Characterizing acoustic propagation within the approach channel to Brandon Road Lock and Dam

A propagation experiment was conducted in the approach channel to the Brandon Road Lock and Dam on the Des Plaines River in Joliet, Illinois, over the course of ten days in 2017. A sequence of frequency sweeps, continuous tones, and white noise was broadcast from an underwater transducer deployed from a shallow draft workboat at nine locations within the channel. A vertical array of one tri-axial particle motion sensor and three hydrophones was deployed from a movable platform and recorded signals throughout the approach channel. An additional bottom mounted, autonomous recorder with one hydrophone and one particle motion sensor was deployed outside of the navigable channel for the duration of the experiment. The engineered channel includes cement walls and floors near the steel lock doors, transitioning to natural surface shoreline down channel. For sources or receivers near the lock, the highly reverberant interfaces dominate propagation effects. This presentation will compare results of the measurement experiment with propagation models.