Need suggestion on the depth of installation and capacity of submersible pump


We got a 6.5 inch dia borewell dug at my residential site, at Hennur area of Bangalore. We went upto 550 feet and stopped. We struck the boulder at 110 feet. Hence, installed MS casing pipe of 110 feet and PVC casing pipe of 100 feet.

The first source of water was found at a depth of 160 feet (0.5 inch) and the second source was found at 480 feet depth (1 inch). The driller has comfirmed at least 1.5 inch of yeild (using V-notch method). I did not put a slotted pipe since the driller mentioned that it should be put until 550 feet depth and the cost was around Rs.85,000/-, which was not within my budget. The overall formation is mainly boulder and silt, but during my observation, I found that small sized stones of different colours (white, grey, pink, red, etc) were coming out while drilling, almost until the end of 550 feet.

Given the above information, I would appreciate if you could suggest:

1. Optimal depth of installation of submersible pump

2. Capacity of submersible pump

Thank you, in advance.