Our pond gets zero run-off and is not spring fed, so a well is the only way we have of raising its level significantly without a major precipitation event. It is two acres in size and it takes about 3 days to raise the water level 5-6 inches. I will have to check the exact specs on the well, but it pumps a heck of a lot of water out a 6 inch diameter pipe.

My advice is to put in a well and pump that exceeds the size of what you think you might need. It will cost you more initially, but you will save in energy costs over the long run.