Cyclone and Storm Surge - Iczmpwb.org

3.31
Station, with a capacity of 4 x 50 = 200 cusecs was constructed in 1966-67 to drain out the water into
Tolly's Nullah.
3.16. Outfall sluices
At the outfall at Kultigong, the cross section of the river is gradually decreasing, resulting in
inadequate disposal capacity of the city’s drainage. Further, at the time of cyclonic storms, the
ingress of the storm surge wave combined with tides casuse a lockage at the outfalls. In order to
dispose the high volume of runoff (which is increasing with the rapid urbanisation of the Kolkata
environs), higher capacity pumps are required. It is estimated that the tidal lockage period has
steadily increased over the years and presently is about 18 hours in 24 hours. The different situations
possible for the outfall and the aggravation of the tidal lockage are shown in the following figures.
Figure 3-4. The downstream of the outfall (the Kultigong River) at low tide – outflowing sluice
Figure 3-5. The downstream of the outfall (the Kultigong river) at high tide – sluice gates closed