Draft Coastal Hazards Plan Change

Communities in low-lying inland and coastal areas around New Zealand and the world are facing challenges with the impacts of climate change and sea-level rise.

Here in Ōtautahi-Christchurch and Te Pātaka-o-Rākaihautū Banks Peninsula we are already experiencing the effects of climate change. The future is expected to bring warmer weather across all four seasons, more days of extreme wind, and more intense rainfall.

Climate change is slowly raising the level of the sea. Water expands with heat, so warmer temperatures are causing our oceans to expand. At the same time, these higher temperatures are melting ice sheets and glaciers adding more water to the oceans.

Ōtautahi-Christchurch is more exposed to coastal hazards than any other metropolitan area in New Zealand, including Auckland and Wellington. Across the Ōtautahi-

Christchurch District, approximately 25,000 properties are exposed to coastal hazards risks over the next 120 years. The National Institute of Water and Atmospheric Research (NIWA) estimates that with 1 metre of sea-level rise, the replacement value of buildings is approximately $6.7 billion, the majority of which are residential properties.

As a region, Canterbury has around $1 billion of local government-owned infrastructure exposed to coastal hazards, the majority of which is in Ōtautahi-Christchurch.

The result is a rise in sea level that will not only affect the open coast but also allow high tides and the effects of storms to reach further inland. This means that more land may be affected by coastal flooding, erosion and rising groundwater in the future, and the severity of those impacts would likely be greater.

This proposed plan change sets out a risk-based approach that involves managing development, land use and subdivision activities according to the level of risk in that location, acknowledging the uncertainty (of when land may be affected by rising sea levels) and the vulnerability of the activity to risk.

It reflects the approach taken to other hazards in the District Plan; (Areas identified at a higher risk of river flooding that could cause harm are classified as High Hazard Management Areas. Similarly on the Port Hills, a graduated approach is taken with a more restrictive set of rules applying to properties subject to a higher risk of rock fall, cliff collapse and mass movement compared with other areas where there is a lower risk) and is consistent with international risk management best practice (ISO 31000: 2009, Risk Management – Principles and Guidelines).

The proposed plan change gives effect to the Resource Management Act’s purpose of enabling people and communities to provide for their social, economic, and cultural well-being and for their health and safety.

It recognises that the level of risk is not the same in every location and enables a responsive approach to the management of development, land use and subdivision within areas of potential coastal hazards.

The objectives we’re seeking to achieve from this draft Plan Change reflect those from the Resource Management Act, New Zealand Coastal Policy Statement and Regional Policy Statement:

• Development, subdivision and land use does not increase the risk of coastal inundation, coastal erosion, rising groundwater or tsunami causing physical, social, economic or environmental harm.
• Existing communities potentially affected by coastal hazards are able to continue to develop and use land, natural and physical resources where the risk of adverse effects from coastal hazards is not increased and the level of risk can be managed to an acceptable level.

The proposed plan change also introduces new policies, rules and methods.

This proposed plan change has been shaped by community feedback. From 8 October–6 December 2021 we engaged with residents on an Issues and Options Paper for the Coastal Hazards Plan Change. You can read the consultation report, and all feedback received online

Generally, the higher the level of risk, the greater the level of control needed to ensure that the risk is appropriately managed. Below is a high-level overview of the level of controls that are proposed to apply to activities across a range of zones.

The proposed Plan Change focuses on risks from coastal flooding and erosion. Areas of rising ground water and tsunami (based on a 1:500 year event) are broadly similar in extent to the areas identified as being at risk of coastal flooding, so we’re proposing that they’re not mapped separately, and that the effects of these hazards are assessed through the plan’s inundation rules.

Objective 3.3.2 of the District Plan seeks to minimise the number, extent, and prescriptiveness of development controls and design standards in the rules, in order to encourage innovation and choice. Consideration is being given to how the Draft Coastal Hazards Plan Change could help to streamline the plan. This could include removing some of the existing provisions where they can be better addressed through the proposed new methods.

How we are identifying different areas of risk

The identification of different levels of risk is based on work by engineering consultancy, Jacobs with input from Council planners and technical specialists, and peer reviewed by Beca. It draws on data from the 2021 Coastal Hazards Assessment (Tonkin + Taylor). You can view the Risk Based Coastal Hazards Analysis for Land-use Planning study 2021 (Jacobs) and maps showing areas of very low, low, medium and high risk on our Coastal Hazards webpage.

The maps have been developed at an area-based scale, to establish the concept of the risk-based approach for district planning purposes. They do not provide a property specific level of assessment. We’re continuing to refine
the methodology for the risk-based approach, including enhancing the mapping, and this work will be done prior to the plan change being formally notified later this year.

As well as the proposed changes to manage the risks from coastal hazards, we’re also consulting on changes to our District Plan to comply with new government direction from the National Policy Statement on Urban Development 2020 (NPS-UD) and the Resource Management (Enabling Housing Supply and Other Matters) Amendment Act 2021. This direction requires us to enable more housing and business development including within and around the city centre and suburban commercial centres.

The proposed plan change creates a number of residential and commercial zones in the city, within which different heights and densities of development are enabled for housing. Increased commercial development will be enabled in the central city and suburban commercial centres. It’s important to remember, although these changes allow for more housing to be built, this won’t happen city-wide overnight. Our city will gradually evolve as our population grows and demand for more and different types of housing increases. You can find out more about this proposed Plan Change on our webpage(external link).

There is some cross-over between the Coastal Hazards Plan Change and the Draft Housing and Business Choice Plan Change. Some areas have qualities, known as Qualifying Matters, which mean rules enabling increased development will not apply, or the level we enable increased development to is limited, and remains subject to resource consent approval. We are proposing that coastal hazards are considered a Qualifying Matter. This is because areas affected by coastal hazards are not suitable for intensification to the extent of other areas – we want to avoid new developments being exposed to an increased risk of harm from coastal flooding, erosion and tsunami. 

Read more about the technical information supporting the proposed changes to the District Plan on our webpage(external link)