[4] The combined catchment area of the Pagla–Bansloi river system is 2,200 square kilometres (850 sq mi).

[5] A number of rivers that originate on the Chota Nagpur Plateau or in Jharkhand, including the Bansloi, flow into Birbhum district.

They generate flood because of high rainfall in their basins and limited carrying capacity of the river Bhagirathi between the towns of Jangipur and Kalna.

In this reach the Bhagirathi has discharge carrying capacity of maximum 3,100 cubic metres per second (110,000 cu ft/s).

If all the rivers receive rainfall simultaneously in their catchment areas they can generate run-off volume of any amount up to 17,000 cubic metres per second (600,000 cu ft/s) at their outfall at the Bhagirathi.