Wilson, Matthew J., Freshwater Research Institute, Susquehanna University, 514 University Ave, Selinsgrove, PA 17870, wilsonmatt@susqu.edu; Ressler, Daniel, Department of Earth and Environmental Sciences, Susquehanna University, 514 University Ave, Selinsgrove, PA 17807, resslerd@susqu.edu; Fathel, Siobhan L., Department of Earth and Environmental Sciences, Susquehanna University, 514 University Ave, Selinsgrove, PA 17807.
Ephemeral streams are critical conduits connecting watersheds to their receiving waters, yet these systems are typically not prioritized in stream restoration. In addition, these systems provide a great opportunity for testing restoration methods with low risk to aquatic life. In Fall 2023, we installed eight beaver dam analogs (BDAs) along a 200-meter stretch of a deeply incised ephemeral and stormwater-driven stream at Susquehanna University’s field station with the goal of aggrading the channel and reconnecting the stream to its floodplain. To quantify the effectiveness of these structures we completed pre- and post-installation survey transects across the stream and floodplain above and below each dam, along the length of the thalweg, and installed pressure transducers (water depth) and temperature loggers above each dam. Transects 8 months-post install show aggradation above dams up to 50% of the incised area, with decreasing aggradation further downstream. Storm events increased in intensity between January and May 2024, yet the rate of increase in water depth (i.e., flashiness) decreased during this same period. In addition, flashiness decreased by a greater magnitude at further downstream BDAs indicating cumulative benefits of these structures when installed in series. To our knowledge, this experiment marks the first use of BDAs as a stormwater management technique in an ephemeral system and the first BDAs installed in Pennsylvania. This has prompted the creation of a state-wide working group for more broad application of process-based restoration and opportunities for collaboration will also be discussed.
process-based restoration, geomorphology, stormwater management