Cyclone and Storm Surge - Iczmpwb.org

3.8
larger volume of sewage and drainage from the north. The next important scheme "The Bidyadhari
Outfall Scheme" was drawn up by Hughes and Kimber in 1894, received administrative approval in
1897 (January 11) and executive sanction in 1900 (June 18). The scheme which became operational
in 1903 incorporated the establishment of Ballyganj pumping station and augmentation of the existing
Palmer's Bridge pumping station and included the following:
• High level sewers from the pumping stations to point "A" at Topsia further cast.
• Excavation of Town and Suburban storm water reservoirs leading to Central lake channel at
Bantola, protected by three sets of Stoney's gates - two for the Town system and one for the
Suburban system.
3.6. Development of the Calcutta Sewage and Storm Water Disposal Committee and the
Calcutta Improvement Trust
Even when Kolkata lost its preeminence as the capital of the British Raj in India in 1912, its
expansion continued, as it still remained the most important center of economic and cultural activities
in the country. Barring the period during which the World War I was raging (1914-18), a systematic
approach for the improvement of drainage in greater Kolkata including Manicktola, Cossipur,
Chitpore and adjoining areas was initiated by the newly formed "Calcutta Sewage and Storm Water
Disposal Committee" (1922) and the Conference of Enginners convened by the Calcutta
Improvement Trust (1911) in 1924. The emerging recommendations inter-alia included formation of a
Main Drainage Board responsible for dealing with the problem of the disposal of the sewage and
surface water in Kolkata and its suburbs, greatest possible use of the existing storm water overflows
to the Hooghly river, Tolly's Nullah and other adjoining waterways and establishment of new storm
water overflows as necessary.
3.7. Rivers and channels in and around Kolkata
Kolkata is located in the lower part of the Bengal Delta and is naturally traversed by a number of
interlaced distributaries emanating from the apex of the delta. Due to Kolkata's nearness to the sea
face, most of these rivers and channels are tidal in nature. As the velocity of tide entering the mouth
of a tidal river is high and as there is a vast reservoir of unconsolidated sediment in suspension along
the sea face, the tide as it flows up these rivers is highly charged with sediment. Duration of ebb tide
in a tidal river is much longer than the duration of the flow tide. As the same volume of water must