Rupsa-Pasur River the pasur river is a continuation of the Rupsa, which is formed of the union of the bhairab and atrai rivers. At present, much of its water is from the gorai diverted through the nabaganga . From near Batiaghata upazila the Rupsa changes its name to Kazibacha, which is given up near Chalna in favour of Pasur. Near the mongla port, the Pasur receives Mongla river, and near the forest outpost at Chandpai it receives the Mirgamari cross-channel from the Bhola, both on the leftbank. On the rightbank the Manki, Dhaki and bhadra are connected with the shibsa system. In the lower delta, the Rupsa-Pasur is second only to the meghna in size. Formerly it was third, after the madhumati, but with the considerable diversion of the Gorai flow through Nabaganga, it is now bigger than that river. From its junction with the Mongla, it is no less than a kilometre and a half in width. Thirty-two kilometres from the open sea, it joins the Shibsa to form the five to eight kilometres wide Morzal river, which empties into the bay of bengal by the Marjat and Pasur estuaries.
The land between the Pasur and the Bhola is drained by the Sela, which lies wholly within the sundarbans. Many cross-channels connect it with the systems on either side. A large cross-channel connects it with the Morzal at the head of its estuary. East of the Sela the next largest river is the Bhola, which begins as a small channel where the Bhairab becomes the Keora tributary of the Baleshwar. The Bhola falls into the Haringhata estuary of Baleshwar. The Baleshwar, which is a continuation of the Gorai-Madhumati, has played a very important role in building up the Mature Delta. The Bagerhat and Pirojpur districts depend upon it for the annual deposit of silt. Formerly the floodwaters kept the seawater from reaching beyond the Bogi at the edge of the Sundarbans but with the diversion of the Gorai into the Pasur, the river is decaying. The flow was sufficient to make the forests of freshwater nature grow within 16 km of the sea. At the point of its junction with the Bhola it widens out to 6 km to form one of the sources of the huge Haringhata estuary, which also receives the flows of the bishkhali and the burishwar and so reaches a maximum width of 19 km. The Rupsa-Pasur is about 142 km long and the entire course is under tidal influence. [Masud Hasan Chowdhury]
See map in ganges-padma river system.