Water Turbidity

AUS-TGP-URB-WTU General High confidence

Benchmark Value

35 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 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

A chronic turbidity level exceeding 35 NTU represents a clear detrimental threshold where significant ecological degradation is expected.

Metric Definition:

Water turbidity measured in Nephelometric Turbidity Units (NTU), indicating water clarity or lack thereof.

Benchmark Definition:

This benchmark indicates the upper detrimental turbidity threshold beyond which significant ecological harm occurs in urban streams within Australia's Temperate Grassy Woodlands & Plains biome.

Justification:

Synthesized from regulatory guidelines, community monitoring, and scientific studies indicating harm above this level.

Sources (2)

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Supporting Sources (42)

Additional references from the underlying research that informed this benchmark.

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Contextual Support Journal

Turbidity | Australia state of the environment 2021

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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

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Effects of Turbid Water on Fish Ecology in Streams and Dam Reservoirs - Korea Science, accessed August 11, 2025,
Contextual Support Journal

Effects of Turbid Water on Fish Ecology in Streams and Dam Reservoirs - Korea Science, accessed August 11, 2025,

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Contextual Support Journal

Ensuring protection of Little Stringybark Creek - Tasmanian Planning Commission, accessed August 11, 2025

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ESTABLISHING THE RELATIONSHIP BETWEEN TURBIDITY AND TOTAL SUSPENDED SEDIMENT CONCENTRATION, accessed August 11, 2025,
Contextual Support

ESTABLISHING THE RELATIONSHIP BETWEEN TURBIDITY AND TOTAL SUSPENDED SEDIMENT CONCENTRATION, accessed August 11, 2025,

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Full article: Impacts of urbanisation on hydrological and water quality dynamics, and urban water management: a review - Taylor & Francis Online, accessed August 11, 2025,
Contextual Support

Full article: Impacts of urbanisation on hydrological and water quality dynamics, and urban water management: a review - Taylor & Francis Online, accessed August 11, 2025,

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Contextual Support GreyLiterature

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How Much Is Enough? Minimal Responses of Water Quality and Stream Biota to Partial Retrofit Stormwater Management in a Suburban Neighborhood | PLOS One, accessed August 11, 2025,
Contextual Support Journal

How Much Is Enough? Minimal Responses of Water Quality and Stream Biota to Partial Retrofit Stormwater Management in a Suburban Neighborhood | PLOS One, accessed August 11, 2025,

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Hugh P. Duncan's research works | Monash University (Australia) and other places, accessed August 11, 2025,
Contextual Support GreyLiterature

Hugh P. Duncan's research works | Monash University (Australia) and other places, accessed August 11, 2025,

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Preview of LITTLE STRINGYBARK CREEK - urbanstreams.net, accessed August 11, 2025,
LITTLE STRINGYBARK CREEK - urbanstreams.net, accessed August 11, 2025,
Contextual Support Direct Evidence Journal

LITTLE STRINGYBARK CREEK - urbanstreams.net, accessed August 11, 2025,

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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

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Preview of NVIS Fact sheet MVG 19 6 Tussock grasslands, accessed July 16, 2025,
NVIS Fact sheet MVG 19 6 Tussock grasslands, accessed July 16, 2025,
Contextual Support Journal

Understanding soil pH, accessed August 28, 2025

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River health and monitoring | Melbourne Water, accessed August 11, 2025,
Contextual Support Government

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Southeast Australia temperate savanna - Wikipedia, accessed August 4, 2025
Contextual Support GreyLiterature

Southeast Australia temperate savanna - Wikipedia

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Stream health in the Lane Cove River and Middle Harbour Catchments - City of Ryde, accessed August 11, 2025,
Contextual Support Journal

Stream health in the Lane Cove River and Middle Harbour Catchments - City of Ryde, accessed August 11, 2025,

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Stream Restoration through Stormwater Runoff Management and Retrofit: New Objectives, New Approaches | Proceedings | Vol , No - ASCE Library, accessed August 11, 2025,
Contextual Support GreyLiterature

Stream Restoration through Stormwater Runoff Management and Retrofit: New Objectives, New Approaches | Proceedings | Vol , No - ASCE Library, accessed August 11, 2025,

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Technical Design Guidelines - for South East Queensland - Redland City Council, accessed August 11, 2025,
Contextual Support

Technical Design Guidelines - for South East Queensland - Redland City Council, accessed August 11, 2025,

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Contextual Support Journal

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Contextual Support Journal

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Contextual Support Direct Evidence GreyLiterature

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Contextual Support GreyLiterature

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Contextual Support Regulatory Framework Government

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Water quality and pollution - Yarra Riverkeeper Association, accessed August 11, 2025,
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Contextual Support Government

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Contextual Support Journal

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Context

  • Region Australia
  • Biome Temperate Grassy Woodlands & Plains
  • Land Use Urban & Developed Use
  • Assessment Not Stated
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 2
  • Effective From 1 Jun 2026

Notes

Chronic turbidity levels above 35 NTU severely limit light penetration, smother habitat, impair organism function, and indicate systemic failure of stormwater management. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

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

— NTU High
Urban & Developed Use · Not Stated
OptimalRange Active v1
5 NTU Moderate
Urban & Developed Use · Not Stated
MaximumOnly Superseded v1