Modelling pollutant build-up and wash-off in urban road and roof surfaces

Abstract

This paper presents outcomes of an investigation into the quality of storm water from urban surfaces. Mathematical replication equations were developed for pollutant build-up and wash-off for road and roof surfaces. Based on the replication equations, pollutant loads from road and roof surfaces from three residential urban catchments were modelled. It was noted that the contribution from roof surfaces is significantly higher when compared to road surfaces for relatively smaller intensity rain events. This could be attributed to the relatively smoother surface texture and higher slopes when compared to road surfaces. This highlights the significance of roof surfaces as an urban water pollutant source.