Just going with the math and Wisdom from Tums. Here is what I come up with.
I am 12 feet down... Right at 9.5 acres of water. That Comes up to 114 acre feet of water.
I multiply this 114 by (326,000 us gal) I get about 38,000,000 gal rounded up! So this is the total amount of gallons I need..
Now lets say I get a pump (Well or stream) of 100 gallons per minute. Doing the math I get about 28 days to fill this lake.. Thats not bad at all! The Million dollar question is. How Do I get a well or pump to pump at LEAST 100 gallons per minute?
Is 100 gallons per minute a stretch??? what 200 gallons per minute?
Your math is pretty much on target. Here is another idea for you to think about. I have another pump I have for pumping out of creeks, ponds ect.... It pumps well over 1000 GPM and can run irrigation reels over a 1/4 mile away uphill. It is a modified Berkely irrigation pump made to run off of a tractor PTO. Alot of times when irrigation pumps go bad it is generally the engine and the pump is still in good shape. Best I remember I think I figured it took me around 10 gallons of diesel per water acre moved.
