Flattening of hillocks played a crucial role in the flooding of the city’s western parts on Friday when a 7.5-cm rainfall threw traffic out of whack for a few hours.
“The topography of the area has been changed, and even rock formations have been levelled, disturbing the hydrology patterns leading to localised flooding,” says Anant Maringanti of Hyderabad Urban Labs who has studied the episodic flooding in the city.
While disappearing lakes have been the focus of debate about flooding, satellite images over the last two decades show the extent to which the hillocks in the city’s western part have been erased over a period of time.
One of the worst gridlocks on Friday evening was in Mindspace Junction. Satellite images from 2003 show a rough terrain with tor formations and a single road passing through it. Cut to 2019, the same area is covered with layers of asphalt and concrete. Rock formations have completely disappeared, affecting the rainwater run-off flow patterns.
“The water from Chiran Kunta used to travel to Shaikpet Kotha Cheruvu. One hillock has been removed and a channel cut through the valley. In the absence of the natural channel, the water is flooding the surrounding areas,” says Mr. Maringanti.
An official of Groundwater Department says, “Hyderabad has 79-80% hard rock where water permeability is negligible. Only 1.5 to 3% rainwater will reach the groundwater as most of the city is on gneiss and granite formations. The problem is compounded by asphalt and concrete closing the pathways for water seepage,” says an official of Groundwater Department of Telangana.
Hyderabad needs about 700 million gallons per day (mgld) of water. The civic body supplies about 340 mgld. Citizens get the rest from other sources, majorly from groundwater. “Officials are proposing massive pump sets to drain flood water. How feasible and effective they will be is a big question,” says Mr. Maringanti.
Absence of regulations
Anuradha Reddy of Indian National Trust for Art and Cultural Heritage says, “The western part was developed in a vacuum of regulations. The area was chosen because there were no municipal regulations. Rock formations there are all gone now. Heritage regulations would have saved the area from this situation.”
