Waitaki Street Stopbank and Wetlands

Christchurch City Council’s Waitaki Street focuses on managing and reducing flooding and stormwater in a smarter, more sustainable way before it reaches the Ōtākaro Avon River.

It’s a key part of the broader vision to revitalise the Ōtākaro Avon River Corridor and protect its long-term environmental health. The project will roll out in stages, with features like a stopbank, a natural tidal wetland, a sedimentation forebay, a first flush treatment basin, and stormwater treatment wetlands. Together, these elements are designed to reduce pollution, improve water quality and help protect the river’s unique ecosystem.

This project was developed in response to growing concerns about the impact of stormwater on the water quality of the Ōtākaro Avon River. Untreated stormwater carries pollutants, like sediment and heavy metals, into the river, putting water quality and local ecosystems at risk.

In line with the Council’s global stormwater consent requirements, the focus is on treating stormwater before it reaches the river, helping to reduce pollution and support the area’s long-term environmental health.

The site itself sits within the Christchurch Red Zone, an area contaminated with asbestos and heavy metals following the earthquakes. Managing these materials safely on-site was critical to prevent further environmental harm.

Through thoughtful land rehabilitation and sustainable design, the project addressed these challenges while also restoring wetlands and enhancing local biodiversity. A bird viewing area has also been added, creating a space for the community to connect with nature and learn more about the importance of ecological restoration.

This project marks the first step in the broader Ōtākaro Avon River Corridor regeneration plan, which aims to transform the area into a more sustainable, biodiverse and community-friendly space. By setting the foundation for future stages, each phase will contribute to the long-term goal of revitalising and strengthening the corridor. We’re proud to play a role in bringing this vision to life. Our team, comprising geotechnical, structural, and water engineers, alongside landscape architects and planners, is working closely to ensure every element supports the project’s overall goals.

One key achievement to date is the creation of a two-hectare tidal wetland, which allows the river to flow into low-lying areas, restoring some of its natural floodplain function. This wetland is the first to be opened to the river in the Ōtākaro Avon River Corridor, with a second one currently under construction at Avon Park. As part of Christchurch’s Red Zone, the wetland will become a thriving habitat for native plants and animals, offering a rich environment for native fish and bird species.

In addition to the newly constructed tidal wetland and stopbank, a stormwater treatment forebay, basins, and wetlands will be constructed on the landward side of the new stopbank, all designed to treat stormwater before it reaches the river.

These efforts will reduce pollution, improve water quality and support ecosystem restoration.

The project’s approach follows the ‘living on a river delta’ philosophy, which works with the river rather than constraining it. This is particularly important as we face the future challenges of sea level rise and extreme weather.

A significant aspect of the project also involved managing site contamination, including asbestos and heavy metals. By following Worksafe guidelines, we were able to carefully handle and contain these materials on-site, minimising environmental harm. This effort, combined with the wetland restoration and the creation of a bird viewing area, helps enhance biodiversity and support local wildlife.

Sustainability has been a key focus throughout. By utilising existing infrastructure and prioritising long-term stormwater solutions, we’re working toward a healthier environment for the future. Looking ahead, the wider regeneration plan will continue to restore wetlands, improve ecological habitats, and enhance biodiversity along the river corridor. The goal is to create lasting environmental solutions while providing spaces that benefit both the community and the ecosystem. Plans also include improving public access to the river, creating recreational areas and maintaining sustainable practices throughout the development.

The project is making a positive contribution to the environment and the community, improving stormwater management and supporting the health of the Ōtākaro Avon River. It also includes important flood protection and a new cycle and walking path that gives people a safe and enjoyable way to explore the area.

With the addition of a bird viewing area, the community now has a space to connect with nature and learn more about ecological restoration. These improvements are boosting local biodiversity and helping to create a more sustainable and enjoyable environment for everyone.