Flood protection

Ko te ārai waipuke

Flood protection

Strengthening our defences

Te Awa Kairangi Hutt River is one of the region’s greatest assets. It is also one of its greatest risks due to flooding potential.

RiverLink’s flood protection work, delivered by Greater Wellington Regional Council, is expected to safeguard residents from large flood events that could aﬀect up to 3,000 homes, five schools and 600 businesses, with the potential to cause an estimated $1.1 billion worth of damage across the community.

Recent flooding events across New Zealand show the need for investment in flood protection infrastructure, and the devastating consequences for unprepared communities.

A community taonga

Te Awa Kairangi Hutt River is an invaluable resource to the Greater Wellington community, supporting the economy, lifestyle, and culture of the Hutt Valley. The river is identified as a taonga, a sacred treasure and serves as an attraction for both locals and tourists - it is visited by over a million people each year.

The river offers many recreational activities, including swimming, walking, cycling, fishing, and scenic views of the Hutt Valley and of Wellington Harbour (Te Whanganui-a-Tara).

It also supplies half of the consumable water for thousands of people living in Wellington, Hutt and Porirua cities, which equals around 75 million litres of water per day.

Flood protection

Community consultation chose in favour of building far-sighted flood protection in Hutt River between Ewen Bridge and Kennedy-Good Bridge. The level of protection alongside the CBD will also rise to deal with bigger floods.

While improving Lower Hutt’s flood defences, this project will protect the ecological health of the river, enhance transport connectivity and significantly improve resilience.

RiverLink will protect the ecological health of the river by creating more space for the river itself, more fish habitats, with a mix of pools, fast-flowing shallow water, vegetation, rocks, and undercut banks - all the things that short-fin eel (tuna), trout, whitebait (inanga) and common bully (toitoi) need to thrive.

Goals

Stopbanks

The height of the stopbanks will be increased by one metre to strengthen flood defences and improve resilience.

River channel

The river channel will be widened to 90 metres giving more room for it to flow naturally. A wide channel will help a higher volume of water to pass during floods.

Environment

The Belmont wetland filters stormwater before it flows into the river. The wetland includes shallow and deep habitats to support indigenous plants that will improve water quality.

Improving resilience

Upgraded stopbanks will strengthen flood defences, while wider river channels will help higher volumes of water to pass during floods.

Projects

Belmont Wetland

A constructed wetland in Belmont within the river corridor, will preserve the habitat for indigenous flora and fauna. It will also act like a kidney to filter storm water. This protects the ecological health of the river while also providing flood defences.

Geotechnical works

Geotechnical work was done to make an informed decision on the stopbank design to protect the city from floods. The ground investigations will also help to design the Melling interchange and a new pedestrian and cycle bridge.

Riverside access

An enhanced river park with more room for the river and for you to explore, play and learn in and around the river. Enjoy new cycle ways and pathways along the river bank, replanted with native plants.

Biodiversity

The Hutt River catchment is home to 13 native fish species, more than half of these are at risk or threatened. Greater Wellington monitors water at various sites to check ecosystem health, which informs long-term management of the catchment.

Process

River works are an integral part of the RiverLink project. We are focused on saving lives and property from a one in a 440 year flooding event that has a 23 percent chance of happening in the next 100 years. During construction, the flood security of Lower Hutt will be a key element.

Funding

We have secured around $145 million to help significantly increase the resilience of Lower Hutt from flooding. A large part of the funding will be used to buy riverside properties, to give Te Awa Kairangi Hutt River more room and to build higher and wider stopbanks.

Project leadership

Providing flood protection to Lower Hutt is at the front and centre of what we do. Our work will provide residents with a significantly improved resilience from large flood events that could affect up to 3,000 homes and cause damage that could cost an estimated $1.1 billion.