Catchment Presets
NPS-FM Aligned
Land Use Allocation (%)
100% Total
Native Podocarp Bush
32%
Pastoral Dairying / Livestock
58%
Urban & Impervious Runoff
10%
Mitigations & Environmental Care
Native Riparian Buffer Strip
15m
Planted mānuka, harakeke, toe-toe filtering sediment and nutrients
Predator Trapping Line Density
45%
Doc200/Goodnature traps controlling stoats, rats & possums
Rainfall Intensity
45 mm/d
Macroinvertebrate Index (MCI)
104
Fair Stream Health
Dissolved Inorganic Nitrogen
1.84 mg/L
Band D: High Toxicity
Galaxiid / Īnanga Habitat
62%
Spawning Viable
Native Bird Nesting Success
54%
Moderate Predation
Longitudinal Watershed Gradient: Headwaters to Lowland Estuary
▲ Alpine Headwaters & Native Podocarp Canopy
▼ Pastoral Grazing & Terraced Valley
► Braided Mid-reaches & Riparian Filter Margin
● Coastal Inanga Spawning Wetland
Observed stream and avian indicators based on current catchment nutrient and predation levels:
Catchment Nitrate Balance: Unattenuated pastoral dairy loading emits approximately ~42 kg N/ha/yr. Riparian margins with planted harakeke (flax), mānuka, and kōwhai filter particulate phosphorus and provide anaerobic denitrification zones in shallow groundwater.
Estimated Sediment Runoff
142 t/yr
Buffer reduces bank erosion
Stream Canopy Cover
48%
Regulates water temp <19°C
Groundwater Denitrification
34%
Wetland root organic uptake
National Policy Statement for Freshwater Management (NPS-FM 2020) Attributes:
- MCI (Macroinvertebrate Community Index): >119 = Band A (Excellent / Pristine bush); 100-119 = Band B (Good); 90-99 = Band C (Fair); <90 = Band D (National Bottom Line breach).
- Dissolved Inorganic Nitrogen (DIN): ≤1.0 mg/L = Band A; 1.0-2.4 mg/L = Band B/C; >2.4 mg/L = Toxic blooms & algal slime risk.
- Ecosystem Health: Requires integrated mana o te wai catchment planning protecting fish passage from mountains to the sea (ki uta ki tai).