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1 Introduction to the Guidance Manual

1.1 Increasing coastal hazards and risk

A high proportion of New Zealand’s urban development has occurred in coastal areas.¹ Some of this development has been located in areas that are vulnerable to coastal hazards such as coastal erosion and inundation (see Box 1.1).

In recent years, coastal development and associated infrastructure have intensified, and property values in some areas have dramatically increased (Figure 1.1). As development and property values in coastal margins increase, the potential impacts and consequences of coastal hazards also increase. Managing this escalating risk over the coming decades now presents a significant challenge for planning authorities in New Zealand.

Climate change will not introduce any new types of coastal hazards, but it will affect existing coastal hazards by changing some of the hazard drivers. It will exacerbate coastal erosion and inundation in many parts of the New Zealand coast, further increasing the impacts of coastal hazards on coastal development from now on.

Climate change effects are gradual. However, as many land-use planning decisions have long-term implications because of the permanency of structures (eg, buildings, roads, network utilities), incorporation of climate change is now a necessary consideration for the majority of coastal planning.

Figure 1.1: Existing coastal development at risk from coastal erosion in the Coromandel Peninsula, Waikato Region

Two carts, one showing an increase in the number of properties at risk from coastal erosion using data points from 1994-1997, August 2003 and June 2004, and another showing the increased capital valuations of properties at risk from coastal erosion using data fromt eh same times.

Source: Environment Waikato 2008.

Text description of figure 1.1: For the Coromandel Peninsula, bar graphs compare the number of properties (and their capital value) currently at risk from coastal erosion and those at risk from erosion in the next 100 years. The growth in the number of properties and the rise in capital value of those assets was tracked by Environment Waikato from the 1994 to 1997 era to June 2004.
In June 2004, 680 properties were at risk from erosion and 900 were at risk in the next 100 years. The capital value for those properties at risk was $650 million and rises to $875 million for those at risk in the next 100 years.

Box 1.1: Ohiwa Spit. What goes around ...
Photo shows a house falling into the sea at Ohiwa Spit in 1976 following a series of storms that cased severe erosion, while in the background, there is a line of vertical railway irons offshore that mark a previous futile attempt to stop erosion in the years up to 1976. The bottom two photos show oblique aerial photos of Ohiwa Spit contrasting the highly eroded state in 1976 with the highly accreted state in 2005, which has precipitated the sale of beach-front properties that were underwater in 1976. Photograph courtesy of RK Smith The patterns of coastal change on Ohiwa Spit in the Bay of Plenty, and the effect this has on coastal development, exemplify the problems in land planning and coastal hazard management that are occurring around the New Zealand coast. Similar issues are being faced at Mokau on the western coast of the Waikato region and in most other regions around the country. Ohiwa Spit has a long history of fluctuations in the position of the coastline. Between 1867 and 1911, the coastline of the Spit tended to build seawards, or accrete. This period was followed by an erosive phase over the next few decades to around 1949. In the decade that followed, the spit once again started to build seaward until around 1959, when an erosive phase once again began. This phase culminated in a series of storms in the mid- to late 1970s, which resulted in a number of properties falling into the sea. However, this was not the first time that property had been lost owing to the natural cyclic changes that occurred on the Spit. In the late 1800s, a hotel was built on the Spit and, in the early 1920s, the area subdivided. Within a few years, subsequent erosion was so rapid that the Ferry Hotel was lost and the township was abandoned, with a tidal channel ending up where the main street had been. In the following years, the Spit appeared to stabilise and a generation or so later, in 1949, a new subdivision further down the spit was created and developed on during the early 1950s. However, by 1965, erosion was again affecting property and several dwellings were lost to the sea over the subsequent decade despite various attempts to protect the coast with ad hoc seawall and railway-iron protection. The buildings that did not fall into the sea during the storms in 1976 were removed from the coastline. In the aftermath, some landowners received compensation whereas others retained their titles to the land. Since these storms, the Spit has been again going through a phase of accretion, with the beach building in width and dunes that had been lost during the storms re-established. In early 2006, a number of the remaining section titles were put up for sale and some have sold. The issue of whether the new owners should be permitted to build new dwellings on these ephemeral sections is currently (April 2008) under appeal to the Environment Court. Sources: from Richmond, B.M., Nelson, C.M., Healy, T.R., 1984, Sedimentology and evolution of Ohiwa Harbour, a barrier impounded estuarine lagoon in the Bay of Plenty, New Zealand, Journal of Marine and Freshwater Research, 18; EDS 2006; Environment Bay of Plenty unpublished

Box 1.1: Ohiwa Spit. What goes around ...

Ohiwa Split
Photo shows a house falling into the sea at Ohiwa Spit
in 1976 following a series of storms that cased severe
erosion, while in the background, there is a line of
vertical railway irons offshore that mark a previous
futile attempt to stop erosion in the years up to 1976.
The bottom two photos show oblique aerial photos of
Ohiwa Spit contrasting the highly eroded state in 1976
with the highly accreted state in 2005, which has
precipitated the sale of beach-front properties that
were underwater in 1976.
Photograph courtesy of RK Smith

The patterns of coastal change on Ohiwa Spit in the Bay of Plenty, and the effect this has on coastal development, exemplify the problems in land planning and coastal hazard management that are occurring around the New Zealand coast. Similar issues are being faced at Mokau on the western coast of the Waikato region and in most other regions around the country.

Ohiwa Spit has a long history of fluctuations in the position of the coastline. Between 1867 and 1911, the coastline of the Spit tended to build seawards, or accrete. This period was followed by an erosive phase over the next few decades to around 1949. In the decade that followed, the spit once again started to build seaward until around 1959, when an erosive phase once again began.

This phase culminated in a series of storms in the mid- to late 1970s, which resulted in a number of properties falling into the sea. However, this was not the first time that property had been lost owing to the natural cyclic changes that occurred on the Spit.

In the late 1800s, a hotel was built on the Spit and, in the early 1920s, the area subdivided. Within a few years, subsequent erosion was so rapid that the Ferry Hotel was lost and the township was abandoned, with a tidal channel ending up where the main street had been.

In the following years, the Spit appeared to stabilise and a generation or so later, in 1949, a new subdivision further down the spit was created and developed on during the early 1950s. However, by 1965, erosion was again affecting property and several dwellings were lost to the sea over the subsequent decade despite various attempts to protect the coast with ad hoc seawall and railway-iron protection. The buildings that did not fall into the sea during the storms in 1976 were removed from the coastline. In the aftermath, some landowners received compensation whereas others retained their titles to the land.

Since these storms, the Spit has been again going through a phase of accretion, with the beach building in width and dunes that had been lost during the storms re-established. In early 2006, a number of the remaining section titles were put up for sale and some have sold. The issue of whether the new owners should be permitted to build new dwellings on these ephemeral sections is currently (April 2008) under appeal to the Environment Court.

Sources: from Richmond, B.M., Nelson, C.M., Healy, T.R., 1984, Sedimentology and evolution of Ohiwa Harbour, a barrier impounded estuarine lagoon in the Bay of Plenty, New Zealand, Journal of Marine and Freshwater Research, 18; EDS 2006; Environment Bay of Plenty unpublished

1.2 Changing paradigms for coastal hazard management

Coastal erosion and inundation are natural processes that help shape the character of the coastline around New Zealand. Most coastal hazard problems have been caused by coastal development and subdivision being located too close to the existing shoreline to accommodate natural changes and trends in shoreline movements. Subsequent management of the hazard has been dominated by reactive and engineering-based approaches that, over time, often lead to the level of risk increasing (not diminishing) and the wider consequences becoming more complex to manage (Box 1.2).

Box 1.2: The development–defend cycle (adapted from Carter et al 1999)
Our traditional approach to managing coastal hazards is predominantly reactive, characterised by ‘holding the line’ using engineering structures, such as rock revetments to protect coastal development. Such ‘solutions’ often adversely impact on other environmental values, conflict with wider public values and typically tend to ignore the human dimension of the problem. They often lead to ongoing intensification of development in hazard areas, resulting in the problems becoming more complex over time. It is now realised that continuing to defy natural coastal processes, and defend the coastline as a means to decrease the risk to coastal development, is an unsound management approach in most instances (Dahm 2007, unpublished).

Box 1.2: The development–defend cycle (adapted from Carter et al 1999)

The development - defend cycle

Our traditional approach to managing coastal hazards is predominantly reactive, characterised by ‘holding the line’ using engineering structures, such as rock revetments to protect coastal development. Such ‘solutions’ often adversely impact on other environmental values, conflict with wider public values and typically tend to ignore the human dimension of the problem. They often lead to ongoing intensification of development in hazard areas, resulting in the problems becoming more complex over time. It is now realised that continuing to defy natural coastal processes, and defend the coastline as a means to decrease the risk to coastal development, is an unsound management approach in most instances (Dahm 2007, unpublished).

The functions of local government are set by the Local Government Act 2002 (LGA) and other specific statutes, particularly the Resource Management Act 1991 (RMA). Key requirements of the Local Government Act² are democratic local decision-making and sustainable development: the social, economic, environmental and cultural well-being of communities, in the present and for the future. The needs and expectations of future generations in the decision-making process need to be considered.

The purpose of the RMA is to promote the sustainable management of the natural and physical resources (specifically: environmental, social, economic and cultural aspects of them). This includes management of coastal environments, particularly preserving natural character from inappropriate development and maintaining or enhancing public access.³ Policies intended to achieve the purpose of the RMA in relation to the coastal environment⁴ are contained in the mandatory New Zealand Coastal Policy Statement.⁵ ‘Avoidance and mitigation of natural hazards’ is also included as a function of local government with respect to the RMA.⁶

The RMA (Energy and Climate Change) Amendment Act 2004 introduced the requirement for anyone exercising powers or functions under the RMA to have particular regard to the effects of climate change.⁷ This amendment has relevance to:

local government decision-making
the increasing need to plan for the effects of climate change that can exacerbate coastal hazards
the increasing need to plan for the effects of adaptation measures put in place to protect natural and physical coastal resources to alleviate the risks from climate change.

Achieving sustainable coastal development that meets the reasonably foreseeable needs of future generations requires a fundamental shift in the way we approach coastal hazard management. Some of the paradigm drivers and shifts are summarised in Figure 1.2.

Figure 1.2: The paradigm changes required to enable successful and sustainable management of the impacts of coastal hazards

Historical or prevailing paradigm		Changing paradigm
Hazards such as coastal erosion viewed as ‘abnormal’ coastal behaviour.		Living with coastal erosion as a natural cyclic process that helps shape the natural characteristics of the coastal margin.
Predominantly re-active approach to managing coastal hazards after an event occurs.		A proactive and strategic long-term approach to managing coastal hazards.
Managing coastal processes.		Influencing people.
Focus on a single management objective based on physical impacts, such as protection of front row property owners.		Balanced consideration of a wide range of environmental and social objectives, including protection, but also issues such as natural character, public access, cultural values, kaitiakitanga, kaimoana and customary uses.
Uncertainty about the occurrence of climate change and a tendency to wait for more certain information.		Certainty about the occurrence of climate change and the need to respond.
Consideration and management of different coastal hazards separately (eg, erosion, storm inundation, tsunamis).		Integrated approach to managing multiple hazards, including dealing with residual risk, eg, emergency management.
Decision-making based on short-term timeframes.		Support for long-term planning appropriate to the intended timeframe of the decisions being made and ongoing climate change impacts.
Little control over existing use rights with respect to hazard management.		Increased control over existing use rights with respect to hazard management.

Source: Adapted from Dahm 2007, unpublished.

However, coastal hazard risk is increasing. This is a result of the legacy of past development decisions, increasing development and property values, and increasingly the effects of climate change. These increased risks place considerable pressure on local authorities to achieve long-term sustainable management of the coastal environment, as well as sustainable development of coastal communities.

Challenges include:

the need to provide for the natural character, ecological, landscape, amenity, public access, cultural and spiritual values of the coast
the increasing social and economic pressures to intensify the use and development of coastal areas, particularly with respect to redevelopment, subdivision and associated infrastructure
the public’s and property owners’ perceptions of existing use rights, permanence of property and local government responsibilities for protection from impacts of coastal hazards
the perceived need to protect people, property and infrastructure from the impacts of natural hazards
the complex and uncertain nature of assessing risks associated with multiple coastal hazards and climate change
potential liability on local authorities for present and future impacts on consented and permitted coastal properties
the need to integrate risk governance and risk transfer, by coordinating land-use planning and the management of residual risk through emergency management arrangements, insurance cover etc
the need to raise people’s awareness and understanding of the risks they face
the need to plan for tomorrow’s coastline, including minimising the costs of inter-generational adaptation and sharing the costs more equitably.

1.3 Purpose of this Guidance Manual

This Guidance Manual has been written primarily to support local authority staff (policy, planning, consents, building and engineering staff) dealing with some of these challenges to effectively manage and minimise coastal hazard risks. It focuses on the three main types of coastal hazards:

coastal erosion caused by storms and long-term processes
coastal inundation caused by storms or gradual inundation from high tides due to sea-level rise
coastal inundation caused by tsunamis.

The Guidance Manual aims to provide best practice information and guidance to strengthen the integration of coastal hazards and climate change considerations within the land-use planning and resource consenting process. More specifically, the Guidance Manual:

provides information on the key effects of climate change on coastal hazards
provides a risk assessment framework for incorporating coastal hazard and climate change considerations into the decision-making processes associated with policy development, planning and awarding resource consents
promotes the development of long-term adaptive capacity for managing (ie, reducing) coastal hazard risk through adoption of adaptive management and no-regrets response options.

1.4 What’s new in this edition?

This is the second edition of the Guidance Manual; it supersedes the first edition published in 2004. It follows an updated assessment of the science of climate change produced by the Intergovernmental Panel of Climate Change (IPCC) in 2007.

The main changes in this Guidance Manual are:

it updates the climate change science and provides guidance and recommendations relevant to coastal margin issues in the New Zealand
there is a new chapter on local government response to climate change, emphasising how climate change adaptation fits within the key principles of local government actions (Chapter 4)
there are minor revisions to the risk assessment process to enable local authorities to better characterise coastal hazard risk (Chapter 5)
the chapter on managing coastal hazards and climate change risk has been extensively revised (Chapter 6)
supporting material in the appendices has been revised and updated as necessary.

The structure and format of the Guidance Manual has also been significantly revised with the aim of making the document and the information contained within it more accessible to the user.

1.5 A roadmap through the Guidance Manual

1.5.1 Structure of the Guidance Manual

This document is in two main sections, supported by a range of resources and further information in appendices (Figure 1.3). The climate change guidance section is generally applicable to all involved with local government activities in coastal margins, whereas the decision-making guidance and supporting resources are aimed at those wanting to assess the coastal hazard risks arising from climate change.

Figure 1.3: Structure of the Guidance Manual

Climate change guidance	Decision-making guidance
Chapter 2: The Changing Climate Chapter 3: Implications for New Zealand’s Coastal Margins	Chapter 4: Responding to Climate Change: Future-proofing Decision-making Chapter 5: Understanding Changing Coastal Hazard Risk Chapter 6: Managing Coastal Hazard and Related Climate Change Risk

Chapter 7: Further Resources
Appendix 1: Relevant Legislation
Appendix 2: Relevant Case Law
Appendix 3: Factsheets: Coastal Hazard Drivers and Related Issues

Throughout the Guidance Manual, links are provided to the coastal hazard factsheets contained in Appendix 3, where further information on the characteristics of coastal hazards can be obtained. These links are shown by the boxed ‘FS’ with a number that refers to the factsheet number. Reading the fact sheets first may be a useful strategy, particularly for those new to the area of coastal hazards and climate change.

1.5.2 Supporting guidance

In addition to this Guidance Manual, a range of complementary guidance is available or in preparation on climate change, hazard management and coastal development aspects from the Ministry for the Environment. These include:

Climate Change Effects and Impacts Assessment: A Guidance Manual for Local Government in New Zealand.⁸
Ministry for the Environment Quality Planning website: Coastal development Guidance Note.⁹
Ministry for the Environment Quality Planning website: Natural Hazard Guidance Note.¹⁰

Further sources of information and guidance are provided in Chapter 7 at the end of this Guidance Manual.

1 In this Guidance Manual, ‘coastal’ refers to all areas defined to be part of the Coastal Marine Area plus the adjacent land referred to as the ‘coastal environment’. So, ‘coastal’ includes open coasts, estuaries, harbours, inlets, river mouths and adjacent land.

2 Local Government New Zealand 2003.

3 LGA section 6.

4 RMA sections 56–58.

5 Under review – out for public consultation: March 2008.

6 RMA sections 30 and 31.

7 RMA section 7(i).

8 MfE 2008a.

9 MfE 2008b.

10 MfE 2008c.

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