Multi–risk quantitative assessment in Reghin city, Transylvania, Romania

Abstract

Multi–risk assessment supposes an integrated analysis of various processes and phenomena generating risks across the territory, highlighting the individual and cumulative impact at different levels of analysis. This paper aims at creating an assessment model of multi–risk generated by the cumulative effects of landslides and floods, processes considered as significant in the study area, the administrative unit of the city of Reghin in the Transylvanian Basin. To obtain the multi–risk, two GIS spatial analysis models have been created. The first model means to identify the probability of landslide occurrence (built on GIS databases in vector and raster format, correlatively analysed by means of spatial analysis functions and equations), and is adapted according to legislative regulations stipulated in the Government Decision no. 447/2003. The second one is a database regarding the floodable area with a 1% probability in raster format, resulted from a nation–wide model created to identify the flooded areas.The multi–risk map was created using the mediation method, in which every class of individual (geomorphological or hydrological) hazard receives equal weight within the final result. As a consequence of applying the above–mentioned models, we obtained areas with different probabilities for cumulative risk processes, which are rendered as favourable or restrictive in terms of locating different structures (roads, settlements, functional areas, shopping centres). According to the degree of validation, these may be used for a more precise determination of the development areas and for territorial planning.