A typical 'calanchi' landscape on the Eastern Apennine margin (Atri, Central Italy): Geomorphological features and evolution

The surroundings of the town of Atri (Abruzzo Region, Central Italy), situated about 10 km from the Adriatic shoreline, can be considered as representative of most part of the Italian seaward peninsular landscape. The subject of this research, the calanchi landscape, often generally considered as “badlands” by non-Italian authors, is, in fact, made up of many singular landforms, each of which (calanco) corresponds to a more or less extended hydrographic unit. The dynamics are mainly the result of the action of the particularly aggressive climatic factors (such as the Mediterranean rainfall regime) on weak substrata (clay, silt and sand of the Plio–Pleistocene marine cycles). The morphogenetic activity is not only limited to channel erosion, but it is also due to repeated superficial slides, so that it should in fact be better to consider the calanco as the result of a “combined erosion” process (sensu [Zachar, D., 1982. Soil Erosion. Elsevier, Amsterdam]). Since the mechanism regulating this process remains unclear, this work wants to offer a contribution to this research field. Multitemporal geomorphological analysis has helped us to distinguish the different areas in which the calanchi evolution has been more or less important in the past. In such a way, it has been possible to characterize the landscape evolution as a function of the parameters that influence soil loss, especially in areas, such as that of Atri, where calanchi-like landforms are highly developed. Moreover, this analysis, coupled with the processing of 40 years rainfall data, also taking into account the concurrent land use changes, has clearly shown that the areas affected by calanchi erosion on the Eastern Apennine margin, still tectonically active, are progressively diminishing.