Water Turbidity

AUS-ASC-CON-WTU General Moderate confidence

Benchmark Value

25 NTU

Direction: Lower is desirable ↓

Form: MaximumOnly

Scoring Curve

Scoring curve unavailable

The scoring engine could not generate a curve for this benchmark context. The primary form is CompositeFramework, but the benchmark data may be missing required fields (e.g., optimal range bounds for an OptimalRange benchmark). This is typically a data quality issue in the benchmark pipeline.

Contributing Benchmarks

CompositeFramework Primary UpperThreshold Guard UpperThreshold Guard MaximumOnly Guard MaximumOnly Guard OptimalRange Guard MaximumOnly Guard

Evidence & Context

The ANZECC 2000/ANZG 2018 guidelines suggest a default trigger value range for upland rivers of 2–25 NTU; values exceeding the upper end of this range, or site-specific trigger values derived from reference conditions (often much lower than 25 NTU in alpine settings), indicate increased risk of adverse ecological effects.

Metric Definition:

Water turbidity as a measure of suspended particulate matter causing cloudiness in water.

Benchmark Definition:

This benchmark sets the maximum turbidity threshold for upland rivers, above which there is increased risk of ecological harm, based on national guidelines.

Justification:

The ANZECC 2000/ANZG 2018 guidelines provide a default upper trigger value of 25 NTU for upland rivers, indicating a threshold beyond which ecological health is compromised.

Sources (1)

NSW alpine resorts environmental performance report 2020–21 Journal

NSW Alpine Resorts Environmental Performance Report 2020–21

View Source

Supporting Sources (5)

Additional references from the underlying research that informed this benchmark.

Kosciuszko National Park EcoHealth Scorecard 2022–23

Contextual Support GreyLiterature

Assessment of the Values of Kosciuszko National Park (Chapter 8)

View Source

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

Contextual Support GreyLiterature

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

View Source

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

Regulatory Framework

Using the ANZECC Guidelines and Water Quality Objectives in NSW

View Source

Turbidity | River Detectives, accessed July 16, 2025,

Contextual Support Journal

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

View Source

Victorian Water Quality Analysis 2022 Technical Report - Water and ..., accessed August 12, 2025,

Contextual Support Journal

Victorian Water Quality Analysis 2022 Technical Report

View Source

Context

Region Australia
Biome Alpine and Subalpine Complex
Land Use Conservation / Protected Natural Areas
Assessment Not Stated
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 2
Effective From 3 Jun 2026

Notes

Values exceeding 25 NTU indicate increased risk of adverse ecological effects. Elevated turbidity can impair light penetration, smother habitats, and negatively impact aquatic biota. AssessmentContext defaulted to 'Not Stated' because the source document did not state one. Pipeline quarantine: Lower confidence than existing active benchmark v1 (High). Accepted by operator on 2026-06-03 07:30 UTC — superseded v1 (#1407)

Related Benchmarks

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