Water Turbidity

AUS-ASC-CON-WTU General Moderate 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 8 benchmarks together — the OptimalRange form drives the primary score, while 7 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary UpperThreshold Guard MaximumOnly Guard OptimalRange Guard MinimumOnly Guard MaximumOnly Guard OptimalRange Guard MinimumOnly Guard

Evidence & Context

While the ANZECC 2000 guidelines provide a default upper trigger value of 25 NTU for upland rivers, adverse effects can occur at lower levels, especially in sensitive alpine ecosystems accustomed to very clear water.

Metric Definition:

Upper detrimental threshold for water turbidity in NTU, above which ecological health is compromised.

Benchmark Definition:

This benchmark represents the upper detrimental turbidity threshold in NTU, above which ecological health in alpine and subalpine streams is at risk.

Justification:

Based on ANZECC 2000 guidelines for upland rivers, indicating increased risk of adverse ecological effects above this value.

Supporting Sources (4)

Additional references from the underlying research that informed this benchmark.

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

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

View Source

NSW alpine resorts environmental performance report 2020–21

Direct Evidence Journal

NSW Alpine Resorts Environmental Performance Report 2020–21

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 - Water and ..., accessed August 10, 2025

View Source

Context

Region Australia
Biome Alpine and Subalpine Complex
Land Use Conservation / Protected Natural Areas
Assessment Pristine Reference
Evidence Type DegradationThreshold

Lifecycle

Status Retired
Version 1
Effective From 17 Mar 2026
Effective To 24 Mar 2026

Notes

Adverse effects include reduced light penetration, habitat smothering, and stress on aquatic biota. Site-specific thresholds in alpine areas may be lower. Retired via Evidence Integrity Review on 2026-03-24 09:41 UTC — all DirectEvidence sources confirmed dead or inaccessible.

Related Benchmarks

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