Water Turbidity

AUS-ASC-FOR-WTU General Moderate confidence

Benchmark Value

100 NTU

Thresholds: Lower: —, Upper: 100

Direction: Lower is desirable ↓

Form: UpperThreshold

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context.

Evidence & Context

Finally, a value of 100 NTU is defined as an 'unsafe level for most aquatic life'.

Metric Definition:

Nephelometric turbidity

Benchmark Definition:

This benchmark represents an unsafe water turbidity level for most aquatic life in the Alpine and Subalpine Complex under production forestry, typically reached during major disturbance events.

Justification:

Such levels are typically only reached during major disturbance events, such as feral animal trampling or extreme storm runoff in degraded catchments.

Sources (1)

Preview of Feral horses increase suspended sediment in subalpine streams

Feral horses increase suspended sediment in subalpine streams Journal

Feral horses increase suspended sediment in subalpine streams

Supporting Sources (23)

Additional references from the underlying research that informed this benchmark.

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

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

Direct Evidence Government

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

Preview of An Examination of Stream Water Quality Data from Monitoring of Forest Harvesting in the Eastern Highlands of Victoria - MDPI, accessed August 1, 2025,

An Examination of Stream Water Quality Data from Monitoring of Forest Harvesting in the Eastern Highlands of Victoria - MDPI, accessed August 1, 2025,

Direct Evidence Journal

An Examination of Stream Water Quality Data from Monitoring of Forest Harvesting in the Eastern Highlands of Victoria.

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 Catchment Health Indicator Program Report (CHIP) 2022 - Upper ..., accessed July 16, 2025,

Catchment Health Indicator Program Report (CHIP) 2022 - Upper ..., accessed July 16, 2025,

Contextual Support Journal

ACT Waterwatch. (2023). Catchment Health Indicator Program Report 2023.

Preview of Catchment Health Indicator Program Report 2021 - Upper Murrumbidgee Waterwatch, accessed August 12, 2025,

Catchment Health Indicator Program Report 2021 - Upper Murrumbidgee Waterwatch, accessed August 12, 2025,

Contextual Support Journal

ANZECC/ARMCANZ (2000) Guidelines

Preview of Default guideline values - Water Quality Australia, accessed August 12, 2025

Default guideline values - Water Quality Australia, accessed August 12, 2025

Contextual Support Government

ANZECC (2000) Australian and New Zealand Guidelines for Fresh and Marine Water Quality.

Preview of Desktop review – Impact of bushfires on water quality, accessed August 10, 2025,

Desktop review – Impact of bushfires on water quality, accessed August 10, 2025,

Contextual Support Journal

Australia's Sustainable Forest Management Framework of Criteria and Indicators 2008 - DAFF

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

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

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

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

Contextual Support GreyLiterature

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

Preview of In-Situ Support. (2024). What are typical turbidity values in natural environments?

In-Situ Support. (2024). What are typical turbidity values in natural environments?

Methodology Source GreyLiterature

Hanna Instruments Australia. (2024). The Complete Guide to Measuring Turbidity in Water.

Preview of Logging Impacts On Streams - Cloudfront.net

Logging Impacts On Streams - Cloudfront.net

Direct Evidence Journal

The effects of forest management on water quality - SLU

Preview of NHMRC. (2011). Australian Drinking Water Guidelines - Part 5 Physical and Chemical Characteristics: Turbidity.

NHMRC. (2011). Australian Drinking Water Guidelines - Part 5 Physical and Chemical Characteristics: Turbidity.

Contextual Support GreyLiterature

Ketos. (2024). Acceptable Turbidity Levels in Industrial Water.

Preview of North Esk Water Quality Study - Part 1

North Esk Water Quality Study - Part 1

Direct Evidence Journal

North Esk Water Quality Study - Part 1.

Preview of NSW Water Quality Index Targets

NSW Water Quality Index Targets

Direct Evidence Journal

NSW Department of Climate Change, Energy, the Environment and Water. (2025). Targets to develop a water quality index for NSW rivers - River condition index.

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

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

Direct Evidence Government

Forest Town Nature Conservation Group. (2024). Spa Ponds Water Quality.

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

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

Regulatory Framework Government

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

Preview of Turbidity layer thresholds - WikiWatershed

Turbidity layer thresholds - WikiWatershed

Direct Evidence Journal

WikiWatershed. (2021). Layering Thresholds for Turbidity.

Preview of U.S. EPA. (2022). Turbidity Benchmark Monitoring for Dewatering under the Construction General Permit.

U.S. EPA. (2022). Turbidity Benchmark Monitoring for Dewatering under the Construction General Permit.

Contextual Support Journal

Tasmania Department of Primary Industries, Water and Environment. (2003). North Esk Water Quality Study - Part 1.

Preview of Upper Murrumbidgee Waterwatch Catchment Health Indicator Program (CHIP) Reports (e.g., 2021, 2023) and associated methodology defining "Excellent" water quality thresholds.

Upper Murrumbidgee Waterwatch Catchment Health Indicator Program (CHIP) Reports (e.g., 2021, 2023) and associated methodology defining "Excellent" water quality thresholds.

Contextual Support Journal

Catchment Health Indicator Program - Upper Murrumbidgee Waterwatch

Preview of Victoria Environment Protection Authority. (2018). State Environment Protection Policy (Waters).

Victoria Environment Protection Authority. (2018). State Environment Protection Policy (Waters).

Regulatory Framework Government

Victoria Environment Protection Authority. (2018). State Environment Protection Policy (Waters).

Preview of Victoria Government. (2021). Environment Reference Standard.

Victoria Government. (2021). Environment Reference Standard.

Contextual Support Journal

Victoria Government. (2021). Environment Reference Standard.

Preview of Water Quality Objectives - Border Rivers - NSW Government

Water Quality Objectives - Border Rivers - NSW Government

Direct Evidence Government

Water Quality Objectives - Border Rivers - NSW Government

Preview of Webb, A. A., & Turner, L. (2004). Impact of mitigated forestry activities on turbidity: assessing the effect of improved harvesting practices.

Webb, A. A., & Turner, L. (2004). Impact of mitigated forestry activities on turbidity: assessing the effect of improved harvesting practices.

Direct Evidence Journal

Webb, A. A., & Turner, L. (2004). Impact of mitigated forestry activities on turbidity: assessing the effect of improved harvesting practices.

Context

Region Australia
Biome Alpine and Subalpine Complex
Land Use Production Forestry
Assessment Not Stated
Season Summer
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 10 Jun 2026

Notes

Level associated with significant damage to riparian zones and loss of aquatic diversity. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

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