Coastal Erosion and Management

What is Coastal/Shoreline erosion? The gradual or rapid removal of sediment from the coastline http://www.geograph.org.uk/photo/1870603

What is Shoreline Erosion? Shoreline erosion happens when an agent of erosion, mostly water, breaks down and carries away sediment from the beach, or bluffs above. Coastlines are constantly changing due to the action of waves, currents, and tides. Landslides and cliff retreats are part of the natural process of coastal erosion along the shore. http://www.public-domain-image.com/free-images/nature-landscapes/cliffs/house-on-cliff-with-erosion-in-progress/attachment/house-on-cliff-with-erosion-in-progress http://www.geograph.org.uk/photo/2164573

Management of Erosion The desire to build structures on coastlines has often interfered with the natural erosion processes. Protecting human-built structures from coastline erosion has been going on for centuries. https://en.wikipedia.org/wiki/Château_de_la_Napoule

Structures Lost to Coastal Erosion

Structures Lost to Coastal Erosion

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Management of Erosion Humans have invented many ways to prevent erosion, and protect structures. Examples include hard-armor and soft-armor engineering. http://patimes.org/sustainable-coastal-restoration-stabilization-living-shoreline-project-floridas-east-coast/ (Photo: David Melville and Ying Chen)

Hard-armor Engineering Requires the use of rock, concrete, or metal Examples include: seawalls, groynes, riprap, jetties, breakwaters Groynes © Bruce Molnia, Terra Photographics Jetty http://www.beachhunter.net/cocoa-beach/jetty-park.htm Breakwater © EPA Seawall http://www.coastlineconsulting-ct.com/bs.htm

Soft-armor Engineering The placement of plant materials into structures that are designed to withstand wave action. Appropriate where there are suitable conditions for plants to grow. As the plants grow, their root structures naturally stabilize the shoreline http://www.shoreline.msu.edu/shorelinemgt/erosion-control/ http://www.shorefriendly.org/your-options/soft-shore-protection/

Vocabulary Coastline/Shoreline Bluff Toe erosion Marine erosion Longshore drift Seawall Groynes Riprap Jetty Breakwater

Coastline/Shoreline The line along which a large body of water meets the land https://commons.wikimedia.org/wiki/File:Indented_coastline_below_the_cliff_top_hay_meadow_-_geograph.org.uk_-_1378368.jpg https://www.goodfreephotos.com/brazil/salvador/coastline-cityscape-and-landscape-of-salvador-brazil.jpg.php

Bluff A steep bank or cliff, especially one formed by water erosion https://commons.wikimedia.org/wiki/File:Bluff_erosion_in_Pacifica.jpg https://en.wikipedia.org/wiki/Scarborough_Bluffs

Toe Erosion Erosion at the base of a landform As waves hit against the base of the bluff, material begins to wear away, leaving the above material unsupported. geosurvey.ohiodnr.gov

Marine Erosion Erosion due to: Hydraulic Action - waves breaking against the foot of a cliff Abrasion - rocks scraping against the land Corrasion- a rock thrown against the cliff face from a surging wave Attrition-rocks carried by seawater colliding https://en.wikipedia.org/wiki/Effects_of_global_warming_on_oceans

Longshore Drift Waves that hit the beach at an angle carry sand and gravel up the beach face at an angle. When the water washes back, the sediment is carried straight back down the beach face. Individual particles are moved along the beach in a zig-zag pattern. https://revisionworld.com/gcse-revision/geography/coastal-landscapes/coastal-processes/longshore-drift

A wall or barrier built to prevent the sea from encroaching on or eroding an area of land Seawall http://www.geograph.org.uk/photo/782406 https://commons.wikimedia.org/wiki/File:Sea_wall_at_Saint_Jean_de_Luz.jpg

Groyne A low wall built out from the coast to the sea to prevent marine erosion https://commons.wikimedia.org/wiki/File:Groyne_on_the_beach_near_Bacton_-_geograph.org.uk_-_775611.jpg http://www.geograph.org.uk/photo/15974

Riprap Naturally interlocking stones that form a barrier http://www.geograph.org.uk/photo/3738285 http://www.geograph.org.uk/photo/770910

Jetty A structure extended into a sea, lake, or river to influence the current or tide, or to protect a harbor https://commons.wikimedia.org/wiki/File:Rock_jetty_in_North_Kingston,_RI.JPG https://en.wikipedia.org/wiki/Jetty

Breakwater A barrier that breaks the force of waves http://www.cowesharbourcommission.co.uk/cowes_breakwater_project_november_2015_report

Sources American Geosciences Institute http://www.k5geosource.org/1content/1sc/rocks/pg9.html Michigan Inland Lake Shorelines http://www.shoreline.msu.edu/shorelinemgt/erosion-control/