Stormwater Harvesting, an Innovative Way of Meeting the Catchment-wide Needs of the Built and Social Environments

Catchment wide stormwater management objectives can incorporate harvesting and reuse, which in turn can benefit commercial and residential developments. The overall aim of the harvesting and re-use objectives is to reduce the environmental impact of large volumes of runoff entering the receiving environment. This can be a challenge for commercial developments with large roof areas and low volume of re-use demand.

This paper presents a case study for a commercial development in the Hobsonville Peninsula, which faced the challenge of accommodating large volumes of runoff from the 20ha catchment with 9.4ha of roof area. A review of an innovative approach to addressing the catchment wide stormwater management objectives was undertaken, which included the assessment of re-use demands for not only the subject site but the wider community. This assessment extended to a cost benefit analysis, for the water harvesting, which not only focused solely on the monetary aspects but introduced the social and environmental benefits that are often missed from these commercial driven assessments.