Environmental Analysis and Assessment of the Mississippi River 9-ft Channel Project Between St. Louis, Missouri, and Cairo, Illinois.

摘要

This project was authorized by the River and Harbor Acts of 1927 and 1930, for the purpose of obtaining and maintaining a 9- by 300-ft channel for navigation from the confluence of the Missouri River (St. Louis, Mo.) to the confluence of the Ohio River (Cairo, Ill.). The main channel will be contracted to 1500 ft between riverward ends of dikes throughout the study area in order 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 physical impact of river contraction works on river morphology and behavior. An intensive study of the terrestrial flora and fauna was also conducted to inventory the existing organisms and communities located in the unprotected floodplain and to assess the impacts of operation and maintenance activities on the organisms and communities. In addition, 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.