The Prevention of Wave ErosionBreakwaters, Jetty’s and Dune Vegetation

Kyle Rosbrook

What is Dune Vegetation?

Dune Vegetation is naturally occurring grass, vegetation, weeds, brush, etc. to keep down wind speeds going out to sea. The slowing of the wind keeps more sand on the beach, preventing faster erosion.

Dune VegetationDune Vegetation Can

prevent wind erosion by decreasing wind speed at ground level

build up sand dunes and thus reduce the extent of recession produced by a storm

reduce wave erosion caused by overwash where dense vegetation exists

regenerate naturally after storm damage, where dune management allows

tolerate a hostile environment of high winds, salt spray, sandblast, covering by sand, sandy soil and little water

accept massive movements of the dunes, both vertically and horizontally

function as a self-supporting community where plants are mutually dependent for protection and nutrient supply

Dune Vegetation Cannot

prevent direct wave erosion – dune sand is notstrongly bound by roots under wave attack survive direct wave attack – much of the seaward

vegetation will be destroyed in a storm tolerate excessive physical damage caused by

people, stock or vehicles tolerate mismanagement such as mowing, which

destroys some species and juveniles of others, andtopsoiling, which prevents free drainage and isunsuitable for growth of many natural dune species tolerate overfertilising, which can be toxic to some

species tolerate introduction of unsuitable plant species –

some undesirable plants displace natural vegetation;others, such as palm trees, do not reduce wind erosionand accelerate wave erosion when they fall

Breakwaters…. A breakwater is a man-made mechanism

designed to lessen the intensity of wave action and ultimately reduce the destruction of the coast

It can be floating of solid(often concrete) and can be out hundreds of feet in shallow water of attached to the coast at one end

When the waves hit them, there destructive power is reduced, and the water coming to shore is far less powerful and less harmful to coastlines

Breakwater… Breakwaters can vary is size, depending

on the size needed to stop or slow the waves.

The are often designed with spaces water can pass through, or over top, both allowing water to pass with less force

This Breakwater in Vietnam cost 1.2 Billion dollars to construct.

Floating breakwater http://www.eco-marine.com/video/swb.h

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This floating breakwater serve the same purpose, to slow the destructive power but allowing the water that pass in a natural way.

Jetty’s Similar to a breakwater,

a jetty’s purpose it to stop the spread/ destruction of the coast.

They are located at river or lagoon mouths where it meets the ocean, so that the water cannot flow further down the coastline or into the river causing further erosion

Jetty…..ArtAlthough not

functional, this spiral jetty was created by Robert Smithson in 1970. It is 15 feet wide and 1500 feet long.