Chittagong is the second largest metropolis and Chief Port of Bangladesh. It is situated on the bank of the river Kharnaphuli, where the river meets the Bay of Bengal. The City area is a unique combination of hillocks in the north, flat land limited by river Kharnaphuli at south and east, coast line on the west and low lying Halda Valley on the north east. Within the city there are number of tidal canals. The serve as the main drainage channels of the area.