Water Electrical Conductivity (EC)

AUS-TMI-AGR-WEC General Moderate confidence

Benchmark Value

50 µS/cm

Thresholds: Lower: —, Upper: 50

Direction: Higher 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 15 benchmarks together — the OptimalRange form drives the primary score, while 14 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

The benchmark of < 50 µS/cm represents the best available condition for surface waters in this biome, derived from comprehensive field measurements in the low-impact Tiwi Islands, which serve as a real-world reference for a high-health natural state.

Metric Definition:

Water Electrical Conductivity (EC) is a physical measure of a solution's ability to conduct an electrical current, serving as a proxy for total dissolved ionic substances.

Benchmark Definition:

This benchmark represents the near-natural background condition of water electrical conductivity in sustainably managed agricultural systems in Australia's Tropical & Subtropical Maritime Islands biome, indicating high environmental health.

Justification:

This value is selected because it represents the highest achievable environmental health based on empirical data from a relevant low-impact tropical island system and is corroborated by analogous mainland catchments.

Sources (4)

Preview of A Compendium of Ecological Information on Australia's Northern Tropical Rivers - Report 5 - Water quality - DCCEEW, accessed August 1, 2025,

A Compendium of Ecological Information on Australia's Northern Tropical Rivers - Report 5 - Water quality - DCCEEW, accessed August 1, 2025, Journal

Threshold Indicator Taxa ANalysis and change points (dots) for the ...

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

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

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Preview of Proserpine River, Whitsunday Island and O'Connell River Basins Environmental Values and Water Quality Objectives - Queensland Environment Department, accessed August 2, 2025,

Proserpine River, Whitsunday Island and O'Connell River Basins Environmental Values and Water Quality Objectives - Queensland Environment Department, accessed August 2, 2025, Journal

Bioregional Assessment of the Clarence-Moreton bioregion, which includes the Richmond River basin

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VOLUME 1 WATER RESOURCES OF THE TIWI ... - Tiwi Land Council Government

VOLUME 1 WATER RESOURCES OF THE TIWI ... - Tiwi Land Council

View Source

Context

Region Australia
Biome Tropical & Subtropical Maritime Islands
Land Use Agricultural Crop Production
Assessment Pristine Reference
Evidence Type ReferenceCondition

Lifecycle

Status Superseded
Version 1
Effective From 25 Mar 2026
Effective To 25 Mar 2026

Notes

The benchmark is corroborated by data from analogous high-quality mainland streams (< 100 µS/cm). There is no evidence supporting a lower critical threshold; very low EC is characteristic of a pristine state. The optimal range for high-health agroecosystems is from natural background levels (< 100 µS/cm) up to a maximum of 650 µS/cm. The upper detrimental threshold for agronomic stress begins above 650 µS/cm, and ecological degradation occurs above ~930 µS/cm.

Related Benchmarks

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