Caring for the environment  |  20 Oct 2022

A multimillion-dollar floodplain management project in the upper catchment of the Ōpāwaho Heathcote River has earned Christchurch City Council a national award for Environmental Sustainability.

The award, from Water NZ, is recognition of the work the Council and its contractors have done to prioritise sustainable resource use and the needs of the wider environment when constructing the new Eastman wetland and storage basin in the Cashmere/Hoon Hay/Halswell area.

This photo taken in May 2021 shows the scale of the Eastman project.

The Council is investing in excess of $50 million into the project, which has involved:

  • Constructing a network of storage basins that can store more than one million cubic metres of flood water in big rain events.
  • Creating three stormwater treatment wetlands to treat urban runoff discharging into the Cashmere Stream. One more wetland is still to be built.
  • Enhancing more than two kilometres of the Cashmere Stream with in-stream features for taonga species such as waikōura (freshwater crayfish), kākahi (freshwater mussels), tuna (longfin eel) and īnanga (whitebait). Another kilometre of enhancement is being added over the coming 12 months.
  • Revegetating the area with 110,000 eco-sourced native trees and 600,000 native plants.
  • Constructing over 10 kilometres of recreational paths for the public to use and large areas of rongoā garden that will provide a sustainable place to learn traditional Māori medicine.

“At every point in the project we have asked ‘how can we deliver sustainable and long-term cultural, ecological, recreational, landscape and heritage benefits along with the core stormwater and flood management function?’’ says Christchurch City Council Head of Three Waters Helen Beaumont.

“These have not been seen as ‘nice to haves’, but rather as the project’s legacy.  While the need to reduce the flood risk for people living along the Ōpāwaho Heathcote River has been the catalyst for this project, sustainability through ecological enhancement and restoration has been maximised at every opportunity.

“We are delighted that Water NZ has acknowledged our efforts through this award but the most important thing to us is that this project is going to have lasting benefits for Christchurch and particularly for the people who live near the Ōpāwaho Heathcote River,’’ Ms Beaumont says.

The first section of the facility will be open for public access from next month, with access from 600 Cashmere Road.