Natural hazards and land damage

The earthquakes exposed a large number of known and new natural hazards such as landslips, rock-fall, and landslide dams. They also caused significant damage to land – such as cracking, lateral spread, and liquefaction – under and around people’s homes, businesses and farms.

Natural hazards and land damage can pose risks to people’s lives, safety, health and well-being. They can reduce the value of people’s homes and land. This, in turn, can impact on whether people can afford to rebuild or to carry on using their land and property in the way they did prior to the earthquake.

Primary accountability for managing and mitigating risks from natural hazards and land damage sits with local and regional councils. However, during recovery, central government agencies play a role in supporting councils to keep people safe; and to identify and implement options for managing and mitigating risks.

There is no ‘one size fits all’ approach for how hazards and risks should be identified or managed – nor is there an agreed threshold for determining ‘intolerable risk’ to people. Each case needs to be assessed on its merits. Risk management options range from accepting a risk, to avoiding it altogether (for example, by prohibiting access to, or use of, an area).

The underlying policy is that people retain their existing use rights following an emergency unless they are specifically restricted from doing so – and that they are not compensated for any restrictions on use where these do occur. There is no standard government policy to compensate landowners for their capital losses, or the costs of relocating, when the risks are deemed too high for existing land-uses to continue.

Private insurance cover is provided where buildings or proximate land sustain damage, but not to compensate for a natural hazard risk (except where EQC determines that a property is at ‘imminent risk’ of damage (or further damage) arising from the same event).

Joint central and local government work programme

As part of its coordination role, the NRO is overseeing a joint local and central government work programme for managing risks from natural hazards and land damage arising from the November 2016 earthquakes.

In managing risks from natural hazards, the primary focus is on protecting the ‘life safety’ of people and communities; and then on identifying long-term measures to reduce risks. Risk reduction measures can include geotechnical solutions such as rock-fall nets, bunds and walls, and policy measures to restrict access or development of ‘at-risk’ sites.

An early focus in managing risks from land damage, is protecting risks to the health and wellbeing of landowners working on damaged land where it is no longer fit for purpose. In the longer term, new strategies are needed to ensure land use is economically and environmentally ‘fit-for-purpose’ within changed landscapes, hazard profiles, and ecological limits. Options need to be assessed farm by farm, and district-wide.

Mitigating risks to communities

Councils have identified six key sites (excluding rural areas), with about 100 buildings affected, where a managed approach to risk reduction may be required, for example through some form of engineering or policy intervention.

Hazard risk assessments have now been completed at three of these sites: Dempsey’s Track, Oaro Boat Harbour and Rakautara, with a view to confirming the nature and scope of the hazard, and assessing the potential for any current placards to be lifted. Hurunui District Council is engaging with affected landowners.

Consultation is also underway on options for reducing risk at Mount Lyford, which sustained significant damage but is also at significantly enhanced risk of a failure of the Hope Fault, and at Lyell Creek, where there is significant land damage from lateral spread, and a managed approach to mitigation and repairs is being considered.

Several buildings in the flatter inland areas of Kaikōura (the Kaikōura Plains) have sustained damage, but it is unclear whether this is from lateral spreading (usually caused by liquefaction) or folding. Further assessment of this damage is needed to inform rebuild options, design specifications for building platforms, and potential changes to land use rules.

More detailed investigations are likely to be needed at these and other key sites to identify more complex issues and options for reducing risk over the long term. These ‘Stage 2’ assessments would involve in-depth geotechnical investigations and community consultation to inform hazard management options – including engineering options (eg, to retain slumping land or catch rock-fall) and/or policy options (along a spectrum of measures ranging from accepting the risk to managed retreat).

For some sites, mitigation options are likely to be expensive and beyond the resources of the community to fund. ‘Special policy’ options may need to be developed in such cases. This would require preparing a business case for consideration by Cabinet.

Mitigating risks to rural landowners

The joint work programme will also support rural landowners and councils to address risks arising from rural land damage, and to plan for future land use. For some rural landowners in the Hurunui, Kaikōura and Marlborough districts, extensive damage to their land means the way the land was used before the earthquake is no longer economically viable. In many cases, land uses were economically marginal even prior to the earthquake, due to prolonged drought and other factors such as changes in production costs or commodity prices.

In the short term, there is a need to manage health and safety risks to landowners who are working on damaged land and staying in damaged properties, and who are under acute financial stress.

Longer term, there is a need – and an opportunity – to review land use options district-wide and agree new land use strategies that are economically and environmentally ‘fit-for-purpose’ within changed landscapes, hazard profiles, and ecological limits.

The Ministry for Primary Industries is active in helping councils and rural land-owners to work through these issues. The $5m Primary Industries Earthquake Recovery Fund announced in the May 2017 will also help with this work. This will fund advisory services (and potentially also land geotech assessments) to assist landowners with decisions on the future use of their land (up to $5,000 per farm); and projects to assess area-wide land use change options (up to $600,000 per project).

This work will inform changes to Councils’ regional and district plans and rules on land use to provide for economic viability (and sustainable land use) over the long term.

Using placards to restrict people’s access to unsafe buildings and places

Following an emergency event, properties that have sustained damage or that are at risk from a hazard, such as a land-slide or rockfall are issued with placards (or stickers) to indicate risk to people’s ‘life safety’. These are a ‘quick’ visual assessment, usually done at speed. Red placards indicate a building is too unsafe to enter; a yellow placard places conditions on entry, for example to certain parts of a building, or at certain times of the day. A white placard indicates that a building has been assessed as safe to occupy (even though it may have sustained some damage).

In the response phase of the emergency, MBIE reports that Kaikoura District Council issued 177 red or yellow placards; Hurunui District Council issued 313; and the Marlborough District Council issued 73.

Since then, councils have continued to assess placards and to lift them where possible (eg, because temporary repairs have been made or the hazard risk has been mitigated in some way). They have also sought to transition placards for dangerous buildings to section 124 dangerous and unsanitary building notices under the Building Act, ahead of the end of the national transition period on 7 June 2017 extended to 22 November. This allows councils to continue to exclude people from a building, or part of a building, that has been assessed to be ‘dangerous’.

It is important to note that, although placards s124 notices provide an expert assessment and useful indicator of hazard and damage, they apply only to buildings and not to land. The full extent of land damage is not yet known, but is being investigated through LiDAR data collection, site inspections and other geotechnical assessments.

Landslip dams

Hundreds of landslip dams were identified and monitored immediately after the earthquake, but the vast majority of these have now resolved naturally, including as a result of Cyclones Cook and Debbie over Easter 2017. A large dam on the Hāpuku River (as at October 2017) continues to be monitored, though the risk has significantly reduced as the crest cut down over successive rainfall events through the winter. The dam above Goose Bay washed out without causing damage over Easter 2017.