Soil erosion risk scenarios in the Mediterranean environment using RUSLE and GIS: An application model for Calabria (southern Italy)

Abstract: Soil erosion by water (WSE) has become a relevant issue at the Mediterranean level. In particular, natural conditions and human impact have made the Calabria (southern Italy) particularly prone to intense WSE. The purpose of this investigation is to identify areas highly affected by WSE in Calabria by comparing the scenarios obtained by assuming control and preventive measures and actions, as well as actual conditions generated by forest fires, also in the presence of conditions of maximum rainfall erosion. Geographic Information System techniques have been adopted to treat data of reasonable spatial resolution obtained at a regional scale for application to the RUSLE model. This work is based on the comparison of such data with a basic scenario that has been defined by the present situation (present scenario). In this scenario: (i) R has been assessed by means of an experimental relation adjusted to Calabria on the basis of 5-min observations; (ii) K has been drawn from the soil map of Calabria including 160 soilscapes; (iii) LS has been estimated according to the RUSLE2 model by using (among other subfactors) a 40-m square cell DTM; (iv) C has been derived by processing the data inferred from the project Corine Land Cover, whose legend includes 35 different land uses on three levels; and (v) P has been hypothesized as equal to 1. For the remaining three hypothesized scenarios, the RUSLE factors have been adjusted according to experimental data and to data in the literature. In particular, forest areas subject to fire have been randomly generated as far as fire location, extension, structure, and intensity are concerned. The values obtained by the application of the RUSLE model have emphasized that land management by means of measures and actions for reducing WSE causes a notable reduction of the erosive rate decreasing from ~30 to 12.3Mg ha−1 y−1. On the other hand, variations induced by hypothetical wildfires in forests on 10% of the regional territory bring WSE over the whole region to values varying from 30 to 116Mg ha−1 y−1. This study can be offered to territorial planning authorities as an evaluation instrument as it highlights the merits and limitations of some territorial management actions. In fact, in Calabria no observations exist concerning the implications of these actions. [Copyright &y& Elsevier]