Pond Construction Calculator - have I left out any variables?
How did you determine a leak rate ? Will it be concrete or rubber , or ? Will there be high edges to keep out roots and prevent capillary action of soil. My small pond in TX ( 800 gal) , rubber liner , leaks over a gallon an hour which I can't find. But one data point ; swimming pool in northern IL essentially stayed full from precipitation Oct to May ( no swimming/splashing ) ; being frozen significantly reduces evaporation which I think will work even better in Maine. Depending on the location and size , wildlife like deer may be a factor. Deer drink out of mine but it leaks so much I have no idea.