Storm Water Drainage
The present Storm Water Drainage (SWD) system in the city is more than 100 years old and is about 480 km long. This network consists of underground drains, roadside open drains, minor and major nallas. The old SWD system is capable of handling rain intensity of 25 mm per hour at low tide. If the rain intensity is more than 25 mm per hour and high tide occurs, there is always a possibility of flooding. There are 107 major outfalls in city, which drain to Arabian Sea directly, 4 at Mahim Creek and 4 at Mahul Creek. There are 29 outfalls in Western Suburbs draining directly into sea while 14 drain into Mithi River, which ultimately joins Mahim Creek. In Eastern Suburbs 14 outfalls discharge in Thane Creek while 6 discharges in Mahul Creek and 8 discharges into Mithi River in suburbs and extended Suburban area, open SWD are constructed on both sides of roads.