Steve:
Thanks for your thoughts- it's makes sense with your dep knowledge baswe that you have history with the DEQ and USGS. For a change I feel good about tax dollars being spent to serve the public!
My brother, pebaugh and I's conclusion is that it is time to plan for a long term replacement for the eventual collapse / dwindling function of the nearly 50 yr. old well. While it is still productive, Cecil made a solid point about the volume of water (15gpm) not being enough input for this size / volume of pond for trout (which is all we are interested in raising in there.
So, I guess ne way of the other, we have decided whether short term or long-term, relying on a rusting 50 yr. old steel pipe with likely no screen is living on borrowed time. FYI- 4 year's ago, we had to replace the horizontal section of 2" pipe going into the pond from this well as it was rusted through in half a dozen spots and leaking all over the ground. And the elbow joint simply broke apart in trying to remove it. That might give you a better picture of what we are dealing with.
On the MI well permit, I did notice anything requiring info. on an existing well, closure nor restrictions about that. If this becomes an issue, we will deal with it by directing attention to the small flow we currently have and that due to deteriorating equipment (rusting pipes) the flow has become insifficient for our current needs (the straight truth). PS it looks like the aerial photos are fairly old as the front property owner added building some eyars back and they don't show up- so I'm not that worried- but I get your point.