Between 1893 and 1989, developers cut about 85% of the native forests in the region; most clearing was done in the early decades of the 20th century. The entire landscape was transformed into farmland by extensive logging, draining of the watershed, channelization, and the construction of flood control structures. High levees along both river courses, an extensive system of drainage ditches and diversion channels, and controlled lakes, pumping stations and cutoffs protect the area from flooding. The soils are predominantly a rich and deep glacial loess, alluvial silt, and a sandy loam, well-suited for agricultural use.