Thursday, 18 October 2018

River of Bangladesh

Rivers are most important geographical feature in Bangladesh, and it is rivers which created the vast alluvial delta. The outflow of water from Bangladesh is the third highest in the world, after the Amazon and the Congo systems.

Bangladesh’s has rivers have been described as ‘young and migratory’, and even in the last 100 years there have been massive changes of course. This is not new. The history of the country is full of important cities becoming ghost towns because the rivers they were built on silted up or changed country exhorts people to stone grain in expectation of future floods. Many of the little lakes and ponds scattered around the country are the equivalent of the Australian billabongs-lagoons created when branches of meandering river are cut of.Annual flooding during the monsoon season is part of life in Bangladesh. But after the 1988 floods, some experts began speculating whether the flooding is getting worse and whether deforestation in India and especially Nepal, which causes increased runoff, may be the reason. Other experts are not so sure there has been change. Regardless, there has been increased pressure to ‘do something’ and find a ‘permanent solution’. Part of the problem of doing anything, however, is that the country depends for its fertility on regular flooding, and simply building massive dykes along riverbanks could be disastrous for agricultural output. The Bramhaputra-Jamuna and the lower Meghna are widest rivers, with the latter expanding to around eight km across in the wet season, and much more when it is in flood.The Ganges, which begins in the Indian state of Uttar Pradesh, enters Bangladesh from the north-west through Rajshahi Division. It joins the Brahmaputra in the centre of the country, north-west of the capital, Dhaka. The Ganges and the Brahmaputra rivers both receive new names once they pass into Bangladesh: the Ganges become the Padma, while the Brahmaputra is known as the Jamuna. It is these great rivers and the countless tributaries that flow from them that have the most apparent effect on the land-from- constant erosion and flooding over the alluvial plains change the course of rivers, landscape and agriculture. The Jamuna alone is estimated to carry down 900 million tones of silt each year.