Variability in channel form in a free-flowing dryland river

This study examines channel form of the Verde River system in order to explain system fragmentation. Morphologic analyses draw from discharge and shear stress calculations generated by modelling the flow through 14 surveyed cross-sections along the Verde River, representing six river segments with distinct hydrologic and geologic characteristics. At-a-station and downstream hydraulic geometries for the Verde River highlight local variability in channel morphology. Modified at-a-station hydraulic geometry analyses using cross-section subsection discharge and shear stress values similarly show greater variability within cross-sections than between cross-sections. Competence and capacity increase at a fairly uniform rate for similar features throughout the system, indicating an overall efficiency in sediment transport. Variations in channel form and associated sediment transport as represented by competence and capacity are largely related to combinations of macroscale local factors, including channel pattern, gradient, valley width, tributary inputs and human activity rather than megascale, basin-scale or subbasin scale factors. Copyright (C) 2006 John Wiley & Sons, Ltd.