Water Turbidity

AUS-AKW-IND-WTU General Low confidence

Benchmark Value

5 NTU
Direction: Lower is desirable ↓
Form: MinimumOnly

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context. The scoring engine uses 9 benchmarks together — the OptimalRange form drives the primary score, while 8 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MaximumOnly Guard MaximumOnly Guard MaximumOnly Guard MaximumOnly Guard MinimumOnly Guard MinimumOnly Guard MaximumOnly Guard OptimalRange Guard

Evidence & Context

A minimal level of background turbidity is a likely feature of a healthy, resilient system, with a lower critical threshold > 5 NTU to protect aquatic life from UV radiation.

Metric Definition:

Lower critical threshold of water turbidity to provide UV radiation shielding in ephemeral pools

Benchmark Definition:

This benchmark represents the minimum turbidity level needed in ephemeral pools to protect aquatic organisms from harmful UV radiation in the biome under industrial land use.

Justification:

Suspended particles and dissolved organic matter absorb and scatter UV radiation, acting as a natural sunscreen. Levels below this threshold may increase UV stress.

Sources (1)

Preview of Australia's inland waters - Water Quality Australia
Australia's inland waters - Water Quality Australia Government

Australia's inland waters - Water Quality Australia, accessed July 26, 2025

View Source

Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Preview of A review of water quality studies relevant to northern Australia - CSIRO, accessed July 21, 2025,
A review of water quality studies relevant to northern Australia - CSIRO, accessed July 21, 2025,
Direct Evidence Journal

Salinity and water quality

View Source

Context

  • Region Australia
  • Biome Arid Karstic Woodlands & Shrublands
  • Land Use Industrial & Infrastructure Use
  • Assessment Not Stated
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 4 Jun 2026

Notes

This threshold applies to the persistent, non-flowing state of ephemeral water bodies where UV exposure is a risk. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

Other benchmarks in the AUS-AKW-IND-WTU family.

50 NTU Low
Industrial & Infrastructure Use · Not Stated
MaximumOnly Active v2
— NTU Low
Industrial & Infrastructure Use · Not Stated
OptimalRange Active v1
20 NTU Low
Industrial & Infrastructure Use · Not Stated
MaximumOnly Superseded v1