Pune: There are around 170 flood-prone areas in the city that will change because of an increase in hard surface concreting , closed streams and improper stormwater drainage , said Shrikant Gabale, urban geomorphologist and an expert member of state govt’s pilot Pavana river rejuvenation project. “I have surveyed the city for ten years and from the change in landscapes it can be observed that Pune currently has over 170 flood-prone areas. These are areas where roads have been constructed recently without taking elevation into account, closing all stormwater drains in the process, near chowks, newly constructed societies, near Metro pillars and of course close to rivers and all of these is due to anthropogenic changes made to the topography of the city,” said Gabale.
Pune is surrounded by hills with multiple streams. “Most of the streams have been blocked due to constructions and encroachment. Hence, 95 percent of the rainwater slips away as run-off and joins the river and only 5 percent gets infiltrated,” Gabale added.
Experts said that heavy rain is likely to trigger floods in areas near 55 confluence regions of Mutha river and low-lying areas mainly due to floodline violations. Also, construction of 60 Metro pillars and piers on the riverbed has increased the chances of floods. Gabale also stated that every road and stormwater drain is designed to account for 70 to 80 mm of rainfall per hour, but this time it exceeded over 120 mm per hour, which the city could not handle.
The experts also blamed the change in topographical aspects of the river, such as the riverfront development project work at Bund Garden. “In 2019, when 90,000 cusecs of water were discharged, Ektanagari was not flooded, but now due to the rise in water level, owing to constructions on the riverbed, the area was flooded with discharge of 24,000 cusecs of water. This is because of afflux (increase in water level near constructions on the riverbed),” said Gurudas Nulkar, director of the Centre for Sustainable Development, Gokhale Institute of Politics and Economics.
“With constructions on hilltops and hillslopes, the rainwater does not recharge the aquifers there but runs down to the rivers and the city. The river water in the nullahs also spreads across the low-lying areas as there is no space to recharge the aquifers because of concreting. If the choked groundwater springs are opened, 30 to 40 per cent of water runoff can be managed,” said Shailaja Deshpande, the founder of Jeevitnadi.
Rajendra Pawar, former secretary, water resources department, said, “The only solution is for the civic body to measure the run-off downstream of the dam, which will help in flood mitigation.”.
