Investigating flood risk cost in Kungsbacka using the ICPR FloRiAn GIS-tool

Sammanfattning: Losses from floods have increased in recent years, worldwide and in Sweden. Understanding the economic and non-monetary cost of being exposed to flood hazard is important from a spatial planning perspective, particularly in urban areas. In order to estimate damage and risk cost of flooding in Kungsbacka – one of the most flood-prone cities in Sweden – the ArcGIS toolbox “ICPR FloRiAn” was used. This model uses data on flood depth, flood probability and vulnerable assets to determine the cost of hazard exposure on the four focal areas or receptors stated in the EU Flood Directive (2007/60/EC): Economic activities, Cultural heritage, Human health and the Environment. The former is assessed in monetary terms, based on the value of land use categories, while the latter three are assessed non-monetarily. The ICPR FloRiAn tools were previously untested in a Swedish context and only sparingly used for local, city-scale assessments. Results showed that risk cost in Kungsbacka is considered low for the non-monetary receptors, although the damage (impact without considering probability of occurrence of floods) was rather high for Environment and Human health. The risk cost on Economic activities is 176 000 SEK/year for the 50-year flood and 226 000 SEK/year for the 100-year flood. Extreme flows such as the ‘Beräknat högsta flöde, BHF’ were problematic to assess. There is potential for FloRiAn to be used in a local context, for comparative studies and scenario modelling of future risk. However, data availability and knowledge on how to assign and interpret non-monetary values and the impact on such values are two key factors that determine success of the outcome. It was concluded that the greatest obstacle for the use of FloRiAn is the lack of data on flood-related damages in Sweden.