Shoreline Waves and Currents (Part 1)
Beaches and shorelines are shaped by the erosion, transportation, and deposition activities of waves, tides, and currents along the coast. These areas contain important ecosystems called estuaries. Shorelines and beaches are affected by changing sea level.
Erosion
• Erosion occurs when waves pick up and move sediment. Storm waves often erode beaches and dunes.
First Landing State Park, Virginia Beach (Photograph by Robert Whisonant)
Waves can erode beaches. At First Landing State Park, shown above, dunes protect against shoreline erosion. Storm waves can wash through and over dunes.
Currents
• Currents, such as a longshore current, also move sediment along the coast.
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Effects of the longshore current as seen as sediment trapped by groins in the Willoughby Spit area of Norfolk, VA. The groins are the pier-like walls built along the beach. The longshore current is moving east to west causing sand to deposit on the east (right) side of the groins. (Data by Google)
The longshore current transports sediment along the coastline. Structures called groins, shown here, are sometimes built to trap sediment carried by the longshore current.