Civic agencies have been caught unawares by the excess rainfall that Bengaluru has received this month. Data from the Karnataka State Natural Disasters Monitoring Centre (KSNDMC) shows that from October 1-18, all eight zones in the city received ‘large excess’ of rain, where the percentage departure is above 60%.
While the normal rainfall across the city during this period is 104 mm, the eight zones have together received 233 mm, which is a 125% departure from the normal rainfall. The maximum departure from normal rains was in West zone with 222%, followed by South zone with 168%, Rajarajeshwarinagar with 166% and Dasarahalli with 138%. The data also shows that during this period, West zone received maximum rains at 319 mm, followed by South (290 mm), Rajarajeshwarinagar (285 mm) and Dasarahalli (241 mm).
Monsoon flooding
KSNDMC director Manoj Rajan said during the monsoon months from June to October, Bengaluru is vulnerable to flooding. A study of the rainfall pattern in the city between 1960-1990 and 1991-2017 has shown that the average annual rainfall in the Bengaluru Urban district increased from 836 mm to 943 mm.
The increase in the quantum of rains received by the city can also be attributed to climate change and the urban heat islands phenomenon, KSNDMC officials stated.
Geeta Agnihotri, scientist and head, Indian Meteorological Department, Bengaluru, attributed the continued heavy spells to the development of low-pressure areas in both Arabian Sea and Bay of Bengal. These active systems have resulted in heavy rains in all the southern states. “The development of such systems is common when the South-West monsoon retreats,” she said.
Meanwhile, as many as 14 districts in the state have recorded ‘large excess’ rains, with the departure from normal rainfall ranging between 150% and 63%. A total of 6 districts have recorded ‘excess’ rains, while rainfall was ‘normal’ in five districts and a ‘deficit’ in six districts.
‘We need one sunny day’
The unusually heavy rains have taken a toll on Bengaluru’s roads that are riddled with craters and potholes. BBMP Chief Commissioner Gaurav Gupta told The Hindu that officials have been directed to take up pothole filling as soon as the rains abate. “We need at least one clear sunny day for the materials to be dry for the making of hot mix and for the road surfaces to be dry. If the road surface is wet, the wet mix will not bond to the surface,” he explained.
The rains that have been lashing every day had hampered the pothole filling work, as well as manufacturing of wet mix at the hot mix plant in Kannur. While instructions have been given to send additional loads to different zones from the plant, officials have also been authorized to procure the hot mix from any other sources, including existing contractors. They may also utilize funds earmarked for each ward in the budget for filling potholes locally, he added.
