Spanning the Mahaweli Ganga and situated between Wasgomuwa and Somawathiya Chaitiya National Park, the Flood Plains National Park is central to the integrity of the Mahaweli system of protected areas, both for its unique ‘villus’ and as a corridor for wildlife migration between grazing lands in both bordering protected areas. It is a great location for spotting a wide variety of resident and migratory waterfowl bird species.
At present, Flood Plains National Park is closed to general visitors in order to enable more effective wildlife conservation.
The area was declared a national park on the 7th August 1984, the same date as neighbouring Wasgomuwa, and covers an area of around 17,350 hectares. The floodplains which dominate the park provide the rich alluvial soil that flanks the Mahaweli Ganga and they are characterised by numerous shallow marshy depressions called villus. The prolonged periods of flooding in these low-lying areas are responsible for the exceptionally high level of primary productivity found here, with species such as water lettuce (Pistia stratiotes), kumbuk (Terminalia arjuna) and rattan cane (Calamus rotang) just some of many to be found here.
The rich vegetation in the villus attracts large numbers of grazing animals and birds, supporting a higher annual biomass than any other type of habitat within the Mahaweli Development Project area. The floodplains are an important habitat for the Asian elephant (Elephas maximus) as well as providing a corridor for the elephants of Wasgomuwa and Somawathiya Chaitiya to move between the two parks. Fishing cat (Prionailurus viverrinus), jungle cat (Felis chaus), rusty-spotted cat (Felis rubiginosus) and wild boar (Sus scrofa) are also present, along with water buffalo (Bubalus bubalis) and many species of deer. For reptile lovers the villus support a large population of herpatofauna including natricine water snakes, mugger crocodile (Crocodylus palustris) and estuarine crocodile (Crocodylus porosus).
The floodplains here are particularly important, however, for the diversity and abundance of their avifauna and particularly migrant birds. It is estimated that around 75 migrant species spend their winter in the marshes of Flood Plains National Park with marsh sand piper (Tringa stagnatilis), Asiatic golden plover (Pluvialis fulva), osprey (Pandion haliaetus) and painted stork (Mycteria leucocephala) among others commonly seen.