Waitaki District Council

Source Documents

These are the council documents used to build the WDC calculator. If a link is broken, the document may have moved on the council website.

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APP1 - Stormwater Tanks on Private Property - Accepted Solutions

PDF Primary Source

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WDC Stormwater Information Page

Council website - may contain updated links if documents above have moved.

Calculation Methodology

Retention

None - detention only system

Method

Table lookup. 3 rows covering 0-249m2 roof. Detention only, no retention/reuse. Dual orifice (12mm low + 25mm high).

Design Requirements

• Tank must be above ground
• Min 80% of roof runoff diverted to tank
• Max 50% impervious site coverage
• Min 20-year manufacturer warranty
• Overflow must NOT connect directly to stormwater system
• Impervious area 30m2 or less exempt from hydraulic neutrality

Submission