Water Electrical Conductivity (EC)

AUS-ASC-CON-WEC General Moderate confidence

Benchmark Value

50 µS/cm

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 6 benchmarks together — the OptimalRange form drives the primary score, while 5 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

Chronic exposure to EC values consistently exceeding the natural background range (e.g., >50-100 µS/cm) should be considered a trigger for investigation and concern in high conservation value alpine streams.

Metric Definition:

Lower limit of electrical conductivity above which ecological concern and investigation is warranted in alpine aquatic ecosystems.

Benchmark Definition:

This benchmark indicates the electrical conductivity level above which chronic exposure in alpine streams triggers ecological concern and warrants investigation.

Justification:

Based on direct evidence from studies showing ecological impacts at EC levels exceeding natural background by significant margins.

Sources (1)

Preview of Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000), accessed May 11, 2025,

Australian and New Zealand Guidelines for Fresh and Marine Water Quality (2000), accessed May 11, 2025, Journal

Northern Territory Government (2020) Darwin Harbour Region Water Quality Objectives, Report Card Section 3.0.

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) - V, accessed July 22, 2025

Direct Evidence Journal

1.5.2.1 Surface water - Bioregional Assessments |

View Source

Impacts of road de-icing salts on water quality and macroinvertebrates in streams of the Australian Alps (Shenton et al., 2021).

Direct Evidence

The Effects of Road De-icing Salts on Water Quality and Macroinvertebrates in Australian Alpine Streams

View Source

Review of water quality studies in the Australian Alps, accessed August 12, 2025,

Contextual Support Government

Feral horses (Equus caballus) increase suspended sediment in subalpine streams

View Source

Context

Region Australia
Biome Alpine and Subalpine Complex
Land Use Conservation / Protected Natural Areas
Assessment Pristine Reference
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 2
Effective From 3 Jun 2026

Notes

Persistent EC above this level is a significant concern for sensitive alpine aquatic biota.

Related Benchmarks

Other benchmarks in the AUS-ASC-CON-WEC family.