Modelling Stormwater Pollutant Reduction with LID Scenarios in SWMM

Abstract

Simple and automatic optimization approaches were used to create Low Impact Development (LID) scenarios for a residential catchment in Espoo, Finland. Ten LID scenarios were simulated with the Storm Water Management Model (SWMM) to evaluate their impact on urban runoff and pollutant load on a catchment scale. Permeable pavements and bioretention cells were located at the asphalted areas in the catchment. A large variability was observed in the simulated load reduction depending on the LID type, location and pollutant. Scenarios with permeable pavements reduced pollutants effectively, but require knowledge about the pollutant sources and pathways. Scenarios with bioretention cells benefitted the most from location optimization due to their smaller spatial footprint and storage capacity compared with permeable pavements.