Lateral Migration Rates of River Bends

Time sequential aerial photographs flown approximately 20–30 yr apart have been used to measure the lateral migration rates of 189 bends on 21 clay, sand and gravel rivers in Western Canada. Channel migration rates transformed to a reference bend curvature $(r/w=2.5)$ are shown to be a simple function of stream power, outer‐bank height, and a coefficient of resistance to lateral migration $Y_b\text{.}$ This coefficient in turn is shown to be a function of the texture of the outer bank materials, with a complex form similar to that of the Hjulstrom or Shields sediment entrainment function. The task of specifying the channel migration rate appears to be essentially a sediment transport problem.