Dendrogeomorphic estimate of changes in sedimentation rate along the Kankakee River near Momence, Illinois

Changes in sedimentation rates wee estimated using root-burial depth and tree-age data at six selected data-collection sites along the Kankakee River near Momence in Kankakee County, Illinois. Five sites were in backwater areas away from the river channel, and one site was on a natural levee near the channel. A summary of the dendrogeomorphic data at the six sites indicates that sedimentation rates were greater after 1950 than before 1950. Greater sedimentation rates after 1950 were observed at four of the five backwater sites, whereas no change in sedimentation rate after 1950 was observed at the fifth backwater site. The observed rates could have been affected by any combination of soil erosion, soil compaction, or increased streamflow. A greater sedimentation rate after 1950 was observed at the levee site, which appeared to have been affected by erosion from a flood in 1950. Effects of erosion were not observed at any of th other sites. No erosional effects and soil not susceptible to compaction at the five backwater sites indicate that neither erosion nor compaction affected observed sedimentation rates. The effect of increased stream- flow in the Kankakee River Basin since the early 1900's on the observed sedimentation rates is not known.