GIS-MORPHOMETRIC ANALYSIS OF BADLANDS IN SICILY (ITALY)

Abstract

Sicily is affected by severe erosion processes, locally causing large volumes of soil loss and high denudation rates. The effects of intense water erosion phenomena are testified by the occurrence of badlands that constitute a common landscape particularly in the central and southern areas of the Island, where slopes are frequently underlain by clay-rich deposits. This paper presents the first results of an investigation carried out in a badlands site located in the head sector of the Imera Meridionale river basin, where geometry of several erosion channels has been characterized. Since length of linear erosion landforms such as rills, ephemeral gullies and permanent gullies, has been proved to be a good estimator of the eroded volume in different environments, this experiment aims at verifying if similar relationships can be identified also for badlands channels. In order to quantitatively describe the geometry of the erosion landforms, a 2 m cell digital elevation model and GIS-spatial analysis tools were exploited. Width, depth and length of the channels have been measured on cross-sections spaced at 5 m or 3 m. Cumulative length and volume of the different channels have been plotted on scatter diagrams showing highly significant power relationships; moreover, length, depth, width and volumes of all measured channel segments were combined into two dimensionless groups, already tested for other channelized erosion landforms, that provided measured pairs also highly correlated by power relationships. The result of this experiment agrees with those of other investigations carried out for rills, ephemeral and permanent gullies, confirming that: i) strong functional relationships between length of linear erosion landforms and eroded volumes can be identified regardless of the channels size; ii) badland channels show a morphological similarity with the other investigated types of linear erosion landforms.