Kostnads- nyttoanalys av införandet av hållbar dagvattenhantering som riskreducerande åtgärd mot översvämning – med fokus på monetär värdering av ekosystemtjänster

Sammanfattning: In this master thesis, a cost-benefit analysis (CBA) is performed on the implementation of a sustainable drainage system in the flood prone area Söderkulla in Malmö. The study focuses on quantifying and performing a monetary valuation of the ecosystem services that the drainage system will provide, in order to incorporate these values in the CBA. Based on a estimated amount of storm water needed to be handled in the area of Söderkulla, a set of open storm water solutions and drainage solutions are suggested. The cost-aspect of the analysis is based on the investment and operative cost of these solutions. The benefit aspect constitutes of the ecosystem services which the system is expected to provide, in terms of flood risk reduction, water and air purification properties, noise reduction, climate regulation and increase of recreational values. The value of flood risk reduction is based partly on site-specific data and partly on national historical observations from floods. The other ecosystem services are valuated though classical economical valuation methods, traditionally used for valuation of aspects without a natural market.