Wahalkada Tank

Location: 80 52’ 0 N and 800 40’ 0 E to 80 38’ 24 N and 800 55’ 0 E; 980128 N and 463348 E to 954316 N and 490831 E; about 35 km northeast of Kebethigollawa in the Anuradapura District, of the North-central Province.

Area: 2,883 ha at full supply level

Altitude: 80 m above mean sea level

Overview: Wahalkada Wewa is one of the largest ancient irrigation tanks, which was built approximately 1,500 years ago during the time of King Mahasen. It was restored in 1973 by the Irrigation Department for the irrigation of paddy cultivation areas and other field crops such as onions, soya beans and groundnut.

Physical features: This relatively shallow tank is situated in the northeastern dry zone in the Yan Oya basin. The tributary of the Yan Oya brings water to the Wahalkada tank. The tank is perennial but large areas of the tank become dry in the dry season, thus exposing large areas of the tank bed.

Ecological features: The aquatic vegetation of the tank comprises of phytoplankton and macrophytes (rooted, rooted with floating leaves and floating plants). The surrounding landscape comprises of degraded dry mixed evergreen forests, chena, paddy lands and home gardens. Furthermore patches of small Tectona grandis plantations can also be observed.

Noteworthy fauna: The freshwater fish fauna is dominated by the exotic species (mainly Oreochromis spp.), while the endemic species include Clarias brachysoma and Puntius singhala. Common birds include Pelecanus philippensis, Mycteria leucocephala, Phalacrocorus fuscicollis and Ichthyophaga ichthyaetus. Herds of Elephas maximus visit the tank to fulfill their water requirements.

Noteworthy flora: Manilkara hexandara, Drypetes sepiaria, Schleichera oleosa, Pterospermum gardneri, Tectona grandis, Maba buxifolia and Flueggia leucopyrus are commonly found tree species around the tank. Among the floating aquatic plants, Nelumbo nucifera and Nymphaea stellata are noteworthy species.

Land use: The surroundings are mainly used for irrigated agriculture, home gardens and forest plantations.

Possible changes in land use: Allocation of more land areas to chena and irrigated agriculture may reduce the natural vegetation cover.

Hydrological and biophysical values: This tank serves as an important water storage tank and regulates the downstream water flow for irrigated agriculture.

Social and cultural values: The fishery related activities are an important livelihood source for the local communities.

Scientific research and monitoring: Information not available

Conservation education: Information not available

Recreation and tourism: Information not available

Conservation measures taken: This reservoir was declared a FMA in 2005 under FARA.

Conservation measures proposed: Information not available

Disturbance and threats: The destruction of natural vegetation adjacent to the tank is caused by expansion of human settlements and agricultural areas. The spread of invasive alien species such as Lantana camara also results in habitat deterioration.

Land tenure: State owned

Management authority and jurisdication: The tank is under the jurisdiction of the Irrigation Department. The fisheries are managed by the DFAR.

References: Paiva (1975)