Bengaluru: Floods and waterlogging are the two major problems faced by people of Bengaluru when it rains. The authorities have repeatedly failed to address the issue. Which is why someone has done a Ph.D on the subject!
Mr. Ajay S. Bharadwaj, Deputy Manager, Air Traffic Control, HAL Airport, has come up with a number of suggestions such as: permeable surfaces, artificial recharge trenches and rain water percolation to arrest flooding and waterlogging. He has been awarded a PhD for his thesis at the recentconvocation of Kuvempu University, Shivamogga.
Mr. Bharadwaj has prepared his thesis (titled ‘Bengaluru City Flood Risk Assessment and Management’) using Remote Sensing and GIS under the guidance of Syed Ashfaq Ahmed, Professor of Geology.
Based on the study of the flooding and rainfall in the state over decades, now Mr. Bharadwaj has come up with six permanent solutions linked to the geographical structure of the city.
According to the findings, the city is highly vulnerable to floods during two months of every year i.e. September (average rainfall: 185.99 mm), October (161.66 mm). As per the flood vulnerability classification, the city is vulnerable to floods in May, July and August while April, June and November are classified as less vulnerable months. January, February, March and December are considered non-vulnerable.
Field observations
Mr. Bharadwaj based his findings on field observations. He has now come up with six permanent solutions to end the rain-related floods in the city. One of the major suggestions is permeable surfaces. According to the study findings, one of the major problems in the city is the lack of pervious layers on the ground due to urbanisation.
As a result a lot of water flows on the ground, resulting in increased surface water runoff and higher flooding in the downstream area. Increased permeable areas on the ground will help in addressing this problem to a great extent.
So it is suggested that in places like parking areas, footpaths, walking and jogging lanes, common areas in apartments, companies and other big structures, permeable surfaces should be used instead of complete concrete. The cost involved would not be much compared to conventional concrete surfaces.
The researcher has suggested construction of artificial recharge trenches dug up at storm water drains at regular intervals. This will result in reduction of water levels in the drain. “Hence with little investment we have increased the capacity of the drain, reducing the possibility of drainage overflow. This will reduce the likelihood of flooding in the vicinity of the drain,” he said.
Another suggestion made to civil agencies is construction of artificial recharge trenches, mostly on the roads, covered with metal or similar material, with an allowance for water to pass into the trenches. “Lack of ground water recharge is again addressed through this method,” he said.
Drainage connectivity, rainwater percolation at places where there is shallow water stagnation and providing gaps in the road dividers and footpaths are the three other solutions projected after the scientific study of the rain and flood situation in the city.
