Conceptual Design and Physical Model Study of Core-Enhanced Dunes as Hybrid Coastal Defence Structures

Core-enhanced sand dunes are hybrid coastal defence structures that combine the storm surge protection offered by traditional hard coastal structures with the aesthetically pleasing appearance and wave energy dissipation potential of coastal sand dunes. Essentially, these are hard coastal structures covered under a sacrificial sand dune. In this study, ongoing conceptual design efforts of such structures for a potential Houston-Galveston region storm surge suppression system are presented along with results from physical model tests of three different core-enhanced dunes. These tests were carried out in a moveable-bed wave flume to determine the erosion evolution and technical feasibility of various core-enhanced dunes under irregular wave attack. Results were compared to a plain sand dune without core-enhancement. The three different cores under investigation were a clay levee, an armour stone revetment, and a T-wall. Findings showed that profile evolution of the core-enhanced dunes varied significantly based on core structure.