The Auckland region is a diverse landscape of varying geologies, three significant harbours, abundant coastline, and flat lowland to steep upland environments.
A site's location within the region should ultimately determine its developmental and environmental responses, including consideration of the following regional resources:
- Regionally significant ecosystems
- Receiving environment classifications
- Landscape typologies and sensitive landscapes from regional landscape assessments
- Protection of headwater and groundwater aquifers
- Regional flood management areas
- Productive soils
- Coastal inundation and storm surge effects
- Region-wide ecological linkages
- Open space frameworks
- Public transportation
- Regional growth and intensification nodes
- Combined sewer systems
The urban transect
An 'urban transect' is a planning method used to illustrate a change in urban density from the regional urban centre out to its hinterland. It is intended to ensure an appropriate transition of built form toward urban centres. It is also a means to consider relative bulk and layout of land uses, to provide for appropriate community character relative to a site's location within the region.
The urban transect is a means to express WSD approaches to support relative densities and specialised land uses (refer to Figure 23), including the following broad approaches:
Increasing density near to stream corridors in suburban environments to capitalise on the value of these ecosystems as connected open space
Buffering streams and other ecosystems where high density development is achievable and desirable
The application of stormwater as a resource in civic centres or capture and re-use, to irrigate isolated landscape areas and to integrate as a dynamic element within the urban environment.
Conventional models of 'countryside living' are an inefficient use of productive landscapes, with individual house sites requiring significant amounts of infrastructure. Furthermore, it is difficult to justify public transport and other public amenities for low density areas. A more appropriate response to residential living outside the rural-urban boundary (RUB) is within rural town centres, or planned clustered developments that retain viable productive landscapes or ecological reserves.
Suburban areas have traditionally been associated with unattached housing typologies with prescriptive lot layout and setbacks. WSD approaches require flexible planning rules to cluster built form and provide for more community open space and resilient natural systems (refer to Figure 24).
Riparian environments should remain open through low density residential areas to provide green and blue linkages from the hinterland to urban environments. This helps to provide ecosystem services, to increase residential amenity, and to ensure resilience of neighbourhoods from flooding by directing overland flow to natural floodplain areas. A significant challenge for WSD in suburban areas is to reconcile natural drainage patterns with road networks. This is discussed in more detail in the WSD street typologies that follow.
In addition to enhanced open space areas, suburban residential areas have less vehicle traffic and provide greater opportunities for streetscape amenity and green infrastructure. Larger private yards can also contribute to broader environmental frameworks and on-site stormwater treatment.
Higher density residential areas retain less natural environments and rely more greatly on capture and reuse of stormwater, and integrated green infrastructure such as raingardens, planter boxes and tree pits (refer to Figure 25). Where streams do occur, they are likely to be confined within a narrow environmental buffer that is designed with minimum environmental tolerances. Surface watercourses can also occur where there is acceptance of these features within roadways, laneways, and through open spaces.
The increased density and impervious surface area associated with civic centres generally results in fewer ecosystem services and increased stormwater flows and contaminants. It is therefore imperative to find design solutions that utilise the natural processes inherent in pervious paving, bioretention (raingardens and tree pits) and subsurface wetland technologies. There is also significant treatment potential available from trees in streets and plazas, where rainfall is captured in canopies and directed via stem flow or overland flows to tree pits.
Architecture can contribute significantly to stormwater management in urban areas, through living roofs, living walls and planted atriums. These contribute valuable urban open space, while potentially capturing and re-using rainfall for passive irrigation and cooling of buildings.