A Numerical Model of the Effects of Propeller Wash and Ship-Induced Waves from Commercial Navigation in an Extended Navigation Season on Erosion, Sedimentation, and Water Quality in the Great Lakes Connecting Channels and Harbors

Forces generated over and above the natural forces created by fluid flow in channels stems from ship traffic in river channels. When the magnitude is sufficient, these forces can have an adverse impact on the natural river flow environment. Propeller jet and displacement or backwater flow velocities, ship waves and drawdown effects all contribute in part to development of these forces. In order to plan for improvement and optimum use of waterways, it is necessary to estimate the magnitude of these forces and the resulting environmental effects, especially channel bed erosion rates and the increase of suspended solids. This report addresses the effects of propeller jet and backwater velocities and ship-induced waves by creating a mathematical model. Predictive equations based on a combination of theory and observations have been developed for estimating the unknown quantities. Equations are used to model forces by vessels transiting harbors and connecting channels of the Great Lakes. The mathematical model has been computerized in FORTRAN 77 code for real-time execution on an IBM-PC-AT computer or compatible machine with at least 10 megabytes of random access memory. The principal objective of the computer model is to permit an assessment of the environmental effects of vessel operation in an extended navigation season when ice cover is present.