The Processes Surrounding Channel Evolution following a Partial Dam Removal on the Coastal Plain of Virginia

摘要

The physical changes to a newly forming river in a slow draining reservoir following partial dam removal are the focus of this investigation. Past research on the effects of dam removal have focused on changes to the morphology of the downstream channel. This research evaluates the independent parameters controlling channel evolution in the draining reservoir. This research uses a case study to determine the controlling parameters in the channel evolution post dam removal and to develop a conceptual model that is applicable to draining reservoirs on the coastal plain where there is high cohesive sediment content. A partial dam breach on a tributary of the James River (VA) has led to slow draining of the reservoir. Data collection included suspended and bedload sediment, discharge rates, bank material samples, and cross sections at twenty-meter increments every four months for two years. A complete documentation of channel adjustments was performed, including the identification and classification of forms and processes observed and the quantification of the dominant processes of channel formation. Data from the study site is to test the accuracy of current methods of predicting channel behavior following a dam break and to develop a conceptual model describing channel formation in draining reservoirs in the coastal plain.