HYDERABAD: Hyderabad stands to lose quite a lot to urban flooding in the future, unless its concretisation is kept under check and existing open spaces are protected.
The August-2000 urban floods caused by a record 241-mm rainfall in a span of 24 hours had resulted in the loss of 26 lives and Rs 135 crore worth of property in the city.
In comparison, the floods in October 2020, when Hyderabad received 192-mm rainfall in a day, claimed 61 lives and destroyed property worth Rs 5,000 crore.
How are these two calamities different? A group of researchers from Sree Vidyanikethan Engineering College, NIT-Warangal and Indian Institute of Remote Sensing used geospatial data to examine how the land use-land cover pattern changed during the 2000-2020 period in the Greater Hyderabad Municipal Corporation’s (GHMC) zone-12.
This zone includes some of the most flood-affected areas from last year, like Begumpet, Ameerpet, Madhapur, Kukatpally, Rajiv Gandhi Nagar and Tulasi Nagar.A stark difference was observed in the percentage of impervious surfaces — areas that do not allow rainwater to seep into the ground, such as paved roads or buildings — in the region across two decades. The researchers found that the impervious surface in zone-12 expanded from 65 per cent in 2000 to a whopping 89 per cent in 2020. They said that it increased due to lack of open lands, which in turn was caused by encroachment of green spaces and water bodies.
‘Govt must insist on rainwater harvesting structures’
The researchers added, “The increased imperviousness limits the infiltration process, thereby increasing the total run-off from the urbanised catchments up to six times and peak flows up to 1.8–8 times. This leads to flooding.” These findings have been reported in the paper titled ‘Rapid assessment of the October 2020 Hyderabad urban flood and risk analysis using geospatial data’, in the journal Current Science. Dr NV Umamahesh, faculty member at NIT-Warangal, said, “At least now, the government must insist that the existing buildings develop rainwater harvesting structures. It is essential to maintain storm water drains properly.”
Rains throw life out of gear
Even as low-lying areas are yet to get relief from inundation, moderate to heavy rainfall added to waterlogging woes in several part of the city on Sunday. Among the most affected areas was Makkah Colony in Basarathnagar, where a nearby nala overflowed due to heavy downpour, resulting in severe inundation. A closed drain also prevented water seepage, leading to water stagnation.
At PVR Expressway, between pillar No 175 and No 200, there was severe waterlogging where the water rose up to a foot in height, causing inconvenience to commuters, most of whom had a tough time wading through the water.
As there was flood-like situation in Khairatabad and on Raj Bhavan Road, vehicular movement was affected with many two wheelers and cars moving at a snail’s pace. There was heavy downpour near Punjagutta circle and it hampered traffic flow for some time. The Disaster Response Force (DRF) teams had a tough time in clearing stagnated rainwater at several points and were also busy in addressing issues like removal of uprooted trees.
T’SHOWERS TODAY
Hyderabad: Many parts of Telangana reported light to moderate rainfall on Sunday. A handful of places recorded heavy rains, with the highest rainfall recorded being 79 mm at Dudyal in Vikarabad district. In the GHMC limits, Bahadurpura recorded the highest rainfall of 50 mm. The India Meteorological Department said that thunderstorms and lightning were likely at isolated places across the State on Monday. The maximum temperatures recorded were more or less normal in most places across Telangana.