Water resources, needs, and conservation: Finding answers in the Indian context

The India Water Portal web site is very interesting. Its a great source of inspiration for me. I am studying in Apeejay School -- Delhi, I seek answers to my following questions.  I am studying in the 5th standard. I have got this project on water from my school:

We are seeking answers to the following questions:

1) Amount of fresh water available from rivers , lakes etc?
2) Is this water sufficient for the population of India. How much water is needed by one person per day for drinking, bathing etc?
3) Why there is scarcity of water all the year round?
4) How can we conserve water besides rain water harvesting?
5) Which countires have no water problems?  If so, what are the methods they have adopted?

Medha Gandotra