This river's widest point, 3 1/2 miles, is just north of Clinton, Iowa
... 
structure has been constructed, just south of the Lapalco Bridge at Mile 2.8, West 
of the .... Current velocities: 1/2 mile per hour at ordinary stages; about 5 miles 
per hour .... Clinton, Iowa, was last dredged in 1975 to project depth and 250 feet 
wide.