Water Turbidity

AUS-TSR-LVG-WTU General Moderate confidence

Benchmark Value

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 13 benchmarks together — the OptimalRange form drives the primary score, while 12 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

Based on this analysis, a reference value of approximately 5 NTU is established.

Metric Definition:

Water turbidity as measured in Nephelometric Turbidity Units (NTU), representing the median event-based turbidity concentration during baseflow conditions in a destocked tropical savanna catchment.

Benchmark Definition:

This benchmark represents the median event-based turbidity derived from a 15-year study of an ungrazed headwater catchment in a wet/dry tropical environment, serving as the best available real-world reference for a high-health system where grazing impacts are eliminated.

Justification:

The value was calculated from the median Total Suspended Solids (TSS) event mean concentration of ~20 mg/L using a site-specific regression (TSS=3.9524×NTU) provided in the source thesis by Koci (2020). Confidence is 'Moderate' as the source is a tropical savanna (a strong proxy, but not identical to tropical rainforest) and required a TSS-to-NTU conversion, though the use of a site-specific formula enhances its reliability.

Sources (1)

Preview of Hillslope gully erosion in savanna rangelands tributary to the Great Barrier Reef: Investigation of hydrogeomorphic processes - USC Research Bank, accessed July 22, 2025,

Hillslope gully erosion in savanna rangelands tributary to the Great Barrier Reef: Investigation of hydrogeomorphic processes - USC Research Bank, accessed July 22, 2025, Journal

Using high-resolution topography for spatial prioritisation of gully erosion management across catchments of the Great Barrier Reef, accessed July 25, 2025,

Supporting Sources (23)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed August 2, 2025,

(PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed August 2, 2025,

Contextual Support

Requirements for graziers | Environment, land and water ..., accessed July 19, 2025,

Preview of (PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed July 19, 2025,

(PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed July 19, 2025,

Contextual Support Journal

Climate change and its implications for Australia´s freshwater fish - CSIRO Publishing, accessed July 19, 2025,

Preview of A Compendium of Ecological Information on Australia's Northern Tropical Rivers - Report 5 - Water quality - DCCEEW, accessed August 1, 2025,

A Compendium of Ecological Information on Australia's Northern Tropical Rivers - Report 5 - Water quality - DCCEEW, accessed August 1, 2025,

Contextual Support Journal

Threshold Indicator Taxa ANalysis and change points (dots) for the ...

Preview of A meta-analytical review of turbidity effects on fish mobility - ResearchGate, accessed July 24, 2025

A meta-analytical review of turbidity effects on fish mobility - ResearchGate, accessed July 24, 2025

Contextual Support Journal

A meta-analytical review of turbidity effects on fish mobility - ResearchGate, accessed July 19, 2025,

Preview of Assessing Water Quality - Secondary Education Years 9 to 12 - Upper Murrumbidgee Waterwatch, accessed August 12, 2025,

Assessing Water Quality - Secondary Education Years 9 to 12 - Upper Murrumbidgee Waterwatch, accessed August 12, 2025,

Direct Evidence Journal

Assessing water quality - ACT Waterwatch

Preview of Backgrounder: Impact of land runoff | AIMS - The Australian Institute of Marine Science, accessed May 11, 2025,

Backgrounder: Impact of land runoff | AIMS - The Australian Institute of Marine Science, accessed May 11, 2025,

Contextual Support Government

Backgrounder: Impact of land runoff | AIMS, accessed July 19, 2025,

Preview of Do regenerative grazing management practices improve vegetation and soil health in grazed rangelands? Preliminary insights from a space-for-time study in the Great Barrier Reef catchments, Australia - ResearchGate, accessed July 19, 2025,

Do regenerative grazing management practices improve vegetation and soil health in grazed rangelands? Preliminary insights from a space-for-time study in the Great Barrier Reef catchments, Australia - ResearchGate, accessed July 19, 2025,

Contextual Support Journal

Do regenerative grazing management practices improve vegetation and soil health in grazed rangelands? Preliminary insights from a space-for-time study in the Great Barrier Reef catchments, Australia - ResearchGate, accessed July 17, 2025,

Preview of Effect of reduced grazing pressure on sediment and nutrient yields in savanna rangeland streams draining to the Great Barrier Reef - CSIRO Research Publications Repository

Effect of reduced grazing pressure on sediment and nutrient yields in savanna rangeland streams draining to the Great Barrier Reef - CSIRO Research Publications Repository

Direct Evidence Journal

Hillslope gully erosion in savanna rangelands tributary to the Great ..., accessed July 19, 2025,

Preview of Effect of reduced grazing pressure on sediment and nutrient yields in savanna rangeland streams draining to the Great Barrier Reef - ResearchOnline@JCU, accessed July 19, 2025,

Effect of reduced grazing pressure on sediment and nutrient yields in savanna rangeland streams draining to the Great Barrier Reef - ResearchOnline@JCU, accessed July 19, 2025,

Direct Evidence Journal

Effect of reduced grazing pressure on sediment and nutrient yields in savanna rangeland streams draining to the Great Barrier Reef - ResearchOnline@JCU, accessed July 19, 2025,

Preview of Grazing Best Practice

Grazing Best Practice

Contextual Support GreyLiterature

Grazing water quality risk framework 2017-2022 - Reef 2050 Water ..., accessed July 19, 2025,

Preview of Impacts of improved grazing land management on sediment yields, Part 1: Hillslope processes - ResearchGate, accessed July 19, 2025,

Impacts of improved grazing land management on sediment yields, Part 1: Hillslope processes - ResearchGate, accessed July 19, 2025,

Contextual Support Journal

Impacts of improved grazing land management on sediment yields, Part 1: Hillslope processes - ResearchGate, accessed July 19, 2025,

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,

Preview of Land management for graziers | Business Queensland, accessed August 8, 2025

Land management for graziers | Business Queensland, accessed August 8, 2025

Contextual Support Government

Reducing the impacts of grazing on water quality - EPA Victoria, accessed July 19, 2025,

Preview of Mutual relationships of suspended sediment, turbidity and visual clarity in New Zealand rivers - PIAHS, accessed July 19, 2025,

Mutual relationships of suspended sediment, turbidity and visual clarity in New Zealand rivers - PIAHS, accessed July 19, 2025,

Contextual Support Journal

Mutual relationships of suspended sediment, turbidity and visual clarity in New Zealand rivers - PIAHS, accessed July 19, 2025,

Preview of Natural water systems | Australia state of the environment 2021, accessed July 16, 2025,

Natural water systems | Australia state of the environment 2021, accessed July 16, 2025,

Contextual Support Government

Characterising the relationship between water quality and water quantity, accessed July 19, 2025,

Preview of Reducing the impacts of grazing on water quality - EPA Victoria, accessed August 8, 2025

Reducing the impacts of grazing on water quality - EPA Victoria, accessed August 8, 2025

Contextual Support Journal

Generic document, accessed July 19, 2025,

Preview of Total-Suspended-Solids-from-Turbidity-Tech-Note.pdf - In-Situ, accessed July 19, 2025,

Total-Suspended-Solids-from-Turbidity-Tech-Note.pdf - In-Situ, accessed July 19, 2025,

Methodology Source Journal

Total-Suspended-Solids-from-Turbidity-Tech-Note.pdf - In-Situ, accessed July 19, 2025,

Preview of Turbidity-based erosion estimation in a catchment in South Australia - ResearchGate, accessed July 19, 2025,

Turbidity-based erosion estimation in a catchment in South Australia - ResearchGate, accessed July 19, 2025,

Methodology Source Journal

Turbidity-based erosion estimation in a catchment in South Australia - ResearchGate, accessed July 19, 2025,

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,

Preview of Water quality for livestock, accessed July 29, 2025,

Water quality for livestock, accessed July 29, 2025,

Contextual Support Journal

Top 10 Strategies for Efficient Water Management on Your Farm - SONIC Natural Farming, accessed July 19, 2025,

Preview of Water Quality Guidelines for the Great Barrier Reef Marine Park.

Water Quality Guidelines for the Great Barrier Reef Marine Park.

Direct Evidence Journal

Impact of Rainfall on Turbidity and Suspended Sediment Load at Five Sites on the Murray River Between Albury and Swan Hill and Possible Relationships to Catchment Attributes D.A Post and A.J. Jakeman - MSSANZ, accessed July 19, 2025,

Preview of Water quality of surface water environments - NSW Government Water, accessed August 1, 2025,

Water quality of surface water environments - NSW Government Water, accessed August 1, 2025,

Contextual Support Government

National Guidelines for Water Quality | Department of Natural ...

Preview of Water-quality and ecosystem impacts of recreation in streams: Monitoring and management, accessed July 22, 2025

Water-quality and ecosystem impacts of recreation in streams: Monitoring and management, accessed July 22, 2025

Contextual Support Journal

Using the ANZECC Guidelines and Water Quality Objectives in NSW, accessed July 19, 2025,

Context

Region Australia
Biome Tropical & Subtropical Rainforests
Land Use Livestock Grazing & Pasture
Assessment Pristine Reference
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 25 Mar 2026

Notes

No upper detrimental threshold — higher values are always worse beyond this benchmark. This value is derived from a tropical savanna catchment and serves as a proxy for tropical rainforest conditions.

Related Benchmarks

Other benchmarks in the AUS-TSR-LVG-WTU family.