A pond goes through many different stages in its lifetime. Over thousands of years sediment, made up of decaying plants, animal matter and eroded soil from the shoreline builds up at the bottom. This sediment contains the essential nutrients that plant life needs to flourish. The less depth to the pond, the more sediment is available for the plants to root and feed from.
Plants grow in a layer of the pond called the Littoral Zone. This is a zone that is a shallow area between the dry land and the open water area of the pond. This usually extends from the shoreline to about 15 feet depth in the water.