The Tanks of Anuradhapura
Basawak-Kulama the oldest tank is the city was originally called Abhaya-Vapi. This tank and its system of canals provided the water to the rice fields of early settlers who were an agricultural population. Pandukabaya (B.C. 437-407) constructed Basawak-Kulama (Abhaya-Vapi)
Tissa Vava built by Devanampiyatissa (307-267 B.C.) on the south provided water for agricultural activities of that part of the city. The tank bund which is over two ½ miles long is twenty-five feet high above bed level of the reservoir. Today this tank provides the drinking water to the ancient city.
Nuwara Vava is by far the largest tank in Anuradhapura. This tank has been endorsed to the second century A.D. it has a bound four meters long and rising to a height of forty feet above bed level. Today this tank sited as it is above the modern city provide all the drinking water to large population of the new built city to fill the ancient city of modern encroachments. Besides these major tanks, there are several small tanks, which provide water for agriculture to the several villages around the city.
Minipe Yoda Ela
In addition to the above, the Trans basin canal from Minipe diversion carried water from Mahaweli Ganga to Amban Ganga. King Dasankeliya (459 AD) constructed this and it had irrigated the left bank of Mahaweli. This gigantic work, which excites the wonder of the modern engineers, consists of a scheme, which turns the river at a bend where a large body of water enters the narrows canal formed by an island contiguous to the bank, partially closed by two rocks, which intercept the water on its return to the main stream. These rocks, when united by the masonry became a dam raising the waters in the natural channel to great height. Sir Henry Ward Basing on his observation on legend describes this canal
could have used for irrigating as well as navigation. The length of this canal is 50miles and it merge with Amban Ganga below Angemedilla anicut. It is important to note that this canal had followed a trace, which has minimized deep cutting.
Parakrama Samudraya consists three tanks and they are Thopa Wewa, Dumbutulu Wewa, and Erabadu Wewa. These three tanks were Inter connected to form the Samudraya and this is fed by the Angemedilla anicut with its Inlet canal of 24 miles long in addition to its own catchment. The total length of the bund Is 9 miles and height varies from 40‑90 ff. According to Brohier, this canal, which traverses about 24 miles, had irrigated large tracts land between Minneriya Oya Ambanganga feeding few tanks namely Nika Wewa and Anaulundawa Wawe.