How Do Waves Affect the Shoreline?

Waves affect the shoreline by constantly moving rock particles. Waves push new particles onto the shore, pull away existing sand, and erode rock formations on the shoreline.

Shorelines are affected by oscillation waves, which produce beach drifts and transport sand along the shore. Oscillation waves are formed by frictional drags of wind over the ocean's surface. The water particles in the waves move in near-circular orbits. The diameter of these orbits does not change, leading to a slowing down of the waves' speed as they approach shore. This churns up sand from the seafloor, eventually forcing waves to break.

When waves break at an angle, they become translation waves. Translation waves are made of water particles moving forward. These waves hit the beach diagonally, and the subsequent backwash forms long shore currents just off the beach. These currents move parallel to the shoreline, and produce beach drifts.

Oscillation and translation waves both cause erosion and transport materials from the shoreline. The materials, collected by erosion, are transported in groups known as dissolved loads, suspended loads and bed loads. Dissolved loads contain solids that move along with the water. Suspended loads consist of clay and silt, which are washed to deeper water. Bed loads consist of sand and gravel, and are transported along the shore in beach drift.