Water Electrical Conductivity (EC)

AUS-AIF-URB-WEC General Moderate confidence

Benchmark Value

No specific value — see range

Range: 125 to 500 μS/cm

Optimal Range: 125 to 500

Direction: Higher is desirable ↑

Form: OptimalRange

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 14 benchmarks together — the OptimalRange form drives the primary score, while 13 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MaximumOnly Guard MaximumOnly Guard LowerThreshold Guard UpperThreshold Guard MaximumOnly Guard MaximumOnly Guard OptimalRange Guard UpperThreshold Guard LowerThreshold Guard OptimalRange Guard MaximumOnly Guard OptimalRange Guard UpperThreshold Guard

Evidence & Context

The proposed optimal range for EC in urbanised arid inland waterways is 125 b3 500 μS/cm. The lower boundary of 125 μS/cm is set to prevent the potential for osmotic stress and ion deficiency that could result from the discharge of unnaturally pure water from advanced treatment processes. It ensures a minimum level of essential minerals is present, reflecting the natural character of inland waters. The upper boundary of 500 b5/cm is set based on the critical tolerance of the most sensitive known life stages of keystone fauna (i.e., Murray Cod larvae). Maintaining EC below this level ensures that the conditions are suitable for successful reproduction and recruitment, and supports the persistence of diverse and sensitive macroinvertebrate communities, which are hallmarks of a system with high ecological integrity. Managing water quality to remain within this optimal range

Metric Definition:

Water Electrical Conductivity (EC)

Benchmark Definition:

This benchmark defines the optimal electrical conductivity range in urban arid inland waterways that supports ecological health and function.

Justification:

This range avoids the dual stresses of ion deficiency at the low end and salinity toxicity at the high end, supporting keystone species and diverse macroinvertebrate communities.

Sources (1)

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

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

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

Supporting Sources (20)

Additional references from the underlying research that informed this benchmark.

Preview of (PDF) Effects of increasing salinity on freshwater ecosystems in Australia - ResearchGate, accessed August 11, 2025,

(PDF) Effects of increasing salinity on freshwater ecosystems in Australia - ResearchGate, accessed August 11, 2025,

Direct Evidence Journal

Effects of increasing salinity on freshwater ecosystems in Australia - ResearchGate

Preview of (PDF) Targets for Urban Stormwater Management in Australia - ResearchGate

(PDF) Targets for Urban Stormwater Management in Australia - ResearchGate

Direct Evidence

(PDF) Targets for Urban Stormwater Management in Australia - ResearchGate

Preview of (PDF) Water Sensitive Urban Design - Case Studies (Australia/Dubai) - ResearchGate, accessed July 13, 2025,

(PDF) Water Sensitive Urban Design - Case Studies (Australia/Dubai) - ResearchGate, accessed July 13, 2025,

Direct Evidence GreyLiterature

(PDF) Water Sensitive Urban Design - Case Studies (Australia/Dubai) - ResearchGate, accessed July 26, 2025

Preview of ANZEC Guidelines - Risk Assessment for Contaminated Sites in New Zealand, accessed July 18, 2025,

ANZEC Guidelines - Risk Assessment for Contaminated Sites in New Zealand, accessed July 18, 2025,

Direct Evidence Government

Salinity - Murray–Darling Basin Authority, accessed July 31, 2025,

Preview of Australia | Request PDF - ResearchGate

Australia | Request PDF - ResearchGate

Contextual Support Journal

central Australia | Request PDF - ResearchGate

Preview of Australian and New Zealand Guidelines for Fresh and Marine Water Quality

Australian and New Zealand Guidelines for Fresh and Marine Water Quality

Contextual Support GreyLiterature

Australian and New Zealand Guidelines for Fresh and Marine Water Quality

Preview of Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000), accessed May 11, 2025,

Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000), accessed May 11, 2025,

Direct Evidence Journal

Northern Territory Government (2020) Darwin Harbour Region Water Quality Objectives, Report Card Section 3.0.

Preview of Australian Water Quality Guidelines for Fresh and Marine Waters 1992

Australian Water Quality Guidelines for Fresh and Marine Waters 1992

Contextual Support GreyLiterature

Macroinvertebrate Tolerance across a Range of Conductivities in the Isaac River Catchment (Central Queensland) | Request PDF - ResearchGate

Preview of Effectiveness of Water-Sensitive Urban Design Techniques on Stormwater Quantity Management at a Residential Allotment Scale - MDPI, accessed August 2, 2025,

Effectiveness of Water-Sensitive Urban Design Techniques on Stormwater Quantity Management at a Residential Allotment Scale - MDPI, accessed August 2, 2025,

Contextual Support

Targets for Urban Stormwater Management in Australia - MDPI, accessed July 13, 2025

Preview of Gardens and Public Open Space Irrigation: A Case Study in Perth - Scientific Research Publishing

Gardens and Public Open Space Irrigation: A Case Study in Perth - Scientific Research Publishing

Contextual Support

National Guidelines for Water Quality - Department of Natural Resources and Environment Tasmania

Preview of Management of major ions in freshwater ecosystems: thresholds of impact and indicators of change - UQ eSpace - The University of Queensland, accessed August 17, 2025,

Management of major ions in freshwater ecosystems: thresholds of impact and indicators of change - UQ eSpace - The University of Queensland, accessed August 17, 2025,

Contextual Support GreyLiterature

Comparison of two commonly used methods for identifying water ..., accessed August 8, 2025,

Preview of New sensitivity grades for Australian river macroinvertebrates - Murray-Darling Freshwater Research Centre

New sensitivity grades for Australian river macroinvertebrates - Murray-Darling Freshwater Research Centre

Contextual Support Journal

AECR - 2016 panel assessment of creeks and rivers from the Adelaide and MLR NRM region - EPA SA, accessed July 13, 2025

Preview of New sensitivity grades for Australian river macroinvertebrates - ResearchGate

New sensitivity grades for Australian river macroinvertebrates - ResearchGate

Direct Evidence Journal

New sensitivity grades for Australian river macroinvertebrates - ResearchGate

Preview of Quarterly Drinking Water Quality Report Broken ... - Essential Water

Quarterly Drinking Water Quality Report Broken ... - Essential Water

Direct Evidence

Murray to Broken Hill pipeline | NSW Government Water

Preview of River Murray �darling to Sea Ecological Community: Expert Technical Workshop Report - DCCEEW

River Murray �darling to Sea Ecological Community: Expert Technical Workshop Report - DCCEEW

Direct Evidence Journal

River Murray �darling to Sea Ecological Community: Expert Technical Workshop Report - DCCEEW

Preview of Salinity - Murray�darling Basin Authority

Salinity - Murray�darling Basin Authority

Contextual Support GreyLiterature

Why test for electrical conductivity, acidity and alkalinity? - The Australian Museum, accessed July 13, 2025

Preview of Salinity sensitivity in early life stages of an Australian freshwater fish, Murray Cod (Maccullochella peelii peelii Mitchell 1838) - University of Canberra Research Portal, accessed August 11, 2025,

Salinity sensitivity in early life stages of an Australian freshwater fish, Murray Cod (Maccullochella peelii peelii Mitchell 1838) - University of Canberra Research Portal, accessed August 11, 2025,

Contextual Support GreyLiterature

Murray Cod (Maccullochella peelii peelii Mitchell 1838) - University of Canberra Research Portal

Preview of Urban Water in the Murray-Darling Basin - DCCEEW

Urban Water in the Murray-Darling Basin - DCCEEW

Contextual Support Journal

Urban Water in the Murray-Darling Basin - DCCEEW

Preview of Using the ANZECC Guidelines and Water Quality Objectives in NSW, accessed August 11, 2025,

Using the ANZECC Guidelines and Water Quality Objectives in NSW, accessed August 11, 2025,

Contextual Support Journal

Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000) - Tuvalu Environment Data Portal, accessed July 19, 2025,

Preview of Water quality of surface water environments - NSW Government Water, accessed August 1, 2025,

Water quality of surface water environments - NSW Government Water, accessed August 1, 2025,

Contextual Support Government

National Guidelines for Water Quality | Department of Natural ...

Context

Region Australia
Biome Arid Inland Floodplains & Ephemeral River Systems
Land Use Urban & Developed Use
Assessment Pristine Reference
Evidence Type HealthyOperationalRange

Lifecycle

Status Active
Version 1
Effective From 18 Mar 2026

Notes

This range supports high ecological health. It is protective of the most sensitive life stages of keystone fish species (e.g., Murray Cod larvae), which is critical for population recruitment and sustainability. It also supports the presence of diverse and sensitive macroinvertebrate communities, indicated by high SIGNAL2 scores.

Related Benchmarks

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