Water Electrical Conductivity (EC)

AUS-TSR-URB-WEC General Moderate confidence

Benchmark Value

1500 µS/cm

Thresholds: Lower: —, Upper: 1500

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 14 benchmarks together — the OptimalRange form drives the primary score, while 13 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MaximumOnly Guard MaximumOnly Guard LowerThreshold Guard UpperThreshold Guard MaximumOnly Guard MaximumOnly Guard OptimalRange Guard UpperThreshold Guard LowerThreshold Guard OptimalRange Guard MaximumOnly Guard OptimalRange Guard UpperThreshold Guard

Evidence & Context

A comprehensive review concluded that aquatic biota are likely to be adversely affected as salinity exceeds 1000 mg/L, which is explicitly equated to an EC of approximately 1500 µS/cm.

Metric Definition:

Electrical Conductivity (EC) is a fundamental measure of water quality, quantifying the ability of water to conduct an electrical current.

Benchmark Definition:

This benchmark marks the critical electrical conductivity threshold above which significant ecological degradation occurs in naturally low-salinity freshwater systems in the Tropical & Subtropical Rainforests biome under urban land use in Australia.

Justification:

This value is widely cited as a conservative and scientifically robust threshold for significant ecological degradation in these naturally low-salinity systems.

Sources (1)

Preview of Ecology of streams in a biogeographic isolate—the Queensland Wet Tropics, Australia | Freshwater Science: Vol 34, No 2, accessed July 22, 2025,

Ecology of streams in a biogeographic isolate—the Queensland Wet Tropics, Australia | Freshwater Science: Vol 34, No 2, accessed July 22, 2025, Journal

Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC/ARMCANZ)

View Source

Supporting Sources (2)

Additional references from the underlying research that informed this benchmark.

(PDF) Water Quality Degradation of Coastal Waterways in the Wet Tropics, Australia, accessed August 2, 2025,

Direct Evidence

Requirements for graziers | Environment, land and water ..., accessed July 19, 2025,

View Source

Water-Quality-Salinity-Standards.pdf, accessed August 11, 2025,

Direct Evidence Journal

What Is The Typical Water Conductivity Range? - Atlas Scientific, accessed July 13, 2025

View Source

Context

Region Australia
Biome Tropical & Subtropical Rainforests
Land Use Urban & Developed Use
Assessment Pristine Reference
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 20 Mar 2026

Notes

Above this level, significant adverse impacts on sensitive aquatic biota are expected. ConsistencyResolver applied 2026-03-23 00:14 UTC: LowerThreshold → (check: MinAboveOptimalHigh, rationale: Clear LowerThreshold field to avoid confusion and ensure proper form auto-correction.) ConsistencyResolver applied 2026-03-23 00:14 UTC: UpperThreshold → 1500 (check: MinAboveOptimalHigh, rationale: The Notes state 'Above this level, significant adverse impacts...' indicating this is an upper threshold. Moving the value to UpperThreshold will auto-correct the form to MaximumOnly, resolving the contradiction.) [Auto-corrected BenchmarkForm: MinimumOnly → MaximumOnly]

Related Benchmarks

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