The process of wave refraction
Wave refraction refers to the process by which waves bend or change direction as they approach a shoreline owing to the shallowing of water. Because of refraction the wave energy becomes concentrated along some parts of the shoreline and is greatly reduced in other parts.
It may be pointed out that in deep water the wave crests are parallel, but in case the depth of water decreases, the wave velocity is diminished.
If there is an irregular coastline with bays and headlands, the shallowing of water and, therefore, slowing of waves will take place initially in front of the headlands, while in deeper water in front of the bays the decrease in the wave motion occurs much later.
Thus, the wave front becomes curved or refracted and approaches the shoreline from a different direction than the initial line of advance, thereby concentrating energy on the headlands. Thus, naturally the wave energy is less toward bays.
It is thus clear that wave erosion is more intensive at the headlands. The debris produced by wave erosion at headlands is carried towards areas of less energy and deposited in the bays between headlands.
Thus, the headlands are pushed back and bays and indentations are filled in thus, reducing the irregularity of the shoreline.
