 Erosion is a natural phenomenon which can be aggravated by manmade situations increasing risks produced by landslides, flood, avalanches, mudfloods, etc..Erosion impact are usually severe on dry areas, due to lack of vegetation.In Colombia, areas such as Cúcuta, Villa de Leyva, Tatacoa desert in Huila, Chicamocha canyon, La Guajira, Valle de Tenza, Valle Medio del Patía are especially vulnerable.