Changing course

The Teesta River is one of the important geographical features of Siliguri. It enters the plains at Sevoke where the narrow mountain torrent opens up to form a wide river. It has been dammed at the Teesta Barrage a little lower on the course.
However I bring up the Teesta because I was reminded of it by the recent change in course of the Kosi River in Bihar. The recent floods caused it to shift to a course that it had not followed for two hundred years. This has caused unprecedented havoc in North Bihar.

I do not know if you are aware, but the Teesta did a similar thing similar in 1787, following a devastating earthquake and a major flood. This earthquake took place on the 12th of June that year. It was probably the same quake that also destroyed one of the towers of St Paul’s Cathedral in Calcutta. Previous to this the Teesta , when it entered the plains divided into three streams, the Karatoya to the east, the Punarbhaba in the west and the Atrai in the centre. This led to its name the Tri srota which was later corrupted to the Teesta. Of these three the Punarbhaba joined the Mahananda, the Atrai passing through a vast marshy area known as Chalan Beel joined the Karatoya and the united stream joined the Padma near Jafarganj. In the destructive floods of 1787, the Teesta forsook its old channel and rushing south-east it joined the Brahmaputra. An earlier map of Bengal prepared by Runnel showed these three streams. All these streams combined lower down with the Mahananda, now the westernmost river in North Bengal, and taking the name of Hoorsagar finally discharged into the Ganges at Jafarganj, near modern Goalundo. . In the Siyar-al-Mutakhkhirin it is recorded that the Karatoya was three times the size of the Ganges when Bakhtiyar Khilji invaded the northern parts of Bengal in 1115
The Hoorsagar river is still in existence being the combined outfall of the Baral, a spill channel of the Ganges, the Atrai, the Jamuna or Jamuneswari (not the main Jamuna through which the Brahmaputra now flows), and the Karatoya, but instead of falling into the Ganges, it falls into the main Jamuna, a few miles above its confluence with the Padma at Goalundo. In recent times, after the flood of 1950’s it is observed that a huge quantity of water of river Teesta is flowing through Buri Teesta and falling into theYamuna in Bangladesh. This led to flood threats to Jalpaiguri town which is now protected by an embankment. The floods of 1968 ( which we remember, I was a schoolboy in Kolkata then) caused the river to open a new course through Upalchand Forest near Kathalbari in Mal block. It devastated huge quantity of forest area. A big chunk of Upalchand Forest was washed out at this time.
There are many concerns about the stability of these rivers. It is quite possible that a major natural event may cause a major geographical change, as we have seen in Bihar. It would be meaningless to try to be prepared as if such a change occurs,it is likely to cause a sort of change that cannot be predicted.

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