Kala Wewa, built by the King Datusena in 307 B.C, is a twin reservoir complex (Kala Wewa & Balalu Wewa) which has a capacity of 123 million cubic meters. This reservoir complex has facilitated with a stone made spillway and three main sluices. From the central major sluice, a 40 feet wide central conveys water to feed thousands of acres of paddy lands and ends at the historical capital Anuradhapura city tank Tissa Wewa meandering over 87 km (54 mi) at a slope of 6 inches per mile and is an another wonder of primeval hydraulic engineering facility in ancient Ceylon.