Council — Ballina Shire Council
Development — Commerical, Alterations and Additions
Services — Stormwater management plan · Water Sensitive Urban Design
Year — 2025
Outcome — Approved
Background
The client wanted to extend an existing hotel in Alstonville and add new parking areas for the upgraded venue.
The problem
The new carpark triggered Ballina Shire Council’s water quality controls. Runoff had to meet Council’s reduction targets for gross pollutants, suspended solids, phosphorus and nitrogen. Tight headroom, and the existing buildings left no single area large enough for a conventional device to treat the whole site. One device would have meant missing Council’s targets or making costly changes to the building.
Our solution
We split the site into sub-catchments and matched each one to a treatment measure that suited its footprint and depth.
The new parking area drains to a bioretention system, the primary treatment measure. Unlike proprietary filter cartridges, which need regular replacement, bioretention uses plants and filter media to remove pollutants. Maintenance is little more than routine landscaping, so the owner’s ongoing costs are much lower.
Where headroom and the existing buildings stopped areas from draining to the bioretention system, we used two compact proprietary devices sized to fit without changes to footings.
MUSIC modelling showed the treatment train met Council targets. We added water quality treatement measures and documented everything in our Stormwater Management Plans. The result was a compliant, low-maintenance design with minimal impact on the existing hotel.
Was it approved? yes.
Bio-retention Detail