Geomorphic Response To The Removal Of The Ward’s Mill Dam On The Watauga River, Western North Carolina

Dam removals are a growing trend in the United States, averaging 90 per year in the past decade. Current removal studies indicate ecological benefits of river re-connectivity outweigh the economic benefits and costs of maintaining aging infrastructure. However, there is a lack of comprehensive studies in certain regions of the United States, including Southern Appalachia. In May of 2021 the Ward's Mill Dam, a 6 m high dam located on the Watauga River in North Carolina, was removed. This removal was an opportunity to study geomorphic impacts to such removals in this understudied region with the objective of identifying changes in channel form, analyzing bed sediment characteristics, and quantifying rates of volumetric evacuation and deposition. To capture geomorphic change repeated pre- and post-removal cross-sectional surveys, longitudinal profiles, and in-situ particle size sampling was conducted in upstream and downstream reaches. Field collections the day after removal show significant deposition of gravel sized particles 200m downstream of the dam and shifted the channel slope to -1.11% grade. Channel bed texture remains significantly finer across the 2km downstream study reach 506 days following removal. Erosion rates of the impoundment during the deconstruction period averaged 860 m3/day and decreased to 75.5 m3/day by day 74.