A multi-criteria approach for erosion risk assessment using a new concept of spatial unit analysis, wave model and high resolution DEMs

Abstract

In this work, field data and model outputs were integrated, processed and analyzed in a GIS environment in order to assess the vulnerability to erosion and to produce associated risk maps using a multi-criteria approach. Erosion risk assessment methodology was developed based on morphological, hydrodynamic, and meteorological indicators that were computed using data obtained from a short term monitoring program. It was applied to a stretch on the NW coastal zone of Portugal. Comparing this methodology to previously developed ones, there are three main distinctive aspects to be considered: (i) the coastal stretch was segmented for computation of indexes (susceptibility, exposure and risk), accordingly to specific coastal types (ii) a new set of vulnerability variables is proposed; and (iii) erosion impact indicators computed from detailed building and beaches data that was extracted from aerial photos.