Johnson, J. H., R. C. Solomon, C. R. Bingham, B. K. Colbert and W. P. Emge 
(1974).  Environmental analysis and assessment of the Mississippi River 9-ft 
Channel Project between St. Louis, Missouri, and Cairo, Illinois. Army Engineer 
Waterways Experiment Station, Report Y-74-1.
	
The Mississippi River 9-ft channel project was authorized by the River and 
Harbor Acts of 1927 and 1930. The purpose of the project was to maintain 
navigation from the confluence of the Missouri River to the confluence of the 
Ohio River. The main channel will be contracted to 1500 ft between riverward 
ends of dikes throughout the area to maintain the 9-ft depth during periods of 
low flow. A comprehensive study of the historical geomorphology supplemented by 
physical models of the river and side channels was made to determine the physica 
impact of river contraction works on river morphology and behavior. An intensive 
study of the terrestrial flora and fauna was conducted to inventory the existing 
organisms and communities located in the unprotected floodplain and to assess 
the impacts of operation and maintenance activities. The aquatic flora and fauna 
were studied to inventory the aquatic communities present in the study area and 
to assess the importance of side channels to the riverine ecosystem. The 
relative biological importance of each side channel, established by ranking 
procedures, provided a rational choice of those side channels that could provide 
maximum benefit to the river 's ecology. Operation and maintenance activities 
include maintenance dredging, disposal of dredged material, and construction and 
maintenance of levees, dikes, and bank revetments. The mentioned activities were 
examined, and the potential environmental impacts resulting therefrom were 
discussed. (Adams-ISWS)