Water Turbidity

AUS-TMI-AQU-WTU General Moderate confidence

Benchmark Value

4.5 NTU
Direction: Higher is desirable ↑
Form: Point

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

The benchmark of 4.5 NTU is derived from a peer-reviewed study that measured turbidity levels on Great Barrier Reef sites described as "unaffected by human activities".

Metric Definition:

Water turbidity measured in Nephelometric Turbidity Units (NTU), representing the degree to which water loses transparency due to suspended particulates.

Benchmark Definition:

This benchmark represents the water turbidity level measured in NTU that reflects a healthy, unaffected aquatic environment in the Tropical & Subtropical Maritime Islands biome under aquaculture land use.

Justification:

The 4.5 NTU value is a direct field measurement from the correct biome and is explicitly associated with a state of high ecological integrity. Its alignment with the 4.1 NTU T90 value from the broader GBR survey adds strong corroborative support.

Sources (2)

Preview of Interactive effects of sedimentary turbidity and elevated water temperature on the Pugnose Shiner (Miniellus anogenus), a threatened freshwater fish | Conservation Physiology | Oxford Academic
Interactive effects of sedimentary turbidity and elevated water temperature on the Pugnose Shiner (Miniellus anogenus), a threatened freshwater fish | Conservation Physiology | Oxford Academic Journal

To fear or to feed: the effects of turbidity on perception of risk by a ..., accessed August 1, 2025,

View Source
Preview of Turbidity and light attenuation in coastal waters of the Great Barrier Reef - ResearchOnline@JCU, accessed August 2, 2025,
Turbidity and light attenuation in coastal waters of the Great Barrier Reef - ResearchOnline@JCU, accessed August 2, 2025, Journal

Australian prawn farming manual Part 4-9.pdf, accessed July 21, 2025,

View Source

Supporting Sources (19)

Additional references from the underlying research that informed this benchmark.

Preview of Acropora tenuis energy acquisition along a natural turbidity gradient - Frontiers, accessed August 1, 2025,
Acropora tenuis energy acquisition along a natural turbidity gradient - Frontiers, accessed August 1, 2025,
Contextual Support Journal

Acropora tenuis energy acquisition along a natural turbidity gradient - Frontiers, accessed August 1, 2025,

View Source
Preview of Aquaculture species | NT.GOV.AU, accessed August 1, 2025,
Aquaculture species | NT.GOV.AU, accessed August 1, 2025,
Contextual Support Government

Aquaculture species | NT.GOV.AU, accessed August 1, 2025,

View Source
Preview of Australis First in World to Achieve Tropical Marine Finfish ASC Certification, accessed August 1, 2025,
Australis First in World to Achieve Tropical Marine Finfish ASC Certification, accessed August 1, 2025,
Contextual Support GreyLiterature

Australis First in World to Achieve Tropical Marine Finfish ASC Certification, accessed August 1, 2025,

View Source
Preview of Black tiger prawn aquaculture | Business Queensland, accessed August 1, 2025
Black tiger prawn aquaculture | Business Queensland, accessed August 1, 2025
Contextual Support Government

Black tiger prawn aquaculture | Business Queensland, accessed August 1, 2025,

View Source
Preview of Cocos (Keeling) Islands Marine Park, accessed August 1, 2025,
Cocos (Keeling) Islands Marine Park, accessed August 1, 2025,
Contextual Support Government

Cocos (Keeling) Islands Marine Park, accessed August 1, 2025,

View Source
Preview of Developing a reef water quality management plan — case study, accessed August 3, 2025,
Developing a reef water quality management plan — case study, accessed August 3, 2025,
Contextual Support Government

Developing a reef water quality management plan — case study, accessed August 1, 2025,

View Source
Preview of Environmental Code of Practice for Australian Prawn Farmers - NTEPA, accessed August 1, 2025,
Environmental Code of Practice for Australian Prawn Farmers - NTEPA, accessed August 1, 2025,
Regulatory Framework Journal

Environmental Code of Practice for Australian Prawn Farmers - NTEPA, accessed August 1, 2025,

View Source
Preview of ESR/2015/1683 Wastewater licencing from existing marine prawn farms, accessed August 1, 2025,
ESR/2015/1683 Wastewater licencing from existing marine prawn farms, accessed August 1, 2025,
Regulatory Framework Journal

ESR/2015/1683 Wastewater licencing from existing marine prawn farms, accessed August 1, 2025,

View Source
Preview of gbr-dredge-material-management-appendixb.docx - DCCEEW, accessed August 1, 2025,
gbr-dredge-material-management-appendixb.docx - DCCEEW, accessed August 1, 2025,
Contextual Support Journal

gbr-dredge-material-management-appendixb.docx - DCCEEW, accessed August 1, 2025,

View Source
Preview of Important Water Quality Parameters in Aquaculture: An Overview - ResearchGate, accessed August 1, 2025,
Important Water Quality Parameters in Aquaculture: An Overview - ResearchGate, accessed August 1, 2025,
Contextual Support GreyLiterature

Important Water Quality Parameters in Aquaculture: An Overview - ResearchGate, accessed August 1, 2025,

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,
Regulatory Framework

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

View Source
Preview of Queensland Aquaculture Policy Statement - The Queensland ..., accessed August 1, 2025,
Queensland Aquaculture Policy Statement - The Queensland ..., accessed August 1, 2025,
Regulatory Framework Journal

Queensland Aquaculture Policy Statement - The Queensland ..., accessed August 1, 2025,

View Source
Preview of Queensland Aquaculture Strategy 2024–2034, accessed August 1, 2025,
Queensland Aquaculture Strategy 2024–2034, accessed August 1, 2025,
Regulatory Framework Government

land and water | Queensland Government

View Source
Preview of Review of Nutrient Release from Aquaculture ... - Griffith University, accessed August 1, 2025
Review of Nutrient Release from Aquaculture ... - Griffith University, accessed August 1, 2025
Contextual Support Journal

Review of Nutrient Release from Aquaculture Activities Final Report - Griffith University

View Source
Preview of Turbidity Characteristics of The Waters on The ... - Omni-Akuatika
Turbidity Characteristics of The Waters on The ... - Omni-Akuatika
Contextual Support Journal

Turbidity Characteristics of The Waters on The ... - Omni-Akuatika, accessed August 1, 2025,

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,
Regulatory Framework 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 Wastewater remediation options for prawn farms, accessed August 1, 2025
Wastewater remediation options for prawn farms, accessed August 1, 2025
Contextual Support Journal

Enhancing Nitrate Removal from Freshwater Pond by Regulating Carbon/Nitrogen Ratio - Frontiers, accessed July 24, 2025

View Source
Preview of Water Quality - GBRMPA eLibrary, accessed August 1, 2025,
Water Quality - GBRMPA eLibrary, accessed August 1, 2025,
Contextual Support

Catchments and corals: terrestrial runoff to the Great Barrier Reef - The Australian Institute of Marine Science, accessed July 28, 2025,

View Source
Preview of Water Quality Guidelines for the Great Barrier Reef Marine Park., accessed August 3, 2025,
Water Quality Guidelines for the Great Barrier Reef Marine Park., accessed August 3, 2025,
Regulatory Framework Journal

Great Barrier Reef Marine Park Authority (GBRMPA). (2010). Water Quality Guidelines for the Great Barrier Reef Marine Park. Rev. ed. 35

View Source

Context

  • Region Australia
  • Biome Tropical & Subtropical Maritime Islands
  • Land Use Aquaculture
  • Assessment Pristine Reference
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 16 Mar 2026

Notes

The benchmark is a proxy from a peer-reviewed study due to lack of direct data from certified best-practice aquaculture sites. The optimal ecological range is <10 NTU, and an upper detrimental threshold exists at >24 NTU where significant negative impacts occur.

Related Benchmarks

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

24 NTU Moderate
Aquaculture · Pristine Reference
UpperThreshold Active v1