Mahāvālukagaṅgā
Mahāgaṅgā, Mahāvālukanadī.– The chief river of Sri Lanka, the modern Mahāveligaṅga. Viewed from the city of Anurādhapura, the right bank was called Pāragaṅgā and the left Oragaṅgā. The river was of great strategic importance, and is mentioned in various accounts of campaigns between opposing armies. It was always regarded as the boundary between North Sri Lanka, with Anurādhapura (and later, Pulatthipura) as the centre, and the South east province of Rohaṇa.
Various fords on this river are mentioned in the books, the chief among these being Kacchakatittha, Gaṇṭhambatittha, Mahārukkhatittha, Mālāgāmatittha, Yakkhasūkaratittha, Sarogāmatittha, Sahassatittha and Suvaṇṇatthambhatittha. There were evidently other fords at the bends of the river with no particular names (e.g., Cv.lxxii.285).
The kings of Sri Lanka constructed various canals branching off from the river to help in their irrigation schemes. One such was the Pabbatanta Canal, built by Mahāsena (Mhv.xxxvii.50); while the Aciravatī, the Gomatī, and the Malāpaharani were constructed by Parakkamabāhu I. (Cv.lxxix.51 f). Dhātusena irrigated the surrounding fields by means of damming up the river (Cv.xxxviii.12), as did Sena II by the construction of the Maṇimekhala dam (Cv.li.72). In the time of Parakkamabāhu II and, later, of Vijayabāhu IV, great ordination ceremonies were held on the river at Sahassatittha (Cv.lxxxvii.72; lxxxix.70 f), and again at Gaṇṭhambatittha in the time of Vimaladhammasūriya I. Cv.xciv.17; also Vimaladhammasūriya II. (Cv.xcvii.12).
The river rises in Samantakūṭa (Cv.c.82). The Mahānāgavana of the yakkhas, where, later, was erected the Mahiyaṅgathūpa, was on the right bank of the river. Cv.lxxxix.70; Mhv.Trs., p.3.