OT_223: Ira & Simcock (2019, Landcare), NZ WSUD stormwater device costs

Source

https://www.buildingbetter.nz/wp-content/uploads/2023/08/Ira_Simcock_2019_WSUD_Costs__Maintenance.pdf — original source (opens in a new tab; the file is not redistributed)

Context: ni · Feeds D03 (stormwater device cost, declared-blank)

Summary

NZ device-level stormwater management costs, retrieved so the model can state its stormwater exclusion accurately or, if ever wanted, put a rough costed line on it. Costs are per device or per square metre; there is no single whole-of-community scheme figure, so any estimate would be built up per device.

Key claims

- claim: "NZ WSUD DEVICE COSTS (COSTnz life-cycle model, 2017 NZD). Rain garden / bioretention maintenance $3.20-8 per m² per year; swale maintenance $4.30-6.10 per linear metre per year (2-3 m top width); a 10,000 L rain tank $4,800-6,500 installed (+5-7.5% design/consent); permeable paving $85-120 per m² (+ pavers); total device acquisition envelope roughly $0-2,500 per m² (excluding land and the piped network). No single whole-of-scheme cost exists, it is built up per device. [verified against the raw]"
  source_location: "Ira & Simcock (2019), device cost tables (COSTnz), 2017 NZD."

Model use

  • Firms the stormwater declared-blank in D03: device costs are minor at community scale and per-device, so stormwater stays an excluded/limitation item; if a costed line is ever wanted, the per-m² device rates above support a sizing-based estimate. OT_223

Notes

  • Scale caveat. Per-device / per-m² only; no whole-of-community scheme figure. Acquisition-cost point estimates live in a box-plot, so only the ~$0-2,500/m² envelope is text-verifiable.
  • Provenance. Landcare Research / Building Better Homes report PDF, authoritative, verified against the raw.

Connections

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