Water Electrical Conductivity (EC)

AUS-TSR-AGR-WEC General Moderate confidence

Benchmark Value

106 µS/cm

Direction: Lower is desirable ↓

Form: Point

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 13 benchmarks together — the OptimalRange form drives the primary score, while 12 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

The reference value of 106 µS/cm is the 80th percentile of baseline data from reference sites used to set the official Water Quality Objectives for the Johnstone River Basin, a representative Wet Tropics catchment.

Metric Definition:

Water Electrical Conductivity (EC) is a measure of the water's ability to conduct electricity, directly proportional to the concentration of total dissolved ions.

Benchmark Definition:

This benchmark represents the reference Water Electrical Conductivity (EC) value for streams in tropical rainforest agricultural landscapes, indicating the best available condition under sustainable agriculture based on local baseline data.

Justification:

This value is based on the 80th percentile of baseline data from local reference sites and is part of official Water Quality Objectives, representing a scientifically defensible proxy for best available condition under sustainable agriculture.

Sources (3)

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

(PDF) Effects of increasing salinity on freshwater ecosystems in Australia - ResearchGate

View Source

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)

View Source

Johnstone River Basin Environmental Values and Water Quality ... Journal

Johnstone River Basin Environmental Values and Water Quality ...

View Source

Context

Region Australia
Biome Tropical & Subtropical Rainforests
Land Use Agricultural Crop Production
Assessment Not Stated
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 10 Jun 2026

Notes

Lower Critical Threshold: 20 µS/cm. Upper Detrimental Threshold: 110 µS/cm. No upper detrimental threshold — higher values are always worse beyond natural saturation. Values above 110 µS/cm indicate departure from high-health conditions. Values exceeding 350 µS/cm signify significant disturbance, and above 1500 µS/cm indicate broad-scale adverse effects. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

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