Water Electrical Conductivity (EC)

AUS-TGP-AQU-WEC General High confidence

Benchmark Value

280 µS/cm

Range: — to 280 µS/cm

Thresholds: Lower: —, Upper: 280

Optimal Range: — to 280

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 4 benchmarks together — the OptimalRange form drives the primary score, while 3 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MaximumOnly Guard Point Guard OptimalRange Guard

Evidence & Context

The peer-reviewed study by Kaestner et al. (2019) on South Australian temperate streams provides precisely this required biological data. The research identifies a distinct threshold of ecological change at an Electrical Conductivity of approximately 280µS/cm. Above this level, the composition of the diatom community—a foundational component of the aquatic food web and a sensitive bioindicator—begins to shift significantly, with a marked decline in salt-sensitive species.

Metric Definition:

Water Electrical Conductivity (EC) is a fundamental measure of water quality that quantifies the ability of a solution to conduct an electrical current, directly proportional to the concentration of dissolved ions, primarily mineral salts, in the water.

Benchmark Definition:

This benchmark defines the upper limit of water electrical conductivity in freshwater streams to maintain high ecological health, based on sensitive aquatic diatom communities in Australia's Temperate Grassy Woodlands & Plains.

Justification:

Based on a robust, peer-reviewed study specific to the target biome's stream types, aligned with national water quality guidelines.

Sources (3)

Preview of Diatom–water quality thresholds in South Australian streams indicate a need for more stringent water quality guidelines - CSIRO PUBLISHING | Marine and Freshwater Research, accessed May 15, 2025,

Diatom–water quality thresholds in South Australian streams indicate a need for more stringent water quality guidelines - CSIRO PUBLISHING | Marine and Freshwater Research, accessed May 15, 2025, Journal

Diatom–water quality thresholds in South Australian streams indicate a need for more stringent water quality guidelines - CSIRO PUBLISHING | Marine and Freshwater Research

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Salinity - Murray�darling Basin Authority Journal

Salinity - Murray–Darling Basin Authority

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

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

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

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Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

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

Contextual Support GreyLiterature

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

View Source

Murray-Darling Basin - Monthly Water Update - AWRA - Bureau of Meteorology

Contextual Support Journal

Murray-Darling Basin - Monthly Water Update - AWRA - Bureau of Meteorology

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Salinity - Murray–Darling Basin Authority, accessed August 11, 2025,

Contextual Support Government

Salinity | Murray–Darling Basin Authority

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Context

Region Australia
Biome Temperate Grassy Woodlands & Plains
Land Use Aquaculture
Assessment Conservation Target
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 3 Jun 2026

Notes

The optimal range for high ecological health is approximately 50 to less than 280 µS/cm. No lower critical threshold is identified. EC levels above 280 µS/cm indicate increasing ecological stress.

Related Benchmarks

Other benchmarks in the AUS-TGP-AQU-WEC family.