Research (RAPID) program, Woodruff was able to conduct a swift response survey of sediments deposited immediately after Irene and compare them with sedimentation rates recorded earlier. The research findings showed that as much as forty years’ worth of sediment from the Deerfield River was transported during the three-day hurricane. Woodruff’s work on Irene’s distinctive sedimentary imprint with doctoral student Brian Yellen is helping to construct an extended record of extreme precipitation events that will go back centuries prior to those currently recorded.
According to Woodruff it is not just the amount of sediment that gets transported that is important to note, but also the type of sediment. In the case of Irene, the sediment was inorganic and fine grained, which is atypical for the lower river system. “In many ways, it served to cap hot spots of industrial contamination in the lower river with this fine grained, impermeable layer of glacial powder still stored in the upper watershed,” says Woodruff.
Woodruff also specializes in the depositional records of tropical cyclones. His doctoral work focused on new methods to quantify and assess the statistical significance of weather trends in the North Pacific. With support from the National Geographic Society, he developed a typhoon reconstruction that extends back 6,000 years; the first record of its kind. His research reveals not just storm impact but also the factors affecting the variability and intensity of the storms. In another project, Woodruff and doctoral student Christine Brandon are developing a unique approach to reconstructing cyclones which will help gauge their intensity as well as their frequency.
Woodruff’s research is also being used to assess the recurrence probability of events such as the 2011 Tohoku earthquake and tsunami. Results of this research, which continues at various sites in Japan, can be used by land developers and insurance companies interested in predicting risk of extreme weather and flooding.
As an educator, Woodruff has been instrumental in enhancing the geosciences curriculum by increasing hands-on experiences for students such as turning the Connecticut River into a “learning, living lab and helping to acquire laboratory equipment such as the department’s new x-ray fluorescence core scanner. These additions, as well as upgrades in the Quaternary Lab and Electron Microprobe/SEM facility, further enhance UMass’s position as a national leader in climate change and extreme weather research, through both the campuses Climate System Research Center housed in Geosciences and the Northeast Climate Science Center.
Banner Photo Courtesy NASA 2011
Woodruff’s work on distinctive sedimentary imprints is helping to construct an extended record of extreme precipitation events that will go back centuries prior to those currently recorded.