HYDERABAD: Hyderabad is just a few centimetres of rainfall away from a man-made calamity, thanks to a combination of climate change induced high intensity rainfall in short duration, encroachment of natural drainage channels carrying water in and out of lakes and shrinking area of lakes due to encroachment of lake beds.Monday’s rainfall of 5-13 cms in a span of 4-5 hours across the city was enough to fill many lakes in Hyderabad to their brim. Surplus water could be seen gushing out from many lakes on Tuesday morning. As per GHMC, 55 lakes were filled up to 75 per cent of their capacity and 25 got filled up to 50 per cent.
It may be recalled that on September 13, after rainfall of about 11 cm in a span of few hours Banda cheruvu in Malkajgiri was filled to the brim causing flooding in areas as far as 2-3 kms from the lake.
While it was just one incident of flooding due to overflowing of lake which occurred that day, it is highly possible that in near future, multiple incidents like these might occur simultaneously across Hyderabad, wrecking human and economic loss of catastrophic proportions.Various studies conducted in Hyderabad have reported that frequency of climate change induced high intensity rainfall in short duration will just increase in coming years.
For example, a study by NIT-Warangal reported that in coming years, at least once in two years, there will be high intensity rainfall of 4.28 cm in just one hour, that can go up to 4.36cm/hr. V Swati, a research scholar at BITS-Pilani Hyderabad who has studied storm-water drainage network in Hyderabad, points out how in September last year, about 16.5 cm rainfall received in a few hours battered Hyderabad and again this year, two incidents of high intensity rainfall has battered the city this September.
Such high intensity rainfall in short duration is becoming a norm and it will just increase the chances of Malkajgiri-type incidents becoming regular as Hyderabad is home to more than 150 lakes. It will be very difficult if more than one lake overflows at the same time. Prof Chigurupati Ramachandraiah of Centre for Economic and Social Studies (CESS) says, “Natural drainage channels carrying run off water from rains in and out of lakes have been encroached along with even the weirs in some cases.
Accumulated water in lakes has to go somewhere. If a channel is not provided, it will obviously flood surrounding areas. Urban development authorities should either remove encroachments or find an alternative for allowing surplus water to flow out of lakes without causing flooding.”