In the Mediterranean areas, specifically in Sicily (Italy), irregular rainfalls, strong seasonal changes, scarcevegetation cover and, frequently, outcropping of clayey deposits favor water erosion phenomena. Badlandlandscapes are the result of severe erosion processes, characterized by steep slopes, sparse vegetation, highdrainage density, rapid erosion rates and a shallow or non existing regolith profile. In this investigation wefocused on the calanchi badland type, consisting of heavily dissected terrain with steep, unvegetated slopes andchannels that rapidly incise and extend headwards. This research was carried out in two calanchi sites located inSicily. The geometry of 25 badland channels was characterized in order to verify if relationships, already testedfor minor linear erosion landforms (i.e. rills, ephemeral and permanent gullies), could also be verified for thesebigger erosion channels. To this aim, two Digital Elevation Models (DEM) were processed in a GeographicInformation System (GIS) environment: the first DEM obtained by a LIDAR survey, with 2 m and 0.1-0.2 m ofhorizontal and vertical resolution; the second DEM obtained by photogrammetry of 840 images captured by adrone, with 0.3 m and 0.05 m of horizontal and vertical resolution. Each channel was divided into segmentsdelimited by transverse sections. Cumulative length and volume of all channels segments were plotted on scatterdiagrams showing highly significant power relationships. Additionally, some morphometric attributes of channelssegments (length, volume) and sections (depth, width), were combined into two dimensionless groups, alreadytested for minor erosion landforms, providing measured pairs also highly correlated by power relationships. Theresults of this experiment confirm that length of erosion channels is sufficient to predict volume of eroded material and evidence a morphological similarity between rill, ephemeral and permanent gullies and calanchi landforms.
|Numero di pagine||1|
|Stato di pubblicazione||Published - 2013|