Auckland’s population is expected to increase by over one million people in the next 30 years, which will see as many as 400,000 new homes built (Auckland Council, 2012).
The Auckland Plan (2012) sets the vision of Auckland becoming the ‘world’s most liveable city’. This places an emphasis on sustainable urban development to accommodate population growth, while ensuring communities are safe and healthy environments to live, work and play.
Water sensitive design (WSD) is essential to support the vision of The Auckland Plan. It promotes land use planning practices that balance land development with the ecosystem services necessary to support it. Ecosystem services are the benefits people receive from nature, and are categorised as provisioning, regulating, cultural and supporting (Millennium Assessment, 2005). This balance between land development and ecosystem services ensures the resilience of our region’s environment and in particular the values and sensitivities of our harbours and watercourses.
WSD is an inter-disciplinary design approach, which considers stormwater management in parallel with the ecology of a site, best practice urban design, and community values. WSD aspires to ensure multiple public benefits from stormwater management and to develop a unique ‘sense of place’ for our communities. It also seeks to deliver low risk and better return on investment for land developers.
This guideline document, Water Sensitive Design for Stormwater, known as GD04, introduces the principles and objectives for WSD and guides the practitioner through a design programme for land development. WSD can be applied to development scenarios in both greenfield (undeveloped) and brownfield (previously developed) situations.
A WSD approach in a greenfield environment directs development to appropriate areas of a catchment, and provides for intensified or clustered development in these locations to minimise land disturbance and earthworks. The result is an effective balance of protected and enhanced natural environments and associated ecosystem services to support the proposed development, and more broadly the lifesupporting capacity of our communities.
In a brownfield situation WSD promotes the integration of ecosystem services into the existing built form. This may be responding to existing environmental concerns on a site, to allow for intensified land use activity, or to enhance environments within and adjacent to the site. Reconstruction of buildings can be congregated within the site to provide space to retrofit ecosystem services. These opportunities may include the construction of raingardens, living roofs and swales, mass tree planting, remediation of existing or contaminated soils, rehabilitation of watercourses and wetlands, and stream daylighting.