Rip currents are strong surface currents. Upstream refers to the direction opposite of longshore drift. The direction roughly points towards the same general direction as sand transport and incoming waves. Longshore drift is parallel to the shoreline in one direction. Longshore drift is the net flow of water along the shore that results from waves that refract along the shoreline. Water flow along shorelines is described with the following terms. The change in direction of a wave once it hits the shoreline transports sand grains along the shore. Waves that hit the shoreline are then refracted perpendicular to the shoreline. Waves typically approach shorelines at an angle rather than head on. The sand that makes up beaches is transported along the shoreline by the following wave action. Wave action creates and changes beaches drastically. Conversely, because submergent coasts are the result of subsidence or sea level rise, we expect depositional processes (such as large accumulations of sediment) and inundation by water of rivers entering the sea to play important roles in shaping them. As a result, we might see steep cliffs and previously submerged features now above water level.
Submergent coasts appear to be sinking and are created when the land is subsiding or sea level is rising.Įmergent coasts are formed by tectonic uplift or sea level fall therefore, erosion processes play an important role in shaping them. Geologists have created two general categories for coastal zones that describe how they change relative to sea level: whether the coast appears to be emerging from underneath the water or submerging below it.Įmergent coasts appear to be moving up out of the water and develop as a result of tectonic uplift or sea level fall. In order to understand the complexities of coastlines, a classification system using sea level as a reference is used.
The erosion susceptibility of the bedrockįrequency of intense storms, and prevailing wind directionĬonfiguration of the coastline and nearshore areas The deformation rate or absence of tectonic activity Proximity to rivers that deliver a great amount of sediment Climatic and geologic factors that influence coasts include: Regional climate and local geology greatly affect the appearance and behavior of coasts.
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