Introduction of GIS based RUSLE model for land planning and environmental management in three different Italian’s ecosystems

Soil erosion is one of the principal causes of soil degradation in Europe. The problems provoked by the erosion, involve economic damages in the agrarian-forest field and they cause directly or indirectly dangers to things or persons for phenomena like landslides, landslips, flood, etc. This natural phenomenon is now accelerated by human activities that change the system of degradation of the rocks and the formation of the soil in natural condition. This acceleration is caused by the degradation of the vegetal cover, wrong cultivations, wrong agricultural techniques etc.: damages that can be prevented with a correct management and territorial planning. There are many erosion prediction models: event-based or long term, empirical or physically based, on basin or plot scale that was improved in the last decades. USLE (Universal Soil Loss Equation) by Wischmeier & Smith is still a world-wide accepted method, despite some limits. RUSLE (revised Universal Soil Loss Equation) is now one most frequently used, as it can be applied under many scenarios, even on topographically complex landscape units (Desmet & Govers, 1996) and can be supported by GIS. Thank to GIS technology and 3D modelling the RUSLE model results a quite easy parametric model that can be used by local administration for a qualitative and semi-quantitative evaluation of the annual soil erosion of their territory. The introduction of soil erosion maps in urban and land planning seems the best way to decrease the erosion’s phenomena and prevent landslides. Here we illustrate three different study case where the GIS based Rusle model was applied in different Italian ecosystems. The aim of this research was the introduction, of an easy and efficient erosion prediction model, for resources management and land planning according to local administrations needs. The first study area is the Susa Valley (Western Italian Alps), the chosen site for the Olympic Winter Games “Torino 2006”. In Alpine pedo-environments erosion is directly influenced both by the rainfall intensity or average values and snow melting or freezing cycles. The complex mountain geomorphology, the topography, the forest cover, influencing the organic matter content, and the conservation practices play a heavy role in soil aggregation and vulnerability to erosion. Therefore, erosion features such as rill gullies can be clearly seen, and in conjunction with this, in certain areas, the phenomenon of mass movement worsens. The second area is Vesuvio Volcano (City of Naples – South Italy). Erosion and mass movement are quite frequent in areas dominated by ashy , pumice and pyroclastic deposits (Andosols). This was the study area chosen by the local administration to test the prediction model as new instrument for land planning. It results useful not only to individuate the most critical areas, but also to predict the effect of land use changes of erosion and indirectly on landslides and floods. The third area is Sillaro river basin (Apennine Tosco-Emiliano–North Italy). The model was applied on basin scale to evaluate soil loss due to sheet, rill and gully erosion in a landscape characterised by clay rocks and abandoned pasture. The final result was match with the solid transport of Sillaro river, monitored for each rainfall event in the last 10 years.