9. Main Causes of Floods Siltation of drains/ nallas Siltation of drains/ nallas Obstructions of utilities Obstructions of utilities No access for desilting Dilapidated drains Slums along outfalls Increase in runoff coefficient Garbage dumping in SWDs/ Nallas mainly in slums Loss of holding ponds Encroachment along nallas Level of outfalls Low ground levels Low ground levels Suburbs City