Bank Erosion of the Illinois River

Causative factors of river bank erosion are many and varied. The major causes of bank erosion are fluvial processes, including floods, seepage, freezing and thawing, waves generated by river traffic, animal activity, overland drainage, eddies, and local flow disturbances. Even though in many cases large floods do have a dominant impact on bank erosion, depending on the composition of the bank materials, other factors may contribute to large-scale river bank erosion. Bank erosion on the Illinois River is caused by almost all the factors mentioned above. In a major investigation of the causes of bank erosion on the Illinois River, it was found that normal fluctuations of stages have a dominant impact of bank erosion, followed by seepage, waves, river traffic-generated disturbances, local secondary circulations near the failed banks, local surface drainage, and weathering due to freezing and thawing. All bank erosion sites on the Illinois River were found to follow about six different types of failure mechanisms. Detailed data were also collected from several severe erosion sites identifying specific failure mechanisms, including causative factors of failure.