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Qasim Zia Coastal Dedradation

May 30, 2018

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    EaES 350-6 1

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    2

    IN THE NAME OF ALLAHIN THE NAME OF ALLAH

    THE MOST BENEFICIALTHE MOST BENEFICIALAND THE MOSTAND THE MOST

    MERCIFULLMERCIFULL

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    3

    PRESENTED TOPRESENTED TO

    Mr. KAMRANMIRZAMr. KAMRANMIRZA

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    4

    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

    4

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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

    EaES 350-6 21

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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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