Increased water sediment load

Impact

Water sediment load refers to the quantity of soil particulate material (usually fine clay or silt particles) suspended within the water.  Suspended fine sediment contributes to water turbidity.  The higher the turbidity (and suspended fine sediment) of the water the lower its clarity. Turbidity is influenced by a range of factors including but not  limited to: catchment soil erosion, streambank and bed erosion, wastewater release, stormwater drainage, algal growth, flow rate and salinity.  Turbidity determines the degree of scattering or absorption of light in the water and thus influences water temperature and the growth of aquatic plants and algae.

Suggested indicators: Fine sediment in water+

Increased water sediment load may be associated with:

Potential associated impacts Suggested indicators+
Reduced light penetration limiting the photosynthesis and growth of aquatic plants and algae
  • Microalgae in water
  • In-stream habitat
Reduced food sources for some species including reduced ability of visual predators to hunt food leading to fauna deaths
  • Fish
  • River & wetland fauna
  • Native land fauna
  • Exotic pest fauna

Suspended particles can clog fish gills, resulting in disease, slower growth and sometimes death
  • Fish

Suspended particles absorb heat, thus increased turbity means increased water temperature and reduced dissolved oxygen

  • If turbidity becomes extremely high it may reduce light penetration and subsequently water temperature
  • Water temperature
  • Dissolved oxygen

Eventually suspended sediments settle to the streambed degrading the habitat of bottom-dwelling organisms
  • In-stream habitat
  • Aquatic macro-invertebrates
Reduced downstream water suitability for agricultural, recreational, industrial and domestic uses

Suspended particles may carry contaminants and pathogens, such as nutrients

+ Descriptions of indicators (PDF, 76K)* provides a brief description of each indicator including techniques and purpose.

* Requires Adobe Reader

Last updated 7 September 2010

Land Manager's Monitoring Guide