Borewell with 515 ft standing water column

Overflowing Borewell
Overflowing Borewell

I have a 525 ft deep borewell dug in granite rock. At the time of drilling, about 5 years ago, water was struck after 480 ft & moreso after 500 ft. After that we noticed that water was over flowing the casing pipe ( 2 ft above ground level) for atleast 6 days. We inserted a 3 hp multistage motor upto 480 ft. Our observation is that the bore output is 1.5 to 2 inch for an hour & after that it gradually drops to 1/2 inch. As of today ( April 2019) when almost 80 % wells have gone dry in our area & day temperatures are 38 deg to 41 deg, I find that the water column is standing barely 5 feet from top. (i.e almost 520 ft). My questions are:

  1. How can a water col stand at 520 ft consistently,?
  2. Can this be a artisan well?
  3. What can be done to increase the outflow?
  4. Will blasting at 500 ft help?