STREAMBANK EROSION ALONG 2 RIVERS IN IOWA

Rates and processes of bank erosion were evaluated for reaches of two alluvial, equiwidth to wide bend, point bar streams in Iowa: East Nishnabotna River and Des Moines River. The evaluation was made using historical records (airphotos, maps, and streamflow records), field measurements, and soil analyses. The erosion rates were correlated with channel characteristics such as width, depth, curvature, arc angle of channel centerline, channel slope, friction factor, and degree of vegetation on the banks. The correlation was studied using a meander flow model developed by the author. The meander flow model simulated the velocity distribution in the bends and the location of the erosion occurrences. Estimates were made of total sediment influx to the rivers from cutbank erosion.