Water Electrical Conductivity (EC)

AUS-AMR-FOR-WEC General Moderate confidence

Benchmark Value

No specific value — see range

Range: 30 to 350 µS/cm

Optimal Range: 30 to 350

Direction: Higher is desirable ↑

Form: OptimalRange

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

Contributing Benchmarks

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

Evidence & Context

The optimal range for maintaining high ecological health, supporting sensitive native biota, and aligning with best-practice management goals is considered to be the benchmark itself: 30 – 350 µS/cm.

Metric Definition:

Water Electrical Conductivity (EC)

Benchmark Definition:

This benchmark represents the optimal range of water electrical conductivity (EC) in Production Forestry areas of the Australian Arid Mountain Ranges, based on proxy values from upland river systems. It aims to maintain high ecological health and support sensitive native biota by keeping water quality within natural baseline conditions.

Justification:

A quantitative benchmark representing the best available condition for this specific context (Production Forestry in Australian Arid Mountain Ranges) is not available in published literature or national datasets. Therefore, a benchmark has been synthesized using the most relevant, scientifically defensible proxy: the default trigger values from the ANZECC (2000) guidelines for the protection of "Upland rivers" in south-east Australia. This proxy is justified because: 1. The hydro-ecology of Arid Mountain Ranges concentrates the highest quality, freshest water in the upper, headwater catchments, which are analogous to the "upland river" ecosystem type. 2. Best-practice sustainable forestry, as specified, aims to maintain ecological processes and avoid the large-scale hydrological changes that cause secondary salinisation. The goal is to keep water quality within the natural baseline of a healthy, forested catchment, making reference ecosystem values a valid proxy. Confidence is Moderate; it is not High due to the use of a proxy rather than direct field data from the target biome/land-use intersection. It is not Low because the proxy is derived from an authoritative national framework (ANZECC) and is supported by qualitative field observations of ecosystem health in analogous arid ranges.

Sources (3)

Preview of ANZEC Guidelines - Risk Assessment for Contaminated Sites in New Zealand, accessed July 18, 2025,

ANZEC Guidelines - Risk Assessment for Contaminated Sites in New Zealand, accessed July 18, 2025, Government

Salinity - Murray–Darling Basin Authority, accessed July 31, 2025,

View Source

ANZECC & ARMCANZ (2000) guidelines - Water Quality Australia, accessed August 12, 2025 Government

ANZECC & ARMCANZ (2000) guidelines - Water Quality Australia

View Source

Preview of SA Arid Lands Landscape Regional Summary 2022 Aquatic ..., accessed July 30, 2025,

SA Arid Lands Landscape Regional Summary 2022 Aquatic ..., accessed July 30, 2025, Government

(PDF) Effects of increasing salinity on freshwater ecosystems in ..., accessed July 31, 2025,

View Source

Supporting Sources (8)

Additional references from the underlying research that informed this benchmark.

Preview of An Examination of Stream Water Quality Data from Monitoring of Forest Harvesting in the Eastern Highlands of Victoria - MDPI, accessed August 1, 2025,

An Examination of Stream Water Quality Data from Monitoring of Forest Harvesting in the Eastern Highlands of Victoria - MDPI, accessed August 1, 2025,

Contextual Support Journal

An Examination of Stream Water Quality Data from Monitoring of Forest Harvesting in the Eastern Highlands of Victoria

View Source

ANZEC Guidelines - Risk Assessment for Contaminated Sites in New Zealand, accessed July 31, 2025,

Contextual Support Government

Salinity (water) - WetlandInfo, accessed July 31, 2025,

View Source

Australia's State of the Forests Report 2018 - DAFF

Direct Evidence Journal

ACTIVE MANAGEMENT AND RESEARCH FOR THE ...

View Source

Salinity - Murray–Darling Basin Authority, accessed August 11, 2025,

Contextual Support Government

Basin Plan water quality targets; Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZG 2018/ANZECC 2000); Australia State of the Environment 2021: Inland water

View Source

TERN - Australia's Terrestrial Ecosystem Research Network, accessed July 30, 2025,

Contextual Support GreyLiterature

The Great Western Woodlands TERN SuperSite: ecosystem monitoring infrastructure and key science learnings, accessed May 19, 2025

View Source

The effects of forest management on water quality - SLU, accessed July 20, 2025

Contextual Support Journal

SA Arid Lands Landscape Regional Summary 2022 Aquatic Ecosystem Condition Report, accessed July 31, 2025,

View Source

The effects of forest management on water quality - SLU, accessed July 31, 2025,

Contextual Support GreyLiterature

(PDF) Rainforest timber plantations and the restoration of plant ...

View Source

tuvalu-data.sprep.org, accessed May 11, 2025,

Contextual Support Journal

Palaeovalley Groundwater Resources in Arid and Semi-Arid Australia - Geoscience Australia, accessed July 31, 2025,

View Source

Context

Region Australia
Biome Arid Mountain Ranges & Uplands
Land Use Production Forestry
Assessment Pristine Reference
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 24 Mar 2026

Notes

The concept of a critically low EC level is not supported by scientific literature for these freshwater ecosystems. Low EC signifies low concentrations of dissolved salts, which is characteristic of high-quality fresh water. Unlike marine or estuarine systems, the primary threat to freshwater ecosystems is consistently an increase in salinity, not a decrease. Therefore, no lower detrimental threshold is defined. The literature does not support a "more is better" model for EC; rather, it clearly indicates that increasing EC above the natural baseline is detrimental. There is a continuum of degradation with defined thresholds: Management Concern Threshold (~800 µS/cm) marks a departure from "low salinity" conditions as defined by the Murray-Darling Basin Authority. This level can begin to impact sensitive irrigated crops and exceeds the World Health Organisation's recommended limit for drinking water aesthetics. It represents a system under significant stress and should trigger a management investigation. Primary Ecological Damage Threshold (~1500 µS/cm) is a critical ecological tipping point. A comprehensive review of Australian data concluded that "aquatic biota will be adversely affected as salinity exceeds 1000 mg L−1 (1500 EC)". Above this level, widespread impacts are expected, including reduced growth and reproduction in most freshwater plants, significant loss of sensitive invertebrate taxa, and reduced survival of the eggs and juveniles of some native fish species. Exceeding 1500 µS/cm signifies a shift from a stressed to a degraded ecosystem state, with fundamental changes in species composition and ecological function.