Water Turbidity

AUS-TDG-CON-WTU General High confidence

Benchmark Value

No specific value — see range
Range: 1 to 10 NTU
Optimal Range: 1 to 10
Direction: Lower is desirable ↓
Form: OptimalRange

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 11 benchmarks together — the OptimalRange form drives the primary score, while 10 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard MaximumOnly Guard MaximumOnly Guard OptimalRange Guard MaximumOnly Guard MaximumOnly Guard OptimalRange Guard MaximumOnly Guard MaximumOnly Guard OptimalRange Guard

Evidence & Context

The optimal range for water turbidity during baseflow conditions is considered to be <1 NTU to 10 NTU, with values towards the lower end of this range (<5 NTU) being more characteristic of the most pristine or best-managed examples.

Metric Definition:

Water turbidity measured in Nephelometric Turbidity Units (NTU) during baseflow conditions.

Benchmark Definition:

Optimal range of water turbidity supporting high ecological health during baseflow in Temperate Dry Woodlands & Native Grasslands conservation areas.

Justification:

Supports high light penetration, clean substrates, and healthy aquatic communities; encompasses natural baseline variation up to "Excellent" status.

Sources (2)

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
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. Journal

Catchment Health Indicator Program - Upper Murrumbidgee Waterwatch

View Source

Supporting Sources (2)

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 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 Pristine Reference
  • Evidence Type ReferenceCondition

Lifecycle

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

Notes

Values closer to <1-5 NTU are typical of the most pristine or best-managed examples.

Related Benchmarks

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

10 NTU Moderate
Conservation / Protected Natural Areas · Pristine Reference
MaximumOnly Active v2
10 NTU Moderate
Conservation / Protected Natural Areas · Conservation Target
MaximumOnly Active v1
25 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