3. INTRODUCTION
Coast are often highly abundant natural resources. The majority of world’s
population live close to sea. As many as 3 billion people live within 60 km of the
shoreline. The coast plays an important role in global transportation, and is the
destination of many of the world’s tourists. The surface of ocean is set in motion
by action of winds blowing across it.
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4. DISCOVERY
Several attempts have been made to classify shorelines but the most
universally accepted scheme was proposed by Franchis P. Shepard I 1937
and revised slightly in 1963.
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5. COAST LINE ????
The boundary of a coast, where land meets the sea, is called
the coastline.
Edge of land along the sea or other large body of water.
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6. FORMATION OF COASTLINE ??
1. Waves, tides, and currents help create coastlines.
2. The energy of waves moving onshore enables them to deposit sediments
obtained through wave erosion to form the most common deposited
feature, the beaches.
3. All coastal features are classified the result of either wave erosion or
wave deposition.
4. Sedimentation or wave deposition always occur parallel to shoreline.
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7. BEACHES
• Beaches are formed by sediments which are transported by waves and tides
and piled up along the shore.
• The sediment found on the beaches are transported by wave energy by back
and forth in rhythm to the movement of swash and backwash.
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10. • The beaches are observable features changing from season and in some
places daily.
• Beaches are composed of sediments according to size known as sand, and
according to the geologist’s scale of sediments sizes called the Wentworth
scale.
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Table :- Wentworth Scale of Particle Sizes for Sediments
11. COASTAL LANDFORMS
Coastal landforms, any of the relief features present along any coast, the
result of a combination of processes, sediments, and the geology of the
coast itself.
There are many factors and forces in the formation of coastal features.
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12. FACTORS AND FORCES IN THE FORMATION OF
COASTAL FEATURES
• The landforms that develop along the coast are the result of a combination
of processes acting upon the sediments and rocks present in the coastal
zone.
• The most common of these processes involves waves and the currents that
they generate, along with tides.
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13. 13
Factors in formation
of coastal feature
Waves
Tides
Rip Current
Climate
change
Rainfall
Temperature
Wind
Gravitational
14. FACTORS AND FORCES IN THE FORMATION OF
COASTAL FEATURES
Waves
• The most obvious of all coastal processes is the continual motion of the
waves moving toward the beach.
• Waves interact with the ocean bottom as they travel into shallow water; as
a result, they cause sediment to become temporarily suspended and
available for movement by coastal currents.
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15. LONGSHORE CURRENTS
• The movement of sediment along the coastline is called longshore
drift.
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Backwash
LongshoreTransport
16. RIP CURRENT
• Another type of coastal current caused by wave activity is the rip
current.
• As waves move toward the beach, there is some net shoreward
transport of water. This leads to a slight but important upward slope of
the water level.
• Water moves seaward through the surf zone in an effort to relieve the
instability of the sloping water.
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18. Tides
• The rise and fall of sea level caused by astronomical conditions is
regular and predictable. There is a great range in the magnitude of this
daily or semi-daily change in water level.
• Tidal currents transport sediment in the same way that longshore
currents do.
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19. 19
Climate
Climate is an extremely important factor in the development of coastal landforms. The
elements of climate include rainfall, temperature, and wind.
Rainfall
Rainfall is important because it provides runoff in the form of streams and also is a factor in
producing and transporting sediment to the coast. This fact gives rise to a marked contrast
between the volume and type of sediment
Temperature
Temperature is important for two quite different reasons. It is a factor in the physical
weathering of sediments and rocks along the coast and in the adjacent drainage basins.
This is particularly significant in cold regions where the freezing of water within
cracks in rocks causes the rocks to fragment and thereby yield sediment.
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Wind
Wind is important primarily because of its relationship to waves. Coasts that
experience prolonged and intense winds also experience high wave-energy
conditions
Gravity
Gravity, too, plays a major role in coastal processes. Not only is it indirectly
involved in processes associated with wind and waves but it also is directly involved
through downslope movement of sediment and rock as well.
21. The coastal environment of the world is made up of a wide
variety of landforms manifested in a spectrum of sizes and
shapes ranging from gently sloping beaches to high cliffs, yet
coastal landforms are best considered in two broad categories:
Erosional
Depositional
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22. LANDFORMS OF EROSIONAL
COASTS
There are two major types of coastal morphology: one is dominated by
erosion and the other by deposition. Erosional coasts are those with little
or no sediment.
These coasts are dominated by exposed bedrock with steep slopes and
high elevations adjacent to the shore.
The type of rock and its lithification are important factors in the rate of
erosion.
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28. LANDFORMS OF DEPOSITIONAL
COASTS
Depositional coasts are characterized by abundant sediment accumulation
over the long term. Both temporal and geographic variations may occur in
each of these coastal types.
Coasts adjacent to the trailing edge of lithospheric plates tend to have
widespread coastal plains and low relief.
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29. DEPOSITIONAL COAST
Depositional coasts can be described in terms of three primary large-scale
types:
Deltas
Barrier island/estuarine systems
Strand-plain coasts
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32. STRAND-PLAIN COASTS
• Some wave-dominated coasts do not contain estuaries and have no
barrier island system. These coasts, however, do have beaches and
dunes, and may even have coastal marshes.
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Beaches Coastal Dunes Coastal Marshes
33. DEVELOPMENT AND CLASSIFICATION OF
COASTLINES
There are two possible types of changes in level of the sea.
either the water level itself will rise or fall.
land uplifted or depressed.
In respect to development processes of coastline, it has two methods of
formation :-
Terrestrial processes
Marine processes
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34. CLASSIFICATION
On the basis of mode of formation of coast shepard classify it in two types :-
Primary Coastline - land based agencies.
Secondary Coastline – marine factors
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Fjord Glaciers Valley
Beaches Mud flat
