Beach erosion is a ubiquitous natural phenomenon worldwide. Submerged berms are widely used in beach nourishment project due to their eco-friendly nature and easy access of material. A series of flume tests were carried out under the guidance of Lightweight Model theory to study the evolution of a submerged berm under the effects of waves. Physical parameters were set up based on a low-energy beach nourishment project with submerged berms. The results indicate that the cross-shore profiles of submerged berms have a significant effect causing asymmetrical shape changes, which is confirmed in field data as well. The crest elevation changes and the duration of profile stabilization are also discussed.
Beach erosion is a ubiquitous natural phenomenon worldwide. According to Xia (2009), most of the sandy beaches in China are experiencing severe erosion processes, retreating at a rate of averaging 1.0∼2.0 m each year. Among the various approaches to protect and broaden eroded beaches, beach nourishment is one of the most effective and eco-friendly methods (Dean, 2005). Submerged berms are becoming an increasing used method for beach nourishment due to its eco-friendly nature and easy access of material.
A submerged berm, also known as shoreface nourishment or submerged mound, is defined as dredged material placement in the nearshore area acting as an underwater sandbar (Dean and Dalrymple, 2002). The performance of a submerged berm can include damping of waves in order to shelter of the landward beach and reduce offshore migration, nourishing of the beach directly by means of increasing onshore migration, or a combination of both (Grasso et al., 2011). The evolution of a natural sandbar is a classic issue of coastal engineering on which many studies have been conducted. However, research studies on the evolution of submerged berms are relatively fewer and are typically carried out by means of case studies based on field surveys, especially on low energy sandy beaches.