The Sundarbans National Park is a national park, tiger reserve, and biosphere reserve in West Bengal, India. It is part of the Sundarbans on the Ganges Delta, and adjacent to the Sundarban Reserve Forest in Bangladesh. The delta is densely covered by mangrove forests, and is one of the largest reserves for the Bengal tiger. It is also home to a variety of bird, reptile and invertebrate species, including the salt-water crocodile. The present Sundarban National Park was declared as the core area of Sundarban Tiger Reserve in 1973 and a wildlife sanctuary in 1977. On 4 May 1984 it was declared a national park. It is a UNESCO World Heritage Site inscribed in 1987, and it has been designated as a Ramsar site since 2019. It is considered as a World Network of Biosphere Reserve from 2001.
The first forest management division to have jurisdiction over the Sundarbans was established in 1869. In 1875 a large portion of the mangrove forests was declared as reserved forests under the Forest Act, 1865 (Act VIII of 1865). The remaining portions of the forests were declared a reserve forest the following year and the forest, which was so far administered by the civil administration district, was placed under the control of the Forest Department. A forest division, which is the basic forest management and administration unit, was created in 1879 with the headquarters in Khulna, Bangladesh. The first management plan was written for the period 1893–1898.
Seven main rivers and innumerable watercourses form a network of channels at this estuarine delta. All the rivers have a southward course towards the sea. The eco-geography of this area is totally dependent on the tidal effect of two flow tides and two ebb tides occurring within 24 hours with a tidal range of 3–5 m and up to 8 m in normal spring tide, inundating the whole of Sundarban in varying depths. The tidal action deposits silts back on the channels and raising the bed, it forms new islands and creeks contributing to uncertain geomorphology. There is a great natural depression called "Swatch of No Ground" in the Bay of Bengal between 21°00' to 21°22' latitude where, the depth of water changes suddenly from 20 m to 500 m. This mysterious depression pushes back the silts towards south and further east to form new islands.
The Sunderban mudflats are found at the estuary and on the deltaic islands where low velocity of river and tidal current occurs. The flats are exposed in low tides and submerged in high tides, thus being changed morphologically even in one tidal cycle. The interior parts of the mudflats are the right environment for mangroves.
© 2017 Concept Conferences Pvt. Ltd