13thICUD2014 - Full Paper Template

Stormwater is often discharged to receiving waters without any treatment. However, treatment facilities are developed and are increasing in frequency but the question how to prioritise which discharges that should be treated still remains. The objective of this paper was to test a multicriteria analysis (MCA) method to be able to prioritise the need of stormwater treatment for different kind of stormwater discharges, where the quantity and quality of the stormwater as well as the status of the receiving water were considered. The study was conducted as a case study where lakes of different status were selected and assumed to be receiving waters for two types of stormwater discharges. A linear additive MCA method was applied. Four indicators were selected and ranked by a reference group: Discharged quantities of pollutants, Maximum depth of lake, Water retention time of lake and Concentrations of discharged pollutants. The tested MCA method showed potential to be further developed and exemplified how negative impacts from stormwater discharges could be compensated for. The analysis also indicated which specific pollutants were most urgent to handle. However, the compensatory criteria may be too simplified and should be developed further.