Planning to Reduce Flood Risk – Takanini North

Over 30km2 of rural land in south Auckland has been earmarked for development. The area has the potential to allow for approximately 50,000 new homes, or four years of Auckland’s housing supply. Approximately 6.5 km2 of this growth area lies within the Greenfield area of Takanini North. The Takanini North area has some promising features including flat topography, close proximity to the CBD, and existing rail and motorway corridors. However flood risk, existing downstream development and the underlying geology are major constraints in the Takanini area. The topography and historic farm practices have also limited the primary drainage network. Therefore considerable investment in bulk stormwater infrastructure is needed to maximise development opportunities.

Greenfield development provides an opportunity to take a holistic design approach to flood risk. An early and integrated planning approach across multiple properties allows a consolidated response to flood risk management as part of the overall strategic planning process. This enables future growth while providing protection from flooding for established urban areas downstream. Other flood management benefits include integrating stormwater infrastructure across ecological and park amenities and multimodal transport. This leads towards high quality social, economic and environmental outcomes for these growth areas. This approach has been followed and is being realised in a similar Greenfields development area in Takanini South.

The Takanini South scheme represents an innovative stormwater management approach applied to a live zoned development area. The Takanini South project has highlighted issues that will need early consideration for any potential development of other rural zoned areas such as Takanini North and the wider south Auckland growth area, including:

• Early, integrated planning.
• Protection of strategic land from subdivision and development.
• Impact of land value as a result of land use changes.
• Importance of comprehensive framework planning.
• Adapting existing or introducing alternative funding models.

This paper explores, from a stormwater planning perspective, the challenges and solutions associated with developing bulk stormwater infrastructure to service Takanini North and mitigate the existing flood risk downstream.