Beaches are coastal landforms that are constantly changing. They are the result of wave action by which waves move sand or other loose sediments and compact and settle in still water. Beach materials are the products of weathering and erosion of rocks offshore, coral reefs and of headlands. Sediments may also be river-borne through the process of coastal erosion. Once compacted, the accumulated sediments are more resistant to erosion. Vegetation establishes shortly after, and their roots will also help resist erosion by slowing the fluid flow at the surface layer. Figure 1. Beach Morphology. The basic morphology of a beach is shown in Figure 1. A berm is a long narrow wedge of sand with its slope towards the water. The berm crest is the highest part of the berm where the sediment builds up and the waves do not pass. The tide …show more content…
There is high wave frequency and weak swash, which brings ashore a minute amount of material. Destructive waves tend to be tall waves, meaning they break with great force upon the beach leading to a strong backwash that removes beach material. Ultimately, destructive waves create steep narrow beaches. Constructive waves on the other hand have long periods between their wave crests and low energy. Their swash is much stronger than their backwash, building up the beach with deposited sediments. Constructive waves are long waves and roll on to the beach rather than crashing. Ultimately, constructive waves create wide, gently sloping beaches (Figure 2).
The beach profile undergoes seasonal changes due to change in wave energy. In temperate areas, summer beach profiles are characterized by: calm seas, long periods between breaking wave crests, and increased deposition thus high beach profiles. On the other hand, the winter months have amplified wave energy and increased sediment suspension thus lowering the beach profiles. In tropical areas, this phenomenon is in