Skip to main content

Predicting Auckland’s exposure to coastal instability and erosion

Ross Roberts, Natasha Carpenter, Paul Klinac, Patrick Knook, Ben Westgate, Rebekah Haughey, Tom Shand, Richard Reinen-Hamill, Tonkin and Taylor
Auckland Council
Publication date:  

Extract from the Executive summary:

The Auckland region has over 3,200 km of coastline including three major harbours and a range of sandy beaches and dunes, rocky shores and cliffs, estuaries and offshore islands. As well as a long and diverse coastline, Auckland has the largest population density to coastline ratio in New Zealand. As a result, the city has a high exposure to coastal hazards including coastal instability and erosion. These hazards can present a safety risk, adversely affect property and infrastructure, and damage or destroy cultural and environmental sites.

A study undertaken in 2006 is the basis for the current coastal erosion rules within the Auckland Unitary Plan. No more up-to-date information related to the potential exposure of Auckland’s coastline to erosion was available at the time of the plan’s development. To fill this knowledge gap, a programme of research has been undertaken to identify, at a regional level, the Area Susceptible to Coastal Instability and/or Erosion (ASCIE). ASCIE is the area landward of the current coastline that is at risk because of coastal erosion or instability caused by coastal erosion. Titled “Regional Assessment of Areas Susceptible to Coastal Erosion and Instability”, this study was undertaken for Auckland Council by Tonkin + Taylor Ltd., with a peer review by the University of Auckland. The study forecasts the areas of Auckland’s coastline that could be affected by coastal erosion and instability under a range of climate change (sea-level rise) scenarios and timeframes.

A non-technical overview of the study is given in Part 1 of this Technical Report while the detailed study as reported by Tonkin + Taylor is presented in Part 2. The intent of this separation is to provide a Council synopsis and interpretation for non-technical readers.

Auckland Council technical report, TR2020/021

Published in February 2021.


Regional assessment of areas susceptible to coastal instability and erosion

Regional Assessment Prepared for Auckland Council by Tonkin & Taylor Ltd, January 2021