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Resilient River Communities

Piako River Ngātea town left stopbank

This project will complete the final section of stopbank on the Piako Flood Protection Scheme to the agreed level of service design height.

Ngātea is reliant on flood protection infrastructure, originally built in the 1960s, for protection from both tidal surge and Piako River flooding. The population of Ngātea is increasing, reflecting its desirability as a rural location with ready access to local, regional and national parklands as well as the Firth of Thames.

The flood protection infrastructure, particularly earth stopbanks, may have limited opportunities to adapt to climatic changes. The current approach of increased stopbank height and mass may have limited viability on the Hauraki Plains due to the underlying strength of the marine mud on which they are built. In 2017, a top up to the stopbank adjacent to Ngātea caused cracking and slumping in three places.

This project includes a trial upgrade section on the stopbank to give greater understanding of the upper soil loading limit of the marine mud to establish the long-term viability of current stopbank design as flood protection infrastructure. Alternative stopbank design approaches may need to be developed if the ability to increase stopbank height is proven limited.

  • Funded: $768,000 by MBIE (climate resilience)
  • Total project cost: $1.2m
  • Project duration: 2 years
  • Jobs expected over project life: 14