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Shocks in the evolution of an eroding channel
Department of Mathematics, Westfield State College Westfield, MA 01086, USA E-mail address: ewelsh{at}wsc.ma.edu
Department of Mathematics, University of California Santa Barbara, CA 93106, USA E-mail address: birnir{at}math.ucsb.edu
Department of Mathematics, University of California Los Angeles, CA 90095, USA E-mail address: bertozzi{at}math.ucla.edu
Analysis of an evolution model for a river channel shows how three types of shocks determine the profile of the channel. This model shows that in a young river channel, evolution is driven by a small perturbation magnifying into a bore followed by a hydraulic jump. This mechanism produces a convex profile typical of young landscapes. A small knickpoint then develops at the bottom of the unstable convex profile. This knickpoint evolves into a diffusive shock which travels upslope, digging into the convex profile until the profile becomes concave, typical of mature landscapes.