Water Turbidity

AUS-TSW-URB-WTU General Moderate confidence

Benchmark Value

25 NTU

Direction: Lower 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 MaximumOnly Guard MaximumOnly Guard MaximumOnly Guard MaximumOnly Guard Point Guard OptimalRange Guard MaximumOnly Guard MaximumOnly Guard MinimumOnly Guard MaximumOnly Guard MaximumOnly Guard MaximumOnly Guard

Evidence & Context

An upper detrimental threshold is identified at 25 NTU. This value is supported by the convergence of the ANZECC guideline upper limit for upland rivers, ecological studies showing direct harm to fish at this level, and its use as an industrial environmental incident trigger.

Metric Definition:

Water turbidity measured in Nephelometric Turbidity Units (NTU), indicating water clarity and ecological health.

Benchmark Definition:

This benchmark defines the upper turbidity threshold of 25 NTU beyond which significant ecological harm to aquatic life is likely in urban semi-arid streams.

Justification:

The threshold is supported by national guidelines, ecological impact studies on fish, and industrial environmental incident reporting standards.

Sources (2)

Preview of DEVELOPING WATER QUALITY CRITERIA FOR SUSPENDED AND BEDDED SEDIMENTS (SABS) - NOAA Office for Coastal Management, accessed July 13, 2025,

DEVELOPING WATER QUALITY CRITERIA FOR SUSPENDED AND BEDDED SEDIMENTS (SABS) - NOAA Office for Coastal Management, accessed July 13, 2025, Journal

Mardie Project – Marine Water Quality Baseline - EPA WA

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, 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

Supporting Sources (36)

Additional references from the underlying research that informed this benchmark.

Preview of 1.1.7.1 Ecological systems | Bioregional Assessments, accessed July 13, 2025,

1.1.7.1 Ecological systems | Bioregional Assessments, accessed July 13, 2025,

Contextual Support Government

NVIS Fact sheet MVG 19 – Tussock grasslands, accessed July 13, 2025

Preview of act practice guidelines for water sensitive urban design - Planning, accessed July 13, 2025,

act practice guidelines for water sensitive urban design - Planning, accessed July 13, 2025,

Contextual Support Journal

act practice guidelines for water sensitive urban design - Planning, accessed July 13, 2025,

Preview of Ambient Water Quality Monitoring of South Australia's Rivers and Streams - EPA SA, accessed July 13, 2025,

Ambient Water Quality Monitoring of South Australia's Rivers and Streams - EPA SA, accessed July 13, 2025,

Contextual Support Journal

Ambient Water Quality Monitoring of South Australia's Rivers and Streams - EPA SA, accessed July 13, 2025,

Preview of Appendix 13 – Water Reports - NET, accessed July 13, 2025,

Appendix 13 – Water Reports - NET, accessed July 13, 2025,

Contextual Support Journal

Appendix 13 – Water Reports - NET, accessed July 13, 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 Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000), accessed May 11, 2025,

Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000), accessed May 11, 2025,

Direct Evidence Journal

Northern Territory Government (2020) Darwin Harbour Region Water Quality Objectives, Report Card Section 3.0.

Preview of Bayswater Brook Catchment - City of Bayswater, accessed July 13, 2025,

Bayswater Brook Catchment - City of Bayswater, accessed July 13, 2025,

Contextual Support Government

Bayswater Brook Catchment - City of Bayswater, accessed July 13, 2025,

Preview of Brownhill Creek, Brownhill Creek Road 2016 Aquatic Ecosystem Condition Report | EPA, accessed July 13, 2025,

Brownhill Creek, Brownhill Creek Road 2016 Aquatic Ecosystem Condition Report | EPA, accessed July 13, 2025,

Contextual Support Direct Evidence Government

Brownhill Creek, Brownhill Creek Road 2016 Aquatic Ecosystem Condition Report | EPA, accessed July 13, 2025,

Preview of Brownhill Creek, Brownhill Creek Road near CFS track 2016 Aquatic Ecosystem Condition Report - EPA SA, accessed July 13, 2025,

Brownhill Creek, Brownhill Creek Road near CFS track 2016 Aquatic Ecosystem Condition Report - EPA SA, accessed July 13, 2025,

Contextual Support Direct Evidence Government

Brownhill Creek, Brownhill Creek Road 2016 Aquatic Ecosystem Condition Report | EPA

Preview of Catchment to Coast (metropolitan Adelaide) | EPA, accessed July 13, 2025,

Catchment to Coast (metropolitan Adelaide) | EPA, accessed July 13, 2025,

Contextual Support Government

Catchment to Coast (metropolitan Adelaide) | EPA, accessed July 13, 2025,

Preview of Characterising the relationship between water quality and water quantity, accessed August 5, 2025

Characterising the relationship between water quality and water quantity, accessed August 5, 2025

Contextual Support Journal

Turbidity | Australia state of the environment 2021

Preview of Draft environmental values and water quality guidelines: Burdekin Basin fresh and estuarine waters - Queensland Environment Department, accessed July 13, 2025,

Draft environmental values and water quality guidelines: Burdekin Basin fresh and estuarine waters - Queensland Environment Department, accessed July 13, 2025,

Contextual Support Journal

Draft environmental values and water quality guidelines: Burdekin Basin fresh and estuarine waters - Queensland Environment Department, accessed July 13, 2025,

Preview of Managing urban water - Department for Environment and Water, accessed July 13, 2025,

Managing urban water - Department for Environment and Water, accessed July 13, 2025,

Contextual Support Government

Managing urban water - Department for Environment and Water, accessed July 13, 2025,

Preview of Mardie Project – Marine Water Quality Baseline - EPA WA, accessed July 13, 2025,

Mardie Project – Marine Water Quality Baseline - EPA WA, accessed July 13, 2025,

Contextual Support Journal

Mardie Project – Marine Water Quality Baseline - EPA WA, accessed July 13, 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,

Contextual Support

Using the ANZECC Guidelines and Water Quality Objectives in NSW

Preview of NVIS Fact sheet MVG 13 – Acacia open woodlands - DCCEEW, accessed July 13, 2025,

NVIS Fact sheet MVG 13 – Acacia open woodlands - DCCEEW, accessed July 13, 2025,

Contextual Support Journal

Database - Resilience Alliance, accessed July 30, 2025,

Preview of Onkaparinga River, downstream from Mount Bold Reservoir 2011 Aquatic Ecosystem Condition Report - EPA SA, accessed July 13, 2025,

Onkaparinga River, downstream from Mount Bold Reservoir 2011 Aquatic Ecosystem Condition Report - EPA SA, accessed July 13, 2025,

Contextual Support Government

Onkaparinga River, downstream from Mount Bold Reservoir 2011 Aquatic Ecosystem Condition Report - EPA SA, accessed July 13, 2025,

Preview of Onkaparinga River, Woodside 2011 Aquatic Ecosystem Condition Report | EPA, accessed July 13, 2025,

Onkaparinga River, Woodside 2011 Aquatic Ecosystem Condition Report | EPA, accessed July 13, 2025,

Contextual Support Government

Onkaparinga River, Woodside 2011 Aquatic Ecosystem Condition Report | EPA, accessed July 13, 2025,

Preview of Planning requirements for Water Sensitive Urban Design | City of Melbourne, accessed July 21, 2025,

Planning requirements for Water Sensitive Urban Design | City of Melbourne, accessed July 21, 2025,

Contextual Support Government

Planning requirements for Water Sensitive Urban Design | City of Melbourne, accessed July 13, 2025,

Preview of Protecting drinking water quality into the future —priority areas and land use compatibility in Adelaide's Mount Lofty Ranges Watershed - epa.sa.gov.a, accessed July 13, 2025,

Protecting drinking water quality into the future —priority areas and land use compatibility in Adelaide's Mount Lofty Ranges Watershed - epa.sa.gov.a, accessed July 13, 2025,

Contextual Support Journal

Protecting drinking water quality into the future —priority areas and land use compatibility in Adelaide's Mount Lofty Ranges Watershed - epa.sa.gov.a, accessed July 13, 2025,

Preview of Semi-arid woodlands (shrubby sub-formation) | NSW Environment, Energy and Science, accessed July 12, 2025, )

Semi-arid woodlands (shrubby sub-formation) | NSW Environment, Energy and Science, accessed July 12, 2025, )

Contextual Support Government

Semi-arid woodlands (grassy sub-formation) | NSW Environment, Energy and Science

Preview of State of the Environment 2023 | Stormwater, accessed July 13, 2025,

State of the Environment 2023 | Stormwater, accessed July 13, 2025,

Contextual Support Government

Characterising the relationship between water quality and water quantity, accessed July 21, 2025

Preview of Streams in the Urban Landscape - Sarasota County Water Atlas, accessed July 13, 2025,

Streams in the Urban Landscape - Sarasota County Water Atlas, accessed July 13, 2025,

Contextual Support Journal

Streams in the Urban Landscape - Sarasota County Water Atlas, accessed July 13, 2025,

Preview of Turbidity | Australian Drinking Water Guidelines - NHMRC, accessed August 11, 2025,

Turbidity | Australian Drinking Water Guidelines - NHMRC, accessed August 11, 2025,

Contextual Support Direct Evidence Government

Turbidity | Australian Drinking Water Guidelines - NHMRC, accessed August 3, 2025

Preview of Turbidity | River Detectives, accessed July 16, 2025,

Turbidity | River Detectives, accessed July 16, 2025,

Contextual Support Journal

Kosciuszko National Park's health a mixed diagnosis in first EcoHealth Scorecard

Preview of Turbidity, accessed August 3, 2025,

Turbidity, accessed August 3, 2025,

Contextual Support Journal

Dissolved Oxygen (DO) Turbidity - Interstate Commission on the Potomac River Basin, accessed July 12, 2025

Preview of Urban Stormwater in Perth: Strengths Weaknesses and Recommendations for Future Management - Parliament of Western Australia, accessed July 13, 2025,

Urban Stormwater in Perth: Strengths Weaknesses and Recommendations for Future Management - Parliament of Western Australia, accessed July 13, 2025,

Contextual Support Journal

Urban Stormwater in Perth: Strengths Weaknesses and Recommendations for Future Management - Parliament of Western Australia, accessed July 13, 2025,

Preview of Urban Streams Monitoring Program - City of Bellingham, accessed July 13, 2025,

Urban Streams Monitoring Program - City of Bellingham, accessed July 13, 2025,

Contextual Support Direct Evidence Government

Urban Streams Monitoring Program - City of Bellingham, accessed July 13, 2025,

Preview of Water quality - EPA SA, accessed July 13, 2025,

Water quality - EPA SA, accessed July 13, 2025,

Contextual Support Journal

Assessing Water Quality - Secondary Education Years 9 to 12 - Upper Murrumbidgee Waterwatch, accessed July 13, 2025,

Preview of Water sensitive urban design - Department for Environment and Water, accessed July 13, 2025,

Water sensitive urban design - Department for Environment and Water, accessed July 13, 2025,

Contextual Support Journal

Water sensitive urban design - Department for Environment and Water, accessed July 13, 2025,

Preview of Water Sensitive Urban Design (WSUD), accessed July 13, 2025,

Water Sensitive Urban Design (WSUD), accessed July 13, 2025,

Contextual Support GreyLiterature

Water Sensitive Urban Design (WSUD), accessed July 13, 2025

Preview of Water sensitive urban design brochures - Government of Western Australia, accessed July 21, 2025,

Water sensitive urban design brochures - Government of Western Australia, accessed July 21, 2025,

Contextual Support Government

Water sensitive urban design brochures - Western Australian Government, accessed July 13, 2025,

Preview of Water sensitive urban design guideline June 2023 - Transport for NSW, accessed July 13, 2025,

Water sensitive urban design guideline June 2023 - Transport for NSW, accessed July 13, 2025,

Contextual Support Journal

Water sensitive urban design guideline June 2023 - Transport for NSW, accessed July 13, 2025,

Preview of Water Sensitive Urban Design Guidelines - Melbourne Water, accessed July 21, 2025,

Water Sensitive Urban Design Guidelines - Melbourne Water, accessed July 21, 2025,

Contextual Support Journal

Section 13 – Water Sensitive Urban Design (WSUD) Guidelines - City of Gold Coast, accessed July 13, 2025

Preview of Water Sensitive Urban Design Solutions for Catchments above Wetlands - Hunter Joint Organisation, accessed July 13, 2025,

Water Sensitive Urban Design Solutions for Catchments above Wetlands - Hunter Joint Organisation, accessed July 13, 2025,

Contextual Support Journal

Water Sensitive Urban Design Solutions for Catchments above Wetlands - Hunter Joint Organisation, accessed July 13, 2025,

Preview of Western Mount Lofty Ranges Prescribed Water Resources Area 2020–21 water resources assessment - WaterConnect, accessed July 13, 2025,

Western Mount Lofty Ranges Prescribed Water Resources Area 2020–21 water resources assessment - WaterConnect, accessed July 13, 2025,

Contextual Support Journal

Western Mount Lofty Ranges Prescribed Water Resources Area 2020–21 water resources assessment - WaterConnect, accessed July 13, 2025,

Context

Region Australia
Biome Temperate Semi-Arid Shrublands & Open Woodlands
Land Use Urban & Developed Use
Assessment Not Stated
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 1 Jun 2026

Notes

Persistent turbidity above 25 NTU indicates a degraded ecosystem where significant harm to aquatic life is likely occurring. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

Other benchmarks in the AUS-TSW-URB-WTU family.