The 2011 Mississippi River Flood and How the Mississippi River Tributaries Project System Provides 'Room for the River'

摘要

The Mississippi River & Tributaries (MR&T) Project was authorized by Congress in the 1928 Flood Control Act following the disastrous 1927 flood and has thus far prevented a repeat of such catastrophic flooding while providing adequate conveyance to safely pass flood events. Despite the magnitude of the 2011 flood event, flooding was limited to the conveyance areas intended for safe passage of major floods as designed by the MR&T system. As with most major floods, public and media interest focused on the areas that were flooded, but provided only limited acknowledgement of the areas that would have flooded without the project. Despite the success of the MR&T Project, some interests have raised concerns that the flood risk reduction system has overly constricted or constrained the river and its floodplain and have suggested that more of the historic floodplain should be made available for major floods, habitat and water quality concerns. The Netherlands' "Room for the River" program consists of measures and projects designed to reopen its Rhine River floodplains to address similar concerns within their river basin. The MR&T project will be compared and contrasted to the Netherlands' program with an emphasis on the differences in scale between the two programs, with respect to the overall area and volume of water that must be conveyed by the systems. Using the 2011 Flood results, this paper compares how the MR&T project system was designed and how it functioned to provide "Room for the River" while limiting flooding impacts to the four million residents of the Lower Mississippi River basin.