This is an assignment on landslide and its impact on hilly region of Bangladesh. This document will help to gather knowledge on this topic.

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Course code: URP 3104
Course title: Natural Hazards and Disaster Management Field work & Lab
Assignment On
Landslide and Its Impact on Hilly Region of Bangladesh
Submission Date: 25 September, 2017
Submitted to
Md. Kamrul Hasan
Lecturer,
Department of Urban & Regional Planning
Submitted by
Group-04
Ritu Saha-151730
KH. Zubiada Gulshan-151707
Abdullah Al Mamun-141714
Tasmia Sultana-151715
Laila Arjuman-151734
Farhana Tasnim-151740
Abdullah Al Monsur Saad-151704
Department of Urban & Regional Planning
PABNA UNIVERSITY OF SCIENCE & TECHNOLOGY

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1. Introduction
A landslide is the movement of rock, debris or earth down a slope. They result from the failure
of the materials which make up the hill slope and are driven by the force of gravity. Landslides
are known also as landslips, slumps or slope failure. Landslides can be triggered by natural
causes or by human activity. They range from a single boulder in a rock fall or topple to tens
of millions of cubic meters of material in a debris flow.
Bangladesh is a disaster prone country. The physiography, morphology and other natural
condition have made her vulnerable to various disaster and environmental hazards. The
common disaster of this country are flood, cyclone induced storm surges, droughts, earthquakes
and river bank erosion. Moreover, landslide has become newly added burning issue. Landslide
and avalanches, while historically not renowned for causing as large a death toll as other natural
disasters such as tropical cyclone or earthquakes, have had just as dramatic an impact on
property and lives .Worldwide record shows that China, Philippines, India, Indonesia, Nepal,
Japan and USA witness the incident of landslide regularly. During the last ten years near about
25 incidents of major landslide have been recorded worldwide killing thousands of lives.
Landslide is an inveterate problem for south eastern part of Bangladesh and Chittagong city is
particularly highly vulnerable to this hazard with an increasing trend of frequency and demand.
2. Landslide classification
The various types of landslides can be determined by the kinds of material involved and the
mode of movement. A classification system based on these parameters is given below:
 Fall:
This is generally characterized by a rapid to extremely rapid rate of movement with the descent
of material characterized by a free fall period. Falls are commonly triggered by earthquakes or
erosion process.
 Topple:
This is characterized by the tilting of rock without collapse, or by the forward rotation of rocks
about a pivot point. Topples have a rapid rate of movement and failure is generally influenced
by the fracture pattern is rock. Material descends by abrupt falling, sliding, bouncing and
rolling.
 Spread:
This phenomenon is characterized by the gradual lateral displacement of large volumes of
distributed material over very gentle or flat terrain. Failure is caused by liquefaction which is
the process when saturated loose sediment with little or no cohesion such as sands or silts are
transformed into a liquid-like state. This process is triggered by rapid ground motion most
commonly during earthquake.

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 Slide:
This is one of the most common forms of failure and can be subdivided into transitional and
rotational slides. Rotational slides are sometimes called slumps because they move with
rotation. In rotational sliding the slide plane is curved and the mass rotates backwards around
an axis parallel to the slope. Transitional slides have a planner, or two dimensional surface of
rupture. Slides are most common when the toe of the slope is undercut. They have a moderate
rate of movement and the coherence of material is retained, moving largely intact or in broken
pieces.
 Flows:
Flows are landslides that involve the movement of material down a slope in the form of a fluid.
There are three types of landslides which are lateral spreading movement, rotational and
transitional movements, and rock falling movements are occurred in Bangladesh. The Dupi
Tila Formation, planner or block movement in Bokabil Formation and rotational, transitional
or block failures in Tipum Formation are responsible for erosional hazards in Bangladesh.
Fig 1.1: Different types of landslide
Source: www.google.com

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3. History of landslide in Bangladesh
Landslide is one of the most significant natural damaging disasters in the hilly environments.
In Bangladesh, the hilly areas are vulnerable to landslide as with the other hilly regions of the
world. Landslide occurs almost every year in the hilly areas in Chittagong, Rangamati,
Bandarban, Cox’s Bazar and Khagrachori. The historical records of landslide in Bangladesh
are given below:
Date Place Description
30 May, 1990 Jhagar beel area of
Rangamati
This landslide damaged road of
embankment in Rangamati.
23 July, 1997 Charaipada of Bandarban The total area of affected by it was 90,000
square meter.
11, August 1999 Aziz Nagar of Bandarban At least 50 houses were completely
vanished and 300 houses are damaged.
24 June, 2000 Chittagong university
campus, and other part of
Chittagong city.
In this incident 13 people were killed, 20
people were injured.
11 June, 2007 Chittagong In this landslide, 135 people were killed,
213 were wounded and 5072 homeless.
18 august, 2008 Matijharna area of
lalkhan bazar.
2 whole families vanished, 11 people
killed.
23 June, 2012 Northern and south-
eastern part of
Bangladesh.
139 people were killed.
24 June, 2015 Cox’s bazar, Rangamati,
Chittagong.
19 people were killed.
12 June, 2017 Rangamati, Chittagong,
Bandarban.
152 people were killed.
Source: www.Scribd.com & en.banglapedia.org

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Source: www.google.com
Source: www. google.com
Fig 3.1: The recent flashback of landslides (2008, 2011, 2015, 2017 from left)
4. Vulnerability Assessment of Landslide in Bangladesh
Vulnerability assessment is the process of assessing the degree of loss to a given elements at
risk. Chittagong, Rangamati, Bandarban, Cox’s Bazar and Khagrachori districts are selected
for vulnerable areas of landslide. Based on research and historic records these areas are
classified into three vulnerable zones:
 High Vulnerable Zone: Lebubagan area, Baizid Bostami area, Kusumbag residential area,
Betail hill area and Motijharna area are included as high risk zones, on the basis of high
slope angle of hills sandy sediment structure and high man made deformation of the hill in
the areas.
 Mid Vulnerable Zone: Marine science colony in Chittagong University campus, North
campus residential colony, Lama Upazila in Bandarban, Jhagar beel area in Rangamati are
classified as moderate vulnerable zone on the basis of position settlements.
 Low Vulnerable Zone: Chandraghona, Azad colony of Chittagong, Charaipada, Aziz
Nagar, Chittaputti, Meounad and Muslimpara of Bandarban are included in this category.

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Source: www. google.com
Fig 4.1: The landslide susceptibility map
5. Causes of Landslide
Landslides are considered as the most destructive hazards in developing countries. The causes
of landslides are usually related to instabilities in slope. Some major factors are given as follow:
 Natural factor:
 Earthquake: If the earth’s crust vibrates enough to disrupt the force of friction holding
sediments in place on an incline, a landslide can strike.
 Weak soil structure: soil structure is also responsible for landslides. Weak soil is
easily eroded and fills up low land areas which create drainage congestion.
 Gravity: Gravity is the ultimate force behind any landslide. Land surfaces are together
by multiple forces. The most important of these is friction. Some soil particles, like
clay, cling to each other tightly, while others, like sand, are only loosely joined. All
landscapes are held together by friction between the sediment cover and the underlying
bedrock, some more tightly than others. Landslides occur when gravity overcomes the
friction.
 Heavy rainfall: Due to the monsoonal heavy rain makes slopes unstable and causes
landslide.
 Increase of lateral pressures: Increases of lateral pressures such as hydraulic pressure,
roots, crystallizations and swelling of clay are responsible for landslide.
 Removal of lateral and underlying slope: Removal of lateral supports soil erosion
and make soil loose which causes landslide.

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 Regional tilting: Slope movements in the hilly region are responsible regional tilting
and causes landslide.
 Fluctuation of water level due to tidal action: Due to the Tsunami or tidal wave
landslide is also occurred.
 Deposition of loose sediments: Soil materials are carried out by water currents and
causes landslide.
 Flash flood: Flash floods are resulted of heavy rainfall and it removes the materials of
soil. For this reason landslide is occurred.
 Anthropogenic factor:
 Hill cutting: Most of the landslides occurred due to indiscriminate hill cutting, these
makes the slopes instable.
 Removal of vegetation in hilly areas: Due to the settlements, jhoom cultivation the
vegetation of the hilly area is also hampered and loses the soil structures.
 Inappropriate drainage system: Due to the unsustainable drainage system surface
runoff of irrigated water on slopes exposes soil under cultivation to erosion.
 Shifting (jhoom) cultivation: Shifting jhoom cultivation is an agricultural system in
which plots of land are cultivated temporarily, then abandoned and allowed to revert to
their natural vegetation. It also responsible for landslide.
 Deforestation: Deforestation is another major region of landslide in Bangladesh. Trees
protect the soil and stable the slope which reduces the landslide. Because of
deforestation the soil structure weakens day by day and causes landslides.
6. Impacts of Landslide in Bangladesh
6.1 Impact of landslide in economy:
There is considerable impact of land slide on the local economy. Some of this is given below:
 Destructions of infrastructure: Many buildings and infrastructure especially those
located on steep slopes usually fail due to landslides.
 Hampered Jhoom and other forms of cultivation: Jhoom cultivation is very good
in the slope of hill but due to land slide jhoom and other types of cultivation are
hampered and thus also effects on local economy.
 Indirect impact: Devaluation of property, high repairing cost, compensation etc. is
included here.
6.2 Impact of landslide in human life:
 Loss of lives: Because of landslide many people lost their life and most of them are
injured. According to the reported of Daily STAR (2012), 127 people are died in
different locations of Chittagong on landslide 11 June, 2007.

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 Loss of shelter: Due to land slide many settlements in the hilly areas are vanished and
damaged as a result people become homeless.
 Hampered utility services: Blocking of roads, interruption of power, water, gas
supply etc. are also hampered by this type of hazard.
 Lack of security: The most vulnerable people of landslide are women and children.
Many women lost their relatives and became homeless. As a result they are faces many
physical and mental harassments.
6.3 Impacts of land slide in urban life:
 Migration: Landslide causes human casualties and massive property destruction and
sometimes vulnerable people will be homeless, jobless. As a result people are migrated
in the urban area and create pressure on urban services.
 Increase social crime: Due to the landslide people lost their property and settlements
and are involved in many urban social crimes.
6.4 Impacts of land slide in environment:
 Loss of soil fertility: Because of landslide soil nutrients are removed from the top
layer and waken the soil structures. As a result soil will be unfertile.
 Loss of biodiversity: Due to landslide wildlife are destroyed, trees are uprooted and
thus also effects on biodiversity.
 Loss of natural scenic beauty: In the hilly areas in Bangladesh, are the sources of
natural beauty and center of attractions near the tourists. Because of land slide these
area loss their natural beauty.
7. Landslide Measures & Management system
Disaster management means to perform the whole range of pre-disaster, disaster and post-
disaster activities. Like any other disaster, landslide management system is divided into three
stages. These are pre-disaster, disaster occurrence and post disaster stages. Risk reduction and
ensure of minimum losses of human life and property are taken in this category and they are
termed as prevention, mitigation and preparedness. Activities taken to ensure that the needs
and provisions of victims are met and sufferings are minimized and they are termed as
emergency response activities. Post disaster stage is related to recovery and rehabilitation
activities.

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Fig 7.1: The disaster management cycle
 Prevention:
 To protect landslide it is necessary to stop all types of hill cutting, deforestation vegetation
removal, sand collection and other activities which all causes landslide.
 Cover the all necked hills by herbs, shrubs, trees etc. It will protect the top soil and
ultimately it control erosion.
 Prepare a retaining wall, drain and strong wall near the hill to protect vulnerable zones.
 Rock fall Protection & Construction of rock buttresses.
 Capacity development (including education, training, documentation etc.) is needed to
protect from landslide.
 Mitigation:
 Appropriate feasibility studies, along with assessments of risk, uncertainty, possible
consequences, constructability, environmental impacts and cost benefit analysis by
independent authorities are needed for any mitigation measure.
 Transferring the vulnerable people sequentially in a safer place is another step of
mitigation.
 Preparedness:
 Understanding the rainfall pattern and its exact relationship with landslide in the region
could also help us be prepared.
 Detailed land use planning of the vulnerable areas, a landslide database, landslide
mapping and geophysical analysis of the region are essential to minimize landslides
and their impacts in the region.
Prevention
Mitigation
Preparedn
-ess
Response
Recovery

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 Early warning systems need to be strengthened, with active participation of community
based organizations, the civil defense wing and local government authorities by
receiving regular data relevant to the area as soon as monsoon season sets from
Bangladesh Meteorological Department.
 Response:
 Installation of better emergency alert system.
 Emergency support of food, shelter, medical, transport and so on. Develop consist of
15-30 members team. This team will observe the vulnerable area and will take steps to
protect the vulnerable people.
 Recovery:
 Early damage Assessment.
 Legal policy or legislation should be made to minimize illegal housing, hill cutting etc.
 Develop a fund for emergency period and develop employee’s socio-economic
condition.
 Re-establishing life-lines transport and communication infrastructure.
8. Adaption of local people after landslide
Tribal people have lived here permanently for few generations and no Bengali was found in
the community. The traditional shifting cultivation is the primary occupation. The architecture
of the houses is helping to make the community physically less vulnerable to landslides. The
raised plinth allows the rainwater to flow naturally and freely below the houses. The
construction materials of the houses are lightweight and therefore not life threatening, even if
the houses collapse in earthquakes or landslides. The tribal people do not cut the hills like in
the urbanized areas, instead they try to build houses horizontally in the same line of hill-slopes
using bamboo or tree trunks in layers. This is the indigenous knowledge applied by the tribal
people to protect themselves from landslides or slope collapses.
Many people in the disaster prone area are shift in less risky zones and started their new lives.
With the help of many government and non-government organizations the people are
reconstructed their physical structures and participated many alternative economic activities
and adapt after landslide,
9. Conclusion
Landslide has become a common disaster in our country. It causes death of large number of
people every year. But no initiative has yet been taken by related authority to overcome this
problem. Affected people are building their residence in vulnerable area when they are

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eliminated from effected areas. Mentioned problem will not be solved so far affected people
are not provided with permanent residence.
The experts will build two small dams for holding the debris that comes along with the stream
and blocks the road underneath. Thereafter, the slope will be cut and hydro seeding done. Hydro
seeding involves injecting seeds with machines on the mountain slopes to help grow grass and
plants. This in turn will hold the top soil and avoid landslide.