Pollutant build-up and wash-off process variability

Abstract

The outcomes of a series of mathematical simulations of pollutant build-up and wash-off are presented in this chapter, strengthening the knowledge base on process variability. It was found that the build-up of particles <150 µm and >150 µm have different temporal patterns. These patterns could be used to differentiate between the behaviour of particles. The behaviour of particles <150 µm was found to play a key role in creating build-up process variability. On the other hand, the load and composition of different sized particles available on urban surfaces prior to a rainfall event were found to significantly influence the wash-off process. Similar to build-up, wash-off process variability is largely dependent on the behaviour of particles <150 µm, although the contribution from particles >150 µm is significant during rainfall events with relatively shorter duration.