Known as the second largest park for herds of wild elephants, the Udawalawa National Park lies in the lower catchment of Udawalawa Reservoir in the country's Intermediate Lowland region. It was established as a National Park on 30th July 1972. This area falls into two administrative districts in two provinces. The parkland on the right bank of Walawe Ganga is within Ratnapura district in the province of Sabaragamuwa and the parkland on the left bank falls within Moneragala district in the province of Uva.
The dry land area of the Park is about approximately 28910 hectare. The reservoir of Udawalawa is surrounded by open plains and foothills such as kalthota Escarpment and spectacular Diyawinne Fallto in the north and Ulgala in the west. The climate in the park is characterized by a seasonal rainfall and uniformly high temperature conditions. A short dry spell is experienced in February- March and a prolonged dry period is observed from mid-May to end of September.
Much of the forest was destroyed by chena (shifting cultivation). Tree species include Satin, Halmilla, Ebony Ehala, Kolon, Milla, Kon and Kunumella. Scattered trees, constituting 20-50% of existing cover, are mainly satin, ehala and lunumidella. In the riverine forest, kumbuk and the endemic mandorang are dominant. Scrub is dominated by damaniya. Savanna grasslands are dominated by Mana, Illuk and Pogon.
This park is very famous for the Elephants. There are herds of elephant feeding in the grasslands. The Sambar deer, spotted deer, Muntjac, wild boar and water buffalo are re-establishing themselves. Other mammals include toque macaque endemic, common langur, jackal, toddy cat, leopard and black- napped hare and small Indian civet cat, endemic golden palm civet cat, three species of mongoose, an endemic shrew, gerbil, rat, soft- furred rat and Indian bush rat.
The Udawalawe reservoir, deep itself and continuously replenished by the never drying Walawe river which draws most of its water from the wooded Peak Wilderness sanctuary, the Horton Plains Nature reserve and the Haputale area. The fringes of the reservoir and the narrow creeks are now characterized by the presence of weather- bleached skeletons of thousands of jungle trees, killed off by the dammed water. Tilapia mossambica has been introduced by the Fisheries Department. The reservoir could become an important breeding place for aquatic birds.