Boulder & yield issues affecting 60 ft borewell in Mulund, Mumbai,Maharashtra

The borewell locatioin is Shastri Nagar, Mulund Area, Mumbai in Maharashtra. I had dug a borewell for 60ft with a yield of 2 inches or 500 LPH as the contractor claims. The casing pipe is for 25ft as boulders were encountered after that. Also loose pebbles which could eventually block the well were also encountered. There are 4 members of the family plus a garden of around 140 sq.meters and we estimate our need at 1000 LPH. My concerns are:

1. How can I confirm the yiled?
2. Will 2 inches of yiled be sufficient or will it dry up soon?
3. Is there a concern that the well is too shallow?

Dr. Arora