Targets for Urban Stormwater Management in Australia

Increasing urbanisation is occurring in Australia’s major cities and in almost every country in the world. This creates a challenge for the urban water sector, which not only needs to provide traditional water services (i.e., wastewater, domestic water) for a rapidly growing population, but also to service potential additional demands to contribute to enhanced amenity, and to do so in the context of climate change. This paper is focused on stormwater management controls for the develop of new greenfield urban sites in the three major east coast Australian cities—Melbourne, Sydney and Brisbane. While stormwater management in all three cities is focused on the protection of community values of the waterways, including environment (ecology), amenity and recreation, the scale or type of the waterways considered is considerably different—Melbourne has adopted a regional waterway strategy, while the Sydney and Brisbane approach is more localised. Pollution load reduction targets (TSS, TP, TN and litter) from new urban areas have been enforced in all three cities for many years, although there is concern that these targets primarily aimed at protecting the values of downstream bays (e.g., Port Phillip Bay, Sydney Harbour and Morton Bay) will not necessarily protect the values of the contributing waterways. However, targets to control stormwater volumes entering waterways are proving to be considerably more difficult to both develop and implement. These targets are typically expressed as volumes of stormwater to be harvested and/or infiltrated for every additional hectare of directly connected impervious (DCI) surface created as a result of urban development. The three cities have approached the setting of stormwater flow targets somewhat differently, as is apparent from the details provided in the paper. Additionally, we argue that there is a need for the development of new targets related to the reuse of stormwater and its integration with wastewater and domestic water management.