Beach Protection Notes

Causes of Sand Depletion 1. Waves 2. Wind 3. Storms Hurricanes & Nor’easters cause the most erosion.

When storm waves carry sand off of the beach and deposit it in an offshore sandbar, it results in a very narrow beach. When gentle waves carry offshore sand back to the beach, it results in a wide, broad beach. Winter Beach Summer Beach

Winter Beach Summer Beach

Average rate is 25-30cm per century, if current studies are credible. Rising Sea Level Average rate is 25-30cm per century, if current studies are credible. Global Warming The melting of glaciers & ice sheets would causes a rise in sea level, should a sustained global warming occur. Longshore Current A current that flows parallel to the coast, which transports sand down a beach in the same direction as the current.

Beach Erosion Solutions Groin or Jetty Description A structure protruding into the ocean perpendicular to the coast. Pros Stops longshore drift from carrying sand away from a localized area of beach. Cons Causes severe depletion of sand on the downside of the structure.

Groin or Jetty

Jetty at Rudy Inlet - Virginia Beach, VA

Description An upright wall that runs parallel along the coast. Seawall Description An upright wall that runs parallel along the coast.   Pros Intended to protect uplands from wave erosion. Cons Causes severe erosion of the beach in front of it.

Seawall

Description An offshore barrier. Japan has many. Breakwater Description An offshore barrier. Japan has many. Pros Protects the shore from the full impact of waves. Cons Not very pleasant to look at.

Breakwaters

Breakwaters at Willoughby Spit - Norfolk, VA

Description A breakwater that does not break Underwater Breakwater Description A breakwater that does not break the surface & acts as a coral reef.   Pros Protects the shore from wave energy. Cons Presents hidden obstacles to surfers & boaters.

Underwater Breakwater

Description Pumping offshore sand back to the beach. Beach Nourishment Description Pumping offshore sand back to the beach.   Pros Presents no problems to the beach. Cons Very expensive & needs to be done about every 5 years. The U.S. spends $1.25 billion/year.

Beach Nourishment