Water Turbidity

AUS-ASC-AQU-WTU General Moderate confidence

Benchmark Value

25 NTU
Thresholds: Lower: —, Upper: 25
Direction: Lower is desirable ↓
Form: UpperThreshold

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 20 benchmarks together — the OptimalRange form drives the primary score, while 19 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary LowerThreshold Guard UpperThreshold Guard Point Guard UpperThreshold Guard MaximumOnly Guard LowerThreshold Guard OptimalRange Guard OptimalRange Guard LowerThreshold Guard MaximumOnly Guard UpperThreshold Guard MaximumOnly Guard OptimalRange Guard MinimumOnly Guard Point Guard LowerThreshold Guard OptimalRange Guard UpperThreshold Guard MaximumOnly Guard

Evidence & Context

An upper detrimental threshold is clearly established at 25 NTU.

Metric Definition:

Upper detrimental threshold of water turbidity beyond which ecological harm occurs in salmonid aquaculture.

Benchmark Definition:

Turbidity level above which sublethal and negative ecological effects on salmonids are documented.

Justification:

Supported by scientific literature on sublethal effects and national water quality guidelines (ANZECC 2018).

Sources (2)

Preview of Australian and New Zealand guidelines for fresh and marine water quality, accessed July 19, 2025,
Australian and New Zealand guidelines for fresh and marine water quality, accessed July 19, 2025, Government

Using the ANZECC Guidelines and Water Quality Objectives in NSW, accessed July 21, 2025,

View Source
Preview of Effects of Turbidity and Suspended Solids on Salmonids - ResearchGate
Effects of Turbidity and Suspended Solids on Salmonids - ResearchGate GreyLiterature

Effects of Turbidity and Suspended Solids on Salmonids - ResearchGate

View Source

Supporting Sources (38)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) Climate change impacts on Australia's alpine ecosystems - ResearchGate, accessed on May 28, 2025,
(PDF) Climate change impacts on Australia's alpine ecosystems - ResearchGate, accessed on May 28, 2025,
Contextual Support GreyLiterature

vegetation | Australian Alps National Parks

View Source
Preview of Alpine Trout Farm
Alpine Trout Farm
Irrelevant

Alpine Trout Farm

View Source
Preview of Aquaculture in NSW facts & figures 2024
Aquaculture in NSW facts & figures 2024
Contextual Support Journal

Aquaculture in NSW facts & figures 2024, accessed August 10, 2025,

View Source
Preview of Australia: aquaculture exceeded the value of wild catch by 2021-22
Australia: aquaculture exceeded the value of wild catch by 2021-22
Contextual Support GreyLiterature

Australia: aquaculture exceeded the value of wild catch by 2021-22

View Source
Preview of Australia's Aquaculture industry - DAFF, accessed August 17, 2025,
Australia's Aquaculture industry - DAFF, accessed August 17, 2025,
Contextual Support Government

Australia's Aquaculture industry - DAFF

View Source
Preview of C:\My Documents\BiOps and Notes\Milltown Dam\MTD Opinion\Appendix A.wpd - US EPA
C:\My Documents\BiOps and Notes\Milltown Dam\MTD Opinion\Appendix A.wpd - US EPA
Contextual Support Journal

C:\My Documents\BiOps and Notes\Milltown Dam\MTD Opinion\Appendix A.wpd - US EPA

View Source
Preview of Caring for our Australian Alps Catchments, accessed August 28, 2025,
Caring for our Australian Alps Catchments, accessed August 28, 2025,
Contextual Support Journal

Caring for our Australian Alps Catchments

View Source
Preview of Dissolved Oxygen (DO) Turbidity - Interstate Commission on the Potomac River Basin, accessed July 12, 2025,
Dissolved Oxygen (DO) Turbidity - Interstate Commission on the Potomac River Basin, accessed July 12, 2025,
Contextual Support Journal

Dissolved Oxygen (DO) Turbidity - Interstate Commission on the Potomac River Basin

View Source
Preview of Does turbidity determine fish growth? - American Fisheries Society
Does turbidity determine fish growth? - American Fisheries Society
Contextual Support GreyLiterature

Does turbidity determine fish growth? - American Fisheries Society

View Source
Preview of From Hatch to Catch - Buxton Trout & Salmon Farm's commitment to Sustainability since 1958.
From Hatch to Catch - Buxton Trout & Salmon Farm's commitment to Sustainability since 1958.
Contextual Support GreyLiterature

From Hatch to Catch - Buxton Trout & Salmon Farm's commitment to Sustainability since 1958.

View Source
Preview of Gaden Trout Hatchery - Away We Go Tours | School Excursions & Group Tours
Gaden Trout Hatchery - Away We Go Tours | School Excursions & Group Tours
Irrelevant

Gaden Trout Hatchery - Away We Go Tours | School Excursions & Group Tours

View Source
Preview of Gaden Trout Hatchery - Snowy Mountains Fishing
Gaden Trout Hatchery - Snowy Mountains Fishing
Irrelevant

Gaden Trout Hatchery - Snowy Mountains Fishing

View Source
Preview of Gaden Trout Hatchery - Thredbo River - Visit Cooma, accessed August 17, 2025,
Gaden Trout Hatchery - Thredbo River - Visit Cooma, accessed August 17, 2025,
Contextual Support Government

Gaden Trout Hatchery - Thredbo River - Visit Cooma

View Source
Preview of Gaden Trout Hatchery EPA Pollution Monitoring Data - August 2021
Gaden Trout Hatchery EPA Pollution Monitoring Data - August 2021
Direct Evidence Journal

Gaden Trout Hatchery EPA Pollution Monitoring Data - August 2021

View Source
Preview of Impacts of Sediment to Aquatic Habitats
Impacts of Sediment to Aquatic Habitats
Contextual Support Journal

Impacts of Sediment to Aquatic Habitats

View Source
Preview of Improved Methods for Correlating Turbidity and Suspended Solids for Monitoring - CLU-IN
Improved Methods for Correlating Turbidity and Suspended Solids for Monitoring - CLU-IN
Methodology Source Journal

Water-quality and ecosystem impacts of recreation in streams: Monitoring and management, accessed July 19, 2025,

View Source
Preview of Improvement of the Water Quality in Rainbow Trout Farming by Means of the Feeding Type and Management over 10 Years (2009–2019), accessed August 10, 2025
Improvement of the Water Quality in Rainbow Trout Farming by Means of the Feeding Type and Management over 10 Years (2009–2019), accessed August 10, 2025
Contextual Support Journal

Improvement of the Water Quality in Rainbow Trout Farming by Means of the Feeding Type and Management over 10 Years (2009–2019) - PMC

View Source
Preview of Lethal Turbidity Levels for Common Fish and Invertebrates in Auckland Streams - CiteSeerX
Lethal Turbidity Levels for Common Fish and Invertebrates in Auckland Streams - CiteSeerX
Contextual Support

Lethal Turbidity Levels for Common Fish and Invertebrates in Auckland Streams - CiteSeerX

View Source
Preview of Managing Recreational Trout Fisheries - VFA
Managing Recreational Trout Fisheries - VFA
Contextual Support Government

Managing Recreational Trout Fisheries - VFA

View Source
Preview of National Guidelines for Water Quality - Department of Natural Resources and Environment Tasmania, accessed August 1, 2025,
National Guidelines for Water Quality - Department of Natural Resources and Environment Tasmania, accessed August 1, 2025,
Contextual Support

Australian and New Zealand Guidelines for Fresh and Marine Water ...

View Source
Preview of Remote Sensing Retrieval of Turbidity in Alpine Rivers based on high Spatial Resolution Satellites - MDPI
Remote Sensing Retrieval of Turbidity in Alpine Rivers based on high Spatial Resolution Satellites - MDPI
Methodology Source Journal

Remote Sensing Retrieval of Turbidity in Alpine Rivers based on high Spatial Resolution Satellites - MDPI

View Source
Preview of Review of water quality studies in the Australian Alps, accessed August 12, 2025,
Review of water quality studies in the Australian Alps, accessed August 12, 2025,
Contextual Support Government

Review of water quality studies in the Australian Alps | Australian ...

View Source
Preview of Snapshot of Australia's commercial fisheries and aquaculture - DAFF, accessed August 17, 2025,
Snapshot of Australia's commercial fisheries and aquaculture - DAFF, accessed August 17, 2025,
Contextual Support Government

Snapshot of Australia's commercial fisheries and aquaculture - DAFF

View Source
Preview of Snowy 2.0 Recreational Fishing Management Plan
Snowy 2.0 Recreational Fishing Management Plan
Contextual Support Journal

Snowy 2.0 Recreational Fishing Management Plan

View Source
Preview of Snowy Mountains Trout | freshtrout.com.au | Snowy Mountains Trout NSW
Snowy Mountains Trout | freshtrout.com.au | Snowy Mountains Trout NSW
Contextual Support GreyLiterature

About | Snowy Mountains Trout | freshtrout.com.au

View Source
Preview of Stony Creek Fish Farm
Stony Creek Fish Farm
Contextual Support GreyLiterature

Stony Creek Fish Farm

View Source
Preview of The conversion of Nephelometric Turbidity Units (NTU) into mg/l for Alberta Transportations turbidity specification is required
The conversion of Nephelometric Turbidity Units (NTU) into mg/l for Alberta Transportations turbidity specification is required
Methodology Source Journal

The conversion of Nephelometric Turbidity Units (NTU) into mg/l for Alberta Transportations turbidity specification is required

View Source
Preview of trout culture in recirculatory aquaculture system (ras) - National Fisheries Development Board
trout culture in recirculatory aquaculture system (ras) - National Fisheries Development Board
Contextual Support

trout culture in recirculatory aquaculture system (ras) - National Fisheries Development Board

View Source
Preview of Turbidity in freshwater habitats of Alaska - A review of published and unpublished literature relevant t
Turbidity in freshwater habitats of Alaska - A review of published and unpublished literature relevant t
Contextual Support Journal

Turbidity in freshwater habitats of Alaska - A review of published and unpublished literature relevant t

View Source
Preview of Using the ANZECC Guidelines and Water Quality Objectives in NSW, accessed August 11, 2025,
Using the ANZECC Guidelines and Water Quality Objectives in NSW, accessed August 11, 2025,
Contextual Support Journal

Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000) - Tuvalu Environment Data Portal, accessed July 19, 2025,

View Source
Preview of Water monitoring - NSW Department of Primary Industries, accessed August 17, 2025,
Water monitoring - NSW Department of Primary Industries, accessed August 17, 2025,
Contextual Support Government

Water monitoring - NSW Department of Primary Industries

View Source
Preview of Water Quality | Snowy Hydro
Water Quality | Snowy Hydro
Contextual Support Journal

Water Quality | Snowy Hydro

View Source
Preview of Water quality data and reports - EPA Victoria, accessed August 12, 2025,
Water quality data and reports - EPA Victoria, accessed August 12, 2025,
Contextual Support Government

Water quality data and reports - EPA Victoria

View Source
Preview of Water quality guidelines - Queensland Environment Department, accessed August 1, 2025,
Water quality guidelines - Queensland Environment Department, accessed August 1, 2025,
Contextual Support Government

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

View Source
Preview of Water Quality Objectives - Border Rivers - NSW Government, accessed August 12, 2025
Water Quality Objectives - Border Rivers - NSW Government, accessed August 12, 2025
Contextual Support Government

(PDF) Impact of mitigated forestry activities on turbidity: assessing ..., accessed August 10, 2025

View Source
Preview of Water Quality Standards - Turbidity Technical Review - Oregon.gov, accessed August 11, 2025,
Water Quality Standards - Turbidity Technical Review - Oregon.gov, accessed August 11, 2025,
Contextual Support Journal

Water Quality Standards - Turbidity Technical Review - Oregon.gov

View Source
Preview of What is NTU? - TecnoConverting Engineering
What is NTU? - TecnoConverting Engineering
Contextual Support GreyLiterature

What is NTU? - TecnoConverting Engineering

View Source
Preview of www.environment.nsw.gov.au, accessed on May 25, 2025,
www.environment.nsw.gov.au, accessed on May 25, 2025,
Contextual Support

Australian Alps Montane Grasslands | One Earth, accessed on May 31, 2025

View Source

Context

  • Region Australia
  • Biome Alpine and Subalpine Complex
  • Land Use Aquaculture
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 17 Mar 2026

Notes

Exceeding this threshold indicates a degraded state with significant negative ecological consequences.

Related Benchmarks

Other benchmarks in the AUS-ASC-AQU-WTU family.

— NTU Moderate
Aquaculture · Pristine Reference
OptimalRange Active v1
0 NTU Moderate
Aquaculture · Pristine Reference
LowerThreshold Active v1
5 NTU Moderate
Aquaculture · Pristine Reference
MaximumOnly Active v1