Cyclic steps on the Loess Plateau, China: Field Survey and Numerical modelling

Cyclic steps are long-wave bedforms that migrate upstream and are bounded by sustained internal hydraulic jumps. Each step has a gentle Froude-subcritical slope in the upstream and a steep slope related to supercritical flow in the downstream (Sun and Fagherazzi, 2003). A hydraulic jump connects two contiguous steps. Cyclic steps can be divided into three categories: purely-erosional cyclic steps, transportational cyclic steps and purely-depositional cyclic steps (Fildani et al., 2006). In purely erosional steps, that usually occur in bedrock or cohesive beds, sediment eroded from the bed is not redeposited again. Transportational steps are formed from a combination of erosion and deposition. In purely-depositional case, that can exist in deep-sea settings, deposition dominates and no sediment entrains from the bed.