Flowpath Engineering Portal
SMAF Calculation (GD01) — Auckland Stormwater Retention & Detention
Calculate stormwater management area factor volumes for Auckland Council resource consents. Covers SMAF zones 1, 2, and 3 with GD01-compliant retention and detention sizing.
What this tool does
SMAF Zone Classification
Automatically determine retention and detention requirements for SMAF zones 1, 2, and 3 across Auckland's stormwater management areas.
GD01 Compliant Volumes
Calculate water quality, retention, and extended detention volumes in accordance with Auckland Council's GD01 guideline document.
Impervious Area Analysis
Input pre-development and post-development impervious areas to determine the net increase requiring stormwater mitigation.
Export-Ready Results
Generate calculation summaries suitable for inclusion in resource consent applications and engineering reports.
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Open SMAF CalculatorPart of the Flowpath Engineering suite of free civil engineering tools for New Zealand.