Homeowner’s guide to landslide assessments

Publish Date : 01 Nov 2023
Homeowners Guide To Landslide Assessments

Geotechnical assessments are a free service provided by the Tāmaki Makaurau Recovery Office to help homeowners and the council understand landslide risks. This handy guide gives you a preview of what to expect.

Geotechnical assessments help us to understand if future severe storms are likely to result in a landslide that poses a risk to life, and whether that risk can be managed so it is safe to live in the property. Assessments also consider feasible interventions that can be taken to manage risk. For example, modifications to a property or to the surrounding area to create resilience.

“At its heart, this is about keeping you and your whānau safe when in extreme natural events. Some homes and neighbourhoods may be vulnerable to a future landslide risk that is unacceptably high, and we are doing what we can to keep people out of harm’s way. This includes providing evidence about ground stability so homeowners can make informed decisions about their safety and any property level risk reduction,” says Mace Ward, Deputy Group Recovery Manager.

Complete this online form if you are unsure or concerned about your landslide risk and would like an assessment to confirm the risk category to your home.

Frequently asked questions

Do I need a geotechnical risk assessment?
In some cases, it will be obvious that a risk assessment is needed – for example if the weather events this year caused damage. Other properties may not have sustained any or much damage at all, but are located in areas that we suspect may be at risk in future. We recommend you complete this online form to participate in the process.

What information do you collect in the desktop geotechnical assessments?
The desktop assessments involve information collection from property files, photographs, published geological information and LiDAR data to calculate slope angles.

What information do you collect through onsite geotechnical assessments?
The onsite assessments collect information to allow an assessment of the geomorphology (land shape), which informs an assessment of the ground stability at each property. In high-risk locations such as Muriwai there are also below-ground investigations and monitoring to provide detailed information on the locations of geological boundaries that affect slope stability. Where appropriate for the landslide style, engineers have created three-dimensional debris flow modelling for typical scenarios to calculate risk for homeowners.

Is the landslide risk assessment the same as what you would find in other countries?
Yes, the risk assessment follows the procedures outlined in the Australian Geomechanics Society 2007 guidelines, which represent internationally accepted best practice. More information on these procedures is available on the Landslide Risk Management website.

What is the difference between an EQC vs a Recovery Office geotechnical report?
While both assess landslides, an EQC report typically focuses on damage to the insured property. The Recovery Office geotechnical reports assess long term risk to life.

Does the risk equation in the geotechnical report take weather patterns into account?
Yes, we consider the weather patterns that are likely to occur over the next 100 years. This is based on current, previous and future weather predictions. We also consider the likelihood of drought, as that would affect land stability too.

Where can I get more information?
There is more information available with the  Our Auckland landslide and liability story and also the article  Recovery office reaches milestone of 1000 landslide assessments.

I want a flooding assessment how do I make this happen and what can I expect?
You can read more information in this Our Auckland article: Risk assessments for flood affected homes.

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