Water Electrical Conductivity (EC)

AUS-TSW-CON-WEC General Moderate confidence

Benchmark Value

1500 µS/cm
Range: 800 to 1500 µS/cm
Thresholds: Lower: —, Upper: 2200
Optimal Range: 800 to 1500
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 7 benchmarks together — the OptimalRange form drives the primary score, while 6 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

The annual median electrical conductivity should remain below 1,500 µS/cm.

Metric Definition:

Water Electrical Conductivity (EC) as a measure of total dissolved ionic salts in water affecting ecological health.

Benchmark Definition:

This benchmark defines the maximum acceptable annual median electrical conductivity for surface waters in temperate semi-arid shrublands and open woodlands under conservation management in Australia to maintain ecological health.

Justification:

The value of <1,500 µS/cm is set at the upper threshold for maintaining the integrity of non-adapted freshwater biota, based on a synthesis of ecotoxicological studies. It is significantly below the EC measured in a known degraded stream (~9,900 µS/cm) and provides a more specific, ecologically-based target than the general ANZECC guideline for lowland rivers (upper bound of 2,200 µS/cm).

Sources (5)

Preview of Accessory Publication Relative salinity tolerance of macroinvertebrates from the Barwon River, Victoria, Australia
Accessory Publication Relative salinity tolerance of macroinvertebrates from the Barwon River, Victoria, Australia Journal

Pine Creek, near Dutton 2010 Aquatic Ecosystem Condition Report - EPA SA

View Source
Preview of Coolgardie woodlands - Wikipedia, accessed July 13, 2025
Coolgardie woodlands - Wikipedia, accessed July 13, 2025 GreyLiterature

Salinity - Murray–Darling Basin Authority

View Source
Preview of Effects of increasing salinity on freshwater ecosystems in Australia - CSIRO Publishing
Effects of increasing salinity on freshwater ecosystems in Australia - CSIRO Publishing Journal

Effects of increasing salinity on freshwater ecosystems in Australia - CSIRO Publishing

View Source
Preview of Technical information supporting the 2023 River Murray: salinity environmental trend and condition report cards.
Technical information supporting the 2023 River Murray: salinity environmental trend and condition report cards. Journal

Technical information supporting the 2023 River Murray: salinity environmental trend and condition report cards.

View Source
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)

View Source

Context

  • Region Australia
  • Biome Temperate Semi-Arid Shrublands & Open Woodlands
  • Land Use Conservation / Protected Natural Areas
  • Assessment Conservation Target
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 25 Mar 2026

Notes

The benchmark acknowledges natural fluctuations with an optimal functional range between the MDBA low-salinity target (<800 µS/cm) during flow events and the upper ANZECC guideline (<2,200 µS/cm) during concentration phases. Persistent median EC values above 1,500 µS/cm indicate degradation.