While ponds and storage lagoons can be the same thing, ponds are not necessarily used for the storage of water to be used for a later purpose, like lagoons are. A pond can just be a body of water used for a variety of purposes. A lagoon is typically used in order to preserve water and utilize it for agriculture, industrial purposes, or human-use.
A storage lagoon is typically lined to prevent seepage, and may be covered in order to prevent precipitation from making its way inside.
