Water Electrical Conductivity (EC)

AUS-TSW-AQU-WEC General Moderate confidence

Benchmark Value

1500 µS/cm

Thresholds: Lower: 1500, Upper: —

Direction: Higher is desirable ↑

Form: LowerThreshold

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 18 benchmarks together — the OptimalRange form drives the primary score, while 17 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

A proposed lower critical threshold is therefore set at < 1,500 µS/cm.

Metric Definition:

Water Electrical Conductivity (EC)

Benchmark Definition:

The lower critical threshold below which water is functionally fresh and unsuitable for efficient osmoregulation of target species.

Justification:

Below this level, water lacks sufficient ionic content and buffering capacity, increasing physiological stress and susceptibility to contaminants.

Sources (1)

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, Government

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

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

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.

View Source

Characterising the relationship between water quality and water quantity, accessed August 5, 2025

Direct Evidence Journal

Report Card 2022-23 - EPA Victoria

View Source

Salinity | Land and soil - Environment and Heritage - NSW Government, accessed August 11, 2025

Direct Evidence Government

Australia state of the environment 2021: land, accessed July 28, 2025

View Source

Context

Region Australia
Biome Temperate Semi-Arid Shrublands & Open Woodlands
Land Use Aquaculture
Assessment Pristine Reference
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 20 Mar 2026

Notes

This threshold aligns with the point where adverse biological effects begin in freshwater ecosystems, marking a transition between aquatic environments.

Related Benchmarks

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