Protection could be a reason once pond liners are used. Once a hole is, a pond liner is placed within the hole so it's stuffed with water. Rocks are then placed round the perimeter of the pond to hide up the sting of the pond liner, and additional rocks are congregated on a mound of dirt lined with another liner to make a falls. To know more please visit http://joankeeleypond.wix.com/joanke...f2ba155ecfc1a8