View all publications

2 Flood Risk Management in New Zealand

2.1 Overview of current practice

Flood risk cannot be avoided in New Zealand. There will always be some risk, regardless of whether risk reduction measures are adopted or strengthened.

Flooding is New Zealand’s most frequent natural hazard. Weather is the biggest contributing factor to flood risk, followed by development and population growth on flood plains. Land use and condition in the upper catchment are also important.

Flood plains are home to many of our larger towns and cities, and development continues to occur on these flood plains. Current risk management practice tends to be reliant on physical works, which may not be the best way to manage the increasing flood risk posed by climate change.

At any one time, the flood risk affecting New Zealand is much higher than the flood risk affecting individual communities. Unless a community is located in an area with more than one river, the community will only experience one large flood at a time, and often years apart. However, regionally or nationally, several floods can occur at the same time, affecting numerous communities. A flood event can also affect several catchments or regions, affecting several communities simultaneously.

Flood risk management in New Zealand has evolved over time, from ad hoc to centralised approaches last century, to the current devolved approach of management by local government. This devolved system is consistent with the Government’s policy in relation to civil defence and emergency management policy: local risks are the responsibility of local authorities. Managing flood risk takes place within the wider context of emergency management and sustainability for central government, local government and communities. Appendix 3 outlines this wider context.

A suite of statutes allocate roles and responsibilities across central government, local government and communities. The Drainage Act 1908, the Soil Conservation and Rivers Control Act 1941, the Resource Management Act 1991 (RMA), the Local Government Act 2002, the Local Government (Rating) Act 2002, the Civil Defence and Emergency Management Act 2002, and the Building Act 2004 are the key Acts for managing flood risk.

Central government’s current role focuses on assisting communities to prepare and recover from large events, providing local government with the necessary powers, funding the science system, and providing weather forecasts and warnings. Regional and territorial local authorities carry out the daily management and funding of flood risk management in consultation with the local community.

Local government uses a variety of methods to manage flood risk, including structural, non-structural and emergency management techniques. As part of the Flood Risk Management Review, a series of case studies was undertaken to understand how councils manage flood risk. This case study work had three important findings.

First, there is no one standard approach to managing flood risk, which makes comparison across the country difficult. The mix of tools reflects the local contexts and can be quite different in different areas. This can be both a weakness and a strength. Some councils have better resources, including information and funding, to achieve robust flood risk management that is responsive to the local conditions. Other councils experience difficulties.

Secondly, most of our larger cities and towns are protected by physical works, which work well up to the point they are designed for. Beyond this point, emergency management is the most often cited response to a larger flood. However, the age of some structures means that in some cases the reliability of the structures is unknown, but works are being maintained and often upgraded.

Finally, good information is critical to understanding the nature of the flood hazard and methods to manage flood risk. Good information is also crucial to withstand scrutiny in planning processes, including developing and implementing plans as well as assessing development proposals.

2.2 Flood Risk Management Review findings and response

2.2.1 Overall findings

The Flood Risk Management Review work programme has been completed by the Ministry for the Environment, and the detailed findings of the review are presented in Appendix 2. The Steering Group considers that the current flood risk management framework is not fundamentally flawed but that there are significant issues that need to be addressed.

The current level of flood risk across New Zealand cannot be stated with any accuracy, and neither can the impact of climate change or variability be meaningfully predicted on the level of flood risk. In addition, there is no way to assess or collate comparable information around the country to make this level of analysis possible. As a result, understanding the potential flood risk requires:

  • broad-scale analysis using a consistent set of parameters and approaches so flood risk can be understood across the country and hot spots identified

  • understanding climate change’s future effects on weather patterns in different parts of the country

  • determining and accounting for uncertainty in climate change and variability, hydrological, hydraulic and economic modelling analysis.

The review findings indicate that practice is variable across the country, with larger communities being able to afford better flood risk management. In some cases this does not reflect the actual level of risk faced by communities.

Ways forward

Improvements are needed to meet the challenge of future climate change and to satisfy communities and central government that an acceptable level of risk remains. Improving practice requires the following actions:

  • an active and engaged risk management approach by central and local government in meeting their respective roles and responsibilities

  • the goal of risk reduction being embedded within the policy framework

  • appropriate resources, including sufficient information, guidance and funding, being made available to promote good practice in the daily management of flood risk

  • central and local government monitoring to understand the levels of flood risk and inform future policy and management practices.

Expected outcome

  • The consequences of flooding are reduced in communities and across the country.


2.2.2 Roles and responsibility

Central government, local government, communities and individuals all have a role and a responsibility to manage and reduce flood risk.

Central government emergency management policy is that local risks are a local responsibility.2 Local government manages flood risks with the local communities at risk. Communities and individuals take responsibility for looking after themselves, families and neighbours before and after a flood. The private sector is responsible for business continuity, undertaking due diligence and managing risk to employees and business.

Currently, there are two parts to central government’s role. First, it has an enabling role focused on the reduction and readiness aspects of risk management. Central government ensures that local government has the necessary powers to manage flood risk. Funding research, providing guidance, forecasting and warnings are also part of this enabling role. Secondly, central government has a response and recovery role in helping communities to prepare and respond to emergencies. When an event occurs beyond local government’s ability to cope, central government will provide assistance − primarily financial. The greatest proportion of resources is directed towards central government’s response and recovery role.

Local government’s roles are set in legislation and councils comply with the requirements set out in the relevant Acts. Councils are responsible for sustainably managing land and water resources for communities’ wellbeing as well as emergency management. The day-to-day management and monitoring of flood risk rests with councils.

Central government has not directed flood risk management outcomes for councils. In the absence of national guidance, local government fulfils its roles and discharges its responsibilities in response to local priorities. This is appropriate for managing local risk, but managing and reducing the flood risk to New Zealand is a different goal.

National flood risk is more than the sum of local risks. National risk includes multiple events occurring with greater frequency across the country and depends on councils being able to manage flood risk effectively. A council’s resources and ability to manage flood risk directly influence the potential costs central government may have to meet when a flood occurs. Climate change is very likely to increase the frequency of events across the country and therefore the impact and potential costs of flooding, which represent an increase in flood risk.

Managing national risk requires managing different factors from those associated with local risk, including the increased frequency of large events across the country, monitoring, and ensuring local government can undertake its roles.

Ways forward

Central and local government roles need to be complementary to reduce flood risk, and a number of actions are suggested.

  • Central government’s current role should be extended to provide direction, assistance and guidance to local government on acceptable outcomes and ways to reduce flood risk across the country. It is then up to each council and community to determine how this can be achieved locally. Central government should also take a more active interest in reducing flood risk by remaining engaged in the flood risk management area and monitoring flood risk nationally.
  • Local government’s role should be aligned to the national goal of reducing risk. Local government should take responsibility for using good practice, informing communities of flood risk, and making sustainable long-term decisions a priority.

The roles below enhance and clarify current roles rather than suggest new roles.

  • Individuals, communities and the private sector should:

    • take responsibility for their family, personal safety and the decisions they make
    • take responsibility for business decisions
    • understand their level of flood risk (including any residual risk) and accept liability for their decisions
    • be informed and active in decision-making.
  • Territorial authorities should:
    • show leadership locally and adopt a risk management approach to implement risk reduction policies, methods and regulation
    • identify and manage residual risk
    • work together with communities, iwi, regional councils, beneficiaries3 and exacerbators4 in decision-making and agreeing on roles
    • sustainably manage the effects of land use and people’s activities to reduce the flood risk
    • sustainably manage the effects of land use and people’s activities to reduce the flood risk
    • use the Building Act and Building Code as part of a comprehensive approach to risk management, including flood-proofing buildings
    • manage civil defence and emergency management locally
    • build stakeholders’ awareness of risk.
  • Regional authorities should:
    • show leadership regionally and adopt a risk management approach to implement risk reduction policies, methods and regulation
    • identify and manage residual risk
    • work together with communities, iwi, territorial authorities, beneficiaries and exacerbators in decision-making and agreeing on roles
    • sustainably manage water and land to reduce the flood risk
    • manage civil defence and emergency management regionally
    • build stakeholders’ awareness of risk.
  • Central government should:

    • show leadership and provide clear direction on reducing flood risk
    • adopt a risk management approach nationally and work with local government
    • ensure local government and communities have the necessary powers and tools to fulfil their roles and responsibilities
    • provide forecasts, weather warnings, science and research relevant to managing flood risk
    • contribute as a beneficiary towards reducing the flood risk, and be a 'good neighbour' by taking responsibility for Crown lands and assets
    • ensure the policy of reducing the flood risk is integrated across all relevant government programmes
    • provide relief when an event has overwhelmed a community’s capacity to respond and recover from a flood.

Expected outcome

Individuals, communities, local and central government understand their roles and work together to reduce flood risk.


2.2.3 Funding and affordability

Greater investment is needed now to reduce the flood risk now and into the future.

Reducing the flood risk and adapting to the challenges of climate change require an extended role for central government. This will involve increased funding for central government to:

  • provide direction, assistance and guidance to local government

  • monitor future progress towards reducing flood risk

  • take an active part in reducing overall flood risk.

Individuals and communities that benefit from flood risk management are generally paying for that benefit, but there are inconsistencies and gaps. A wider mix of funding tools could be used by local government.

Beneficiaries that do not currently pay include some central government and local government owned lands and activities. Rating exemptions mean that education and health facilities, in particular, do not contribute to the full cost of flood risk management. When beneficiaries do not pay, other funding is needed to cover the shortfall. Generally this falls on ratepayers, which results in inequity. Some communities may also settle for a higher level of flood risk than if all potential beneficiaries paid their share.

Lower-income areas and areas with a smaller rating base also experience difficulties in affording good flood risk management. Councils with better resources, including better information and funding, are more likely to achieve more robust flood risk management. This results in an equity issue, as some communities may not be able to afford an acceptable level of flood risk management. Reducing flood risk across the country requires that all councils are able to manage the flood risk effectively.

Ways forward

More resources are required to reduce flood risk. Suggested actions are:

  • ensuring all beneficiaries pay towards the cost of flood risk management, including:

    • central government, particularly the education and health sectors
    • local government assets that benefit from protection
    • some utility providers that do not pay rates
  • addressing affordability issues in low-income communities by central government providing a contestable 'safety net' funding mechanism based on affordability using a similar model to the Sanitary Water Subsidy Scheme

  • local government more fully using the mix of tools provided in the Local Government (Rating) Act 2002, including increasing rates, loans and targeted rates

  • central government more actively funding science, research, guidance and forecasting systems to enable local government to achieve good practice.

Expected outcomes

  • Resources applied to flood risk management reflect the benefits received.

  • Communities live with a level of flood risk that is acceptable and affordable to the community and New Zealand in the long term.


2.2.4 Future flood risk management practice

Current flood risk management practice will need to improve to meet the challenges of increasing flood risk.

Flood risk management practice is variable across the country, and central government policy has focused on responding to and recovering from flooding. The Steering Group believes this situation needs to change. Local and central government need to ensure future actions are complementary to achieve risk reduction. Integration is required across all levels of decision-making affecting flood risk management. If flood risk management is not improved, future generations may become more vulnerable, greater losses from flooding may occur, and greater spending will be required to respond to and recover from floods.

There is no comparable baseline information around the country, nor are there standard definitions of risk or methods to assess risk. Flood risk management is often restricted to areas of historical flooding rather than the risk being managed over a district or region. There is ongoing pressure to develop land, and development is still occurring in flood plains. In addition, there is a lack of good information on the economic, environmental and other applied aspects of flood risk management. Practitioners are looking for practical guidance and ways to benchmark performance.

Ways forward

Local government must have the resources, tools and information necessary to adopt good practice and ensure flood risk management is sustainable in the long term, particularly in relation to future climate change impacts.

Central government needs to understand and monitor flood risk across the country to effectively manage the risk to New Zealand, to ensure that local government is able to effectively manage local flood risk. Providing information on a national basis − including warnings, forecasts, climate change predictions and good practice guidance − is required.

Future practice will be improved by the following actions:

  • individuals, communities, business, and local and central government adopting a risk management approach that is integrated across the 4 Rs

  • central government enhancing its risk reduction role to show leadership, by:

    • strengthening the policy framework to enable flood risk to be reduced
    • providing clear guidance on flood risk assessment and good practice
    • producing better information on flood frequency estimates, climate change predictions, weather warnings and flood forecasts across the country
    • ensuring local government has the necessary tools and resources to adopt good practice
  • local government adopting the latest good practice, as well as acknowledging and actively managing residual risk

  • ongoing monitoring and dialogue between local and central government to ensure progress towards reducing the flood risk

  • completing and implementing a national policy statement on flood risk management, and a New Zealand Standard to improve practice, as agreed by government.

  • All communities and levels of government are able to make sustainable long-term decisions based on the best available information to reduce flood risk.


2  Part 10, 89(2) National Civil Defence Emergency Management Plan Order 2005.

3  Beneficiary: A party, in terms of section 101(3)(a)(ii) of the Local Government Act 2002, that benefits from flood risk management activities.

4  Exacerbator: A party, in terms of section 101(3)(a)(iv) of the Local Government Act 2002, that contributes to the need to undertake flood risk management activities.