|
Location: Southern Asia, bordering the Bay of Bengal, between
Burma and India
Geographic coordinates: 24 00 N, 90 00 E
Map references: Asia
Area:
total: 144,000 sq km
land: 133,910 sq km
water: 10,090 sq km
Area - comparative: slightly smaller than Wisconsin
Land boundaries:
total: 4,246 km
border countries: Burma 193 km, India 4,053 km
Coastline: 580 km
Maritime claims:
contiguous zone: 18 nm
continental shelf: up to the outer limits of the continental
margin
exclusive economic zone: 200 nm
territorial sea: 12 nm
Climate: tropical; cool, dry winter (October to March);
hot, humid summer (March to June); cool, rainy monsoon (June to
October)
Terrain: mostly flat alluvial plain; hilly in southeast
Elevation extremes:
lowest point: Indian Ocean 0 m
highest point: Keokradong 1,230 m
Natural resources: natural gas, arable land, timber
Land use:
arable land: 73%
permanent crops: 2%
permanent pastures: 5%
forests and woodland: 15%
other: 5% (1993 est.)
Irrigated land: 31,000 sq km (1993 est.)
Natural hazards: droughts, cyclones; much of the country
routinely flooded during the summer monsoon season
Environment - current issues: many people are landless and
forced to live on and cultivate flood-prone land; limited access
to potable water; water-borne diseases prevalent; water pollution
especially of fishing areas results from the use of commercial pesticides;
intermittent water shortages because of falling water tables in
the northern and central parts of the country; soil degradation;
deforestation; severe overpopulation
Environment - international agreements:
party to: Biodiversity, Climate Change, Desertification,
Endangered Species, Environmental Modification, Hazardous Wastes,
Nuclear Test Ban, Ozone Layer Protection, Wetlands
signed, but not ratified: Law of the Sea
Bangladesh
Geography
Size: Total 144,000 square kilometers, land area
133,910 square kilometers.
Topography: Broad deltaic plain. Chittagong Hills
in southeast, Low Hills in northeast and modest-elevation highlands
in north and northwest.
Climate: Subtropical monsoon climate, wide seasonal
variations in rainfall, moderately warm temperatures, high humidity.
Climate generally uniform throughout entire country. Subject to
severe natural disasters, such as floods, tropical cyclones, tornadoes,
and tidal bores.
Data as of September 1988
Bangladesh
GEOGRAPHY
The Land
The physiography of Bangladesh is characterized by two distinctive
features: a broad deltaic plain subject to frequent flooding, and
a small hilly region crossed by swiftly flowing rivers. The country
has an area of 144,000 square kilometers and extends 820 kilometers
north to south and 600 kilometers east to west. Bangladesh is bordered
on the west, north, and east by a 2,400-kilometer land frontier
with India and, in the southeast, by a short land and water frontier
(193 kilometers) with Burma. On the south is a highly irregular
deltaic coastline of about 600 kilometers, fissured by many rivers
and streams flowing into the Bay of Bengal. The territorial waters
of Bangladesh extend 12 nautical miles, and the exclusive economic
zone of the country is 200 nautical miles.
Roughly 80 percent of the landmass is made up of fertile alluvial
lowland called the Bangladesh Plain. The plain is part of the larger
Plain of Bengal, which is sometimes called the Lower Gangetic Plain.
Although altitudes up to 105 meters above sea level occur in the
northern part of the plain, most elevations are less than 10 meters
above sea level; elevations decrease in the coastal south, where
the terrain is generally at sea level. With such low elevations
and numerous rivers, water--and concomitant flooding--is a predominant
physical feature. About 10,000 square kilometers of the total area
of Bangladesh is covered with water, and larger areas are routinely
flooded during the monsoon season (see Climate;
River
Systems , this ch.).
The only exceptions to Bangladesh's low elevations are the Chittagong
Hills in the southeast, the Low Hills of Sylhet in the northeast,
and highlands in the north and northwest . The Chittagong Hills
constitute the only significant hill system in the country and,
in effect, are the western fringe of the northsouth mountain ranges
of Burma and eastern India. The Chittagong Hills rise steeply to
narrow ridge lines, generally no wider than 36 meters, 600 to 900
meters above sea level. At 1,046 meters, the highest elevation in
Bangladesh is found at Keokradong, in the southeastern part of the
hills. Fertile valleys lie between the hill lines, which generally
run north-south. West of the Chittagong Hills is a broad plain,
cut by rivers draining into the Bay of Bengal, that rises to a final
chain of low coastal hills, mostly below 200 meters, that attain
a maximum elevation of 350 meters. West of these hills is a narrow,
wet coastal plain located between the cities of Chittagong in the
north and Cox's Bazar in the south.
About 67 percent of Bangladesh's nonurban land is arable. Permanent
crops cover only 2 percent, meadows and pastures cover 4 percent,
and forests and woodland cover about 16 percent. The country produces
large quantities of quality timber, bamboo, and sugarcane. Bamboo
grows in almost all areas, but high-quality timber grows mostly
in the highland valleys. Rubber planting in the hilly regions of
the country was undertaken in the 1980s, and rubber extraction had
started by the end of the decade. A variety of wild animals are
found in the forest areas, such as in the Sundarbans on the southwest
coast, which is the home of the worldfamous Royal Bengal Tiger.
The alluvial soils in the Bangladesh Plain are generally fertile
and are enriched with heavy silt deposits carried downstream during
the rainy season.
Data as of September 1988
Bangladesh
Climate
Bangladesh has a
subtropical monsoon climate characterized by wide seasonal variations
in rainfall, moderately warm temperatures, and high humidity. Regional
climatic differences in this flat country are minor. Three seasons
are generally recognized: a hot, humid summer from March to June;
a cool, rainy monsoon season from June to October; and a cool, dry
winter from October to March. In general, maximum summer temperatures
range between 32°C and 38°C. April is the warmest month
in most parts of the country. January is the coldest month, when
the average temperature for most of the country is 10°C.
Winds are mostly from the north and northwest in the winter, blowing
gently at one to three kilometers per hour in northern and central
areas and three to six kilometers per hour near the coast. From
March to May, violent thunderstorms, called northwesters by local
English speakers, produce winds of up to sixty kilometers per hour.
During the intense storms of the early summer and late monsoon season,
southerly winds of more than 160 kilometers per hour cause waves
to crest as high as 6 meters in the Bay of Bengal, which brings
disastrous flooding to coastal areas.
Heavy rainfall is characteristic of Bangladesh. With the exception
of the relatively dry western region of Rajshahi, where the annual
rainfall is about 160 centimeters, most parts of the country receive
at least 200 centimeters of rainfall per year (see
fig. 1). Because of its location just south of the foothills
of the Himalayas, where monsoon winds turn west and northwest, the
region of Sylhet in northeastern Bangladesh receives the greatest
average precipitation. From 1977 to 1986, annual rainfall in that
region ranged between 328 and 478 centimeters per year. Average
daily humidity ranged from March lows of between 45 and 71 percent
to July highs of between 84 and 92 percent, based on readings taken
at selected stations nationwide in 1986 .
About 80 percent of Bangladesh's rain falls during the monsoon
season. The monsoons result from the contrasts between low and high
air pressure areas that result from differential heating of land
and water. During the hot months of April and May hot air rises
over the Indian subcontinent, creating low-pressure areas into which
rush cooler, moisture-bearing winds from the Indian Ocean. This
is the southwest monsoon, commencing in June and usually lasting
through September. Dividing against the Indian landmass, the monsoon
flows in two branches, one of which strikes western India. The other
travels up the Bay of Bengal and over eastern India and Bangladesh,
crossing the plain to the north and northeast before being turned
to the west and northwest by the foothills of the Himalayas .
Natural calamities, such as floods, tropical cyclones, tornadoes,
and tidal bores--destructive waves or floods caused by flood tides
rushing up estuaries--ravage the country, particularly the coastal
belt, almost every year. Between 1947 and 1988, thirteen severe
cyclones hit Bangladesh, causing enormous loss of life and property.
In May 1985, for example, a severe cyclonic storm packing 154 kilometer-per-hour
winds and waves 4 meters high swept into southeastern and southern
Bangladesh, killing more than 11,000 persons, damaging more than
94,000 houses, killing some 135,000 head of livestock, and damaging
nearly 400 kilometers of critically needed embankments. Annual monsoon
flooding results in the loss of human life, damage to property and
communication systems, and a shortage of drinking water, which leads
to the spread of disease. For example, in 1988 two-thirds of Bangladesh's
sixty-four districts experienced extensive flood damage in the wake
of unusually heavy rains that flooded the river systems. Millions
were left homeless and without potable water. Half of Dhaka, including
the runways at the Zia International Airport--an important transit
point for disaster relief supplies--was flooded. About 2 million
tons of crops were reported destroyed, and relief work was rendered
even more challenging than usual because the flood made transportation
of any kind exceedingly difficult.
There are no precautions against cyclones and tidal bores except
giving advance warning and providing safe public buildings where
people may take shelter. Adequate infrastructure and air transport
facilities that would ease the sufferings of the affected people
had not been established by the late 1980s. Efforts by the government
under the Third Five-Year Plan (1985-90) were directed toward accurate
and timely forecast capability through agrometeorology, marine meteorology,
oceanography, hydrometeorology, and seismology. Necessary expert
services, equipment, and training facilities were expected to be
developed under the United Nations Development Programme .
Data as of September 1988
Bangladesh
River Systems
The rivers of Bangladesh mark both the physiography of the nation
and the life of the people. About 700 in number, these rivers generally
flow south. The larger rivers serve as the main source of water
for cultivation and as the principal arteries of commercial transportation.
Rivers also provide fish, an important source of protein. Flooding
of the rivers during the monsoon season causes enormous hardship
and hinders development, but fresh deposits of rich silt replenish
the fertile but overworked soil. The rivers also drain excess monsoon
rainfall into the Bay of Bengal. Thus, the great river system is
at the same time the country's principal resource and its greatest
hazard.
The profusion of rivers can be divided into five major networks
. The Jamuna-Brahmaputra is 292 kilometers long and extends from
northern Bangladesh to its confluence with the Padma. Originating
as the Yarlung Zangbo Jiang in China's Xizang Autonomous Region
(Tibet) and flowing through India's state of Arunachal Pradesh,
where it becomes known as the Brahmaputra ("Son of Brahma"), it
receives waters from five major tributaries that total some 740
kilometers in length. At the point where the Brahmaputra meets the
Tista River in Bangladesh, it becomes known as the Jamuna. The Jamuna
is notorious for its shifting subchannels and for the formation
of fertile silt islands (chars). No permanent settlements
can exist along its banks.
The second system is the Padma-Ganges, which is divided into two
sections: a 258-kilometer segment, the Ganges, which extends from
the western border with India to its confluence with the Jamuna
some 72 kilometers west of Dhaka, and a 126-kilometer segment, the
Padma, which runs from the Ganges-Jamuna confluence to where it
joins the Meghna River at Chandpur. The Padma-Ganges is the central
part of a deltaic river system with hundreds of rivers and streams--some
2,100 kilometers in length--flowing generally east or west into
the Padma.
The third network is the Surma-Meghna system, which courses from
the northeastern border with India to Chandpur, where it joins the
Padma. The Surma-Meghna, at 669 kilometers by itself the longest
river in Bangladesh, is formed by the union of six lesser rivers.
Below the city of Kalipur it is known as the Meghna. When the Padma
and Meghna join together, they form the fourth river system--the
Padma-Meghna--which flows 145 kilometers to the Bay of Bengal.
This mighty network of four river systems flowing through the Bangladesh
Plain drains an area of some 1.5 million square kilometers. The
numerous channels of the Padma-Meghna, its distributaries, and smaller
parallel rivers that flow into the Bay of Bengal are referred to
as the Mouths of the Ganges. Like the Jamuna, the Padma-Meghna and
other estuaries on the Bay of Bengal are also known for their many
chars.
A fifth river system, unconnected to the other four, is the Karnaphuli.
Flowing through the region of Chittagong and the Chittagong Hills,
it cuts across the hills and runs rapidly downhill to the west and
southwest and then to the sea. The Feni, Karnaphuli, Sangu, and
Matamuhari--an aggregate of some 420 kilometers--are the main rivers
in the region. The port of Chittagong is situated on the banks of
the Karnaphuli. The Karnaphuli Reservoir and Karnaphuli Dam are
located in this area. The dam impounds the Karnaphuli River's waters
in the reservoir for the generation of hydroelectric power.
During the annual monsoon period, the rivers of Bangladesh flow
at about 140,000 cubic meters per second, but during the dry period
they diminish to 7,000 cubic meters per second. Because water is
so vital to agriculture, more than 60 percent of the net arable
land, some 9.1 million hectares, is cultivated in the rainy season
despite the possibility of severe flooding, and nearly 40 percent
of the land is cultivated during the dry winter months. Water resources
development has responded to this "dual water regime" by providing
flood protection, drainage to prevent overflooding and waterlogging,
and irrigation facilities for the expansion of winter cultivation.
Major water control projects have been developed by the national
government to provide irrigation, flood control, drainage facilities,
aids to river navigation and road construction, and hydroelectric
power. In addition, thousands of tube wells and electric pumps are
used for local irrigation. Despite severe resource constraints,
the government of Bangladesh has made it a policy to try to bring
additional areas under irrigation without salinity intrusion .
Water resources management, including gravity flow irrigation,
flood control, and drainage, were largely the responsibility of
the Bangladesh Water Development Board. Other public sector institutions,
such as the Bangladesh Krishi Bank, the Bangladesh Rural Development
Board, the Bangladesh Bank, and the Bangladesh Agricultural Development
Corporation were also responsible for promotion and development
of minor irrigation works in the private sector through government
credit mechanisms .
Data as of September 1988
|
