Hydro-geomorphological conditions for the classification of terrain susceptibility to shallow translational landslides: a geo-hydro ecological approach

This work is part of the review of methodological procedures for the analysis and classification of terrain susceptibility to shallow translational landslides, following the geohydro ecological approach. The pilot area is located in Nova Friburgo (RJ), specifically in the D’Antas Creek basin (53 km2). At this stage of the work, geomorphological parameters and indices were evaluated, including slope angle, curvature, drainage efficiency index (DEI) and topography position index (TPI), seen as relevant in regulating the hydrological and mechanical behavior of soils. The results obtained were intersected with an inventory of landslide scars (n = 382) referring to the extreme rainfall event in January 2011, which occurred in the highland region, called Região Serrana, of the state of Rio de Janeiro. This intersection allowed an evaluation between these parameters and the slopes rupture. The concentration of landslide area per class subsidized the establishment of weights for each of the adopted classes, based on the AHP method. A readjustment of the slope angle classes was proposed, as well as the inclusion of the standard curvature in the construction of the Hydro-Geomorphological Conditions Map. The results were promising, with a concentration of 88.74% (0.85 km2) of the landslide areas in the class of high erosive potential.