Physical changes due to navigation in the Upper Mississippi River System

The Mississippi, Illinois, Ohio, and Missouri Rivers are used
extensively for the transport of goods and commodities, as well as
for recreational activities.  The Upper Mississippi River System,
extending from its confluence with the Ohio River to its
headwaters near St. Paul, Minnesota, is used extensively by
commercial barge traffic with typical configurations of about 32.1
by about 335.5 meters in plan form, with a draft of 2.74 m.  A
barge convoy such as this can move up and down the river at speeds
from about 1.35 to 4.4 meters per second.  Movement of such a body
through a river whose cross section in low-flow conditions can be
as little as 275 by 3 to 4 m creates significant disturbances of
the river environment.  The changes in the river environment
resulting from the movement of such traffic may include creation
of waves and drawdown, altered velocity and pressure regimes,
resuspension and lateral movement of sediment, and temporary
changes in flow direction due to the return flow.  Research has
been initiated to determine the physical changes associated with
navigation within the Illinois and Mississippi Rivers. Field data
on various hydraulic and sediment resuspension characteristics
have been collected and analyzed to determine functional
relationships.  These physical relationships will be used in the
biological models to identify and determine changes in the aquatic
environment due to navigation traffic.  This paper discusses some
of the physical changes in a large river environment due to
navigation traffic.