Hydrodynamic effects of navigation traffic in large rivers Bhowmik, N. G., T. Soong, and R. Xia. 1994. Hydrodynamic effects of navigation traffic in large rivers. Pages 439-447 in H. Cheong, N. J. Shankar, E. Chan, and W. Ng, editors. Proceedings of the Ninth Congress of the Asian and Pacific Division of the International Association for Hydraulic Research, Developments in Hydraulic Engineering and Their Impact on the Environment, Volume 2, Singapore, Republic of Singapore, August 24-26, 1994. Reprinted by the National Biological Survey, Environmental Management Technical Center, Onalaska, Wisconsin, December 1994. LTRMP 94-R012. 9 pp. (NTIS #PB95-171864) ABSTRACT The hydrodynamic characteristics of large rivers differ from those observed in smaller streams. Large rivers by nature carry substantially larger volumes of water, and their flow more closely resembles a two-dimensional pattern than does the flow of small streams. Ambient flow patterns of large rivers can be altered at least temporarily by external disturbances created by the movement of large-scale navigation traffic. Within the Upper Mississippi River System (UMRS), consisting of about 2,100 kilometers (km) including the Illinois River, navigation traffic with a geometric configuration of about 32 meters (m) by 297 m and a draft of 2.74 m can move up and down the river at speeds ranging from 0.03 to 4 or 5 meters/second (m/s). When moving through a sandbed river about 260 m wide and 4 to 5 m deep on the average during the low flow stages, this solid body can and will temporarily alter the hydrodynamic characteristics of the river. These alterations include increased turbulence, changed velocity structures, creation of return flows, resuspension and redistribution of sediments, pulsed input of sediment and water to the side channels and backwater areas, and the generation of waves and drawdown. This paper will briefly present some of the results from a major research project conducted on the UMRS. KEYWORDS Mississippi River, Illinois River, hydrodynamics, navigation, navigation traffic, turbulence, hydraulics, rivers, sediment, sediment suspension, waves, drawdown