Lower Rangitāiki stopbank upgrade

We’ve upgraded around 1.25km of stopbanks along the lower Rangitāiki River (next to Thornton Beach Road).

About the project

Flood protection assets (such as stopbanks) are periodically checked to ensure they are still fit for purpose to help reduce the risk of flood events on local communities.

Soil testing and computer modelling were undertaken on the flood defences along sections of the Rangitāiki River (awa).

Using this information, as well as what we know about climate change, several flood defences along the awa have been identified as needing an upgrade – including this stretch of stopbanks along Thornton Beach Road.  

This upgrade addressed the identified issues in the stopbank and ensured these defences can continue to reduce the impacts of flooding on the community, now and into the future.

This project is part of a wider work programme to upgrade our flood protection network on the Rangitāiki River. Other projects include the Rangitāiki River Floodwalls and Rangitāiki Floodway and Spillway.

Flood protection is the first line of defence when it comes to reducing the impact of significant flooding and we currently manage more than $440M of flood defences on behalf of the community.

Find out more about our flood protection.

What did we do?

The stopbank upgrades included:

• Deconstructing the stopbanks and rebuilding them with suitable soil.
• Raising the height of the stopbanks and the land level in the properties across the road.
• Upgrading culverts.
• Installing drainage. This involves building a trench at the base of the stopbank (land side) and filling it with drainage material (such as gravel). This will allow water to pass through in a controlled manner, and relieve the water pressure building up inside and under the stopbank.

The completed stopbank has been covered with a gravel layer to future-proof the infrastructure. This ensures the stopbank can support potential new developments, making the area more adaptable and durable for different recreational and transportation uses.