Shorelines

Shorelines Shorelines are shaped by waves, tides and currents by erosion and deposition

Long shore Current A longshore current is when a water approaches the shore at an angle Longshore currents causes and is wash up and down the beach in a zigzag pattern

Spits Spit-Outward extension of sand that develops as a result of longshore currents moving sand down a beach

Spit, Baymouth Bar

Barrier Islands – Islands that run parallel to the mainland 1) Longshore currents create a spit then a hurricane breaks the spit off from the mainland 2) Wave energy drops sand out in the ocean and forms a sand bar. Continued deposition causes the sandbar to rise out of the ocean and form a Barrier Island 3) Rising sea level causes part of the mainland to break off and form an Island

Jetties Jetties-Walls of concrete or boulders that extend into the ocean on either side of the entrance to a harbor Designed to keep sand from blocking the channel Ends up causing sand to build up on one side and erode on the other side

Groins Groins-Similar structures to jetties that trap sand on one side and not the other Designed to keep sand from moving down the beach Ends up trapping sand on one side and causing erosion on the other side

Seawall Seawall-An embankment built along the shore to protect the land from powerful waves Erosion increases because waves are bounced back with most of their original energy. Will protect mainland but will destroy beach

Beach nourishment Beach nourishment is when an eroded beach is replaced with sand Sand is dumped where the beach has been eroded Beach nourishment does solve the problem however it is very expensive As well beach erosion is still occurring so it must continually be done

Changes in Sea Level Sea level has fluctuated over time Rises in sea level after often attributed to melting glaciers (fossil fuel burning) Tectonic forces can cause a change in sea level