Bay of Bengla
The Bay of Bengal (BoB) is an arm of the Indian Ocean, between India on the west and the Malay Peninsula on the east, measuring about 2,090 km long by about 1,600 km wide. The Bay is generally considered to extend southwards beyond Sri Lanka, and as far as the coastlines of Thailand, Malaysia and the Indonesian island of Sumatra that border on the Andaman Sea and the Straits of Malacca, after which it merges into the waters of the Western Indian Ocean. The BoB region is defined as including selected coastal and Exclusive Economic Zone (EEZ) areas of eight countries (Bangladesh, India, Indonesia, Malaysia, Maldives, Myanmar, Sri Lanka and Thailand) as well as the international waters between them.
The above eight countries with the greatest extent of EEZ area in the Bay area, from largest to smallest and Bangladesh, Myanmar and Sri Lanka have 100% of their coastlines within the BoB area, while other countries have only parts of their coastline in the Bay. Several large rivers in the region flow into the BoB: the Ganges and the Brahmaputra (of Bangladesh) on the north; the Irrawaddy (of Myanmar) on the east; and the Mahanadi, the Godavari, the Krishna and the Cauvery (of India) on the west. These rivers introduce large quantities of silt into the bay from July-September during the summer monsoon season.
The coastal and marine zones of Bangladesh includes coastal plain lands, islands, tidal flat, estuaries, neritic and off-shore waters that extends to the edge of the continental shelf. A dynamic system of estuaries, islands and chars (silted submersed areas) is located along the entire coast. In terms of land area 32% (47,200 km2) of Bangladesh with 19 coastal districts out of 64 (11 meet sea or lower estuary directly), 147 upazillas out of 484 (48 are exposed to coast– exposed coast) belongs to the coastal zone with a population of about 40 million (28% of country total). The remaining 99 Upazillas of the coastal districts are termed interior coast.
However, depending on the tidal fluctuations, salinity (soil, surface and ground water), cyclone and storm surge risk, the coastal zone of Bangladesh has been delineated administratively as considering 19 districts and 147 Upazillas and also the EEZ. The rivers contributing to the coastal Bangladesh have deep sea connection through the 'Swatch of No ground' (a deep sea canyon) and thus have the potentiality to influence the tropical marine ecosystem due to its chemical load, which has far reaching spatial and temporal environmental and ecological consequences in the coast of Bangladesh.