An Inland wetland of Natural origin located in the Dry Zone of the North-Central province. The Mahaweli Ganga floodplain is an extensive system of wetlands composed of river channels, riverine marshes, villus, mangroves, lagoons, and tidal creeks associated with the Mahaweli Ganga, Sri Lanka?s longest river. The presence of elephants, rich plant diversity and a large number of aquatic birds including 75 migratory species led to the area being accorded protected status through three National Parks. The flood plains also serve as a migratory corridor between the dry and wet season feeding grounds of a large elephant population. The Alluvial plain associated with the Mahaweli Ganga begins a few kilometres upstream and the deltaic plain commences with the first distributary, the Kandakadu Aru, with the combined flow entering the sea near Verugal, on the east coast. Around 38 villus have been recorded from the floodplains. The flood plain in general and associated villus in particular, have a high diversity of microscopic and larger plant forms. 231 plant species were recorded at Handapan and Bendiya villus and swamp forests. Distribution of the larger vegetation in the villus shows a characteristic pattern closely related to the hydro-period and depth of flooding. Aquatic vegetation consists of floating plants (Salvinia molesta, Trapa bispinosa, Pistia stratiotes and Azolla pinnata), submerged plants, grasses and emergent plants (Aponogeton crispus, A. natans and Nymphoides spp.). On the margins of villus, where wet conditions are brief and flooding is low, creeping grasses such as Cynodon dactylon are common. Mangroves are less diverse than those in other parts of the country and the major species recorded are Rhizophora mucronata, Avicennia marina, Acanthus ilicifolius, Lumnitzera racemosa, Aegiceras corniculatum and Scyphiphora hydrophyllacea. Sonneratia apetala exists in small numbers near the mouth of the Mahaweli River. Freshwater fish are dominated by exotics (Oreochromis spp., Osphronemus gourami), while endemics include Esomus thermoicos, Garra ceylonensis and Schistura notostigma. Aquatic reptiles include Melanochelys trijuga, Lissemys punctata, Crocodylus palustris, and Varanus salvator. Water birds include rare species such as Leptoptilus javanicus. Mammals include Lutra lutra, Prionailurus viverrinus, Moschiola meminna, Cervus unicolor, Panthera and large herds of elephants. The villus in the floodplain are surrounded by tall dense dry zone forest dominated by Manilkara hexandra, Chloroxylon sweitenia, and Terminalia arjuna species. Prominent grass species include Panicum repens, Hygroryza aristata and Crachiaria mutica. Threatened aquatic plants in the floodplains include Aponogeton jacobsenii, and Aponogeton natans. The flood plains are important for flood detention during the wet season. The flood plain also acts as a sediment and nutrient trap and reduces the input of sediments and nutrients into near-shore marine waters at the river mouth.

Mahaweli Flood Plains National Park Related references