Bed armouring processes: Systematization of theoretical bases and case study in Southern Serra Do Espinhaço (MG)

Abstract

The bed armouring processes refer to the presence of immobile (or immediately immobile) sediments in the river channels, preventing the removal of potentially transportable grains. Thus, a detrital floor is formed on the bed surface, which offers great resistance to the abrasive processes. Although widely discussed in the international literature, there are few national contributions to bed armouring studies. The present work proposes, from a systematization of the theoretical bases, to investigate the occurrence of the armouring processes from the geomorphological point of view. In order to do so, the Rio Grande Stream (Southern Serra do Espinhaço, MG) is adopted as a case study. Based on the in situ investigation of the detrital pavements that characterize the bed armouring processes, it was possible to associate the bending of the presence of the immobile sediments to the hydrogeomorphological conditions of the fluvial channel in three of the four segments investigated. Field evidence indicates the hydrogeomorphological dynamics consequent to the presence of the clusters is characterized by morphology in riffle-pools and by a morphodynamics marked by meandering processes.