Our Beaches Are Funky Strange shapes

Primary Coasts Shaped by terrestrial processes, earth movements Earthquakes – land rifts or sinks Glaciers – erosion, melting Volcanoes – collapse, get built up or shift Stream/river action –can erode or deposit Our coastlines are highly irregular! No distinct pattern!

Deltas Deposition of sediment at the river mouth from river run-off Fan-shaped deposits of sediment Land extends into the ocean or sea

This is the Nile River The river slows when it meets the ocean and drops sediment Result is build up of land

Estuary Estuary – drowned river mouth; ocean water fills in channels eroded by streams Bays – when ocean water comes into land areas

Drowned river mouth – ocean water flows inland at the river mouth Streams erode channels and ocean water fills them in Get a mix of fresh and salt water The Thames River Estuary in southern England

Fjord! Fjord – long deep indentations in the coast caused by erosion from glacier movement and often have steep sides

Long, deep steep sided indentations into the coast Caused by glacial erosion This is Iceland

Bay a body of salt or brackish (more salt then fresh water, less salt then sea water) water sheltered by a barrier island from the ocean, usually occurring where a river mouth is

Secondary coast Shaped by marine processes: Erosion from waves and longshore current Deposition from waves and longshore current Over time coastlines smooth out and straighten

Long shore current The flow of water along the shore created by waves breaking on an angle Longshore transport – The movement of sand due to long shore current.

Erosional Coastline

Depositional shorelines Primarily deposited by longshore drift Barrier island Spit Lagoon Beach Fig. 10.7

Barrier Island – an elongated island of sand separated from the mainland by a body of water

Barrier Island Caused by deposition of sediment by the long shore current and waves Unattached and parallel to the coast Long, narrow and low elevation. LBI NC Outer Banks

Salt marsh An area of soft wetland typically found behind barrier islands

Spit Sand is deposited by longshore currents, builds up at the end of the island or mainland

Spit Spit – long, low, narrow barrier island attached at one end to the mainland Sandy Hook, Cape Cod

Lagoon Wide shallow protected estuarine system; protected by a circular coral reef or atoll or

Protected by a barrier island or spit This is Venice, Italy

Beach the portion of the shore stretching from the berms to the sand bars, usually 30ft below the water

S Fig. 10-1

Berm A place on the beach that looks like a small cliff where the waves have eroded the beach.

Breaker Zone – where we find breakers

Surf zone The area between the outermost breaking waves and the swash zone

Litter Line The line of garbage and debris that is left by tides and waves on the beach.

Sandbar A narrow mound of sand that lays just a short distance away from the shore and runs parallel to it.

Dunes Mounds of wind deposited sand

Inlet a break in a barrier island where ocean water and bay water can mix

Jetty Jetty – A structure built to alter long shore currents and protect the entrance into a harbor. Jetties push the long shore currents away from the beach and cause serious erosion on their other sides.

Breakwater An area of rock made to protect the shoreline, often times does more harm then good

Groin A smaller jetty like structure. Found all along the NJ shore.

Washover Waves that wash over the dunes

Washover

Rip current Fast moving water that runs perpendicular to the shore and away from the beach. Occurs when there is a break in sand bar.

Undertow The rush of water back away from the beach after the wave breaks. This does not suck you under but it does feel like it is pulling you.

Impress your friends this summer with all your new knowledge!

What should we do? On the beach profiles you have made (the graphing), mark off what parts of the graph represent the different parts of the beach. Read the Groins and Jetties article

Home work Why are Jetties and breakwaters bad?

Accretion is a process in which the size of something gradually increases by steady addition of smaller parts