The Grand Kankakee Marsh and Kankakee River
The Kankakee River originates near South Bend, Indiana and flows west for about 140 miles until its confluence with the Des Plains River near Channahon, Illinois forming the Illinois River. Approximately 5,800 square miles in portions of 22 counties in Illinois and Indiana presently drain into the river.
Originally about 80% of the length of the Kankakee flowed through an immense wetland known as the Grand Kankakee Marsh. It was the lowest and wettest part of a vast flat plain made up of a thick layer of sand laid down by glaciers some 10,000 to 15,000 years ago. It was about 100 miles in length, averaged about 8 miles in width, and was 3 to 4 feet deep about 8 months a year. The size of the marsh is constantly debated; however, the area most of the public would identify as “wet land” was probably near 500,000 acres. Include different types of habitat that support wetland plants and it may have been twice that size.
Prior to 1852, about 250 miles of the Kankakee River and 95% of the Grand Marsh were found in Indiana. Dredging from 1852 to 1917 removed 2,000 river bends. The river that had meandered 250 miles creating oxbows, bayous, marshes, and sand islands was channeled into a straight 90 mile ditch. Illinois citizens successfully fought channelization and most of the 60 miles of the river in Illinois remains in its natural, meandering state. The Grand Marsh, which had been the largest wetland in North America, was reduced to approximately 30,000 acres.
The destruction of the marsh and the channelization of the river created a lot of good farmland. It also created problems that exist to this day. Flooding and erosion are now serious and expensive issues in both states. Sand and silt is changing the Illinois portion of the river. It covers the rock bottom of the river there drastically affecting its biology and with every rain it displaces more water thereby increasing the potential for flooding and affecting the river’s flow.
Restoration of parts of the river and a portion of the floodplain are feasible and cost effective solutions to addressing these problems, much more than dealing with the issues years from now after more development in the basin. Restoration can also be done in a way that will attract visitors and create a local tourism industry.