Maintaining and restoring the ecological integrity of the Mississippi River Sparks, R. E. 1995. Maintaining and restoring the ecological integrity of the Mississippi River: Importance of floodplains and floodpulses. Pages 90 97 in Transactions of the 60th North American Wildlife and Natural Resources Conference, Minneapolis, Minnesota, March 24 29, 1995. Reprinted by U.S. Geological Survey, Environmental Management Technical Center, Onalaska, Wisconsin, June 1997. LTRMP 97-R006. 8 pp. (NTIS #PB97-176622) ABSTRACT Although the upper Mississippi River and one of its tributaries, the Illinois River, are altered, they retain a surprising degree of structural and functional integrity because they have floodplains and seasonal floodpulses. The rivers have not been impounded for water storage behind high dams, such as those on the Colorado, Columbia, or upper Missouri Rivers. The navigation dams on the Mississippi and Illinois maintain water depths for navigation during the low flow season, but do not stop floods. Sizable floodplains have been preserved north of St. Louis in the National Fish and Wildlife Refuge System and in a collection of state refuges, parks, and hunting and fishing areas along both rivers. Managing the rivers to maintain and recover ecological integrity involves: (1) maintaining water and sediment quality within limits that enable native plants and animals to perpetuate themselves; (2) maintaining or restoring the master processes that enable the river-floodplain ecosystems to maintain, repair, and rejuvenate itself; and (3) preventing invasions by nonindigenous species. Master processes include the abiotic processes of flooding, erosion, and sedimentation that maintain floodplains and deltas and the biotic processes of colonization and succession that rebuild biological communities following disturbances. Examples of ecosystem management include: (1) improving land and water management in the tributary basins to reduce excessive run off and sediment delivery to the main rivers; (2) changing the operating procedures of the navigation dams to provide more natural floodpulses; (3) taking advantage of periodic droughts or dam repairs to draw water levels down sufficiently during the summer to expose mud flats, dry and compact sediments, and stimulate regeneration of vegetation; (4) using deflection dikes, hard points, and selective dechannelization of some tributaries to guide ongoing sedimentary processes so that the river maintains or recreates the landform diversity that maintained biodiversity; and (5) reducing introduction and spread of invasive species through regulation, public education, and use of dispersal barriers at invasion points (e.g., at the interbasin connection between the Great Lakes and Mississippi drainages at Chicago). KEYWORDS Backwater, basin, biodiversity, biological integrity, channel, conservation, ecological health, ecological integrity, ecosystem management, flood, floodplain, floodpulse, habitat diversity, Illinois River, invasive species, landform, landscape, levee, Mississippi River, navigation dam, restoration, sediment, water regime, watershed, wetland