Movement of navigation traffic such as barge tows within a restricted inland waterway such as the Illinois, Mississippi, or Ohio Rivers can and will alter the flow field in and around the moving vessel. These changes in the flow field will include altered velocity distributions, increase and/or decrease in the pressure field, and a directional change of the flow within the zones of return flows. Normally, as a barge-tow configuration of about 105 feet by 1,100 feet in surface area and a 9-foot draft moves within a river cross section of about 800 feet by 12 feet, significant changes on the flow field occur. River traffic such as this can also generate waves and drawdown, which sometimes range from a few inches to 12 inches or more. Appropriate management alternatives for large river systems must accommodate recreation, water supply, and water quality considerations, aquatic habitats, commercial navigation, and maintenance of appropriate environmental quality. Therefore, the physical forces associated with the movement of such a large body in the river must be properly evaluated and clearly understood. This paper describes the various physical forces that are either acting on or are being altered by the movement of navigation traffic within the river and how these forces can be evaluated and quantified.