Flood hazard, Santa Cruz do Bispo Sector, Leça River, Portugal: a methodological contribution to improve land use planning

This paper presents a 1:4000 scale flood hazard map, covering 4,2 km2 of a sector belonging to the Leça river watershed (Portugal), named the Santa Cruz do Bispo sector. The map is the outcome of the combination of several hydrodynamic parameters – velocity, water column height and flood-prone – defined for three return periods (T10, T50, T100), which were calculated.

An intensity-probability matrix supports the hazard map which combines the modelling results as a base layer to classify flood hazard along the alluvial plain and to identify exposed elements located inside the T100 prone-flood area, notably roads, bridges and buildings. The hazard map is an important document to support land planning, assisting the definition of correct land use and occupation restrictions that should be applied along this floodplain.