Describe the refraction process that occurs when waves reach an irregular coastline. Why is the coastline straightened?

Coastal geography is the study of the constantly changing region where land meets the sea. The coastline is a unique environment characterized by a variety of landforms like beaches, cliffs, headlands, and bays. These landforms are shaped by the dynamic interaction between the terrestrial biotic and abiotic processes and the aquatic influences of the oceans and seas.

Wave refraction plays a critical role in coastal geography as it directly impacts the morphology of the coastline. When ocean waves approach the coast at an angle, the part of the wave in shallower water moves slower than the part still in deeper water, due to friction with the seafloor. This difference in velocity causes the waves to bend, or refract, toward the protruding parts of the coastline creating a more uniform shoreline over time. Understanding this process is vital for predicting changes in coastal landforms and for developing coastal management strategies.

Physical geography processes involve the natural mechanisms that shape the earth's landscapes. Wave refraction is a classic example of such a process in the coastal environment. It highlights how energy (from waves) interacts with the physical properties of the earth's surface (varying bathymetry).

Other processes include weathering, erosion, sedimentation, and tectonic activity, which all interplay to transform the physical scenery of our planet. The depth of the water and the contours of the sea floor direct the energy distribution of incoming waves, causing them to refract and redistribute sediments along the coast. Over time, these processes can lead to significant geographical features and landform changes, as well as influence human coastal activities.

Coastline erosion is a natural consequence of wave action where land is worn away and carried into the sea. The power of erosion can be seen in the sculpting of cliffs, the formation of sea caves, and the overall shaping of the coastal landscape.

The irregularity of a coastline impacts the energy dissipation of waves where headlands, which protrude into the sea, experience higher energy impacts and undergo greater erosion than recessed bays. As the waves continue to refract and erode protruding areas more aggressively, they transport the eroded materials into the bays, filling them up and helping to level out the coastline. Coastal erosion is not just a natural process but also a matter of significant concern for coastal settlements and ecosystems, as it can lead to the loss of habitat, property, and infrastructure.