coastal protection) structures

Coastal (Protection) Structures

Miyazaki PrefectureNovember 07, 2007

PANTAI

PELINDUNG PANTAI

Night scene of the earth— What this indicates?

http://veimages.gsfc.nasa.gov/1438/earth_lights_lrg.jpg

Earth at Night by C. Mayhew & R. Simmon (NASA/GSFC), NOAA/NGDC, DMSP Digital Archive

Night scene—What this means ?

http://veimages.gsfc.nasa.gov/1438/earth_lights_lrg.jpg

http://veimages.gsfc.nasa.gov/116/pop_density.jpgPopulation density(NASA)

Concentration of humans and assets

Earth at Night by C. Mayhew & R. Simmon (NASA/GSFC), NOAA/NGDC, DMSP Digital Archive

Concentration of population and assets

(possibility of catastrophic disasters) 人口・資産の集中（大災害の可能性）

Advancement of civilization

(strong? / vulnerable? against disasters)文明の発展（災害に強い ?逆に脆弱）

Energy consumption(accelerating global

warming)エネルギーの消費（温暖化に荷担）

Storm surge: Yokohama, 2007

Coastal Protections Needed


Ten years after the constructionof the Narrowneck Reef, Australia


Miami Beach

Before

After

Five Generic Solutions

Contoh Kasus: Holbeck Hall, Scarborough,North Yorkshire, England

Why does cliff recession occur?What are the effects of cliff recession?How can the coastline be protected?What are the disadvantages of coastal protection?What is the best method of coastal protection?

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Why does cliff recession occur?


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What are the effects of cliff recession?


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How can the coastline be protected?

How do groynes work?

Groynes trap the sand which is carried along the coast by longshore drift.

The sand acts as a natural protection against the force of the waves. The waves break on the beach and not the cliffs.

How can the coastline be protected?

Hard engineering techniques aim to stop coastal processes from occurring. Soft engineering methods try to work with nature to protect the coast.

What has been done to protect coastal areas?

Match the correct protection method to its purpose!


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What problems do sea walls create?

Why might a sea wall cause more coastal erosion?

What are the disadvantages of groynes?

In 1991 a rock revetment and two rock groynes were built. Sand accumulated and halted erosion.

South of Mappleton the rate of erosion has increased significantly.

Material that usually moves south via longshore drift is becoming trapped within the groynes.

Now there is no beach to protect the cliffs - the sea reaches the base of the soft cliffs and erosion occurs.

Mappleton is located on the Holderness Coastline.


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What is the best method of coastal protection?

This is the imaginary coastal town of ‘Seaview’. Seaview has been suffering from coastal erosion for the last 15 years since the nearby larger town of ‘Engleton’ had groynes built to protect its own coastline.


There are strong feelings about what should be done to protect Seaview!

Give each scheme a score from 1 (poor) to 5 (good). For example, an expensive scheme should have a low score.

Would you choose the scheme with the highest score? Why?

Which is the most important criteria?


coastal protection) structures

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