According to the rain impact assessment done by the consultant, if the watershed witnesses a rainfall of 68 mm in an hour, there would be 773 million litres of storm water. “At present, 70 to 80 per cent of the water enter the streets. The soil can absorb only 303 million litres and rest will stagnate. If the drain is built using the German technology of eco block and rainwater harvesting infrastructure, we will be able to save an additional 326 million litres, which is almost 90 per cent of the total rainfall. Only the rest will be let into the sea,” he added.