"A dam is an engineering construction erected over a valley or depression with the aim of reserving water. Dams are one of the oldest water installations known to man They are usually classified according to their forms, the materials used in their construction, and the objectives for which they were constructed. The common types   Of dams that arise from one type of material or earthen backfill and rockfill with earthen block, or with a concrete facade" *metadata sheet included in the file