The study of river channel processes both has a long history and is of very broad concern. Since the time of Leonardo da Vinci, and more particularly in the last century, the scientific investigation of river channels has expanded to incorporate such fields as flow hydraulics, bed mechanics, sediment transport and sedimentation. Morphology—and particularly the cross section and plan-form properties of channels—has increasingly been linked to river flow characteristics and related to the properties and quantities of bed materials and transported sediments.