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was slightly improved but the ventage at the sluice was too inadequate. Subsequently a scheme was
originally framed to drain a total area of 33.15 sq.km. (12.80 sq.mls.) of which 22.53 sq.km. area is
urban and 10.62 sq.km. being rural. Drainage indices @ 75 mm per day for urban and 20 mm for
rural area were adopted. The area is located on the east of the Budge Budge Rly. line and Tolly's
Nullah, Salt Lake Basin on the west, on the south of SWF channel and on the north of Tolly's Nullah.
The scheme was executed in 1972. It is one of the largest drainage arteries of the Kolkata
Metropolitan area. Apart from domestic discharges, it carries industrial wastes, decaying materials
and carcasses. Lots of unauthorised shanty dwellers residing on its banks also use it for their
sanitary purposes and disposal of solid wastes. The area is very much prone to water logging having
some low lying pockets.
T.P. Basin Drainage Scheme was designed to drain the additional urban run-off by excavating
another new lower level drainage channel named as "Intercepting Channel" connecting the Branch
Channels BB1, CC1, DD1, EE1, segregating the urban area from rural area and the urban run-off
would find its way through these channels to the Intercepting channel and the old TP Main Canal with
its outfall pumping station would cater for the rural run-off and some of the urban run-offs through
the other branch channels, viz. A1-A2, A3-A4, A5-A6 It was imperative to provide for pumping for
disposal of the additional discharge from the basin and accordingly, the new pumping station,
known as Chowbhaga New Pumping Station was constructed near the old one with 10 nos. of pumps
of 50 cusecs each making a total of 500 cusecs ( 14.16 cumecs ).
Originally, there were 9 nos. of Pumps of capacity 50 cusecs each at Chowbhaga being constructed
during the year 1966-67. Afterwards, the basin condition changed, additional basin area was
included, thereby increasing the area to 47.40 sq. km. (18.30 sq.mls.). A scheme for installation of
additional pumps was drawn up to drain out the extra water due to urbanisation and inclusion of more
rural areas. The capacity of new additional pump house was so designed that this pump house along
with the existing ones may cater a limited discharge of 41 cumecs (1450 cusecs) to the SWF
channel. As such, 1 5 nos. of pumps in total of capacity 50 cusecs each were installed.
The drainage of the South-Suburban and the Garden Reach areas falling within Kolkata Municipal
Corporation Ward nos. 115 to 132 and 133 to 141 areas is catered through Monikhali, Churial
Keorapukur Khals, a brief outline of which is discussed in the following paragraphs.
Monikhali Khal
Monikhali Basin, with an area of 54.00 sq. km. consists of two main drainage arteries (1) New
Monikhali Khal and (2) Old Monikhali Khal, the lengths being 6.931 Km. and 4.998 Kms.