Is your pond spring fed or does it have a lining. If it's spring fed, the pond can take any amount of water you dump to it. The hydrostatic pressure of the pond equalizes with the pressure of the aquafer. In my case, I put in a winter heating season, over one million gallons of water, and my water level went up 3-4 inches, then stayed there. If the pond is lined, it's like a bath tub, so all the water you dump to it will raise the level, unless you have an overflow somewhere.
