What matters is the depth to your water table. This site seems like a good resource: https://www.usgs.gov/faqs/how-can-i-find-depth-water-table-specific-locat

What matters is the depth to your water table. This site seems like a good resource: https://www.usgs.gov/faqs/how-can-i-find-depth-water-table-specific-location https://www.usgs.gov/faqs/how-can-i-find-depth-water-table-s... Note that the water table in that case would only fill the pond to the depth of the water table. Otherwise the surface of your pond will flow out into the water table. The other strategy (as used in this video) is to instead cut off flow with ground water. In that case, what matters is whether more water flows in on the surface (rain, creeks, what have you) verses evaporation and any leakage.