You can have or maintain a sediment trap as long as you can meet permitted standards. These apply whether the river or creek flows all the time or some of the time.  

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

A sediment trap is a dug out hollow or a built bund in a waterway that collects sediment-laden water and slows the water long enough for the sediment to settle out of the water.

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: 

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

Constructing (and maintaining) a sediment trap is a permitted activity under our Regional Plan: Water rule 13.5.1.10. 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

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 Consent Public Enquiries team consent.enquiries@orc.govt.nz for further information.