INTEGRATED THINKING TO IMPROVE STORMWATER MANAGEMENT

Urban catchment management has traditionally focused on the design and construction of infrastructure to reduce risks of flooding and provide basic water quality treatment. This approach has not only discouraged community involvement, but has also overlooked many opportunities to implement water-sensitive urban design to reduce impacts on the natural water cycle and help restore and enhance natural ecosystems within our towns and cities. To realise these more sustainable solutions, planners must look beyond their current models and give greater attention to multi-functional land use and environmental sustainability. It is proposed that catchments and development areas be delineated into ecosystem units to assess the potential environmental pressures within and between these units likely to follow land-use change. This knowledge can facilitate improved management of the location and design of urban developments, and the integration of urban design and stormwater management to enhance both the aesthetic and amenity value of the urban landscape, and the preservation of aquatic ecosystems. Our ecosystem-based approach, focused on Environmentally Sensitive Area (ESA) mapping, has been employed at the 1:25 000-scale to provide a planning and modeling framework for Waitakere City's Northern Strategic Growth Area (NOSGA). This 2200-ha study area, which may be significantly urbanised over the next 50 years, drains into the ecologically sensitive estuarine environments of the Upper Waitemata Harbour. The resulting map of ecological units and the associated management guidelines provide a basis for investigating development options, building stakeholders awareness of environmental issues and their impacts on development opportunities, and facilitating a more integrated approach to catchment management.