ABSTRACT:

In 2018 the Bloede Dam was removed from the Patapsco River near Ilchester, Maryland, USA. Located within Patapsco State Park, the 30ft Bloede Dam was the first hydroelectric dam in the U.S. and the generator was enclosed within its superstructure. However, it had been defunct for nearly a century at the time of its removal and was a considered a safety hazard for swimmers and for the nearby county sanitary sewer main, as well as a barrier to fish passage. As part of the dam removal effort, a study of the channel morphology was initiated by NOAA Fisheries and American Rivers before and after dam removal. Surveyed cross sections were located by Maryland Geological Survey at selected points along the channel upstream, downstream, and within the dam pond itself. To complement the surveyed cross sections, aerial photographs were collected using off-the-shelf aerial drones. The imagery was collected over a similar river length encompassing the Bloede pond prior to, during, and after removal was completed. Structure-from-motion photogrammetry was used to develop point clouds and topo-bathymetric digital elevation models to document channel change between just upstream of the dam pond and about a quarter mile downstream of the dam. This data release includes the imagery from that collection effort used to document sediment evacuation from the dampond. This archive was referenced in the paper by Collins, M.J., Baker, M.E., Cashman, M.J., Miller, A. and Van Ryswick, S., 2024. Impounded sediment and dam removal: Erosion rates and proximal downstream fate. Earth Surface Processes and Landforms, 49(9), pp.2690-2703.