Flowpath Engineering Portal
Shallow Soakage Design — NZ Stormwater Disposal Calculator
Design soakage systems for stormwater disposal on NZ sites. Calculate soakhole dimensions, infiltration rates, and storage volumes to NZ Building Code E1 and council standards.
What this tool does
NZ Building Code E1 Compliance
Design soakage systems in accordance with NZ Building Code clause E1 for surface water disposal on residential and commercial sites.
Infiltration Rate Analysis
Input field-measured soakage test results to determine design infiltration rates and factor of safety for long-term performance.
Soakhole Dimensioning
Calculate required soakhole depth, diameter, and storage volume based on catchment area, rainfall intensity, and soil permeability.
Multiple Storm Return Periods
Verify soakage capacity across different storm durations and return periods to ensure adequate performance under design conditions.
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Open Soakage Design CalculatorPart of the Flowpath Engineering suite of free civil engineering tools for New Zealand.