Physical Features
The Sundarbans, covering some 10,000 square kilometers (km2) of mangrove forest and water (of which some 40% is in India and the rest in Bangladesh), is part of the world's largest delta (80,000 km2) formed from sediments deposited by three great rivers, the Ganges, Brahmaputra and Meghna, which converge on the Bengal Basin. The whole Sundarbans area is intersected by an intricate network of interconnecting waterways, of which the larger channels are often a mile or more in width and run in a north-south direction.
These waterways, apart from the Baleswar River on the eastern edge of the Bangladesh Sundarbans, now carry littlere freshwater as they are mostly cut off from the Ganges, the outflow of which has shifted from the Hooghly-Bhagirathi channels progressively eastwards since the seventeenth century. This is due to subsidence of the Bengal Basin and a gradual eastward tilting of the overlying crust. In the Indian Sundarbans, the western portion receives some freshwater through the Bhagirathi-Hooghly river system but that portion designated as the tiger reserve is essentially land-locked, its rivers having become almost completely cut off from the main freshwater sources over the last 600 years. Thus, waterways in the tiger reserve are maintained largely by the diurnal tidal flow, the average rise and fall being about 2.15 m on the coast and up to 5.68 m on Sagar Island. Tidal waves are a regular phenomenon and may be up to 75 m high. The land is constantly being changed, molded and shaped by the action of the tides, with erosion processes more prominent along estuaries and deposition processes along the banks of inner estuarine waterways influenced by the accelerated discharge of silt from seawater. About half of the Sundarbans is under water and the rest of the landscape is characterized by low-lying alluvial islands and mudbanks, with sandy beaches and dunes along the coast. As with the rest of the Bengal Plain, alluvial deposits are geologically very recent and deep, sediment of just the last few million years being as much as 1,000 m thick. The subsoil consists of alternate layers of clay and sand, gradually changing into shales and sandstone. The soil is clayey loam down to a depth of 1.1-1.4 m and thereafter stiff black clay. It is alkaline due to an excess of sodium chloride. An estimation of land loss and accretion has been made using remote sensing techniques
These waterways, apart from the Baleswar River on the eastern edge of the Bangladesh Sundarbans, now carry littlere freshwater as they are mostly cut off from the Ganges, the outflow of which has shifted from the Hooghly-Bhagirathi channels progressively eastwards since the seventeenth century. This is due to subsidence of the Bengal Basin and a gradual eastward tilting of the overlying crust. In the Indian Sundarbans, the western portion receives some freshwater through the Bhagirathi-Hooghly river system but that portion designated as the tiger reserve is essentially land-locked, its rivers having become almost completely cut off from the main freshwater sources over the last 600 years. Thus, waterways in the tiger reserve are maintained largely by the diurnal tidal flow, the average rise and fall being about 2.15 m on the coast and up to 5.68 m on Sagar Island. Tidal waves are a regular phenomenon and may be up to 75 m high. The land is constantly being changed, molded and shaped by the action of the tides, with erosion processes more prominent along estuaries and deposition processes along the banks of inner estuarine waterways influenced by the accelerated discharge of silt from seawater. About half of the Sundarbans is under water and the rest of the landscape is characterized by low-lying alluvial islands and mudbanks, with sandy beaches and dunes along the coast. As with the rest of the Bengal Plain, alluvial deposits are geologically very recent and deep, sediment of just the last few million years being as much as 1,000 m thick. The subsoil consists of alternate layers of clay and sand, gradually changing into shales and sandstone. The soil is clayey loam down to a depth of 1.1-1.4 m and thereafter stiff black clay. It is alkaline due to an excess of sodium chloride. An estimation of land loss and accretion has been made using remote sensing techniques
Cultural Heritage
Baghmara Forest Block contains the ruins of a city built by the Chaand Sandagar merchant community approximately 200-300 AD. Much later, during the Moghul Empire, Raja Basand Rai and his nephew took refuge in the Sundarbans from the advancing armies of Emperor Akbar.
The buildings which they erected subsequently fell to Portuguese pirates, salt smugglers and dacoits in the 17th century. The ruins are evident at Netidhopani and elsewhere. The Sundarbans feature prominently in Bengali literature, for example Bankim Chandra Chatterjee's novel "Kapal Kundla". Banbibi, incarnation of the Goddess Durga, is the reigning deity in the area. Her blessings are sought for protection from the tiger. Reclamation of the Sundarbans commenced in 1770 and is described by Bandyopadhyay (1985).
The buildings which they erected subsequently fell to Portuguese pirates, salt smugglers and dacoits in the 17th century. The ruins are evident at Netidhopani and elsewhere. The Sundarbans feature prominently in Bengali literature, for example Bankim Chandra Chatterjee's novel "Kapal Kundla". Banbibi, incarnation of the Goddess Durga, is the reigning deity in the area. Her blessings are sought for protection from the tiger. Reclamation of the Sundarbans commenced in 1770 and is described by Bandyopadhyay (1985).
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