9 Northeast Water Cycle Research: Collaborative Studies of Watershed Processes to Address Water Resource Challenges in a Changing Climate (Posters)

Friday, 28 March 2025
8:30 AM - 5:30 PM
North Great Hall

WELL-CONNECTED FLOODPLAINS ENHANCE RESILIENCE TO EXTREME EVENTS: A CASE STUDY IN FLOOD ATTENUATION FROM THE LEWIS CREEK WATERSHED, CENTRAL VERMONT

Paper number: 9-3
Program: Theme Sessions
Time: 8:30 AM – 5:30 PM

Authors

Abstract

Extreme precipitation events are happening more frequently in the Northeast, causing significant flooding impacts. In July 2024, Vermont experienced widespread flooding from the remnants of Hurricane Beryl, impacting communities across the state. To mitigate these hazards, floodplain restoration and rehabilitation can be used to attenuate flood waters. Well-connected floodplains can temporarily hold water and slow runoff, reducing downstream peak flood levels, stream power, and erosion. By restoring floodplains, we can help build flood-resilient communities and better prepare for future precipitation events.

To look deeper into this, we studied the role of floodplain attenuation in the Lewis Creek watershed in Vermont during the July 2024 flood, using precipitation records, imagery, streamflow measurements, and flow frequency analysis. In the upstream portion of the Lewis Creek watershed, a peak runoff rate corresponding to an approximate 200-year flood event, with a discharge of 2.8 cubic meters per second (cms) per square kilometer was recorded. Approximately 27 kilometers downstream, at the USGS gage, peak flow was attenuated to 0.81 cms per square kilometer and classified as a 50-year flood event, despite the increased contributing drainage area. High-water marks and peak flow estimates further corroborated this attenuation. Lewis Creek has several accessible floodplains between the upstream and downstream locations that stored flood water, reduced the flow, and protected the North Ferrisburg village in the downstream watershed.

The decrease in runoff rates between the upstream and downstream measurements allow us to conclude the benefits of rehabilitated and preserved floodplains in reducing downstream inundation, erosion, and infrastructure damage during extreme events. The Lewis Creek watershed serves as a case study demonstrating that floodplain management can mitigate flood hazards and protect communities as Vermont, and other states, experience more intense weather events.

Geological Society of America Abstracts with Programs. Vol. 57, No. 3

doi: 10.1130/abs/2025NE-408093

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