Cyclone and Storm Surge - Iczmpwb.org

Chapter Seven
Mitigation Strategies and Proposed Measures for
Kolkata and Surroundings
7.1. Present Status of the drainage system
CHAPTER 7
Dr. B.N. De's famous "Kulti Outfall Scheme" was commissioned with some gaps in 1943. Since then,
it has undergone major modifications and expansion to meet the rapid growth of the city's area and
population. Following the partition of the country, the city experienced an unprecedented and
protracted exodus from the east. Drainage lines were obstructed due to habitation. Too much and
rapid urbanisation resulted in inadequate drainage capacities of the channels. The city of Kolkata and
its burgeoning environs became victims of notorious flooding and drainage congestion every year.
Serious thinking started to see if anything can be done to ameliorate the distress of the people. The
outfall channels have been cleared from time to time; the capacities of the pump houses were
increased. But the lone Kultigong remains the ultimate drainage outfall from a much larger area. The
discharge is more but the dry weather flow contains a large quantity of domestic sewage. There is
practically no arrangement for treatment of this sewage. Hence the possibility of sedimentation of the
Kultigong cannot be ruled out. The prevailing tides at the outfall resulted in a sluggish disposal of
drainage water. All the drainage channels, viz. SWF, DWF, Bhangarkata, Bagjola have their outfalls
in Kultigong. The Kolkata Drainage Outfall System along with DWF, SWF, THC channels were
handed over by the Kolkata Municipal Corporation to the I.& W. Department on 01.5.1966. The
different outfalling channels being excavated long back as the carrier of drainage water and sewage
began to deteriorate. With the passage of time, due to heavy pressure under increased population
and other factors, the canals had a dwindling flow, somewhere being almost stagnant, the water
being in a brackish state mixed with toxic materials resulting in environmental and health hazards.
The effluent of the channels does not only contain simply house drainage but a large part of it
contains sewarage, toxic matters from small industries, tanneries and other solid wastes even from
Kolkata Slaughter House in the Town Head Cut Channel. The channel sections being worsened for
years together, disposal of drainage water suffered a setback and the purpose for which these
channels were excavated began to frustrate. The situation took its worst turn during the last week of
September, 1999 when heavy concentrated rainfall of 330 mm. within a period of only 10 hours