How is topographic simplicity maintained in ephemeral dryland channels?

摘要: The lack of topographic complexity in ephemeral dryland channels, despite large variations hydraulic controls and sediment texture, presents an unexplained paradox that limits understanding their long-term evolution. In basins, spatially temporally discontinuous channel flow transports sorts along the bed intermittently irregularly. cumulative effect these processes counterintuitively produces simple topography, manifest straight longitudinal profiles symmetrical cross sections, contrast with perennial channels. This paper numerical modeling experiments based on field measurements to investigate development through responses bed-material flux net storage hydrology. We show variable creates subsequently destroys incipient topography reaches, flood events above a threshold overcome grain-size dampen fluctuations smoothing bar forms. results provide physical explanation for emergent simplicity channels higher variability streamflow sedimentary characteristics compared systems.