Water Turbidity

AUS-TSW-FOR-WTU General Moderate confidence

Benchmark Value

25 NTU

Range: 3.3 to 10 NTU

Thresholds: Lower: —, Upper: 25

Optimal Range: 3.3 to 10

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

The optimal range for mean turbidity is defined as < 10 NTU.

Metric Definition:

Mean water turbidity in NTU representing the optimal range for ecological health in production forestry catchments.

Benchmark Definition:

This benchmark defines the maximum turbidity level within the optimal range indicating effective mitigation of forestry impacts and high ecological health in temperate semi-arid woodland catchments.

Justification:

Based on empirical data showing pre-harvest baseline of 3.3 NTU and post-harvest mean of 8.5 NTU under best-practice conditions.

Sources (1)

(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

Supporting Sources (20)

Additional references from the underlying research that informed this benchmark.

1.1.5.2 Surface water quality - Bioregional Assessments |, accessed August 5, 2025,

Contextual Support Government

1.1.5.2 Surface water quality - Bioregional Assessments |, accessed July 12, 2025,

View Source

Australia's forests – overview - DAFF, accessed August 5, 2025,

Contextual Support

Boland, D. J., & Dunn, A. T. (1985). Eucalyptus delegatensis: Its ecology and management. Forestry Commission of NSW.

View Source

Australia's State of the Forests Report, accessed August 12, 2025

Contextual Support Journal

Criteria and Indicators for Sustainable Forest Management in Victoria, accessed March 28, 2026,

View Source

Australia's Sustainable Forest Management - DAFF, accessed July 12, 2025,

Contextual Support

Sustainable forest management: the Australian context - DAFF, accessed July 12, 2025,

View Source

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

Contextual Support Regulatory Framework Government

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

View Source

Deriving guideline values using reference-site data - Water Quality Australia, accessed August 12, 2025

Contextual Support Government

Water Quality Guidelines Home - Water Quality Australia

View Source

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

Contextual Support Journal

Dissolved Oxygen (DO) Turbidity - Interstate Commission on the Potomac River Basin

View Source

How Sustainable Forestry Works - Science | HowStuffWorks, accessed July 12, 2025,

Contextual Support GreyLiterature

How Sustainable Forestry Works - Science | HowStuffWorks, accessed July 12, 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

National Guidelines for Water Quality - Department of Natural Resources and Environment Tasmania, accessed August 1, 2025,

Contextual Support Direct Evidence

Australian and New Zealand Guidelines for Fresh and Marine Water ...

View Source

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

Contextual Support Journal

NVIS Fact sheet MVG 13 Acacia open woodlands - DCCEEW, accessed July 10, 2025,

View Source

Protecting waterways - Forestry Corporation, accessed July 12, 2025,

Contextual Support Government

Protecting waterways - Forestry Corporation, accessed July 12, 2025,

View Source

The Turbidity Effect on Aquatic Life - Number Analytics, accessed July 12, 2025,

Contextual Support GreyLiterature

The Turbidity Effect on Aquatic Life - Number Analytics, accessed July 31, 2025,

View Source

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

Contextual Support Government

Australian Drinking Water Guidelines

View Source

Turbidity | River Detectives, accessed July 16, 2025,

Contextual Support Journal

Turbidity | River Detectives, accessed July 27, 2025,

View Source

Turbidity and Water | U.S. Geological Survey - USGS.gov, accessed August 12, 2025,

Contextual Support

Turbidity and Water | U.S. Geological Survey - USGS.gov, accessed July 31, 2025,

View Source

Turbidity, accessed August 3, 2025,

Contextual Support Journal

Turbidity, accessed July 31, 2025,

View Source

Water Quality and Forestry Best Management Practices, accessed July 12, 2025,

Contextual Support Government

Water Quality and Forestry Best Management Practices, accessed July 12, 2025,

View Source

Why Measure Turbidity? - Montclair State University, accessed August 12, 2025,

Contextual Support GreyLiterature

Feral horses (Equus caballus) increase suspended sediment in subalpine streams, accessed August 3, 2025

View Source

Woodlands of Australia - A biography of the Australian continent, accessed July 12, 2025,

Contextual Support GreyLiterature

Semi-arid woodlands (shrubby sub-formation) | NSW Environment, Energy and Science, accessed July 8, 2025, )

View Source

Context

Region Australia
Biome Temperate Semi-Arid Shrublands & Open Woodlands
Land Use Production Forestry
Assessment Pristine Reference
Evidence Type HealthyOperationalRange

Lifecycle

Status Active
Version 2
Effective From 15 Mar 2026

Notes

Maintaining turbidity within this range indicates effective mitigation of forestry impacts and high ecological health. ConsistencyResolver applied 2026-03-23 00:14 UTC: BenchmarkValue 10 → 25 (check: MinAboveMax, rationale: Swapping the MaximumOnly benchmark's BenchmarkValue from 10 to 25 aligns with the upper degradation limit described in the Notes and EvidenceStatement.) ConsistencyResolver applied 2026-03-24 20:12 UTC: UpperThreshold → 25 (check: MinEqualsMax, rationale: Setting the MaximumOnly benchmark's UpperThreshold to 25 NTU aligns with the Notes indicating that sustained turbidity above 25 NTU signals degradation, establishing a proper upper ceiling threshold.)

Related Benchmarks

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