Water clarity

Water clarity or turbidity is the cloudiness or haziness in a fluid caused by individual small particles (suspended solids).

An increase in turbidity results in a corresponding decrease in water clarity. High turbidity may be from an increase in phytoplankton (algae) or an increase in sediments. This may be in response to nutrient inputs and erosion due to land development, stormwater runoff from paved surfaces, wastewater/other discharges, or farming/forestry practices. Urbanisation, forestry, agriculture, industries that discharge into waterways, and mining are all likely to increase turbidity of nearby waterways, especially when these involve large quantities of stormwater and surface runoff.

Potential impacts of turbidity on water quality and mahinga kai

  • Cloudy water that may be green or brown reduces the ability of fish to see prey and detect predators.
  • Reduced light penetration - reduces or inhibits growth of aquatic plants and their ability to produce food and oxygen (DO) for species that depend on them.


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Audited on 8 March 2021