Discharging into a waterway is likely to impact water quality.

A discharging consent is needed if someone is proposing to discharge contaminated water (or water containing sediment), effluent, treated or untreated wastes, into a waterway. Examples of discharges that need consents are: stormwater discharges, wastewater disposal, factory discharges from pulp and paper mills, and dairy and meat processing.

The quality of the receiving waters may quickly deteriorate as a result of a discharge. Mahinga kai are likely to be impacted if water quality or the surrounding habitats are affected. Any potential impacts need to be taken into consideration and assessed before an application is submitted.

You may need a discharge consent if your activity is likely to:

  • Discharge potentially contaminated water (or water containing sediment) into water, or onto/into land.
  • Discharge effluent into water, or onto/into land.
  • Discharge treated or untreated wastes into water, or onto/into land including landfills or cleanfills.
  • Discharge water and associated contaminants into water, or onto/into land, in association with a geothermal take.

The impacts of discharges to waterways on water quality and mahinga kai can include:

  • Increased nutrient loading - promotes nuisance algae growths. Excessive plant growth and die-off can lead to oxygen depletion and death of aquatic life or eutrophication.

Find out more about nutrient overloading

  • Elevated ammonia levels that are toxic to fish species.
  • Microbial contamination - that makes the water unsuitable for human or stock drinking, contact recreation, and/or shellfish collection from downstream estuaries.

Find out more about infectious substances

  • Agro-industrial effluents that may contain chemical contaminants that are directly toxic to aquatic life (e.g., tannins and chromium in tannery effluents; un-ionized ammonia).

Find out more about chemical contamination

  • Increased suspended solids - reduce water clarity and smother aquatic life.

Find out more about reduced water clarity

  • Increased water temperatures that can cause fish death.

Find out more about temperature changes


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