Ressler, Daniel E., Department of Earth & Environmental Sciences, Susquehanna University, 514 University Ave, Selinsgrove, PA 17870, resslerd@susqu.edu; Wilson, Matthew J., Freshwater Research Institute, Susquehanna University, 514 University Ave., Selinsgrove, PA 17870, wilsonmatt@susqu.edu; Fathel, Siobhan, L., Department of Earth & Environmental Sciences Susquehanna University, 514 University Ave., Selinsgrove, PA 17870, fathel@susqu.edu.
Ephemeral streams are often conduits for stormwater runoff from agricultural and urbanized landscapes. These channels are quickly inundated by storm flows, convey large quantities of water at high velocity during short episodes, then drain completely soon after the storm event. Water flows often scour the channel and threaten nearby vegetation and infrastructure by eroding banks and carving a deeply incised channel. Beaver dam analogs (BDAs) are a stream restoration structure that might reduce water velocity, create sediment traps, and store more water in the subsurface to reduce the destructive energy of these high storm flows.
Eight BDAs were installed in October 2023 in an ephemeral stream on Susquehanna University’s field station where storm flows have been incising a channel and threaten mature trees, railroad culverts, and roadway ballast by undercutting the channel banks. The channel bottom was sampled prior to BDA installation, then 6 months after installation. Channel surveys show significant sediment retention in the upstream “beaver ponds”. We are evaluating whether the retained sediment is finer than the initial sediment, which would suggest slower velocity water and less energy to move coarse gravel during bed-load transfer events. Stormwater delivery to the channel has significant exposure to railroad ballast (diabase and industrial slag), parking stormwater infrastructure (No. 2 limestone gravel), and agricultural fields (sandstone cobbles). By recording the mineralogy of the cobbles and gravel during examination, we hope to also demonstrate changes in transport of each material along the ephemeral channel.
Beaver Dam Analog, Stream Restoration, Sediments, Gravel size distribution