It takes a short spell of rain to expose the chinks in the monsoon preparedness of the Bruhat Bengaluru Mahanagara Palike (BBMP), and this year appears to be no different. With every spate of pre-monsoon showers received this month, low-lying areas were inundated and the condition of roads deteriorated.
The Karnataka State Natural Disaster Monitoring Centre (KSNDMC) has identified 211 vulnerable spots in the city that are prone to flooding.
BBMP’s chief engineer Prahallad B.N. said that of the 211 vulnerable spots, 58 have been categorised as sensitive and the remaining 153 as moderately sensitive. KSNDMC, he said, had identified flood-prone areas based on a model that they had created.
According to a senior official at KSNDMC, a digital elevation model had been created based on historical data on frequently flooded areas, satellite terrain mapping, and data on black spots (junctions that get water logged) identified by traffic police.
“All this was overlaid on the GIS platform to identify the vulnerable spots. The amount of rainfall that could trigger flooding or inundation ranged between 1.5 cm to 4 cm. The variation is dependant on terrain and was location specific,” said the official, adding that they have identified nearly 10 locations that could get inundated with just 1.5 cm of rainfall.
Desilting of drains
To ensure free flow of water, the civic body had taken up desilting of stormwater drains, Mr. Prahallad said. Under the comprehensive annual maintenance, desilting of 440 km of drains had been taken up. The silt that is being cleared from these drains is being dumped in the Anjanapura quarry pit, he added.
Meanwhile, the KSNDMC had installed 28 water level sensors in the stormwater drains to get real-time data. The data is colour coded – green or blue (normal water level), red (danger level) and black (flooded).
KSNDMC official said the plan was to initially install 50 sensors at vulnerable points. “However, due to fund crunch, we have only installed 28. The remaining 22 may be installed with funds from the State government,” the official added.