Council — Ku-ring-gai Council
Development — Residential, Alterations & Additions
Services — Stormwater management plan · On-Site Detention (OSD) · Hydrology Assessment · Flood Risk Assessment
Year — 2025
Outcome — Approved
Background
The owner planned an extension to the rear of the existing house.
The problem
Two issues stood in the way. First, council's stormwater controls limit the maximum built-upon area for the site, which put a ceiling on how big the extension could be. Second, the site carried flood risk, but the client didn't want to commit to flood modelling because of the cost. We needed a flood risk management plan that council would support without a flood model.
Our solution
Stormwater - Getting the most out of the built-upon area (BUA) meant knowing council's stormwater policy in detail. With that, we worked backwards to tell the architect the maximum area the design could reach before they started. We then pushed the BUA limit further by using a charged line system.
Flood - We worked closely with the architect to shape the design around a flood risk management plan council could accept. Council supported the plan without a flood model, which saved the client a significant cost.
Was it approved? yes.
Maximum Built Upon Area Stormwater Calcuations
Flood Risk Overlay