Gully morphology in a semi-arid environment: application of laser scanning techniques

Recent studies carried out in semi-arid Mediterranean regions have shown gully erosion to have an increasingly significant contribution to soil loss in hillslopes. There is therefore a great need for further monitoring, experimental and modelling studies of gully erosion as a basis for predicting the effects of environmental, climatic and land use changes on erosion rates. Fieldwork was carried out at two sites in the Rambla de Nogalte catchment, south east Spain in order to identify factors which influenced gully morphology at different spatial scales. Laser scanning techniques were also applied in order to obtain topographic data that could be related to gully morphology and provide a new level of precision in monitoring gully erosion. The field results showed that there were many components to the erosional response of the hillslopes and gully morphological development, some of which proved to be more significant for gully morphological development than others. At the hillslope scale, the role of topography and land use characteristics were highlighted, and at the smaller scale, the soil surface roughness was the main factor affecting runoff generation and erosional processes.