Coastal management - responding to climate change

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We need to better prepare our communities for the effects of ongoing changes to weather patterns and rising sea levels.

The impacts of climate change affect us all, and in Tasman we continue to experience the effects of significant weather and storm events.

Our first round of community engagement (22 July – 27 September 2019) sought feedback on what you value that may be affected by sea level rise and coastal hazards, your observations of coastal hazards around our district, and any comments on our coastal hazards map viewer.

Thank you to everyone who attended one of our community drop-in sessions in early August and/or provided feedback. We’ve summarised the feedback into this report:

This feedback will be used to help inform our future work programme.  Following the Ministry for the Environment’s Coastal Hazards and Climate Change Guidance (2017), we’ve now started work to “consider what matters most” by identifying areas, objects or experiences that we value and may be impacted by sea level rise and coastal hazards, and to assess their risk and vulnerability.

Read the FAQ

This is just the start...

We need to prepare for long-term change

We’re working on a project aiming to enable our Tasman Bay / Te Tai o Aorere and Golden Bay/Mohua communities to work towards long-term adaptive planning for sea level rise and coastal hazards.

While the rate and magnitude of future sea level rise is uncertain, we do know that rising sea levels will have increasing implications for development and infrastructure in coastal areas along with environmental, cultural and societal effects. 

We've prepared a map showing various scenarios, and will have several community drop-in sessions in the coming weeks.

View the map

The first of many conversations

We’ve started the conversation with our communities on coastal management.

At this early stage, the focus of the programme has been on raising awareness, developing a common understanding of the information and gathering your feedback on what you value that may be affected by sea level rise and coastal hazards. This will help us understand what is most important to people and communities, and will help inform options for future coastal management.

While our community engagement during July – September 2019 was the first opportunity to talk about the effect of sea level rise and coastal hazards, it won’t be the last.

Long-term adaptive planning work will take several years to complete and the community conversation will be ongoing.

A view of Tata beach in 1957. Photo courtesy Golden Bay Museum Te Waka Huia o Mohua 

Tata 1957

Our Te Tau Ihu coastal environment is diverse and dynamic

Tasman's coastline spans over 700km of open coast and estuary shorelines, the geography ranges from rocky and cliff landforms to dunes, sandy beaches and sand spits.

Treasured by our communities and visitors alike, it stretches from the rugged northwest coast, the uniqueness of Farewell Spit, the seaside communities in Golden Bay/Mohua, the golden sands of Abel Tasman National Park, and the expanse of the Waimea Inlet.

Over time our communities across Tasman Bay / Te Tai o Aorere and Golden Bay / Mohua have become synonymous with summer sun, sea and camping.  As well as permanent residents, these areas attract holiday makers from across New Zealand and internationally.

Our coastal communities have diferent characteristics. Some are linear development (e.g. Pakawau, Ruby Bay), some are on sandspits and small peninsulas (e.g. Totara Avenue, Parapara, Tata Beach, Torrent Bay, Kina), while aothers are in bays (e.g. Ligar Bay, Kaiteriteri), or are larger townships on river/coastal plains (e.g. Collingwood, Motueka, Richmond). 

Our coastal environment holds significant environmental and cultural values, provides employment and economic opportunities, numerous recreational activities and experiences, as well as being a great place to live.

Like other coastal communities around New Zealand, Tasman has experienced and will continue to experience the impacts of coastal hazards.  Many parts of our coastline are vulnerable to coastal storm inundation and/or coastal erosion. Ex-tropical cyclones Drena (1997) and Fehi (2018) are two notable examples of storm surge events which caused significant damage along our coastline.

The probability, severity and extent of coastal inundation and erosion hazards will increase as a result of projected climate change and associated sea level rise and increased storminess.

The historic view

Legends tell of Uruao, the first of the Polynesian voyaging canoes to land ... like the rest of New Zealand, Nelson was first settled around the ninth century.

Gardens were quickly established throughout the region, including alongside the Waimea River, and in Motueka and Riwaka, Mapua and Parapara.

Most villages were on the coast, close to river valleys. The location of each settlement was planned with both transport and food in mind. Waka (canoes) were used around the coast and up river valleys.”

From Jim McAloon’s “Nelson: A Regional History” (1997)

What are the issues?

Ruby Bay Storm Surge 200px

Climate change

Human activities such as driving, flying in planes, making things in factories, farming and so on release greenhouse gases in the atmosphere. These gases trap heat and are causing the world’s climate to change.

Climate change will affect different parts of the world in different ways. It is likely global temperatures and sea levels will rise, and weather such as rain, snow and wind will become more intense.

These changes will affect our lives, our health, economies, natural ecosystems and more.

New Zealand, and Tasman, needs to be prepared for a future of changing climate. As well as mitigating the problems, we need to work together to ensure that we, as a community, are prepared and ready to adapt to our ever changing environment and natural hazards.

Read more about how climate change is affecting our district and Council’s Climate Action Plan.

Why climate change matters

From the Ministry for the Environment website:

Climate change is the biggest environmental challenge of our time. It is already affecting our climate, agriculture, native ecosystems, infrastructure, health and biosecurity. If left unchecked it will have broad social and economic impacts.

Read more about climate change on the Ministry for the Environment website

See also:The Intergovernmental Panel on Climate Change

We cannot afford to ignore what is happening in New Zealand and globally.

Source: Ministry for the Environment website

Read the FAQ

Sea level rise and coastal storm inundation

Historic sea level rise in New Zealand has averaged 1.78mm per year, with the Port Nelson tide gauge recording a slightly lower rate than the national relative average of 1.57mm per year (MfE, 2017).  Measured sea levels at Port Nelson have risen approximately 150mm since the early 1940s.   

The rate and magnitude of future sea level rise is uncertain, especially later this century and beyond.  Scientists advise that sea levels will continue to rise and that levels are likely to rise at an accelerated rate over time as the earth’s temperature rises, meaning changes could happen sooner than predicted – or there may be changes to emission rates that reduce the rate of warming. Uncertainty is a key message.  What we do know is that rising sea levels will have increasing implications for development and infrastructure in coastal areas along with environmental, cultural and societal effects. 

Ex-tropical cyclone Fehi was a significant coastal storm inundation event that effected our district on 1 February 2018.  The large storm surge which coincided with a high spring tide and large waves damaged the coastline and flooded roads, reserves and nearby properties and houses.  Sea level rise will increase the exposure of our coastal land to these type of events, creating new hazards in areas that have not previously been exposed.

Coastal erosion

Our sandy beaches and shorelines are subject to natural processes of coastal erosion (sediment loss) and coastal accretion (sediment gain). Beaches or shorelines will often experience a cycle of erosion followed by accretion, with the duration of the erosion-accretion phase ranging from weeks (the period of a storm event and post-storm recovery) to longer periods over a year(s), a decade or several decades.   

In some areas of the district, coastal erosion is already affecting roads, reserves and private property. Mitigation measures (such as walls, rock revetments, sand push-ups) are already undertaken on parts of the district’s coastline. Sea level rise will increase the exposure of our coastal margins to coastal erosion and accretion, creating new erosion hazards in areas that have not previously been exposed.  

The Ministry for the Environment has developed a series of factsheets which provide further information on the different elements of coastal processes. View the factsheets on the Ministry for the Environment website.

Read the FAQ

What do we already know?

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Some Council infrastructure and assets are vulnerable

Through Council’s activity management plans we already identify Council infrastructure and assets that are vulnerable to the impacts of climate change. 

View our Activity Management Plans

Information from our iwi partners

Nationally, climate change and any adaptation response will present new challenges (as well as new opportunities) for iwi, hapū, whānau and Māori enterprise.

Eight iwi are tāngata whenua in Te Tau Ihu (the top of the South Island). Tasman District also covers the northern part of the Ngāi Tahu takiwā (tribal area/territory).  These iwi have all been through Treaty of Waitangi settlement processes and the resulting statutory acknowledgement documents contain information on the cultural, spiritual, historic and traditional associations each of the iwi have with the coastal areas in Tasman District. 

VIew Te Tau Ihu Statutory Acknowledgements

Some iwi authorities have also lodged iwi management plans with the Council.  These plans are a written statement identifying important issues regarding the use of natural and physical resources for the iwi and are lodged with councils under the Resource Management Act 1991. 

View Iwi Management Plans

These information sources provide a starting point for our discussions with iwi on responding to climate change.  

Information from other agencies

Several other agencies have also started to quantify New Zealand-wide risks and vulnerabilities to climate change and sea level rise and their reports include Tasman-specific data.

Parliamentary Commissioner for the Environment

The 2015 Parliamentary Commissioner for the Environment identifies that in Motueka approximately 1,043 homes, 117 businesses, and 41km or roads lie less than 1.5m above the spring high tide mark (MHWS level).

Preparing New Zealand for rising seas: Certainty and Uncertainty (2015)

Local Government New Zealand

A Local Government New Zealand’s 2019 report quantifies and values local government infrastructure exposed to sea level rise (increments of 0.5, 1.0, 1.5 and 3.0 metres). 

The report identifies Tasman roading, ‘3 waters’ infrastructure (water, wastewater and stormwater), green spaces, and other facilities which are vulnerable to rising sea levels.

Vulnerable: the quantum of local government infrastructure exposed to sea level rise (2019)

Department of Conservation

The Department of Conservation’s report identifies the Abel Tasman Coast Track as one of seven ‘icon destinations’ which have 10 or more vulnerable assets and/or more than 5% of vulnerable track.

Risk exposure of Department of Conservation (DOC) coastal locations to flooding from the sea (2019)

Where are we at in the process?

Using the principles of the Ministry for the Environment’s Coastal Hazards and Climate Change Guidance (2017), our work programme will span a number of years as we engage with our Tasman Bay and Golden Bay communities to:

Identify what is happening

by developing an understanding of sea level rise and coastal hazards in our district.

Consider what matters most

by identifying areas, objects or experiences that we value that may be impacted and assess their risk and vulnerability.

Discuss what we can do about it

by identifying and evaluating options to enable adaptation.

Develop an adaptive planning strategy

which will be implemented through a number of work programmes such as the Tasman Resource Management Plan, infrastructure and reserves asset management planning, and to help inform emergency management.

Assess how the strategy is working

by monitoring and regular review of the strategy.

This is a long-term process to agree how our community deals with climate change and coastal management issues. We are at the second stage of this process.

About the map

We’ve developed a coastal hazards map viewer which illustrates the extent of low lying coastal land in Tasman Bay and Golden Bay that may be affected by a range of sea level elevations. 

The map shows a range of sea level rise scenarios in 0.5m increments up to 2m. It also shows the impacts of higher tides caused by storms, mapped as a present day 1% AEP (annual exceedance probability) joint probability storm-tide event. A 1% AEP event has a 1% chance of occurring in any year.

We have also mapped areas of historical coastal erosion (sediment loss) and accretion (sediment gain) and the presence of coastal protection structures such as stopbanks, walls and rock revetments. 


The methodology used to develop the coastal hazards information shown on the map viewer is described in the accompanying report: 

Coastal Hazards Assessment in Tasman Bay/Te Tai o Aorere and Golden Bay/Mohua (2019) (pdf, 2 MB)

Open map viewer in a new window

How to use the map

With our coastal hazards map viewer, you can:

  • Click on the About symbol to read more about the mapped information.
  • Click on the Layer List symbol to view the map legend.
  • Turn map layers on or off by clicking individual boxes in the Layer List. 
  • Click on the Basemap Gallery symbol to view either aerial or street (topographic) basemaps.
  • Click on the Swipe symbol to compare scenarios (left hand side) to the underlying basemap (right hand side). Click and drag the swipe bar (in centre) either left or right across the map. 
  • Find an address or place by typing the location (e.g. 189 Queen Street) into the text box and click on the magnifying glass.
  • Click on the Bookmark symbol to view predefined areas e.g Motueka, Takaka, etc.


You can turn layers off and on - either view several layers at the same time, or a single scenario. 

Mapping the uncertainty of sea level rise

The mapped sea level rise elevations information is based on the Ministry for the Environment’s Coastal Hazards and Climate Change Guidance (2017)

The Guidance outlines the approximate years, from possible earliest to latest, when specific sea level rise increments (in metres above 1986-2005 baseline) could be reached for various projection scenarios of sea level rise for the wider New Zealand region, as shown in the table below. 

The representative concentration pathways (RCPs) listed are four comparable scenarios used to predict how future global warming may contribute to climate change and sea level rise. The lower scenario (RCP2.6) represents the rise in sea level if the Paris Agreement was achieved, namely to keep the global average temperature well below 2° C above pre-industrial levels, while pursuing efforts to limit the temperature increase to 1.5° C. The upper scenario (RCP8.5 H+) represents continuing high emissions and no effective emissions mitigation, plus runaway instabilities in polar ice sheet melting. The other two scenarios (RCP8.5 and RCP4.5) are in between those two different futures.

For example, based on current information we may expect 1m sea level rise by the years 2100 (RCP8.5+), 2115 (RCP8.5), 2170 (RCP4.5) or beyond 2200 (RCP2.6). 

SLR (metres) Year achieved for RCP8.5 H+ (83%ile) Year achieved for RCP8.5 (median) Year achieved for RCP4.5 (median) Year achieved for RCP2.6 (median)





















*extrapolated out based on MfE’s 1.9m sea level rise scenario.

Given that the rate and magnitude of future sea level rise is uncertain, all four RCP scenarios should be considered when developing our long-term adaptive planning approach. 

Each increment of sea level rise will depend on the rate of future global warming and climate change.

Ongoing uncertainty

Scientists advise that sea levels will continue to rise and that levels are likely to rise at an accelerated rate over time, meaning changes could happen sooner than predicted.  We don’t know exactly when each increment will occur, but our mapping helps to identify where sea level rise may impact low lying land.


Broadly speaking, the warmer the climate becomes, the faster sea levels will rise



Read the FAQ

Want to get in touch?


Phone: 03 543 8400

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