'Wetland' denotes any area covered with water, which includes all rivers, lakes, paddy fields and periodically flooded lands. As per the definition given at Ramsar Convention (Ramsar, 1996), 'Wetlands are areas of marsh, fen, peat land or water, whether natural or artificial, permanent or temporary, with water that is static or flowing; fresh, brackish, or salty, including areas of marine water the depth of which at low tide does not exceed 6m'.