Water Electrical Conductivity (EC)

AUS-TSR-URB-WEC General Moderate confidence

Benchmark Value

1500 μS/cm

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 10 benchmarks together — the OptimalRange form drives the primary score, while 9 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

A comprehensive review concluded that aquatic biota are likely to be adversely affected as salinity exceeds 1000 mg/L, which is explicitly equated to an EC of approximately 1500 ³S/cm.

Metric Definition:

Electrical Conductivity (EC) level beyond which significant adverse effects on aquatic biota occur.

Benchmark Definition:

Critical electrical conductivity threshold above which significant ecological harm to sensitive aquatic species occurs in tropical & subtropical rainforest streams under urban and developed land use.

Justification:

Widely cited threshold based on observed declines in sensitive macroinvertebrate species at this EC level.

Sources (1)

Preview of Ecology of streams in a biogeographic isolate—the Queensland Wet Tropics, Australia | Freshwater Science: Vol 34, No 2, accessed July 22, 2025,

Ecology of streams in a biogeographic isolate—the Queensland Wet Tropics, Australia | Freshwater Science: Vol 34, No 2, accessed July 22, 2025, Journal

Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC/ARMCANZ)

Supporting Sources (16)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed August 2, 2025,

(PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed August 2, 2025,

Direct Evidence GreyLiterature

Ecology of streams in a biogeographic isolate 6the Queensland Wet Tropics, Australia, accessed July 21, 2025

Preview of A Bayesian approach to understanding the key factors influencing temporal variability in stream water quality – a case study in the Great Barrier Reef catchments - HESS

A Bayesian approach to understanding the key factors influencing temporal variability in stream water quality – a case study in the Great Barrier Reef catchments - HESS

Contextual Support Journal

(PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed July 21, 2025

Preview of Effects of salinity on stream ecosystems: improving models for macroinvertebrates - CSIRO Research Publications Repository, accessed July 21, 2025

Effects of salinity on stream ecosystems: improving models for macroinvertebrates - CSIRO Research Publications Repository, accessed July 21, 2025

Direct Evidence

Effects of salinity on stream ecosystems: improving models for macroinvertebrates - CSIRO Research Publications Repository, accessed July 21, 2025

Preview of Global perspectives on the urban stream syndrome | Freshwater Science: Vol 35, No 1, accessed July 21, 2025

Global perspectives on the urban stream syndrome | Freshwater Science: Vol 35, No 1, accessed July 21, 2025

Contextual Support Journal

Global perspectives on the urban stream syndrome | Freshwater Science: Vol 35, No 1, accessed July 21, 2025

Preview of Impact of secondary salinisation on freshwater ecosystems: effects of contrasting, experimental, short-term releases of saline wastewater on macroinvertebrates in a lowland stream - CSIRO Publishing, accessed August 8, 2025,

Impact of secondary salinisation on freshwater ecosystems: effects of contrasting, experimental, short-term releases of saline wastewater on macroinvertebrates in a lowland stream - CSIRO Publishing, accessed August 8, 2025,

Methodology Source Government

Comparison of two commonly used methods for identifying water quality thresholds in freshwater ecosystems using field and synthetic data - PubMed

Preview of Nonpoint Source: Urban Areas | US EPA, accessed July 21, 2025

Nonpoint Source: Urban Areas | US EPA, accessed July 21, 2025

Contextual Support Journal

(PDF) An Overview of Water Sensitive Urban Design Practices in Australia - ResearchGate, accessed July 21, 2025

Preview of State of the Environment 2023 | Stormwater, accessed July 13, 2025,

State of the Environment 2023 | Stormwater, accessed July 13, 2025,

Contextual Support Government

Characterising the relationship between water quality and water quantity, accessed July 21, 2025

Preview of Stormwater - State of the Environment Report 2023, accessed July 21, 2025

Stormwater - State of the Environment Report 2023, accessed July 21, 2025

Contextual Support Journal

Stormwater - State of the Environment Report 2023, accessed July 21, 2025

Preview of Stormwater Management in a Water Sensitive City blueprint2012, accessed July 21, 2025

Stormwater Management in a Water Sensitive City blueprint2012, accessed July 21, 2025

Contextual Support

Stormwater Management in a Water Sensitive City blueprint2012, accessed July 21, 2025

Preview of Water quality guidelines - Queensland Environment Department, accessed August 1, 2025,

Water quality guidelines - Queensland Environment Department, accessed August 1, 2025,

Regulatory Framework Government

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

Preview of Water quality guidelines - Queensland Environment Department, accessed August 4, 2025,

Water quality guidelines - Queensland Environment Department, accessed August 4, 2025,

Regulatory Framework Journal

Seasonal changes in water quality and macrophytes and the ...

Preview of Water Sensitive Urban Design - Townsville City Council, accessed August 2, 2025,

Water Sensitive Urban Design - Townsville City Council, accessed August 2, 2025,

Contextual Support Journal

Human society and wellbeing | Australia state of the environment 2021

Preview of Water Sensitive Urban Design in North Queensland, accessed July 13, 2025,

Water Sensitive Urban Design in North Queensland, accessed July 13, 2025,

Contextual Support GreyLiterature

HLW Report Card - Healthy Land & Water, accessed July 21, 2025

Preview of Water-Quality-Salinity-Standards.pdf, accessed August 11, 2025,

Water-Quality-Salinity-Standards.pdf, accessed August 11, 2025,

Direct Evidence Journal

(PDF) Effects of increasing salinity on freshwater ecosystems in ..., accessed July 21, 2025

Preview of Water-Sensitive Urban Design (WSUD) Performance in Mitigating ..., accessed July 21, 2025,

Water-Sensitive Urban Design (WSUD) Performance in Mitigating ..., accessed July 21, 2025,

Contextual Support Journal

Water-Sensitive Urban Design (WSUD) Performance in Mitigating Urban Flooding in a Wet Tropical North Queensland Sub-Catchment - MDPI, accessed July 21, 2025

Preview of www.rrrc.org.au, accessed May 15, 2025,

www.rrrc.org.au, accessed May 15, 2025,

Contextual Support Journal

Sediments and nutrients in north Queensland tropical streams: changes with agricultural development and pristine condition status (Technical Report No. 62, Australian Rainforest CRC, 2006)

Context

Region Australia
Biome Tropical & Subtropical Rainforests
Land Use Urban & Developed Use
Assessment Not Stated
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 5 Jun 2026

Notes

Represents a conservative and scientifically robust threshold for significant ecological degradation in naturally low-salinity tropical freshwater systems. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

Other benchmarks in the AUS-TSR-URB-WEC family.