Simulating Barge Drawdown and Currents in Channel and Backwater Areas

Abstract

The act of a barge train navigating along a waterway produces waves and alters the river's currents. The drawdown wave causes flow exchange with the backwaters and side channels. The return currents in narrow waterways can also result in sediment resuspension. The highly variable topography along the waterway complicates this behavior by means of reflections, amplification, and resonance. Simple empirical solutions are applicable to idealized channel shapes but are too limited for general riverine topography. Physical models are unrestricted in this respect but have limitations related to expense and scale effects. In this paper, vessel effects are modeled numerically using a moving pressure field to represent the vessel's displacement. A comparison of a moving pressure field in a shallow-water model to flume tests has been previously reported. This study extends the model testing to include field data. The numerical results for return flows and water-surface elevations from vessel passages are presented for various types of river systems. Emphasis is given to describing the waterways' response to barge-generated currents and waves.