Flood control structures (e.g. levees) and navigation dams on the Upper Mississippi River modify river hydrology, potentially changing the comporition of floodplain forests. Channel constriction and impoundment contribute to differing reductions in water level variation within navigation pools. Historic hydrologic conditions (e.g. flood frequency, flood depth, etc.) on the Mississippi River differ greatly from current conditions, so older trees may no longer be growing in under the hydrolic conditions in which they established. This may potentially affect the success of seedlings from particular species to establish. This study is intended to (1) quantify differing patterns in forest community with Navigation Pool 24 and (2) describe the differential responses of species in relation to the varying hydrology. U.S. Army Corps of Engineers forest survey data, river level data, and elevation data were integrated using GIS. These data were analyzed by plot, in addition to being aggregated to stands defined by U.S. Army Corps of Engineers management unit, river mile, historic land class, and elevation, respectively. The results of this study indicate that forest communities and individual species respond differentially along the hydrologic gradient that exists within Navigation Pool 24.

The River and Harbor Act of 3 July 1930 authorized the construction and maintenance of a 9-ft-deep by 300-ft-wide channel for commercial navigation of the Upper Mississippi and Lower Illinois Rivers. Construction of locks and dams supplemented by dredging and bank stabilization was required to maintain the 9-ft depth, particularly during periods of low flow. An investigation was performed by Colorado State University to evaluate the river reaches before and after man-made changes and overall changes in geomorphology. Additionally, trends of future geomorphic changes that could result from existing and potential future developments were addressed with the aid of a mathematical simulation model. Vegetation and vegetative successional patterns of the floodplain were characterized by the Missouri Botanical Gardens. Vegetation maps were produced delineating vegetational communities adjacent to the rivers and on islands. An inventory of the animals and their habitats was conducted by Southern Illinois University.