FROM SLOPE MORPHOMETRY TO MORPHOGENETIC PROCESSES: AN INTEGRATED APPROACH OF FIELD SURVEY, GIS MORPHOMETRIC ANALYSIS AND STATISTICS IN ITALIAN BADLANDS

Abstract

Calanchi (singular calanco) represent a typical example of badlands in the Italian peninsula, which rapidly evolve on clayey terrains such as the widespread Pliocene-Pleistocene marine clays. The present study aimed at investigating the role of the slope morphometry on the typology and distribution of morphogenetic processes in a calanchi area located in southern Italy. The research included detailed geomorphological surveying, morphometric and statistical analysis. The study area was first subdivided into individual hydrographic units (HUs), for which field survey allowed to identify the dominant denudation processes, their intensity and the distribution of the associated landforms (pipes, rills, gullies, landslides). The morphometry of each HU was characterized by calculating the Morphometric Slope Index (MSI) on a reconstructed digital elevation model (DEM). By statistically comparing the morphogenetic and morphometric data, the influence of the slope morphometry on the type, distribution and evolution of the calanchi erosion process has been highlighted. In particular, through a Cluster Analysis the groups of HUs having similar dominant processes were identified and, by applying the Analysis of the Variance, the effect of the MSI on the identified clusters was analysed. Two clusters were identified which revealed the relative importance of morphogenetic processes and the strict connection between surface and subsurface landforms. These two clusters were discriminated by the MSI value (high MSI favoured mass movements, whilst low MSI favoured gully erosion and piping), highlighting the importance of slope morphometry in driving the morphogenetic hillslope processes.