Beachside Masterplan – Flood Insight

By Nathan Green, Associate and Flood Lead

Situated fronting Dundowran Beach in Hervey Bay, the Beachside development is a 250-hectare masterplanned community set to contain over 1,500 residential lots. This coastline development is set to be delivered over 50 stages. As part of consultancy services provided for our client QM Properties, a masterplan flood study was undertaken to establish the developable footprint on-site, confirm that all proposed lots achieve sufficient flood immunity and ensure that flooding conditions are not worsened on surrounding properties.

The design challenges involved dealing with limited grade across the site, loss of flood storage from tidal inundation and working around some legacy design issues of road and stormwater infrastructure in the nearby area.

Through extensive hydraulic modelling, we were able to design a solution that involved earthworks to provide additional flood storage in the area while respecting the existing natural watercourses through the site. This resulted in a solution that gained 80 hectares of developable area (30% of the total site area) that was previously within the 1% AEP event flood plain, while not impacting on flooding characteristics external to the site.

Being located close to the coastline, it was also important to consider how the impacts of climate change could affect the flooding characteristics on site. The design considers the impacts of sea level rise and increase rainfall intensity to ensure that future lot owners can rest assured that their land will be protected from flooding now and into the future.