A coastal restoration plan developed by eCoast included a range of nature based solutions designed to restore the beach amenity. Components of the plan included beach nourishment and reprofiling, seagrass restoration, beach stabilisation through replanting with native vegetation and establishment of a fringing reef system in front of the heavily eroded section of beach.

Fringing reefs are an example of hard barriers, built over thousands of years by corals which provide critical ecosystem services both as habitat and as wave attenuators.  A combination of building engineered reefs followed by natural or assisted recruitment enables large scale reef geomorphology and wave attenuation functionality to be established immediately, rather than over thousands of years.  Subcon’s design featured one continuous reef structure of 350 m long comprising 1000 individual units along with the inshore patch reefs. The features of the reef include a perforated flat top shape providing a wider shelf area to enhance wave breaking and energy dissipation. Submerged reef designs such as this are historically regarded by coastal designers as ineffective during peak surges and tides.  Subcon and UWA considered the time varied performance of the submerged reef considering local tidal cycles and forecast storm surge.  Wave flume testing confirmed time averaged transmission with tidal variance enabling optimisation of future designs to target specific wave heights and periods.  Reef geometry is tailored to avoid visual impacts, target specific wave periods and attenuate wave energy in the peak conditions, whilst maintaining passage of average daily wind driven waves and littoral processes.

The reef was designed to mimic the ecosystem services provided by naturally occurring reefs. While wave attenuation was the primary ecosystem service driving the design, the design features also provided habitat and hard substrate to support recruitment of reef builders including herbivorous fishes, corals and other marine species. Meanwhile, the reef permitted the protection of visual amenities. It was designed partially submerged – only being exposed for short durations during peak low tides, so the visual impact remains negligible.