GIS-based hazard and risk maps of the Douro river basin (north-eastern Portugal)

The Douro river basin, in north-eastern Portugal, is a very complex region in terms of its geomorphological structure and morphodynamics. More specifically, the region - the Port Wine-growing region, a UNESCO heritage site - is a landslide-prone area resulting from several factors intrinsic to the bedrock and its detritic cover, combined with factors capable of triggering slope instability mechanisms, such as intense rainfall and human activities. Recently, due to intense rainfall and human activities, frequent rock and mud slides occurred, some of them catastrophic, killing people and damaging property. In the last decade (2000-2010), an accurate inventory of these catastrophic events was made, showing that these events occurred near local small towns, Peso da Regua (2001), Armamar (2003) and Carrazeda de AnsiAes (2007). In this paper, we present a case study using field data and Geographic Information Systems (GIS) tools to evaluate landslide hazard and risk assessment following multicriteria evaluation techniques.