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.

The only exceptions to Bangladesh's low elevations are the Chittagong Hills in the southeast, the Low Hills of Sylhetin the northeast, and highlands in the north and northwest. The Chittagong Hillsconstitute 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 non urban 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.

Bangladeshhas a tropical monsoon climate with a distinct dry season in the winter. It receives an average annual rainfall of 80 in. (203 cm), with most falling during the summer monsoon period; the Sylhet district in the northeast is the wettest part of the country, having an annual average rainfall of 140 in. (356 cm). The low-lying delta region is subject to severe flooding from monsoon rains, cyclones, and tidal waves that bring major crop damage and high loss of life. The cyclones of 1970 and 1991 and the monsoon floods of 1998 were particularly devastating.

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. 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.

Natural Regions

Most of Bangladesh lies within the broad delta formed by the Ganges and Brahmaputra rivers and is exceedingly flat, low-lying, and subject to annual flooding. Much fertile, alluvial soil is deposited by the floodwaters. The only significant area of hilly terrain, constituting less than one-tenth of the nation's territory, is the Chittagong Hill Tracts District in the narrow southeastern panhandle of the country.

There, on the border with Myanmar, is Mowdok Mual (1,003 m/3,291 ft), the country's highest peak. Small, scattered hills lie along or near the eastern and northern borders with India. The eroded remnants of two old alluvial terraces-the Madhupur Tract, in the north central part of the country, and The Barind, straddling the northwestern boundary with India-attain elevations of about 30 m (about 100 ft). The soil here is much less fertile than the annually replenished alluvium of the surrounding floodplain.

Climate

The climate of Bangladesh is of the tropical monsoon variety. In all areas about 80 percent of the annual rainfall typically occurs in the monsoon period, which lasts from late May to mid-October. Mean annual precipitation ranges from about 1,400 mm (about 55 in) along the country's east central border to more than 5,080 mm (200 in) in the far northeast.

In addition to the normal monsoonal rainfall, Bangladesh is subject to devastating cyclones, originating over the Bay of Bengal, in the periods of April to May and September to November. Often accompanied by surging waves, these storms can cause great damage and loss of life. The cyclone of November 1970, in which about 500,000 lives were lost in Bangladesh, was one of the worst natural disasters of the 20th century.

More than 120,000 were killed and millions left homeless in April 1991 when a powerful cyclone struck the coastal areas in the Ganges delta. Tornadoes, which also accompany the monsoon season, can cause harm to Bangladesh as well. In May 1996 a tornado ripped through northern Bangladesh, killing more than 440 people, injuring thousands, and destroying at least 80 villages.

Bangladesh has warm temperatures throughout the year, with relatively little variation from month to month. January tends to be the coolest month and May the warmest. In Dhaka the average January temperature is about 19° C (about 66° F), and the average May temperature is about 29° C (about 84° F).

Rivers and Lakes

Rivers are a prominent and important feature of the landscape in Bangladesh. Some rivers are known by different names in various portions of their course. The Ganges(Ganga), for example, is known as the Padma below the point where it is joined by the Jamuna River, the name given to the lowermost portion of the main channel of the Brahmaputra. The combined stream is then called the Meghna below its confluence with a much smaller tributary of the same name. In the dry season the numerous deltaic distributaries that lace the terrain may be several kilometers wide as they near the Bay of Bengal, whereas at the height of the summer monsoon season they coalesce into an extremely broad expanse of silt-laden water. In much of the delta, therefore, homes must be constructed on earthen platforms or embankments high enough to remain above the level of all but the highest floods. In nonmonsoon months the exposed ground is pocked with water-filled borrow pits, or tanks, from which the mud for the embankments was excavated. These tanks are a chief source of water for drinking, bathing, and small-scale irrigation.

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.

1 Jamuna-Brahmaputra
The Jamuna-Brahmaputra is 292 kilometers long and extends from northern Bangladesh to its confluence with the Padma.
2 Padma-Ganges
The second system is the Padma-Ganges, which is divided into two sections: a 258-kilometer segment,

3 Surma-Meghna
The third network is the Surma-Meghna system, which courses from the northeastern border with India to Chandpur, where it joins the Padma.

4 Padma-Meghna
This mighty network of four river systems flowing through the Bangladesh Plain drains an area of some 1.5 million square kilometers.
5 Karnaphuli.
A fifth river system, unconnected to the other four, is the Karnaphuli.

Vegetation and Animal Life

With the exception of the Chittagong Hill Tracts District, portions of the Madhupur Tract, and the Sundarbans (a great tidal mangrove swamp in the southwestern corner of the country), few extensive forests remain in Bangladesh, the forested and wooded area amounting to about one-eighth of the total area. Broadleaf evergreen species characterize the hilly regions, and deciduous trees, such as acacia and banyan, are common in the drier plains areas. Commercially valuable trees in Bangladesh include sundari (hence the name Sundarbans), gewa, sal (mainly growing in the Madhupur Tract), and garyan (in the Chittagong Hill Tracts District). Village groves abound in fruit trees (mango and jackfruit, for instance) and date and areca (betel) palms. The country also has many varieties of bamboo.

Bangladesh is rich in fauna, including 109 indigenous species of mammals, 684 types of birds, 119 kinds of reptiles, 19 different amphibians, and 200 varieties of marine and freshwater fish. The rhesus monkey is common, and gibbons and lemurs are also found. The Sundarbansarea is one of the principal remaining domains of theBengal tiger, and herds of elephants and many leopards inhabit the Chittagong Hill Tracts District. Other animals living in Bangladesh include mongoose, jackal, Bengal fox, wild boar, parakeet, kingfisher, vulture, and swamp crocodile.

Mineral Resources

The mineral endowment of Bangladesh is meager. The principal energy resource, natural gas, is found in several small fields in the northeast. There is a coalfield in the northwest and large peat beds underlie most of the delta. Limestone and pottery clays are found in the northeast.

Bangladesh an area of about 144,000 sq km, Bangladesh is situated between latitudes 20°34' and 26°38' north and latitudes 88°01' and 92°41' east. The country is bordered by India on the east, west and north and by the Bay of Bengal on the south. There is also a small strip of frontier with Burma on the southeastern edge. The land is a deltaic plain with a network of numerous rivers and canals.

Southern Asia, bordering the Bay of Bengal, between Burma and India.Bangladesh lies in the northeastern part of South Asia between 20° 34’ and 26° 38’ North latitude and 88° 01’ and 92° 41’ East longitude.
 

Total: 144,000 sq km
Land: 133,910 sq km
Water: 10,090 sq km

Slightly smaller than Wisconsin

Total: 4,246 km
Burma 193 km, India 4,053 km
Contiguous zone: 18 nautical miles.Continental shelf: up to the outer limits of the continental margin exclusive economic zone: 200 nautical miles.Territorial sea: 12 nautical miles.

Mostly flat alluvial plain; hilly in southeast
west point: Indian Ocean 0 mHighest point: Keokradong 1,230 meters
Natural gas, Arable land, Timber

Arable land: 73%, permanent crops: 2%, permanent pastures: 5%, forests and woodland: 15%, other: 5% (1993 est.)

Numberof Thana, Union Mouza and Municipality by Zila