Qasim Zia Coastal Dedradation

8/9/2019 Qasim Zia Coastal Dedradation

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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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Qasim Zia Coastal Dedradation

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