LIST OF FIGURES 



Map of Study Area, Showing Sampling Stations, 



Navigation Pools, and Sections of the Illinois River ... 10 



Map of Study Area, Showing Cities, Lock and Dam Sites, 



and the Drainage Basin 11 



Mean Water Levels, Mean Discharge, and Mean Dissolved 



Oxygen Levels During July and August and the Number of 



Largemouth Bass Taken Per 30 Minutes of Electrof ishing 



in the Fall at Chillicothe Island Chute (Mile 180) on 



the Illinois River 39 



Minimum Dissolved Oxygen Levels in the Illinois River 



in 1965 and 1966 58 



Dissolved Oxygen Concentrations and Turbidity in the 



Middle of the Navigation Channel of the Illinois River 



at Mile 25.9, During Passage of Towboats on Three 



Occasions on November 7, 1963 64 



