Sediment traps

There are permitted standards for sediment traps in ephemeral or intermittently flowing rivers. If the standards can’t be met, then resource consent may be required.

Apply for consent to install a sediment trap

What is sediment?

Sediment is soil particles that are moved in water. It can be rich in both nutrients and contaminants.


What is a sediment trap?

A sediment trap is a dug out hollow or a built bund in a watercourse that collects sediment-laden water and slows the water long enough for the sediment to settle out of the water. It is encouraged for sediment traps to be constructed in non-flowing sections of watercourses.


What are they used for?

By slowing down the water’s movement, a sediment trap allows the sediment to drop out of the water. There are a number of benefits to sediment traps, including:

  • The prevention of flooding because sediment build up can obstruct water channels and reduce drainage
  • Preventing excessive levels of sediment in waterways, which can affect water quality for stock water, domestic supply and irrigation as well as the natural flora and fauna that live in the water; and
  • Sediment that is trapped can be phosphate-rich and can be returned to paddocks for soil health and pasture growth.


Do I need resource consent to build a sediment trap?

Constructing (and maintaining) a sediment trap is a permitted activity under our Regional Plan: Water rule However, if you are planning on constructing (or maintaining) a sediment trap, there are still some things you need to be aware of, including:

  • It has to be solely for sediment control purposes
  • No destabilisation of any lawful structure or increased risk of flooding or erosion can occur
  • No works can occur in flowing water
  • Any build-up of sediment must be removed
  • Reasonable steps are taken to minimise the release of sediment (water remains clear 200m downstream of the disturbance) when constructing or maintaining a sediment trap
  • It cannot affect any lawful water take; and
  • It cannot cause any change to water level or hydrological function or any damage to fauna/flora in a regionally significant wetland.


You may still require consent

If you will be impounding water by the creation of a dam crest or considering taking or using water from the sediment trap, then further permits may be required – please contact our Public Enquiries team for further information.

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