Water Nitrate — Benchmark Detail

Benchmark Value

1 mg/L

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 5 benchmarks together — the OptimalRange form drives the primary score, while 4 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MaximumOnly Guard MaximumOnly Guard MaximumOnly Guard Point Guard

Evidence & Context

Upper Detrimental Threshold: 1.0 mg/L (as N). Concentrations consistently exceeding this value pose a risk of toxicity to sensitive stygofauna and indicate a deviation from the best available natural condition.

Metric Definition:

Water nitrate concentration (as nitrogen) in groundwater relevant to conservation areas in Arid Karstic Woodlands & Shrublands.

Benchmark Definition:

This benchmark defines the upper limit of nitrate concentration in groundwater to protect sensitive stygofauna in conservation areas of Arid Karstic Woodlands & Shrublands. Concentrations above 1.0 mg/L indicate potential toxicity and deviation from natural conditions.

Justification:

Derived from proxy data from a comparable karstic GDE and aligned with the ANZG 99% species protection guideline value.

Sources (2)

"Water quality in caves of the Yanchep National Park and on adjacent private property" (Jasinska & Knott, 2007) Government

"Water quality in caves of the Yanchep National Park and on adjacent private property" (Jasinska & Knott, 2007)

View Source

Preview of WESTERN AUSTRALIAN WATER QUALITY GUIDELINES FOR FRESH AND MARINE WATERS - DBCA Library, accessed July 16, 2025,

WESTERN AUSTRALIAN WATER QUALITY GUIDELINES FOR FRESH AND MARINE WATERS - DBCA Library, accessed July 16, 2025, Journal

WESTERN AUSTRALIAN WATER QUALITY ... - DBCA Library, accessed July 25, 2025,

View Source

Context

Region Australia
Biome Arid Karstic Woodlands & Shrublands
Land Use Conservation / Protected Natural Areas
Assessment Conservation Target
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 2 Jun 2026

Notes

The benchmark is based on a weight-of-evidence approach due to lack of direct data. The lower critical threshold is not applicable as the ecosystem is naturally oligotrophic and adapted to nutrient scarcity. The optimal range is from detection limit to 1.0 mg/L (as N).

Related Benchmarks

Other benchmarks in the AUS-AKW-CON-WNI family.