Cyclone and Storm Surge - Iczmpwb.org

7.7
12
Excavation of Channel Down Stream
with side & bed lining and protection at LS 5,700,000
13 th Bridge tfdownstream ll i l di th of pump t house ti t m 36 100,000 3,600,000
14 Concrete /Metalled road Sq.m 1200 800,00 960,000
15 Boundary wall m 180 3,000,00
16 Sub-station Building (Electrical) L.S 3,500,000
17 Gates Sq.m 40 1,600,00 64.000
18 Guard posts on road Each 16 1,040 16,640
19 Soil Investigation & Survey LS 100,000
SubTotal 77, 518, 640
Add 5% for Contingency (Rs.) 3,875,932
Total of Civil Works (B) 81,394,572
Grand Total ( A + B)
178,684,222
Say, Rs. 18 Crore
7.4. Recommendations for water conveyance
It has been explained how the river Bidyadhari, which used to convey the sewage and storm
water of Kolkata more than a century back had become choked with sediment and silt over
the years forcing Dr. B N Dey to suggest a 35 km long water disposal channel to the river
Kultigong. It is apparent that the untreated sewage that has been disposed off into the river
Kultigong has caused it to reduce in cross section over the years (Table 3-3). It may not be
very far fetched to imagine that this river is likely to get choked in another 50 years’ time,
unless some action is taken now to correct it. As may be apparent, once the riverbed level of
Kultigong rises, the tidal lockage period is likely to increase due to the rise of the high tide
levels, which has to be countered by setting up further high capacity pumps at the outfall
points of the drainage disposal channels. In the event of a high precipitation (as during a
cyclonic storm) the city of Kolkata and its surroundings discharging storm water through the
Bagjola, Kestopur and SWF channels would face a difficult situation of storm water disposal
and may be waterlogged for more than a day in much of its parts. This is because, the storm
water that would be carried down these channels may have difficulty in discharging into the
Kultigong as its water level is expected to be reigning high at this time by an action of high
tide and storm surge. The effect of the river Kultigong reflecting upon the water disposals of