Model for preliminary catchment-scale planning of urban stormwater quality controls

A systems modelling approach was adopted for the preliminary planning of urban stormwater quality controls, and this approach was applied to the city of Christchurch, New Zealand. The model considers the spatial location of potential control measures throughout the catchment. A simple quantitative optimization model was used to identify effective and efficient control measures to meet goals of chemical quality of the streambed sediments, groundwater recharge and flood control. The model predicts that stormwater treatment ponds and infiltration are of little benefit in relation to improving sediment quality. Contaminant source abatement measures are therefore required to control the long-term cumulative toxic effects of stormwater. Various strengths and weaknesses of the modelling approach are also discussed.