The BBMP has been actively removing encroachments on Storm Water Drains (SWD) over the last few days, but experts are sceptical about the situation on the ground, as they believe the actual number of encroachments is way more than what is being reported.
According to data released by the civic body recently, only 696 encroachments have been identified across 842 kilometres of the SWD network in the city.
“This is only an indicative number. The activity is being carried out superficially without understanding the science behind it,” said Prof T V Ramachandra from the Indian Institute of Science (IISc).
V Ramprasad, co-founder of Friends of Lakes (FoL), said the methodology of identifying encroachments is important.
“There are instances where the BBMP hasn’t considered the absence of a drain as an encroachment, stating that an alternative drain exists. But the officials have to verify if the water carrying capacity of the other drain is similar to the one that existed and if its placement is topographically correct. Else, the alternative drain is useless,” Ramprasad said.
Ramachandra said the authorities should not encourage parallel drains.
“Water flows according to hydrological norms, and drains are formed according to topography. Changing the path of drains does not help. Wherever such instances are reported, they should be considered as encroachments,” he said.
Acknowledging that the number of encroachments could be far more than what has been identified, a senior BBMP official said only evident violations have been marked.
“These encroachments have been identified based on the disruptions of water flow and other factors that are evident. To identify all the encroachments, we will have to look through the revenue maps and do a reassessment,” an official said.
While encroachment removal could be a temporary solution, experts suggested that there is a need to conduct a scientific topographical and hydrological study to address the flooding woes of the city.
“There is a need to re-establish interconnectivity among the lakes in a scientific manner. A comprehensive study has to be taken up to achieve this,” Ramachandra said.