Kala Oya

Kala Oya (Sinhala: කලා ඔය; Tamil: கலா ஓயா) is a river in northwest Sri Lanka. It originates at Dambulla, Kandalama mountains at an elevation around 870 metres Above Mean Sea Level (Iresh, 2020; Iresh et al, 2021). In the lower reaches, a few tributaries join the river and it enters into the Indian Ocean at Gangewadiya belongs to the Wilpattu National Park (Iresh et al, 2021). It is the third-longest river in the country (Iresh, 2020).

History

King Vankanasika Tissa (111-114 A.D.) is said to have built the Mahamangala Viharaya temple on the bank of the Gona-nadi [(present Kala Oya) Nicholas, 1963]. King Datusena (459-477 A.D.) built Kala Wewa by damming the waters of Kala Oya (Arumugam, 1969).

River basin

The Kala Oya river basin extending in an area of about 2,870 km² is the 3rd largest basin among the named 103 major river basins in Sri Lanka (Iresh et al, 2021; Perera et al., 2018; Vidanage et al., 2005; Young et al., 2009). The upper part of the basin falls within the Matale District and the middle reach falls within the Anuradhapura and Kurunegala districts while the lower reach is located in the Puttalam District (Iresh et al, 2021). There are about 600 minor irrigation tanks within the basin (Vidanage et al., 2005). The lowland area of the basin receives water via diversions from Mahaweli Basin with unlined canals running on either side (Young et al., 2009).