Q&A: What is a blue-green network?

Source: Auckland Council

A blue-green network is a system of waterways (blue) and parks (green) that give stormwater space to flow and help reduce flooding where people live.

After severe weather events in 2023, Auckland Council prioritised blue-green projects to better protect our communities from flooding.

As part of our Making Space for Water 10-year flood resilience programme, we identified 12 focus areas around the region that could benefit the most from a blue-green project.

What has the council been doing to reduce flood risk in Auckland?

We have been working hard to assess all the potential project areas to decide if there is an infrastructure solution that can deliver significant flood reduction to the community and that is affordable for ratepayers.

These assessments are very complex, they involve multiple stages of research, analysis and decision making before a feasible solution can be presented to the council’s Governing Body and central government funding partners for approval. If approved, further stages of design, consenting and engagement are undertaken before a project is ready to construct. This process before construction generally takes 2-3 years.

Why has the amount of funding allocated to these projects changed?

Following major 2023 storms, a co-funding package with the Government has given us the opportunity to ‘retreat’ high-risk homes and deliver some key resilience projects sooner than expected.

Within this funding package, buy-outs have been the first priority to get high-risk homeowners out of harm’s way. Now that we understand more which high-risk areas still need mitigations, and how much funding we have remaining from the package, we can start prioritising flood resilience projects.

What is the process for delivering the blue green projects?

While we are working as quickly as possible, we can’t progress all projects at the same time, so they’ll be developed and delivered across several years.

Central and local government representatives will work together to guide each project through a five-stage process. At each stage decisions will need to be made which will determine whether the project can proceed to the next stage.

Our staged approach is crucial due to the scale of these projects – they’re expensive and can be disruptive. We want to ensure value for Aucklanders.

As these projects are made up of a number of connected works and they will make a huge difference to those that live in the area, we will be working together with iwi and the community in prioritised project areas and setting up opportunities in the coming months to meet and start to gather their input to help shape the designs.

What stage is each project at?

Two projects in Māngere have already been prioritised, with construction starting soon, because they could be delivered in a reasonable timeframe to reduce the risk to life for local homes.

Feasibility assessments have been completed for all 12 areas originally identified in the blue-green networks initiative.

In Ōpoutūkeha / Cox’s Creek, Grey Lynn and Meola-Epsom, much of the flood risk has been managed through the voluntary buy-out programme. Removing these houses will give sufficient space for water to flow.

Finding a suitable solution to reduce flooding for the Kumeū River catchment has been challenging. The council, with engineering experts, has thoroughly explored several options including building stop banks, extending a flood way, diverting the river, and creating detention ponds upstream.

Although a lot of work has gone into these ideas, none are feasible due to high costs, environmental impacts, and the high level of residual flood risk faced by the community. We are now working with other council teams and the government to find the best solutions for the community.

The remaining blue-green projects will take longer to develop as they will need to be funded by the council through the Long-term Plan process. We will aim to deliver these projects over the following 10 years. In areas where larger scale projects cannot be funded right now, we will look for ways to accelerate smaller works that may help to reduce the impacts of lower-level flooding.

Blue-Green project status

What are the current priorities for development?

Projects in Harania Creek and Te Ararata Stream are underway and expected to start construction later this year.

A detailed prioritisation analysis has determined that Clover Drive in Rānui is the next area proposed to progress. Auckland Council’s Transport, Resilience and Infrastructure Committee approved funding in February 2025.

This area was identified as the next priority based on several criteria due to its potential for reducing risk to life, improving community health and wellbeing, and delivering economic benefits to residents and businesses. Addressing flooding risks in this area also stands to lead to improved water quality and broader environmental benefits. Approval to progress is also required from Crown, with a decision expected in March.

How does Wairau Valley fit into the overall plan?

Given the Wairau Valley’s size and the complexity of required mitigations, addressing flooding issues requires a phased approach. This will involve significant long-term investment, community input, and collaboration. The council will be promoting opportunities for the community to participate and provide input into early designs to maximise local benefits before submitting a detailed business case in the coming months. A catchment-wide approach will ensure optimal outcomes for the community.

This flood resilience work will bring many additional benefits to the community, including better water quality, more open space, improved biodiversity, and better connectivity. We look forward to working together to develop and deliver these improvements.

What else is being done to reduce flooding in blue-green areas in the meantime?

We understand that residents may feel anxious about more storms and heavy rain, especially if they were seriously affected in the 2023 storms.

For those areas that have not been prioritised in this phase but are still included in the blue-green programme, early design and modelling is underway so that projects are ready to progress as soon as funding can be allocated.

Maintenance and monitoring of critical waterways and infrastructure has been increased to help to improve water flow during smaller storms. We are also looking at other opportunities such as flood intelligence and flood warning systems that will help to reduce risks from severe weather events. Alongside this we continue to update our flood modelling data so that we can base our decisions and recommendations on the most up-to-date information and better prepare and support Aucklanders when future weather events occur.

Guides offering property level advice to reduce the impacts of flooding in multiple languages can be found on Flood Viewer and in libraries across the region.

What are the plans for the vacant land once Category 3 houses are cleared?

More than 1,200 high-risk Auckland properties are expected to be purchased by Auckland Council before the end of 2025 – making it one of the largest land acquisition programmes undertaken in New Zealand.

We are carefully deciding what to do with this storm-affected land, with decisions expected to take years.

We want to ensure Auckland’s land is used effectively to provide homes and maintain strong communities, while managing risk and reducing the financial impact to ratepayers.

If we keep the land, options for use could include:

• flood resilience and stream management

• adding it to neighbouring parkland or bush

• managing it as high-hazard land.

If we don’t keep the land, options could include:

• sale for safe redevelopment

• sale with conditions to manage the risk (such as converting ground floor units to storage)

• sale to neighbours for extra backyard space.

MIL OSI