Water Electrical Conductivity (EC)

AUS-TMS-URB-WEC General High confidence

Benchmark Value

200 µS/cm

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

Within this key document, a specific water quality objective is set for freshwater rivers and streams in the Darwin Harbour catchment. The objective states that for the protection of aquatic ecosystems, Electrical Conductivity should be maintained at less than 200 µS/cm.

Metric Definition:

Water Electrical Conductivity (EC) in freshwater rivers and streams

Benchmark Definition:

Water Electrical Conductivity (EC) as a measure of dissolved ionic substances in freshwater streams in the tropical monsoonal savanna biome under urban and developed land use.

Justification:

This value was calculated based on the 80th percentile of data from local, minimally-disturbed reference sites, aligning with the national best-practice framework outlined in the Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC/ANZG). It represents the upper limit of natural variability in healthy streams in this biome and serves as the performance target that any sustainable urban development should be designed to meet.

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 Journal

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 Pristine Reference
Evidence Type TargetCondition

Lifecycle

Status Active
Version 1
Effective From 19 Mar 2026

Notes

No upper detrimental threshold — higher values are always better up to natural saturation. It is the official water quality objective designed to be protective of high-value aquatic ecosystems in the Darwin Harbour region, a key urban center within the tropical savanna biome.

Related Benchmarks

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