Flooding and paleoclimatology of central NH wetlands

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Student Showcase of Research & Engagement Spring 2019
Larose, Kayleen
Every watershed has its own local potential for flooding, but the scale of regional events affect multiple watersheds. By examining paleoflood records of regional events, we can determine the frequency of regional floods and improve resilience to them at the local scale. Selecting the right management style for a particular wetland is important for maintaining a functioning and sustainable environment. Increased development or unsustainable management approaches can lead to changes in local hydrology and increased erosion of the shore, enhancing sediment build up on the lake/wetland beds and causing eutrophication at an increasing rate. This project aims to enhance community preparedness by identifying the frequency of high magnitude flooding over several thousands of years in central New Hampshire. Multiple sediment cores have been extracted from two flood-sensitive wetlands, Quincy Bog in Rumney, NH and McLane Bog located on Newfound Lake. I have been working on these cores in the laboratory to determine evidence of flood deposits through calculating water content, loss on ignition (organic matter), magnetic susceptibility, and particle size distribution. Using Carbon-14 and Lead-210 isotopes, layers within each core have been dated and correlated to determine whether flooding events are local or regional, overlapping at both sites.