Concept design of a multipurpose submerged control structure for Palm Beach, Gold Coast Australia

Palm Beach has been identified as being one of the Gold Coast beaches currently under the greatest risk with regards to loss and damage to beach front properties due to beach erosion during significant wave events. Previous studies conclude that despite no prevailing erosional trend has been recorded; the beachfront developments are located too close to the beach inside the natural coastal buffer zone. The current beach width does not provide sufficient protection at many locations along Palm Beach. The land value alone of vulnerable beach front properties has been estimated to the excess of $406 million outlining the requirement for the implementation of an effective coastal protection strategy. The City of Gold Coast commissioned DHI to carry out a concept design study for Palm Beach using state-of-the-art numerical modelling of to quantify changes to wave transformation, sediment transport and shoreline response. The study involved the assessment of three (3) potential shoreline protection strategies, which was completed in autumn 2014. Of the three strategies a solution involving 750,000 m3 capital nourishment, seawall upgrades and a submerged control structure (SCS) was identified as the preferred solution. This presentation will provide an overview of the design considerations that have gone into the concept design of the submerged control structure. The design will incorporate lessons learned from past similar projects and will present a selection of state of the art methods for assessing the performance of the SCS with regards to coastal response, surfing amenity and beach safety.