Floods... floods...floods

All that i have been hearing since the monsoon started in India 2 months back has been the floods, why are there floods every time there is a rain in any part of the country

They can be any of the following causes ,

1. Excessive rain
2. Dams reaching capacity and excess being discharged at a higher rate, etc

Some of the questions that remain unanswered in my mind that need you thoughts

1. What is the cause of all these sudden heavy down pour ?
2. Were there floods when there were no dams ?
3. Were there such heavy rains in the past when there no pollution ?

I also fear the following might occur

1. Epedemics
2. Displacement of people
3. The top soil being washed away into the seas leading to more waste lands