Most of the areas of Bangladesh lies within the broad delta formed by the Ganges and Brahmaputra rivers. Lands are 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 in the narrow southeastern panhandle of the country. There, on the border with Burma, is Mowdok Mual (1003 m/3292 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.
Total area: 144,000 square kilometers;
Land area: 133,910 square kilometers
Land boundaries: 4,246 km total; 193 km with Myanmar, 4,053 km with India, Coastline: 580 km.
Rivers and Lakes :
Bangladesh is a land of rivers that crisscrossed throughout the mostly flat territories of the country. They include hundreds of brooks and a good number of big ones. The Ganges (Ganga) 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 non-monsoon months the exposed ground is pocked with water-filled borrow pits, or tanks, from which the mud for the embankments was excavated. Throughout the country there are bils, haors and lakes that meet the need of drinking, bathing and irrigating water.
Traditionally Bangladeshis subdivide the year into six seasons: Grismo (summer), Barsha (rainy), Sharat (autumn), Hemanto (cool), Sheet (winter), and Bashonto (spring). For practical purposes, however, three seasons are distinguishable: summer , rainy, and winter.
Bangladesh has a tropical monsoon-type climate, with a hot and rainy summer and a dry winter. January is the coolest month with temperatures averaging near 26 deg C (78 d F) and April the warmest with temperatures from 33 to 36 deg C (91 to 96 deg F). The climate is one of the wettest in the world. Most places receive more than 1,525 mm of rain a year, and areas near the hills receive 5,080 mm ). Most rains occur during the monsoon (June-September) and little in winter (November-February).
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 country in the 20th century.
In Dhaka the average temperature in January is about 19° C (about 66° F), and in May about 29° C (about 84° F).
Flora and Fauna
Chittagong Hill Tracts, portions of the Madhupur Tract, and the Sundarbans (a great tidal mangrove forest in the southwestern corner of the country) are principal vegetation in Bangladesh. The wooded area amount to less than one-sixth 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 garan (in the Chittagong Hill Tracts). Village groves inslude 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 nearly 250 indigenous species of mammals, 750 types of birds, 150 kinds of reptiles and amphibians, and 200 varieties of marine and freshwater fish. The rhesus monkey is common, and gibbons and lemurs are also found.
The Sundarbans area is one of the principal remaining domains of the Royal Bengal tiger, and herds of elephants and many leopards inhabit the Chittagong Hill Tracts. Other animals living in Bangladesh include mongoose, jackal, Bengal fox, wild boar, parakeet, kingfisher, vulture, and swamp crocodile.
Bangladesh is not so rich in mineral resources. The principal energy resource, natural gas, is found in several small fields in the northeastern part. With the assistance of some foreign especially American companies gas expedition has increased. There is a coalfield in the northwest and large peat beds underlie most of the delta. Limestone and pottery clays are found in the northeastern Bangladesh.