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IN THE NAME OF ALLAHIN THE NAME OF ALLAH
THE MOST BENEFICIALTHE MOST BENEFICIALAND THE MOSTAND THE MOST
MERCIFULLMERCIFULL
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PRESENTED TOPRESENTED TO
Mr. KAMRANMIRZAMr. KAMRANMIRZA
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PRESENTED BYPRESENTED BY
ATIF ALI HASSANATIF ALI HASSAN QASIM ZIAQASIM ZIA
ABDUL SAEED KHANABDUL SAEED KHAN BILALILYASBILALILYAS
SHAFIQSHAFIQ--URUR--REHMANREHMAN BILAL TAHIRBILAL TAHIR
M.IHTASHAMM.IHTASHAM M. FAIZANM. FAIZAN
M.ALIM.ALI
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Coastal DegradationCoastal Degradation
Coastal degradation means wearing away
ofa shore ofa body ofwater
covered by sand, gravel orlargerrock
fragments by
an instance orproduct oferosive action.
(Dees and Davis)
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Coastal Degradation Coastal erosion is the wearing away of
land orthe removal ofbeach ordune
sediments by wave action, tidal currents, or
drainage.
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Indeed coastal erosion is a natural
process that has been going onsince the earth evolved into its
threefold complex ofair, land
and sea.It, however, became a
hazard only when man began to
settle and locate facilities in thishighly dynamic and sometimes
destructive zone.7
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CAUSES
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CAUSES Coastal erosion is the result ofdeficit of
sand as a result ofboth naturaland
anthropogenic activities.
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Natural Causes Wave Action
Sea level rise
Coastal subsidence due to tectonic events
Climaticchanges
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Wave Action
The fourmain types ofwave action are:
HydraulicAction
Attrition
Corrasion
Corrosion
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HydraulicAction It occurs when waves striking a cliffface
compress airincracks on the cliffface. This
exerts pressure on the surrounding rock, and
can progressively splinterand remove
pieces ofrock. Overtime, the cliffface
cracks can grow, sometimes forming a cave.The rockfrom the cliffface which was
removed falls to the sea bed where it is
subjected tofurtherwave action.EaES 350-6 12
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HydraulicAction
The force of the waves pushes air
into cracks in the rock
The compressed air exerts enormous pressure at the tip of the crack. As the water falls back
the air pressure is released and rock is pulled out from the crack further enlarging the hole.
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Attrition Attrition occurs when waves causes loose
pieces ofrockdebris (scree) tocollide with
each other. The effect is that pieces of scree
collide, grinding and chipping each other,
progressively becoming smaller, smoother
and rounder. Scree alsocollides with thebase ofthe cliffface, and canchip small
pieces ofrockfrom the clifforhave a
corrasion effect.EaES 350-6 1
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Corrasion Corrasion (abrasion) occurs when the
waves breakon the cliffface pounding the
cliffface and slowly erode it.
As the sea pounds clifffaces it also uses
the scree from otherwave actions to batter
and breakoffpieces ofrock.
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Corrosion Corrosion orsolutionoccurs when the
sea's pH corrodes rocks on a cliffface.
Limestone clifffaces, which have a high
pH, are particularly affected in this way.
Wave action also increases the rate of
reaction by removing the reacted material.
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Sea level Rise
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Coastal Subsidence
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Before
Earthquake
After
Earthquake
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ClimaticChange
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AnthropogenicCauses The damming ofrivers
Sand mining and dredging activities
Deforestationofcoastal vegetation
Urbanization
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EFFECTS
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EFFECTSDamages ofcoastal erosion may depict itself
in the followings
Life ofpeople
Property and associated economical values
Ecological values
Cultural values
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Life ofPeople This is a serious issue forpeople living in
low-lying lands (below the sea level)
adjacent to seas and oceans.
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Property and associated
economical values Loss ofextremely valuable land
(recreational and tourist beaches) and
damages to urban infrastructure.
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Ecological values Good examples to this type ofdamage are
turtle nesting beaches that have been
loosing critical turtle nesting grounds due toanthropogenic erosion.
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Cultural values There exist numerous examples to this type
ofdamage all along the Mediterraneancoast
in areas where people have settled sinceancient times
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REMEDIES There are five generic strategies forcoastal
defense
1.Donothing
2.Managed retreat orrealignment,
3.Hold the line
4.Move seawards
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Do nothing No protection, leading to eventual
abandonment
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Managed retreat or
realignmentwhich plans forretreat and adopts
engineering solutions that recognize natural
processes ofadjustment, and identifying anew line ofdefence where toconstruct new
defenses
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Hold the line
Shoreline protection, whereby seawalls are
constructed around the coastlines
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Move seawards
by constructing new defenses seaward the
original ones
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SOLUTIONS OF COASTALSOLUTIONS OF COASTAL
DEG
RADATIONDEG
RADATION Shelterthe sands from wavesShelterthe sands from waves
SeawallsSeawalls
BreakwatersBreakwaters
Hold the sand in placeHold the sand in place
Plant the
coastsPla
nt the
coasts
JettiesJetties
Beach Nourishment
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Seawall A seawall is a structure constructed parallel
to the coastline that shelters the shore from
wave action. This structure has manydifferent designs; it can be used to protect a
clifffrom wave attackand improve slope
stability and it can also dissipate waveenergy on sandy coasts.
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Breakwater Breakwaters are structures constructed on
coasts as part ofcoastal
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BeachNourishment
The aim ofbeach nourishment is tocreate a
widerbeach by artificially increasing the
quantity ofsediment on a beachexperiencing sediment loss, improving the
recreational value ofthe coast.
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Before
After
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Plant the coastsPlant the coasts The presence ofvegetation incoastal areas
improves slope stability, consolidates
sediment and reduces wave energy movingonshore; therefore, it protects the shoreline
from erosion.
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