Waikanae River

We are currently updating the modelling and information for these maps. More information, including how you can provide feedback, is below.

To find flood hazard information about a specific area, please view our GIS maps online: GWRC GIS flood Hazard Areas or KCDC GIS flood extents.

Flood hazard modelling  

Flood hazard modelling involves the use of hydrological and hydraulic models that predict a range of possible flooding outcomes that could occur in the region and the hazards associated with these events. Flood hazard models create maps and data for each scenario. 

The models are used by Greater Wellington for flood warning, floodplain management planning, asset management and advice during emergency responses. Greater Wellington shares the models with organisations such as Wellington Region Emergency Management Office (WREMO), territorial authorities and the public for emergency planning and management, district planning, consenting, insurance and ownership information and decision making.  

Although we cannot predict exactly what impact the effects of climate change or natural hazards will have on specific locations, the information the models provide will help communities and councils prepare for a range of potential impacts.  

We’ve undertaken similar projects on Hutt River / Te Awa Kairangi where flood protection, river restoration and public transport work is now underway.  

Why are we doing this? 

Up to date maps can be used in the Kāpiti Coast District Plan review and the Whāitua Implementation Programme.  

We are also seeing advances in flood modelling computer software, which means this review is timely.

Who’s involved? 

Greater Wellington works in partnership with local council, mana whenua, key interest groups, businesses and the wider community. 

We have a team of hydrologists and engineers who are experts in their fields of gathering and crunching data about river flows, weather patterns and impacts on the environment.  We want to ensure continued access to Kāpiti homes and services, roads and infrastructure to support a thriving community and environment.  

Flood Hazard Maps may be integrated into district plans for future-proofing our communities and environments, while also planning for future growth and development.  

What’s the process?

We’re updating the flood hazard maps on the Kāpiti Coast for the following catchment areas: 

• Ōtaki River including the nearby Waitohu Stream and Mangapouri Stream 
• Waikanae River 
• Mangaone Stream 

The first step is to analyse rainfall patterns. We use technical experts for this part. Once the rainfall is modelled, we will combine this with river flow data and the information provided on previous events and develop models that help determine where the flood waters might go in the future. This will help develop options for minimising the impacts of the flooding for these communities. 

We’ll keep you informed along the way 

Beginning December 2024, we’ll update you on project progress and opportunities for the community to provide feedback and get involved. Follow our social media channels, check the website or read your local newspaper for details on consultation and drop-in sessions around Kāpiti flood hazard modelling and maps for your area. 

How can the community be involved? 

To ensure we capture as much information as possible to develop these models, we need your help to understand the flooding patterns and impacts from rivers and streams in the Kāpiti area.  

We value your knowledge and experience of flooding in the area. We want to work with you to build a resilient and prepared community that can still enjoy and flourish in the dynamic environment.  

We’d like you to share any photos or stories you might have from previous flooding events from the following areas: 

• Ōtaki River and its tributaries – the Waitohu Stream and the Mangapouri Stream. 
• Waikanae River 
• Mangaone Stream 

Waikanae Floodplain Management Plan, which is the result of work done by the Waikanae River Communities, Ati Awa ki Whakatongotai, Greater Wellington, and the Kāpiti Coast District Council, provides a blueprint for managing the river and the floodplain over the next 40 years. It is a living document, which means it will be changed and further developed over time. 

We at Greater Wellington are responsible for managing flood risks associated with the Waikanae River. The Waikanae Floodplain Management Plan sets out what we will do manage this flood risk. Our role in managing the river involves removing gravel, prevent erosion, repair and maintain stopbanks to reduce the risk of flooding.

You can download a copy of the plan:

Waikanae River Floodplain Management Plan

A major flood in the Waikanae River could cause millions of dollars’ worth of damage to property and community assets in the Waikanae area. The social and psychological costs, although… Read more here

date_range Published 01 Oct 1997

Download now (PDF 13 MB) get_app

Waikanae River Environmental Strategy, an outcome of the Waikanae Floodplain Management Plan, identifies key features of the river environment with a focus on the river corridor downstream of the Water Treatment Plant. The document is the combined effort of the Regional Council and Kāpiti Coast District Council with valuable contributions from the Department of Conservation, Ati Awa ki Whakarongotai and members of the community.

There have been significant environmental improvements in respect of restoration planting, development and enhancement of access and pathways for walking, cycling and horse riding. Many of these improvements are recommendations from an earlier version of the strategy, which have been implemented by us with Kāpiti Coast District Council and the community. You can download a copy of the plan:

Our operation and maintenance activities in Waikanae River are carried out under consent. Here is the land use consent link:  Resource Consent. (PDF 270 KB)

This consent has been extended until a new consent is granted.

Please visit Kāpiti Coast District Council’s Local Restoration Groups webpage.

Friends of Waikanae River

The Friends of the Waikanae River set up a nursery where they grow eco-sourced native plants for each planting season in winter. The group holds regular working bees. Find out more.

Contact: Russell Bell at russelljamesbell@gmail.com

Te Ati Awa ki Whakarongotai

Te Ati Awa ki Whakarongotai are the mana whenua iwi for the Waikanae River, and engage with Greater Wellington on matters relating to river management and environmental enhancement. Find out more.

River walk overs

Our Flood Protection Department holds an annual public walkover along the banks of the Waikanae River, where flood protection projects, operational activities and environmental enhancements are discussed. To register your interest in attending, please email info@gw.govt.nz or phone 0800 4WN REG (0800 496 734).