Without protection measures, earthworks and other land-disturbing activities can result in erosion and sedimentation of waterways and estuaries.
If you're planning earthworks on your property, you may need to apply for resource consent so we can monitor the effect of the earthworks. If the site is contaminated, you will need to notify us before you start.
We can also provide guidance on the most appropriate protection measures to put in place before you start your earthworks.
Call us on 09 301 0101 for information and advice on what to do before starting to dig. Check the relevant district plan and the unitary plan. If you're considering larger-scale or more complex earthworks, check the regional plan.
For minimum requirements for addressing land stability and earthworks, see the earthworks and geotechnical code of practice (PDF 1.5MB) .
When sediment is carried into waterways and estuaries it reduces water quality, harms fish and other species. It can also smother feeding areas and habitats for kai moana (seafood).
Sediment can also block streams, which can increase flooding and causes sediment build-up in our harbours.
Erosion causes sediment. Control erosion by:
- minimising the area of disturbance
- doing earthworks in stages
- stabilising exposed areas quickly
- keeping as much existing vegetation as possible, especially on steep slopes or areas close to watercourses.
Control sediment by:
- working in the driest season (2 October to 31 April)
- using appropriate sediment retention devices (including perimeter controls to keep clean run-off out of your work area)
- coordinating with services, like roading, gas, power, telephone and drainage, to put erosion and sediment control measures in place.
Both the landowner and the contractor doing the earthworks are responsible for taking appropriate measures to prevent soil loss and erosion. This is regardless of the size of your earthworks, and even in cases where a resource consent is not required.
For more, see these technical publications:
Find out more about land use consents on types of resource consent.
Earthworks on contaminated land
If you are planning to dig or disturb contaminated land, for testing or for any other reason, you need to notify us in writing before you start.
Download, complete and send us the land disturbance notification form (PDF 137KB) .
Return the completed form: