I drilled a well at my place a few years ago. When I put the cap on I had been blowing the well. A few weeks later I went to remove the cap and when I got it loose it blew up 2-3 ft. Turns out I had put the cap on before the static had come fully up so the casing had a little pressure on it but not enough to blow off the cap.
I would not worry at all about any air or water fall noises. Get her pumping and make sure the water coming out is clear and clean. What kind of pump are you going with?
PS LLigetfa: There is no bedrock on the wells in this part of Tx. They are all fully cased to the water bearing sand.