Sedimentation in the Illinois River valley and backwater lakes

The Illinois River valley has experienced a tremendous amount of sediment deposition in recent years. Many of the 53 or so backwater lakes along this major river have lost 30 to 100% of their capacity to sediment deposition. Peoria Lake, a bottomland lake, has lost 68% of its 1903 capacity, and upper Peoria Lake will eventually attain the appearance of an incised river with broad and shallow wetlands on both sides. On the average about 18.7 million metric tons of sediment is deposited annually over the entire river valley, with a deposition rate of 20.5-53.3 mm yr^-1. Recently implemented nonpoint source pollution control measures are showing their impacts on the receiving bodies of water through substantially lower concentrations of trace elements within the recently deposited sediment.