During the past two centuries the Illinois River and its hydrology have been altered numerous times. Early navigation works, levees, diversion, agricultural and urban drainage practices, locks and dams and other changes all contributed to habitat modification. Over the years the river has changed from a free flowing stream bisecting a broad floodplain to a series of pools with substantial areas of leveed floodplain. The image conjured by the term “restoration” varies with the time frame used as a base. Given that all major navigation dams were in place by the1940's, a common vision of a restored river includes permanently flooded lakes and
backwaters with sufficient depth to support the flora and fauna which were abundant in the early 1950's as well as recreational boating. Others envision a relatively free flowing river with a variety of backwater and side channel habitats.Ope