Influence of Vessel Movements on Stability of Restricted Channels

Predictive equations based on a combination of theory and observations have been proposed for quantifying the environmental effects of ship passages through restricted, ice‐covered channels. In addition to natural channel flow, the forces considered include ship‐induced backwater, propeller jet, and surface‐waverelated flows. The equations are used to model forces created by vessels transiting the St. Marys River in northern Michigan during open water conditions and in an extended navigation season when an extensive ice cover is present. Vessel‐induced sediment transport as related to water quality problems is examined. Results of model calibration with data collected during summer and winter ship transits of the river suggest a capability for estimating, with reasonable accuracy, environmental effects of navigation activities in all seasons. The model has been calibrated specifically for the St. Marys River; however, it is sufficiently general to be of use in other geographic and environmental settings.