Water Turbidity

AUS-ASC-IND-WTU General High confidence

Benchmark Value

0.5 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. The scoring engine uses 9 benchmarks together — the OptimalRange form drives the primary score, while 8 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MaximumOnly Guard MaximumOnly Guard MaximumOnly Guard MaximumOnly Guard MinimumOnly Guard MinimumOnly Guard MaximumOnly Guard OptimalRange Guard

Evidence & Context

The recommended reference value for water turbidity, representing a state of high environmental health, is <0.5 Nephelometric Turbidity Units (NTU).

Metric Definition:

Water turbidity measured in Nephelometric Turbidity Units (NTU) representing the clarity of water in alpine streams under industrial and infrastructure land use.

Benchmark Definition:

This benchmark defines the maximum turbidity level indicating high environmental health in alpine streams affected by industrial and infrastructure use.

Justification:

This benchmark is directly informed by the 0.37 NTU average observed at the best-performing site, providing a small operational margin while remaining firmly within the range of a minimally disturbed system.

Sources (1)

Preview of NSW alpine resorts environmental performance report 2020–21

NSW alpine resorts environmental performance report 2020–21 Journal

NSW Alpine Resorts Environmental Performance Report 2020–21

Supporting Sources (23)

Additional references from the underlying research that informed this benchmark.

Preview of An Assessment of Feral Horse Impacts on Treeless Drainage Lines in the Australian Alps - December 2015, accessed August 17, 2025,

An Assessment of Feral Horse Impacts on Treeless Drainage Lines in the Australian Alps - December 2015, accessed August 17, 2025,

Contextual Support Journal

An Assessment of Feral Horse Impacts on Treeless Drainage Lines in the Australian Alps - December 2015, accessed August 17, 2025,

Preview of bioone.org, accessed August 17, 2025, )023[0247:EIOTOT]2.0.CO;2.pdf

bioone.org, accessed August 17, 2025, )023[0247:EIOTOT]2.0.CO;2.pdf

Contextual Support GreyLiterature

Feral horses (Equus caballus) increase suspended sediment in subalpine streams, accessed August 17, 2025

Preview of DRINKING WATER QUALITY ANNUAL REPORT 2022-2023, accessed August 17, 2025,

DRINKING WATER QUALITY ANNUAL REPORT 2022-2023, accessed August 17, 2025,

Contextual Support Journal

Full article: Evaluating the impact of low intensity farming on alpine river water quality: case study from south Westland, Aotearoa New Zealand

Preview of EAWAG news 54e: The Ecology of Alpine Streams, accessed August 17, 2025,

EAWAG news 54e: The Ecology of Alpine Streams, accessed August 17, 2025,

Contextual Support

EAWAG news 54e: The Ecology of Alpine Streams, accessed August 17, 2025,

Preview of Effects of Sedimentation and Turbidity on Lotic Food Webs: A Concise Review for Natural Resource Managers - Southern Research Station, accessed July 16, 2025,

Effects of Sedimentation and Turbidity on Lotic Food Webs: A Concise Review for Natural Resource Managers - Southern Research Station, accessed July 16, 2025,

Contextual Support Journal

Effects of Sedimentation and Turbidity on Lotic Food Webs: A Concise Review for Natural Resource Managers - Southern Research Station, accessed August 17, 2025

Preview of Effects of turbidity and introduced tilapia (Oreochromis spp) on macrophytes and invertebrates in a shallow tropical lake | Knowledge and Management of Aquatic Ecosystems, accessed July 24, 2025

Effects of turbidity and introduced tilapia (Oreochromis spp) on macrophytes and invertebrates in a shallow tropical lake | Knowledge and Management of Aquatic Ecosystems, accessed July 24, 2025

Contextual Support Journal

Waterhouse, J. (2010) Thresholds of major pollutants with regard to impacts on instream and marine ecosystems, accessed July 21, 2025

Preview of Environment - Perisher, accessed August 17, 2025,

Environment - Perisher, accessed August 17, 2025,

Contextual Support Government

Environment - Perisher, accessed August 17, 2025,

Preview of Environment & Sustainability - Thredbo, accessed August 17, 2025,

Environment & Sustainability - Thredbo, accessed August 17, 2025,

Contextual Support GreyLiterature

Environment & Sustainability - Thredbo, accessed August 17, 2025,

Preview of Environmental Impacts of Tourism on the Australian Alps Protected Areas - ResearchGate, accessed August 17, 2025,

Environmental Impacts of Tourism on the Australian Alps Protected Areas - ResearchGate, accessed August 17, 2025,

Contextual Support Journal

Environmental Impacts of Tourism on the Australian Alps Protected Areas - ResearchGate, accessed August 28, 2025,

Preview of Environmental Initiatives 2021 | Thredbo, accessed August 17, 2025,

Environmental Initiatives 2021 | Thredbo, accessed August 17, 2025,

Contextual Support Journal

Environmental Initiatives 2021 | Thredbo, accessed August 17, 2025,

Preview of Feral horses (Equus caballus) increase suspended sediment in subalpine streams, accessed August 12, 2025,

Feral horses (Equus caballus) increase suspended sediment in subalpine streams, accessed August 12, 2025,

Direct Evidence Journal

Determining Tipping Points and Responses of Macroinvertebrate Traits to Abiotic Factors in Support of River Management

Preview of Kosciuszko National Park water quality monitoring, accessed August 12, 2025,

Kosciuszko National Park water quality monitoring, accessed August 12, 2025,

Contextual Support Government

theaustralianalpsnationalparks.org, accessed August 17, 2025

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,

Direct Evidence

Using the ANZECC Guidelines and Water Quality Objectives in NSW

Preview of NSW Alpine Resorts Environmental Performance Report 2019–20, accessed August 17, 2025,

NSW Alpine Resorts Environmental Performance Report 2019–20, accessed August 17, 2025,

Contextual Support Journal

NSW alpine resorts environmental performance report 2020–21, accessed August 17, 2025,

Preview of Preliminary information for developing sediment guidelines for streams of the West Coast, New Zealand - Envirolink, accessed August 17, 2025,

Preliminary information for developing sediment guidelines for streams of the West Coast, New Zealand - Envirolink, accessed August 17, 2025,

Contextual Support Journal

Preliminary information for developing sediment guidelines for streams of the West Coast, New Zealand - Envirolink, accessed August 1, 2025,

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

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

Preview of Snowy - NSW Government Water, accessed August 17, 2025,

Snowy - NSW Government Water, accessed August 17, 2025,

Contextual Support Government

ANZECC 2000 guidelines for fresh and marine water quality

Preview of Snowy Mountains Hydro | National Museum of Australia, accessed August 17, 2025,

Snowy Mountains Hydro | National Museum of Australia, accessed August 17, 2025,

Contextual Support GreyLiterature

Snowy Mountains Hydro | National Museum of Australia, accessed August 17, 2025,

Preview of The Snowy Mountains Hydro-electric Scheme:how did it manage without an EIA? - Open Research Repository, accessed August 17, 2025,

The Snowy Mountains Hydro-electric Scheme:how did it manage without an EIA? - Open Research Repository, accessed August 17, 2025,

Contextual Support

The Snowy Mountains Hydro-electric Scheme:how did it manage without an EIA? - Open Research Repository, accessed August 17, 2025,

Preview of Thredbo village environment walk, accessed August 17, 2025,

Thredbo village environment walk, accessed August 17, 2025,

Contextual Support Journal

Sustainability Report 2023 - Thredbo, accessed August 17, 2025

Preview of Turbidity and Water | U.S. Geological Survey - USGS.gov, accessed August 17, 2025,

Turbidity and Water | U.S. Geological Survey - USGS.gov, accessed August 17, 2025,

Contextual Support

Turbidity and Water | U.S. Geological Survey - USGS.gov, accessed August 17, 2025,

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 ...

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

Positive responses of benthic macroinvertebrates to spatial and temporal reductions in water pollution downstream from a trout farm outlet | Knowledge and Management of Aquatic Ecosystems, accessed August 17, 2025

Context

Region Australia
Biome Alpine and Subalpine Complex
Land Use Industrial & Infrastructure Use
Assessment Not Stated
Evidence Type ReferenceCondition

Lifecycle

Status Superseded
Version 1
Effective From 1 Jun 2026
Effective To 1 Jun 2026

Notes

No upper detrimental threshold — higher values are always worse beyond this maximum. The benchmark represents the average downstream turbidity (0.37 NTU) from the best-performing managed site, demonstrating negligible impact compared to upstream reference. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

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