A METHOD FOR ESTIMATING LAND LOSS ASSOCIATED WITH STREAM CHANNEL DEGRADATION

Since the turn of the 20th century, stream channel widening has accompanied channel degradation in areas of thick loess deposits along the Missouri and Mississippi Rivers. The objective of this study is to illustrate improved methods of estimating land loss associated with these processes. It has been established that the main cause of bank retreat is mass movement, not the tractive force of flowing water. The method suggested here combines the semilog equilibrium longitudinal profile used to predict the maximum depth of channel erosion with a planar failure-surface slope stability analysis to estimate the amount of widening. Equations and a flow diagram are provided describing the sequence of calculation.