Water Electrical Conductivity (EC)

AUS-TMI-FOR-WEC General Moderate confidence

Benchmark Value

No specific value — see range

Range: 120 to 400 µS/cm

Thresholds: Lower: —, Upper: 800

Optimal Range: 120 to 400

Direction: Lower 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 11 benchmarks together — the OptimalRange form drives the primary score, while 10 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

Based on these guidelines, the default trigger value range for electrical conductivity in tropical Australian lowland rivers (defined as those below 150 m altitude) is 120 – 800 µS/cm.

Metric Definition:

Electrical conductivity (EC) in water, measured in microsiemens per centimetre (µS/cm), indicating dissolved ion concentration.

Benchmark Definition:

This benchmark represents the default trigger values for electrical conductivity in tropical Australian lowland rivers, indicating water quality thresholds relevant to production forestry in the specified biome.

Justification:

This benchmark is derived from the ANZECC & ARMCANZ (2000) default trigger values for 'slightly disturbed' tropical Australian lowland rivers, used as a scientifically defensible proxy due to the absence of direct field data from a best-practice production forestry site in the specified biome.

Sources (1)

ANZECC & ARMCANZ (2000) guidelines - Water Quality Australia, accessed August 12, 2025 Government

ANZECC & ARMCANZ (2000) guidelines - Water Quality Australia

View Source

Supporting Sources (4)

Additional references from the underlying research that informed this benchmark.

Preview of Investigating the potential for groundwater from different vegetation, soil and landuses to stimulate blooms of the cyanobacterium, Lyngbya majuscula, in coastal waters - CSIRO PUBLISHING | Marine and Freshwater Research

Investigating the potential for groundwater from different vegetation, soil and landuses to stimulate blooms of the cyanobacterium, Lyngbya majuscula, in coastal waters - CSIRO PUBLISHING | Marine and Freshwater Research

Contextual Support Journal

View Source

Norfolk Island Water Resource Assessment

Contextual Support Journal

Norfolk Island Water Resource Assessment

View Source

The most beautiful Australian islands - Tourism Australia, accessed August 2, 2025,

Contextual Support

Lord Howe Island Subtropical Forests | One Earth

View Source

The relationship between groundwater and surface water character and wetland habitats, Bribie Island, Queensland - ResearchGate

Contextual Support Journal

The relationship between groundwater and surface water character and wetland habitats, Bribie Island, Queensland - ResearchGate

View Source

Context

Region Australia
Biome Tropical & Subtropical Maritime Islands
Land Use Production Forestry
Assessment Pristine Reference
Evidence Type TargetCondition

Lifecycle

Status Active
Version 1
Effective From 19 Mar 2026

Notes

Lower Boundary: 120 µS/cm marks the boundary between pristine and well-managed systems; not a minimum functional threshold. Upper Detrimental Threshold: 800 µS/cm is the upper limit beyond which ecological harm is likely. Optimal Range: 120 – 400 µS/cm reflects minimal anthropogenic impact and high environmental health under production forestry. [Migration] Original wider evidence range: 120 – 800 (retained OptimalRange: 120 – 400)