With unprecedented growth in urban centers like Bengaluru, the lakes have been subjected to encroachment, illegal mining of earth & sand, dumping of debris, ingression of untreated sewage, discharge of industrial waste etc. Lakes are interconnected through storm water drains, commonly called Raj-kaluve. In many areas, Raj-kaluve is also connected with domestic sewage and are encroached.
During flash flood, very little passage is available for water to flow from higher to lower lakes, which results in flooding roads, houses and public areas.
Looking into the rainfall pattern, flash floods are going to be more common in years to come. Scientists at the National Center for atmospheric research in US have analysed the data collected at weather stations across the globe and have concluded that half of the measured global precipitation in a year falls in just 12 days. The climate models project that this lopsided distribution of rain and snow is likely to become even more skewed. Recent flooding in Mumbai, Chennai and other urban centers is testimony to the aforesaid conclusion. Bengaluru has also faced four to five flooding of high magnitude in last 15 years.
Lakes are important for recharging underground water. Flow of untreated sewage is continuously contaminating it.
From July 2002 till March 2018 urban lakes were managed by Lake Development Authority (LDA). An Act was passed empowering LDA for initiating criminal action against culprits. Action was initiated in some cases and within two years, the Act was repealed. Even LDA was closed down and management of urban lakes were handed over to Tank Development Authority, who are to deal with these lakes along with all irrigation tanks in the state. State lost the focus on conservation of urban lakes. This is believed to be the handiwork of land sharks with their eye on lake lands.
Mining in the beds also have consequences. It can expose impervious layers and can also change the natural course of water, causing undue misery to people during flash flood.
Forest Department has not been effective in taking action under Forest Act against illegalities in lakes. LDA would have checked more effectively.
– B K Singh, Retd Principal Chief Conservator of Forests (Head of Forest Force) Karnataka...