Chapter 15 Section 3

By- Robert Sterling, Sam Dixon, Ryan McCarthy, Mikaela Cormier, and Sarah Fournier

Wave Erosion

*High power waves wear away the land that it strikes through erosion

*Abrasion is the act of sawing and grinding of land that waves do to the coast

*Wave-cuts are when the surf "cuts" the base of the coastal land

*A relatively flat, bench like surface called a wave cut platform is left behind by the receding cliff

Wave Erosion

*Marine Terraces are an erosion feature where the seaward edge is sloped gently. These are where many coastal roads or buildings are placed

*Cliff formed by erosion is called a headland

*When seawaves create "sea caves" and they unie a sea arch is formed

*When the arch falls in an isolated remnant, or sea stack, is left on the cut platform

https://www.youtube.com/watch?v=y0C5sQ_Ns8&norWedirect=1

Wave Erosion

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Decompositional features along coasts• Depositional Features- Produced when sediment is eroded

from the beach and deposited in areas where wave energy is relatively low.o Spit/Spine- An elongated ridge of sand that projects

from the land into the mouth of an adjacent bay Often hooks landward in response to the dominant

direction of the longshore current.

Decompositional features along coasts•Baymouth Bar- A sandbar that completely crosses a bay,

sealing it off from the open ocean.o Tend to form across a bay where currents are weak,

allowing a spit to extend to the other side.

Decompositional features along coasts•Tombolo- A ridge of sand that connects to an island to the

mainland or to another island.o Forms in the same manner as a spit.

Decompositional features along coasts•Barrier Islands- Low ridges of sand parallel to the coast

o Usually occur at distances from 3 to 30 kilometers (1.9 to 19 miles) off shore.

o Nearly 300 barrier islands rim the coast.o Formed by spits that were severed from the mainland

by erosion or by turbulent waters in the line of breakers that heaped up sand that had been scoured from the ocean bottom

Factors Influencing Shoreline ErosionTHE FOLLOWING ARE FACTORS THAT INFLUENCE

SHORELINE EROSION• The adjacency of a coast to sediment-laden rivers• the amount of tectonic activity• the topography and what the land is made of• wind and weather patterns• the arrangement of the coastline and nearshore areas

Solutions to shoreline erosional problems - Hard Stabilization

* Structures made to prevent the movement of sand

- Short walls built at a right angle called groins- Breakwaters

* Parallel structures built along the shore made to protect boats.- Seawalls

* Armoring the coast to prevent waves from going behind the wall

- Alternatives* Beach nourishment- Addition of sand*Relocation- Of damaged or threatening buildings

Definitions

• barrier island- a low, elongated ridge of sand that parallels the coast

• baymouth bar- a sandbar that completely crosses a bay, sealing off from the open ocean

• beach- an accumulation of sediment found along the landward margin of the ocean or a lake

• beach nourishment- the process by which large quantities of sand are added to the beach system to offset losses caused by wave erosion

• breakwater-a structure protecting a nearshore area from breaking waves

Definitions (continued)

• estuary- a partially enclosed coastal water body that is connected to the ocean, salinity here is measurably reduced by the freshwater flow of rivers

• groin- a short wall built at a right angle to the shore to trap moving sand

• hard stabilization- any formation of artificial structure built to prevent the movement of sand along a beach

• marine terrace- a wave cut platform that has been exposed above sea level

• sea arch- an arch formed by wave erosion when caves on opposite sides of a headland unite

Definitions

• sea stack- an isolated mass of rock standing just off shore, produced by wave erosion of a headline

• seawall- a barrier constructed to prevent waves from reaching the area behind the wall

• shore- seaward of the coast, this zone extends from the highest level of wave action during storms to the lowest tide level

Bibliography

http://www.geocaching.com/seek/cache_details.aspx?guid=43b9fa76-a44a-43bc-85d1-6a0efd3eb18c

http://www.learnnc.org/lp/editions/nchist-recent/6374

Works Cited

"Herp Walk Stop #11: Glass Lizards | SREL Herpetology." Herp Walk Stop #11: Glass Lizards | SREL Herpetology. N.p., n.d. Web. 22 May 2013.

"Joseph J. Gerencher, Jr." Joseph J. Gerencher, Jr. N.p., n.d. Web. 22 May 2013.

"ReefNews Goes To Washington's Dungeness National Wildlife Refuge." ReefNews Goes To Washington's Dungeness National Wildlife Refuge .

N.p., n.d. Web. 22 May 2013.

"South West Coastal Group." South West Coastal Group. N.p., n.d. Web. 22 May 2013.