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