When building a round fountain, you'll want to locate placement of the fountain's central feature. If you're wondering what the best way to do this is, we have one idea that'll ease your dilemma.
Once you've dug your pit and laid out the pond liner, tie string to stakes at the perimeter of your pit. You should have two strings running perpendicular to each other. The result would be that your pit would be divided into four equal pies. The intersection in the middle would be the center point of your fountain.
You can mark the center without damaging your pond lines. Simply attach a PVC pipe to a small piece of wood and you have your center point at the base of the pit.