Increase in paved surfaces leading to urban flooding

Plastic clogging drainage channels also playing a role in urban flooding: expert

A Telangana minister linked the recent flooding in parts of the State to the rise in groundwater table. But is there a link? “It is simple understanding that if the water table becomes shallow or near the surface, the percolation will be limited. And Telangana has seen a big rise in the water table,” says Pandith Madhnure of Telangana Ground Water Department.

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“But one of the main reasons for urban flooding has been the increase in asphalted and concrete surfaces. This has led to reduced percolation and more run-off leading to floods,” says Mr. Madhnure. A researcher investigating climate change and flooding in Hyderabad says 75% to 80% of the surface in the city has become impervious, leading to flooding. Telangana has seen a big increase in roads at the district, State and national highway levels. In 2016, Telangana had 2,696 kilometres of national highways; this went up by nearly a thousand km in 2019 with national highways covering 2,795 km. Coupled with increasing road density and urbanisation, plastic clogging surface and drainage channels is also playing a role in urban flooding.

The Groundwater Department statistics show that Telangana has seen a big improvement in water table that can be seen from the fact that only 1% of the State has water table less than 20 metres below ground level (MBGL) this year. In 2020, the area was 3% and in 2019 it constituted 12.3%. This stunning rise in water table is being credited to above normal rainfall over the past few years, clutch of big irrigation projects as well as the lake rejuvenation programmes undertaken by the State.

“Siddipet and Sircilla have shown one of the sharpest rise in water table. In Sircilla, it is due to the Upper Manair and Mid-Manair dams being full and are recharging the aquifer,” says Mr. Madhnure. In August 2019 the water table for Sircilla district was at 12.65 metres BGL, in 2020 it was at 5.54 mts BGL and in this year it is at 4.69 mts BGL. The decadal average of the district is 16.10 mts BGL. “Mission Kakatiya has led to rejuvenation of 27,000 lake bodies as well as 10,000 irrigation tanks. The dependency on ground water for drinking water too has dipped,” informs Mr. Madhnure.

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