Water Turbidity

AUS-TDG-CON-WTU General Moderate confidence

Benchmark Value

25 NTU
Direction: Lower is desirable ↓
Form: MaximumOnly

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context.

Evidence & Context

Persistent turbidity values >25 NTU would likely indicate significant ecological stress and degradation.

Metric Definition:

Water turbidity measured in Nephelometric Turbidity Units (NTU).

Benchmark Definition:

Upper limit of turbidity indicating significant ecological degradation in Temperate Dry Woodlands & Native Grasslands conservation areas.

Justification:

Exceeds general upland river trigger values; levels associated with significant ecological stress, habitat degradation, and potential loss of biodiversity.

Sources (1)

Preview of Default guideline values - Water Quality Australia, accessed August 12, 2025
Default guideline values - Water Quality Australia, accessed August 12, 2025 Government

ANZECC (2000) Australian and New Zealand Guidelines for Fresh and Marine Water Quality.

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of Feral horses (Equus caballus) increase suspended sediment in subalpine streams
Feral horses (Equus caballus) increase suspended sediment in subalpine streams
Contextual Support Journal

Feral horses (Equus caballus) increase suspended sediment in subalpine streams

View Source
Preview of Upper Murrumbidgee Waterwatch Catchment Health Indicator Program (CHIP) Reports (e.g., 2021, 2023) and associated methodology defining "Excellent" water quality thresholds.
Upper Murrumbidgee Waterwatch Catchment Health Indicator Program (CHIP) Reports (e.g., 2021, 2023) and associated methodology defining "Excellent" water quality thresholds.
Direct Evidence Journal

Catchment Health Indicator Program - Upper Murrumbidgee Waterwatch

View Source
Preview of Yellow Box – Red Gum Grassy Woodland, accessed August 12, 2025,
Yellow Box – Red Gum Grassy Woodland, accessed August 12, 2025,
Contextual Support Journal

Indicator W3: Water quality - ACT State of the Environment

View Source

Context

  • Region Australia
  • Biome Temperate Dry Woodlands & Native Grasslands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Conservation Target
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 10 Jun 2026

Notes

Persistent turbidity above this level signals probable significant ecological degradation.

Related Benchmarks

Other benchmarks in the AUS-TDG-CON-WTU family.

10 NTU Moderate
Conservation / Protected Natural Areas · Pristine Reference
MaximumOnly Active v2
— NTU High
Conservation / Protected Natural Areas · Pristine Reference
OptimalRange Active v1
10 NTU Moderate
Conservation / Protected Natural Areas · Conservation Target
MaximumOnly Active v1
50 NTU Moderate
Conservation / Protected Natural Areas · Conservation Target
MaximumOnly Active v1
5 NTU Moderate
Conservation / Protected Natural Areas · Pristine Reference
MaximumOnly Superseded v1