Estuary Description
Hooghly  (R1) ➢ It forms the western border of Indian Sundarbans.
➢ It is the main river of West Bengal and is a direct continuation of the River Ganges.
➢ Most of the coastal industries of West Bengal are concentrated along the western bank of this river.
Muriganga (R2) ➢ It is a branch of the Hooghly River.
➢ It flows along the east of Sagar Island, the largest island in the deltaic complex.
➢ Unique mangrove vegetation is found along its bank.
Saptamukhi (R3) ➢ It has its origin at Sultanpur.
➢ It is connected with the Muriganga (Bartala) branch of the Hooghly River through the Hatania-Duania canal.
Thakuran (R4) ➢ It begins near Jayanagar in 24 Parganas (South) and has a number of connections with the Saptamukhi.
➢ It was connected in the earlier times with the Calcutta Canal through the Kultali and the Piyali Rivers, which exist today in a dying state.
Matla (R5) ➢ This river originates at the confluence of Bidyadhari, Khuratya and the Rampur Khal close to the town of Canning in 24 Parganas (South).
➢ Matla is connected to Bidya and ultimately flows to the Bay of Bengal. The fresh water connection and discharge to this river has been lost in recent times.
➢ Salinity of the river water is relatively high (in comparison to Hooghly or Muriganga) owing to freshwater cut-off from the upstream region.
Bidyadhari* ➢ This was a flourishing branch of the Bhagirathi during the 15th and 16th centuries, but now serves only as a sewage and excess rainwater outlet from the city of Kolkata.
➢ The river bed is completely silted and presently is almost in dying condition.
Gosaba (R6) ➢ The waters of Matla and Harinbhanga (Raimangal) through a large number of canals form the estuary.
➢ The estuary and its numerous creeks flow through the reserve forests.
Harinbhanga (R7) ➢ It is the extreme easternmost river in the Indian Sundarbans deltaic complex.
➢ The Harinbhanga (also known as Ichamati and Raimangal) forms a natural demarcation between India and Bangladesh.
* Presently a dying estuary and not considered within the seven major types
Table 1: Seven most important rivers in the Indian Sundarbans.