The dangers of flood events don't stop when the water recedes. As the land dries, there are health risks with all the leftover floodwater, mud and silt.

As this is a big safety issue, especially in areas where flooding is prevalent, we will look at why silt safety post-flood event is very important and what to do to stay safe.

Just remember that if you need support or someone to talk to, our Sonder support team is available 24/7 to chat whenever you need it.

What exactly is silt?

Silt refers to solid, dust-like sediment that's found in soil and other types of sediment, including clay, sand and gravel. For a solid to be classified as silt, each particle must be less than 0.05mm in diameter. By comparison, sand particles is between 0.05 to 2mm in size.

As silt can be transported around by water, wind, and ice, this sediment can change landscapes by settling in water bodies and filling up spaces such as lakes and wetlands. During flooding events, silt can be deposited along riverbanks and flood plains.

Why is silt dangerous after flood events?

When water levels rise due to flood events, toxins, dangerous chemicals, and harmful substances like faecal matter get mixed into the floodwater and mud. All of these things can make you very sick if you come into enough contact.

Once the flood event is over and the contaminated muddy silt starts drying out, it turns into dust and becomes airborne. Once this happens, people can be exposed to the toxic dust via inhalation and become sick.

How do I stay safe?

If you're in an area where flood events occur, here's what you can do to stay safe from potentially contaminated silt:

  • Wash your hands before and after handling flood debris or silt.

  • Wash your hands before handling food.

  • Wear a face mask, goggles and gloves.

  • Wear long-sleeve shirts, pants and sturdy, enclosed shoes.

  • Cover any cuts and grazes to avoid them getting infected.

Where to dispose of silt and other flood debris in NZ

Residents with Insurance:

  • If you have insurance, contact your insurance company to confirm the process for disposing of storm-related waste, including building debris, soft furnishings and storm-damaged household items

  • A number of private waste companies can provide you with a skip bin or flexi bag to collect your waste. A list of these companies can be found here.

  • You can also take your debris and damaged items to a Waste Transfer station in Auckland. A list of these can be found here.

Residents without Insurance:

  • Auckland Council has arranged for waste to be taken for free at participating transfer stations within the Auckland region. If you would like to take your waste to one of these stations, contact Auckland Council on 0800 22 22 00 to confirm your visit. A list of participating facilities can be found here.

Roadside rubbish and recycling collections

  • This will continue as normal.

Storm-related waste on public land:

  • For significant blockages or debris (including vehicles) in streams and waterways or vegetation, contact Auckland council on 0800 22 22 00

  • If you need skip bins to be placed in communal areas where the storm damage has been extensive, contact 0800 22 22 00 so that Auckland Council can assess the need and provide the required service.

For more information:

  • If your rubbish or recycling bins have gone missing or been damaged during the storm, please request a new one through the council’s online form. Please mention the flood in the “Let us know if there's anything you want to say about this bin” section to ensure your request is processed with urgency.

  • Please report illegal dumping on 0800 NO DUMP.

  • For normal roadside collections please visit Auckland Council’s website

If you have any questions or need extra support, we're here to help you anytime in any language. Simply start a chat with us via the home screen of the Sonder app.

Image credit: Star Wars Episode II: Attack of the Clones

All content in Sonder's Help Centre is created and published for informational purposes only. It is not intended to be a substitute for professional advice.

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