Hydrodynamic effects of navigation traffic in large rivers

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.