Flood Modelling – Coburg Precinct Framework

Rain Consulting is supporting MGS Architects on Merri-bek City Council’s “Revitalising Coburg” Precinct Framework. Our role is to undertake detailed hydrological, hydraulic, and climate-risk modelling to inform the tender submission and future master planning. The work covers flood behaviour, integrated water management (IWM) opportunities, and climate-resilience measures across mixed-use redevelopment sites in central Coburg.

Above & Beyond Strategies

The precinct is situated on several overland flow paths with depths exceeding 0.3 m in the 1% AEP plus climate change event, creating safety and floor-level constraints. Existing models use superseded climate change guidance, so rainfall intensities and potential Merri Creek breakouts must be reassessed to provide the Council with confidence in future designs.

Rain delivered the following solutions.

• Efficient review and validation of Council’s flood models and Special Building Overlays (SBOs and interrogated datasets on earlier Merri-bek projects.
• Mapped and explained key overland flow hotspots
• Update climate-change scenarios to current SSP 8.5 guidelines, including liaising with Melbourne Water if waterway re-modelling is needed.
• Prepare high-level water-balance modelling (MUSIC) to test IWM and rainwater-reuse opportunities.
• Optimise TUFLOW models and run multiple precinct-layout scenarios, delivering depth, velocity, hazard and afflux mapping.
• Facilitate virtual and in-person workshops to enable architects, the Council, and Melbourne Water to iterate on designs quickly.
• Provide concise memos, reports and GIS layers that integrate seamlessly into the broader framework documentation.
• Offset all project carbon emissions at no cost, aligning with the Council’s sustainability goals.

Rain has updated the existing and proposed flood conditions model, produced preliminary climate-risk maps, and provided the design team with clear thresholds for floor levels, access/egress, and runoff reuse. Early workshops have aligned stakeholders and de-risked data needs ahead of option testing.

Rain will propose mitigation solutions on the preferred layout and run the updated model to investigate the effectiveness of measures. In addition, Rain will prepare a flood impact assessment report.