Hal,
  It seems that I have run across a study or two about how the river
affected the communities along it.  I, for one, am very interested in how
Twain represents and imaginatively reconstructs the Mississippi to serve his
fictive purposes.  My chapter in the proposed Mark Twain's Geographical
Imagination addresses some of these issues.  Of course, being a "river rat"
myself helps.  For example, I have intimate knowledge of how Alton's
location was central to that community's development, culturally and
economically.
  Regards,

  Sandra Littleton Uetz