Protecting the Pahurehure Inlet and Manukau Harbour East coastlines

Publish Date : 30 Oct 2024
Manukau Harbour

At its most recent meeting, the Policy and Planning Committee endorsed the latest two Shoreline Adaptation Plans – Pahurehure Inlet and Manukau Harbour East. Collectively, these plans cover the coast from Karaka Point in the south to Onehunga.

Shoreline Adaptation Plans are living plans that focus on how we manage Auckland Council-owned coastal land and assets. This includes reserves, public facilities, transport and water infrastructure, as well as any associated coastal defence structures like seawalls.

Councillor Richard Hills, Chair of the Policy and Planning Committee welcomes these Shoreline Adaptation Plans and emphasises their importance as a strategic guide.

“We’ve seen the impacts of climate change on our coastlines, public assets and our coastal communities have directly experienced the effects. This is about working with mana whenua and Aucklanders to plan for the future of our shorelines,” says Cr Hills.

“It’s great to see more and more of these plans adopted and encouraging to see the level of involvement from the community as we have these important conversations.”

What is included in these plans?

Our Shoreline Adaptation Plans recommend one of four adaptation strategies for each stretch of shoreline and can apply a mix of these strategies. These are:

Hold the line

  • The coastal edge is fixed at a certain location.

  • Defence of the coastal edge may be through nature-based options (like beach nourishment) or engineered hard structures (like sea walls).

Limited intervention

  • Generally focussed on maintaining and making the area safe.

  • The coastal edge does not need to be fixed and can be altered.

No active intervention

  • Natural processes are allowed to continue.

  • No investment into coastal hazard protection or flood protection and reserved for coastlines that are not exposed or vulnerable to coastal hazards.

Managed retreat

  • Assets and the way the land is used are relocated or realigned to reduce risk.

  • Any relocation is planned and undertaken over time.

  • Managed retreat does not signal abandonment of ‘at risk’ areas – it is about identifying a process to reconfigure council assets to accommodate natural coastal processes and build a more resilient shoreline.

Strategies are recommended over short-term (now to 20 years) medium-term (20 to 60 years) and long-term (60 to 100+ years) timeframes reflective of projected sea level rise over the coming decades of 0.5 to 1m. This long-term view of our changing coastal areas is a first step in adaptive planning and lays a foundation for consistent coastal management.

Paul Klinac, Auckland Council General Manager, Engineering, Assets and Technical Advisory explains that these high-level strategies provide guidance on how council-owned coastal land and assets can be adapted over time to sustainably manage the escalating impacts of coastal hazards and climate change.

“The development of shoreline adaptation plans across the region is funded through the Long-term Plan 2024-2034 as part of the climate action investment package,” says Mr Klinac.

“Shoreline Adaptation Plans – like the ones for the Pahurehure Inlet and Manukau Harbour East – will help guide us in future decision-making around these public assets. This could be reserve management, operational maintenance and renewal of coastal structures or initiation of new capital works projects. This will be alongside ongoing monitoring of council-owned coastal assets and the surrounding coastal environment.”

Pahurehure Inlet Shoreline Adaptation Plan

The Pahurehure Inlet Shoreline Adaptation Plan includes the area of the coastline from the Puhinui Creek in the north up to Karaka Point south. This coastline covers the Manurewa, Papakura and Franklin local board areas.

It recommends limited and no active intervention for many areas of the Pahurehure Inlet shoreline over the next 100 years.

It also suggests a ‘hold the line’ approach for specific areas, including Karaka Harbourside, Conifer Grove and Keith Park, due to an increased risk from coastal inundation over time. This is to maintain existing infrastructure and highly valued coastal connections from coastal erosion.

Lastly, it states a ‘managed retreat’ approach to support proactive adaptation planning in the mid to long-term for Waikirihinau / Bottle Top Bay, Youngs Point and in the Drury Creek area should be adopted. This is as the increasing risk from coastal hazards will impact the long-term use of the land in these areas.

Manukau Harbour East Shoreline Adaptation Plan

The Manukau Harbour East Shoreline Adaptation Plan includes the area of the coastline from the Puhinui Creek in the south to Taumanu Reserve in the north. This coastline includes the Ōtara-Papatoetoe, Māngere-Ōtāhuhu and Maungakiekie-Tāmaki local board areas.

It states that limited intervention is the best approach for many areas of this shoreline over the next 100 years and continuing to maintain existing coastal management practices.

It also recommends a ‘hold the line’ approach for specific areas due to the highly modified shoreline and the location of significant (council-owned) infrastructure like the Māngere Wastewater Treatment Plant.

This also reflects iwi values and aspirations and the importance of ensuring we are managing past land use decisions and asset owner requirements alongside community values and uses.

Managed retreat (in the longer-term) is identified where space is constrained and there will be a need to ensure that valued community activities avoid hazard areas to remain safe and functional.

Get involved

The remaining shoreline adaptation plans are continuing to be developed and will be completed in 2025. Plans will continue to be presented to the Policy and Planning Committee for approval.

Tell us what you think over the course of 2024 and for some areas, we’re also asking for your feedback on our draft adaptation strategies – head to akhaveyoursay.nz to see what plans are currently open for feedback.

You can also help by joining the conversation and telling us what you value about your local coastline today by visiting our regional interactive map – drop pins to leave comments on coastal areas not yet open. 

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