Identification of study approaches to determine physical impacts of commercial navigation on the Upper Mississippi River System

Vessel traffic and river environment descriptor variables have
been listed and the magnitudes of their ranges defined.  Target
physical variables were selected on the basis of their likelihood
of having biological effects.  The total number of variables is
34, not including several basic quantities like water density and
viscosity, which were introduced in a discussion of dimensional
analysis.  Dimensional analysis was used as a rational approach to
a conceptual model of the physical impacts of navigation on
constructed waterways.  Eight parameters characterizing the
physical effects of tow passages were discussed in detail. 
Because of its complexity, special attention was given the effects
of the propulsion system.  Study approaches to determine the
relationships between tow passage characteristics and typical
target physical variables were treated from the perspective of
hydraulic engineering.  The basics of scale for physical effects
were presented, but the appropriate scale for the biological
aspects remains unknown.  A final section presented an approach
that involves three levels of model to conceptually relate tow
passage to population scale effects on the biota of the riverine
ecosystem.