Water Electrical Conductivity (EC)

AUS-TMS-URB-WEC General Moderate confidence

Benchmark Value

20 µS/cm

Direction: Lower is desirable ↓

Form: MinimumOnly

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 10 benchmarks together — the OptimalRange form drives the primary score, while 9 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

A value of 20 µS/cm is proposed as a plausible lower critical threshold.

Metric Definition:

Lower critical threshold of Electrical Conductivity below which essential ion availability may be compromised.

Benchmark Definition:

This benchmark represents the lower critical threshold of Electrical Conductivity below which aquatic ecosystems may experience physiological stress from over-dilution.

Justification:

Based on ANZECC 2000 default trigger value range and ecological understanding of ion requirements for aquatic life.

Sources (1)

Water Quality Objectives for the Darwin Harbour Region - Background Document - Department of Lands, Planning and Environment, accessed July 16, 2025, Journal

Water Quality Objectives for the Darwin Harbour Region - Background Document - Department of Lands, Planning and Environment

View Source

Supporting Sources (2)

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,

Direct Evidence GreyLiterature

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

View Source

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

Direct Evidence Government

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

View Source

Context

Region Australia
Biome Tropical Monsoonal Savannas
Land Use Urban & Developed Use
Assessment Not Stated
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 5 Jun 2026

Notes

Values consistently below this level may indicate critically low ionic concentration affecting biotic health. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

Other benchmarks in the AUS-TMS-URB-WEC family.