Landforms of Bangladesh and their Relation to natural hazards: Bangladesh is situated between 23 34’ and 26 38’ North latitude and 88 01’ and 92 41’East longitude. The topography is flat with elevation not exceeding 10 meters above mean sea level. Floodplain and piedmont plains occupy almost 80 percent of the land area. It is a low-lying, riverine country located in South Asia with a largely marshy jungle coastline of 580 km (360 mi) on the northern littoral of the Bay of Bengal. Bangladesh has a tropical monsoon climate characterized by heavy seasonal rainfall, high temperatures, and high humidity. To know about the land forms of Bangladesh. To know about the hazards of Bangladesh. To find out the relationship between landforms and Hazards. Topography is a configuration of a land surface including it’s relief and contours, the distribution of mountains and valleys , the patterns of rivers and other natural features that produce the landscape . There are three distinctive natural features in Bangladesh. A broad alluvial plain subject to frequent flooding. A slightly elevated relatively older plain A small hill region drained by fant flowing rivers.

1. “Landforms of Bangladesh and their
Relation to natural hazards”
MSDM-5113: Geological and Geo-
morphological Perspective
 Presented to:
 Dr. A.S.M
Woobaidullah
 Professor
 Department of
Geography and
Environment
 Dhaka University

2. INTRODUCTION
1. Bangladesh is situated between 23 34’ and 26
38’ North latitude and 88 01’ and 92 41’East
longitude.
2. The topography is flat with elevation not
exceeding 10 meters above mean sea level.
3. Floodplain and piedmont plains occupy almost
80 percent of the land area.
4. It is a low-lying, riverine country located in
South Asia with a largely marshy jungle
coastline of 580 km (360 mi) on the northern
littoral of the Bay of Bengal.
5. Bangladesh has a tropical monsoon climate
characterized by heavy seasonal rainfall, high
temperatures, and high humidity.

3. What is the objective of our
presentation.
To know about the land forms of Bangladesh.
To know about the hazards of Bangladesh.
To find out the relationship between landforms
and Hazards.

4. Topography of Bangladesh
 1. Mountainous region of
Topography is a configuration of a
land surface including it’s relief and
contours, the distribution of mountains
and valleys , the patterns of rivers and
other natural features that produce the
landscape .
There are three distinctive natural
features in Bangladesh.
A broad alluvial plain subject to
frequent flooding.
A slightly elevated relatively older
plain
A small hill region drained by fant
flowing rivers.

5. Location and characteristics of main landforms
1. Mountainous region of tertiary period:
It is situated in the Northeastern, Eastern
and the Southeastern part of
Bangladesh occupy 12% of the land.
2. The land rose in Terraces of
Pleistocene period(25000 years ago)
Lalmai region, Modhupur terrace and
Barind region are the main areas of
this land form in Bangladesh (8%).
3. Alluvial or recent floodplain The rest
part of Bangladesh are created by
rivers occupy 80% of the land

7. Recent flood plains
About 80% part of
Bangladesh is covered by
flood plains . It is a very
important type of landscape.
It have been divided into 15
sub-units.
Old himalayan
piedmonthplain
Tista floodplains
Old Brahmaputro
floodplains
Jamuna floodplains
Haor Basin
 Surma-Kushiyara floodplains
 Meghna floodplains
 Ganges river floodplains
 Ganges Tidal floodplains
 Sundarbans
 Lower Atrai Basin
 Arial Beel
 Gopalgonj-Khulna peat Basin
 Northern and Eastern piedmont plain

8. MAJOR NATURAL HAZARDS
Major type Sub-types
Flood •Flash flood
•Normal flood (river and rain fed)
Storm •Cyclone associated with tidal surge
•Tornado
•Nor’wester (Kalbaisakhi)
•Hailstorm
Drought •Seasonal
•Occasional (non-seasonal)
Erosion •Riverbank erosion
•Coastal erosion
•Afal (Haor region settlement erosion in flood season)
Earthquake •Earthquake
Rain •Heavy rain (sudden or prolonged period)
•Irregular rain
Sea level rise •Sea level rise (multi-hazards)
Heat & Cold waves •Heat waves
•Cold waves
Arsenic •Arsenic contamination

9. WHY BANGLADESH IS A DISASTER-PRONE COUNTRY
Geographical factors Type of hazard or risk
Deltaic low lands (30% land above 1m
from sea level)
Flood, tidal surge, intrusion of saline water, tsunami, riverbank erosion, sand
carpeting, sea level rise (SLR)
Vast floodplains and wetlands Floods, siltation, drought, drainage, water logging, afal, water pollution,
Riverine country Flood, riverbank erosion, intrusion of saline water, SLR, water pollution,
siltation, arsenic, embankment, transport accidents etc.
Hills and uplands Landslides, soil erosion, drought, deforestation, bushfire, earthquake,
Funnel shape coast Prone to high tidal surge, intrusion of saline water over extensive areas,
health hazards etc.
Hot and humid monsoon climate Flood, storms, cyclone, tidal surge, nor’wester, heavy rain, drought,
hailstorm, tornado, malaria and other climate induced diseases etc.
Regional and global geographic location The occurrence and impact of natural hazards in Bangladesh are, to a great
extent, depends on regional and global position of the country

10. Floods:
In the 19th century, six major floods were recorded in 1842,
1858, 1871, 1875, 1885 and 1892. Eighteen major floods
occurred in the 20th century. Those of 1987, 1988 and 1951
were of catastrophic consequence. More recent floods
include 2004 and 2010.

12. Cyclones and Storm SurgesDate Maximum Wind speed (km/hr) Storm Surge height
(metres)
Death Toll Date
11 May 1965 161 3.7-7.6 19,279
15 December 1965 217 2.4-3.6 873
01 October 1966 139 6.0-6.7 850
12 November 1970 224 6.0-10.0 300,000
25 May 1985 154 3.0-4.6 11,069
29 April 1991 225 6.0-7.6 138,882
19 May 1997 232 3.1-4.6 155
15 November (SIDR)2007 223 -- 3363
25 May (AILA) 2009 92 -- 190
11 May 1965 161 3.7-7.6 19,279

13. Tornado
14 April 1969 Demra (Dhaka)
17 April 1973 Manikganj (Dhaka)
10 April 1974 Faridpur
11 April 1974 Bogra
09 May 1976 Narayanganj
01 April 1977 Faridpur
14 April 1969 Demra (Dhaka)

14. District Upazila
Total
Land
(ha)
Eroded Infrastructures
Settleme
nt (ha)
District
Road
(m)
Upazila
Road
(m)
Rural
Road (m)
Embankm
ent (m)
Sirajganj
Kazipur 177 50 176 84 1617
Sirajgan
j Sadar
170 13 1 164 2107
Belkuch
i
0 0
Chauhal
i
207 45 395
Shahjad
pur
148 31 159
Total 702 139 160 571 248 3724
Faridpur
Faridpur
Sadar
200 57 1175 370
Char
Bhadras
an
78 17 320
Sadarpu
r
3 1
Total 281 75 320 1175 370

15. The relationship between landforms and Hazards in Bangladesh
Causes river bank erosion in Bangladesh
 Rivers in Bangladesh are
morphologically highly dynamic
 The flat delta land offer little resistance
to the hydraulic forces of its river during
the period of high flows
 When the BGM enters its mature stage
they become sluggish and meander.
These oscillation cause massive river
bank erosion
 Sedimentation in the river bed with a
catchment 1.65 M sq Km and 7.5% lies
with the border of BD
 Carry about 1.1 billion tons of
sediments every year

16. Drought
It faces unpredictable drought hazard in the dry
monsoon due to inadequate and uneven rainfall.
It varies from place to place, however, and the
northwestern region suffers most from the drought.
Three types of droughts in Bangladesh:
1.Permanent drought characterizes regions with the
driest climate, having sparse vegetation that is
adapted to aridity. Agriculture cannot be practiced
without irrigation.
2.Seasonal drought occurs due to abnormal rainfall
shortage in places where there are well- defined
annual rainy and dry seasons.
3.Unpredictable drought involves an abnormal
rainfall failure, mostly in localized areas of humid and
sub-humid climates.

17. Salinity Intrusion
 Saline water intrusion is mostly
seasonal in Bangladesh; in
winter months the saline front
begins to penetrate inland, and
the affected areas rise sharply
from 10 percent in the monsoon
to over 40 percent in the dry
season

18. Landslide
 Common in the hilly areas of southeastern
Bangladesh, especially in Bandarban,
Rangamati, Khagrachhari and Cox's Bazar.
 In Bangladesh, landslides are mostly
triggered by heavy rainfall. However,
underlying causes of landslide include
deforestation, hill cutting, unregulated
development work, etc.
 recently landslide has emerged as a major
hazard, particularly after the Chittagong
Landslide 2007.
 Around 90 mm of rainfall during 24 hours or
284 mm rain fall during 48 hours could
cause a landslide in Cox’s baxar and
Taknaf
 landslides and collapsed walls caused
widespread damages in six areas of
Chittagong city and in different Upazilas of
the District

19. The relationship between landforms and Hazards in Bangladesh
The landform factors that cause floods in Bangladesh
 Flat topography with elevation not exceeding 10
meters above mean sea level
 major rivers draining through Bangladesh
including a congested river network system
 Floodplain and piedmont plains occupy almost 80
percent of the land area
 About 50% of the country is within 6- 7m of MSL.
 About 68% of the country is vulnerable to floods.
 25%-30% of the area is inundated during normal
floods.

20. The relationship between landforms and Hazards in Bangladesh
The Physical Causes of the Floods:
 Most of the country consists of a huge flood
plain and delta.
 Snowmelt from the Himalayas takes place in
late spring & summer.
 70% of the total area is less than 1 meter above
sea level.
 10% of the land area is made up of Lakes and
Rivers.
 Bangladesh experiences heavy monsoon rains,
especially over the highlands.
 Tropical storms bring heavy rains and coastal
flooding.
 The main cause was the above average & long
period of heavy rain which caused all 3 rivers to
have their peak flow at the same time.
 In the spring, melting snow from the Himalayas
further increases the flood risks as torrents of
melt water enter the rivers at their source.

21. The landform factors that cause Cyclone in Bangladesh are:
 Cyclones enter the Bay as the remnants that
originate in the South China
 In the northern Bay of Bengal, a unique
combination of high tides, a funnelling
coastal configuration, the low flat coastal
terrain associated with storm surges
 The phenomenon of tropical cyclones is
related to the Bay of Bengal
 Shallow continental shelf especially in the
eastern part of Bangladesh with high tidal
range
 Triangular shape at the head of the Bay of
Bengal
 Because of the funnel shaped coast,
Bangladesh repeatedly becomes the
landing ground of cyclones formed in the
Bay of Bengal

22.  Formed by a delta plain at the
confluence of the GBM Rivers and their
tributaries, Bangladesh's alluvial soil is
highly fertile, but vulnerable to flood
and drought
 Bangladesh is at higher risk from
droughts. Between 1949 and 1991,
droughts occurred in Bangladesh 24
times.
 Very severe droughts hit the country in
1951, 1957, 1958, 1961, 1972, 1975,
1979, 1981, 1982, 1984 and 1989. Past
droughts have typically affected about
47% area of the country and 53% of the
population.

23. Earthquake
 Bangladesh is located in the
tectonically active Himalayan
organic belt that developed by the
collision among the Indian and
Eurasian plate. The number of active
fault is suggested within the
Chittagong. Tripura fault belt and the
Modhupur blind fault on the western
margin of Modhupur tract. Dauki
fault having the potential of
generating 8 magnitute earthquake

24.  Movement of Indian plate
towards the north
 Subduction of Burmese plate
Active fault line

25. Statistics of Arsenic Calamity in Bangladesh
Total Number of Districts in Bangladesh 64
Total Area of Bangladesh 148,393 km2
Total Population of Bangladesh 125 million
GDP Per Capita (1998) US$260.00
WHO Arsenic Drinking Water Standard 0.01 mg/l
Bangladesh Arsenic Drinking Water Standard 0.05 mg/l
Number of Districts Surveyed for Arsenic Contamination 64
Number of Districts Having Arsenic above 0.05 mg/l in
Groundwater
59

26. Arsenic Contamination
1. Arsenic concentrations in about half of the measurements
were above the
maximum permissible level of 0.05 mg/l in Bangladesh. In
1998, British
Geological Survey (BGS) collected 2022 water samples from
41 arsenic-affected
districts4. Laboratory tests revealed that 35% of these water
samples were found to
have arsenic concentrations above 0.05 mg/l.
2. The alluvial and deltaic sediments containing
pyrite has favored the arsenic
contamination of groundwater in Bangladesh. Most
regions of Bangladesh areomposed of a vast
thickness of alluvial and deltaic sediments

27. Conclusion
The impact of hazards due to our landform is enormous on our economy and life.
1.Total impact on economy due to natural hazards is enormous.

28. With Global warming and Climate change added to our
current problem. We are at the brink of a major
catastrophe. We can’t change our landform but we can
prepare and plan and take long term projects to protect
our selves and our resources. By being aware and being
prepared we can minimize the impact of any hazard.
Lets have a reality check and watch the below video.
https://www.youtube.com/watch?v=C2hXq47wz3Q

29. THANK YOU
Q & A