Mumbai’s three big lakes-Tulsi , Vihar and Powai were each developed to meet the city’s rising demands for water supply , with Vihar beginning in 1860.
Fifteen years after Vihar started supplying water to the increasing number of households, Tulsi was proposed to boost the supply to 63 million litres a day . Soon , Powai was developed as an emergency measure to mitigate an anticipated water famine in 1890 . “The scheme for Tulsi was launched for augmentation of Vihar , since both the lakes connected during the monsoon . But there was a need for more water and hence Powai was developed ,” says Pramod Guhe, a former BMC hydraulic engineer . While Tulsi and Vihar continue to supply water to the city , Powai’s water is deemed unfit for consumption and used only for industrial purposes . “Of the three big lakes in Mumbai , Vihar and Tulsi are better off because they lie within the national park . Powai has suffered because it has been impacted by humans . But it is rich in biodiversity ,” says naturalist and writer Sunjoy Monga .
Guhe agrees that Vihar and Tulsi are in better shape because they are in a protected forest , where human intervention is minimal . But, ironically , even in the 1800 s the quality of water from Powai attracted several complaints from the public , according to the Bombay Gazetteer .
Gauri Gurav , a member of the project team for World Wide Fund for Nature that studied city lakes , adds that Powai is polluted mainly because of an invasive species called eichornia . “This flowering plant grows on the surface of the water , blocking sunlight . It spreads fast and chokes the water body of oxygen . In addition , waste dumping , untreated sewage and washing in the lake have caused further deterioration,” she says .
Gurav says that in the past , Powai had healthy aquatic life; it attracted migratory birds and even harboured crocodiles . “There are some crocodiles there even today ,” she says .