Linking levee-building processes with channel avulsion: geomorphic analysis for assessing avulsion frequency and channel reoccupation

Abstract. A natural levee is a typical wedge-shaped deposit adjacent to river channel. Given its location and distinctive features, the can serve as key revealing depositional processes of coupled channel floodplain system preserved in rock record. Levee–floodplain topographic evolution also closely linked avulsion which cause catastrophic floods. Nonetheless, geometry aggradation pattern on have not been fully incorporated study avulsion. Here, we present levee-building model using advection settling suspended sediment reproduce fluvial over floods examine effects boundary conditions grain-size trend deposit. We further investigate frequencies potential reoccupation associated with distribution overbank flux overflow velocity into floodplain, both control geometry, especially rate at crest. In modeling results, develops (1) concave-up profile, (2) an exponential decrease grain size away from main channel, (3) relatively steeper shape for coarser supply vice versa. The subsequent scaling analysis supports that input profile slope are positively correlated frequency, whereas inversely proportional frequency. connection styles suggest slopes tend promote more reoccupations preexisting channels protecting abandoned healing, but gentler levees likely create new their remnant vulnerable removal memory. insights drawn current work may thus implications reconstructing paleoenvironments regard transport flood dynamics via deposits. Based roles frequency reoccupation, hazards triggered by avulsions well alluvial architecture sedimentary records be better assessed.