A current is a movement of water. Currents can occur in oceans, seas, and rivers. In coastal waters, tides cause the greatest daily changes in water currents.
Coastal currents are intricately tied to winds, waves, and land formations. Winds that blow along the shoreline—longshore winds—affect waves and, therefore, currents.
The friction between the sea floor and water slows water movements in the direction of the wind/wave travel. Water over land is not slowed so much by friction, but is slowed by gravity.
Landmasses push water in their direction, causing it to pile up. This process is called “pushing” because of the action of the wind/wave transmitted by the bed or bottom or capillary effect upon the surface layers of water.
When waves break, the water is thrown with great force onto the shore, and simultaneously, there is a great churning of sediments on the sea bottom.
Constant impact of breaking waves drastically affects the coasts. Storm waves and tsunami waves can cause far-reaching changes in a short period of time than normal breaking waves. As wave environment changes, the intensity of the force of breaking waves changes.
