Water Turbidity

AUS-TGP-FOR-WTU General High confidence

Benchmark Value

25 NTU

Thresholds: Lower: —, Upper: 25

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 MinimumOnly Guard MaximumOnly Guard Point Guard OptimalRange Guard MaximumOnly Guard MaximumOnly Guard UpperThreshold Guard

Evidence & Context

A persistent median or baseline turbidity > 25 NTU can be defined as the upper detrimental threshold for this context.

Metric Definition:

Water turbidity as a measure of water clarity, quantified by the degree to which light is scattered and absorbed by suspended and dissolved materials in the water column.

Benchmark Definition:

Upper detrimental threshold for water turbidity indicating chronic degradation in catchments under production forestry.

Justification:

Values above this level indicate chronic erosion, systemic failure of soil and water protection, and ecological harm.

Sources (2)

(PDF) Impact of mitigated forestry activities on turbidity: assessing ..., accessed July 12, 2025,

(PDF) Impact of mitigated forestry activities on turbidity: assessing ..., accessed July 12, 2025,

View Source

Preview of Water Quality Objectives - Border Rivers - NSW Government

Water Quality Objectives - Border Rivers - NSW Government Government

Bioregional Assessment: Gippsland Basin - Surface Water Quality

View Source

Supporting Sources (14)

Additional references from the underlying research that informed this benchmark.

(PDF) Determining reference conditions for management and ..., accessed August 5, 2025,

Contextual Support

(PDF) Impacts of tree invasion on floristic composition of subtropical grasslands on the Bunya Mountains, Australia - ResearchGate, accessed May 19, 2025

View Source

Best Management Practices - National Association of State Foresters, accessed July 12, 2025,

Contextual Support Government

Best Management Practices - National Association of State Foresters, accessed August 10, 2025

View Source

Canadian Water Quality Guidelines for the Protection of Aquatic Life - Total Particulate Matter - CCME, accessed August 10, 2025

Contextual Support Journal

Canadian Water Quality Guidelines for the Protection of Aquatic Life - Total Particulate Matter - CCME, accessed August 10, 2025

View Source

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

Contextual Support Journal

Report Card 2022-23 - EPA Victoria

View Source

Ecosystems | Australia state of the environment 2021, accessed August 10, 2025

Contextual Support Journal

Poplar Box Grassy Woodland on Alluvial Plains: Proposal to list as a nationally protected ecological community - DCCEEW, accessed August 10, 2025

View Source

Preview of Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 5, 2025,

Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 5, 2025,

Contextual Support Journal

(PDF) Identifying ecological barriers to restoration in temperate grassy woodlands: soil changes associated with different degradation states - ResearchGate, accessed August 4, 2025,

View Source

Improved forest management - CSIRO, accessed July 12, 2025,

Contextual Support Government

Ecosystem wicks: Woodland trees enhance water infiltration in a fragmented agricultural landscape in eastern Australia, accessed May 15, 2025,

View Source

Logging Impacts On Streams - Cloudfront.net

Contextual Support Journal

The effects of forest management on water quality - SLU, accessed August 10, 2025

View Source

TB966 Compendium of Forestry Best Management Practices for Controlling Nonpoint Source Pollution in North America - NCASI

Contextual Support Journal

New York State Forestry Best Management Practices for Water Quality Field Guide, accessed August 10, 2025

View Source

The effects of forest management on water quality - SLU, accessed July 20, 2025

Contextual Support Journal

SA Arid Lands Landscape Regional Summary 2022 Aquatic Ecosystem Condition Report, accessed July 31, 2025,

View Source

Preview of Victorian Government Department of Sustainability and Environment. (2003). Victoria's Criteria and Indicators for Sustainable Forest Management.

Victorian Government Department of Sustainability and Environment. (2003). Victoria's Criteria and Indicators for Sustainable Forest Management.

Direct Evidence Journal

Australia's State of the Forests Report 2018 – Criterion 4 - DAFF, accessed March 28, 2026,

View Source

Water clarity around Australia – satellite and in situ observations 3.1 - IMOS Ocean Report, accessed August 10, 2025

Contextual Support Journal

Water clarity around Australia – satellite and in situ observations 3.1 - IMOS Ocean Report, accessed August 10, 2025

View Source

Water Quality Objectives - Border Rivers - NSW Government, accessed August 12, 2025

Direct Evidence Government

(PDF) Impact of mitigated forestry activities on turbidity: assessing ..., accessed August 10, 2025

View Source

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

Contextual Support Government

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

View Source

Context

Region Australia
Biome Temperate Grassy Woodlands & Plains
Land Use Production Forestry
Assessment Pristine Reference
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 24 Mar 2026

Notes

Aligned with ANZECC guidelines and supported by data from degraded catchments. ConsistencyResolver applied 2026-03-24 20:14 UTC: LowerThreshold → (check: MinAbovePointValue, rationale: Clear LowerThreshold to null to allow the threshold to be correctly interpreted as an upper limit.) [Auto-corrected BenchmarkForm: MinimumOnly → MaximumOnly] ConsistencyResolver applied 2026-03-24 20:14 UTC: UpperThreshold 25 → 25 (check: MinAbovePointValue, rationale: Set UpperThreshold to 25 to correctly represent the upper degradation threshold as per Notes and EvidenceStatement. This will auto-correct the form from MinimumOnly to MaximumOnly.) ConsistencyResolver applied 2026-03-24 20:15 UTC: BenchmarkValue 25 → 25 (check: MinAboveOptimalHigh, rationale: BenchmarkValue remains 25 to align with UpperThreshold.) ConsistencyResolver applied 2026-03-24 20:15 UTC: UpperThreshold 25 → 25 (check: MinAboveOptimalHigh, rationale: UpperThreshold is correctly set to 25 NTU as the upper degradation limit per Notes and EvidenceStatement.) ConsistencyResolver applied 2026-03-24 20:15 UTC: LowerThreshold → (check: MinAboveOptimalHigh, rationale: No change needed to LowerThreshold as it is already null.)

Related Benchmarks

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