Dealing with silt or sediment inundation

Debris and silt inundation, like that seen after Cyclone Gabrielle, can cause a significant amount of damage and can be difficult to remove. Whether and how you remove it will depend on what it is, how deep it is, and where it is.

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Silt and sediment clean-up is sometimes needed after a major disaster, such as a storm, flood, earthquake, or volcanic eruption. Following the Canterbury earthquakes in 2010 and 2011, liquefaction left silt deposits on a lot of properties. More recently, Cyclone Gabrielle floodwaters moved tonnes of sediment in some areas of the North Island, particularly in Hawke's Bay's Esk Valley.

Debris and silt inundation can cause a significant amount of damage to residential areas and can be difficult to remove. Whether and how you remove it will depend on what it is composed of, how deep it is, and where it is. Below is a general guide to help with silt inundation.

What is debris and silt inundation?

Debris and silt inundation are deposits of soil, sand, or other items that are swept up and moved by water and/or wind during a storm or flood. During the storm and/or flood event, the debris and silt is deposited on residential land.¹

Does silt always need to be removed?

Not all silt needs to be removed.

For example, if silt is non-hazardous, minimal (less than 15mm deep), and in an open area, there's no need to remove the silt. The silt will erode away and disappear over time.²

Silt may also not be removed from underneath a property if there is sufficient room between the ground and the property (generally 400mm) and no black polythene underneath it.³

If you have lodged a claim with Tower and you're unsure about silt on your property, please talk to your assessor.

If you're concerned about potentially contaminated or hazardous silt on your property, you should call your council for further guidance.

Who can I contact about removing silt?

Each council will manage the removal of debris and silt differently. Some councils will collect the waste from your property and cover the costs. Others may provide specific disposal sites for private landowners or contractors to safely dispose of silt.

Don't wash silt into drains or dispose of it at unapproved sites. This could increase future flood risks.

It's important that you contact your council to find out more. For advice following Cyclone Gabrielle, some helpful resources include:

What role does Toka Tū Ake EQC play in removing debris and silt?

Toka Tū Ake EQC is a government agency that provides residential natural hazard insurance (called EQCover) for some natural disasters, including damage from landslips, floods, and storms.

If your home is insured with Tower and you need to make a claim, we'll manage your EQCover on behalf of Toka Tū Ake EQC. We'll be your single point of contact for your EQCover claim at all times.

Generally speaking, EQCover will repay you for the cost of the removal of:

Silt that is 15 mm or deeper from your insured residential land, up to the EQCover land cap.
Debris inundation (that is on your insured residential land, up to the EQCover land cap).¹

In most cases, you'll be compensated (repaid) for the loss that you've experienced. In other words, the cost to remove silt where there is an eligible EQCover claim and the silt needs to be removed.

Silt itself isn't considered damage to land, and this means there's no payable claim unless there is a loss incurred.

Not all land is covered by EQCover, which has limits, such as residential land being limited to 8 metres around the home. Your assessor will work with you to let you know which parts are and aren't covered. Silt damage to homes is generally covered under your Tower insurance policy.*

*Please make sure you read your Tower policy wording to understand the terms, conditions, limits, and exclusions that may apply.