Silt and sediment control

We're looking to the future – promoting proactive building practices that ensure mud and sediment don't fill up our Porirua Harbour.

Small earthworks guide

Small earthworks guide

This booklet will give you information on:

  • Preparing for your project
  • How to do the work right, first time
  • Managing sediment on your site
  • Achieving council sign-off

Download it here

Why we need erosion, silt and sediment control

Unless significant changes are made now to the way we are operating in Porirua, we will have no harbour in approximately 200 years time.

Our main aim is to save Porirua's Harbour (which includes Pāuatahanui Inlet). The harbour needs saving because it is silting up, becoming shallower and its aquatic life is being smothered and killed by contaminants, which includes sediment off small building sites.

On your building site

Sediment control is mostly about common sense. If your site has sediment, mud and/or brown-coloured stormwater running off it, muddy vehicle tracks leaving your site, or the stormwater drain next to your site is getting filled up with sediment from your building site, the way that construction operations on the site are occurring will need to change. 

For more information

If you need help on the best way to deal with identified problems, please phone us on (04) 237 5089.

The bylaw

Sediments from building sites end up in our stormwater drains, and are generally not filtered out of stormwater, but simply gets discharged into the Harbour. With development in Porirua increasing, specifically small building sites from 50 to 2,500 square meters, sediments are causing significant problems with the way the Harbour operates and exists. 

Porirua's biggest asset is in jeopardy and the time for education and action must occur now.  The Council has therefore introduced the Bylaw to address this problem.

The bylaw states that owners of properties must ensure that any development activity disturbing the soil is carried out in a way to prevent soil erosion and to stop silt and sediment from entering the stormwater system or watercourses. 

This means that before carrying out any development activity in relation to land you need to ensure that:

  • surface runoff from the site is isolated from other sites and roading systems; and
  • surface runoff from the site containing silt and sediment is prevented from entering the stormwater system or watercourses; and
  • silt and sediment control measures are installed, where necessary

Read our Stormwater (pollution prevention) bylaw 2021

Pauatahanui inlet aerial

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