Natural hazards like storms, floods, and earthquakes can leave behind a challenging aftermath of silt and debris.
Whether it's liquefication following the 2010-2011 Canterbury earthquakes or the sediment deposits from Cyclone Gabrielle in 2023, cleanup efforts can be daunting.
Debris and silt inundation can cause a significant amount of damage to residential areas and can be difficult to remove.
Our guide below can help you understand silt and debris inundation to residential homes and what you can do if your property is affected.
Understanding silt and debris inundation
Silt inundation occurs when fine particles build up and settle after flooding. It often comes with debris such as rocks, fallen trees, and damaged structures that are swept onto properties during storms.¹
When to remove silt
Not all silt needs to be removed. If it's non-hazardous (less than 15mm deep), and in an open area, the silt should disappear on its own within a few weeks.¹
In some situations, the silt underneath your home can be left if it's inaccessible and meets the following criteria:
- There is sufficient room between the ground and your home of at least 400mm and the foundation vents are not blocked.
- There are no foul smells.
- The debris contains no organic matter.²
If you're unsure about silt on your property or concerned about potential contamination, consult your assessor or local council for guidance.
Silt removal process
Each council will manage the collection and removal of silt and debris differently. Some may collect and dispose of it at no cost, while others might have specific disposal sites. It's important to contact your local council for area-specific information and avoid disposing of it incorrectly as this could increase future flood risks.
Some helpful local council resources include:
- Auckland Emergency Management: Tips for cleaning up your home after a flood
- Hawkes Bay Regional Council: Silt, debris and waste
- Napier City Council: Cyclone Gabrielle FAQs
- Gisborne District Council: Silt removal and disposal
The role of Natural Hazards Commission Toka Tū Ake (NHC)
The Natural Hazards Commission Toka Tū Ake (NHC) is a government agency that provides residential natural hazard insurance (called NHCover) for certain natural hazards, including storms, floods, and landslides. If you're insured with Tower, we'll manage your NHCover claim on NHC's behalf and be your single point of contact for your claim at all times.
NHCover contributes to repair and cleanup costs of your insured residential land, up to the land cover cap.¹ This includes removing silt 15mm or deeper and debris removal.
It's important to note that NHC won't pay you for any work you do to clean up your land yourself and will only contribute to costs you may incur.¹
Understanding NHCover
There is limited land cover provided by NHCover, which includes:
- Land under your home and separate buildings and structures
- Land within 8m of your home, separate buildings and structures
- Land under or supporting your main access way up to 60m from your home.
Limited cover is also available for certain retaining walls, bridges, and culverts within specific areas. You can find out more information on the cover and its limits on the NHC website.
Your insurance assessor can also clarify which areas are covered. Generally, silt damage to homes is covered under your Tower insurance policy.*
For more specific cleanup advice following a natural hazard event, check out your local emergency management and council websites.
By understanding these guidelines and working closely with your insurance provider and local council, you can navigate the challenges of cleaning up silt or debris after a natural hazard more effectively.
* For specific information about the terms, conditions, limits, and exclusions that may apply to your claim, please read your Tower policy wording or contact us directly.
The links we provide to third-party websites are for your convenience and do not constitute any endorsement or authorisation by us. The information provided on this page about silt and sediment inundation is general in nature and is not intended to be professional or legal advice. Tower does not accept any liability for the accuracy or content of information on this website that belongs to third parties or on any third-party website.
Sources
¹Cover for storm, flood, and landslide damage :: Natural Hazards Commission Toka Tū Ake
²BRANZ Bulletin: Restoring a home after flood damage
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