AbheyaWewa Reservoir located on MalwathuOya River, Sri Lanka with 932 hectares catchment areais the most ancient reservoir in Sri Lanka that continues to serve even today playing a key role in fulfilling need of water for millions of pilgrims besides providing irrigation facilities. Abhaya Wewa Reservoir is identified as “Bassawakkulama" and is associated with the reign of King Pandukabhaya, 4th century B.C.
The reservoir is located west of the present city of Anuradhapura, the first ancient capital of Sri Lanka which served as the capital of the country for the longest period. It is famous for its well preserved ruins of the Great Sri Lankan Civilization. The Hydraulic Civilization which was built upon this city was one of the greatest civilizations of Asia and in the world and serves as one of the very important preserve of world heritage.The British found and surveyed this in 1870 and renovated it in 1874. The length of the earth embankment is about 1425 m. Present full capacity is 2 MCM and water spread at full supply level is about 107 hectares. Even after 2500 years, the reservoir continues to supply water to Anuradhapura. Presently, the reservoir is fed by Tissa Wewa reservoir which is augmented by Mahaweli diversions.It may be mentioned that this reservoir had only one sluice for the agricultural purposes and served a cultivated area of about 141 hectares. The priority of use of reservoir water appears to have been domestic and not the Irrigated Agriculture. The reservoir is important to locals and tourist for religious, historical and the cultural reasons.
The operation and maintenance of Abhaya Wewa reservoir, the main system including embankment, spills, sluices, main canals, branch canal and feeder canals are carried out by the Irrigation Department. The two farmer organizations established by Irrigation Management Division take care and manage the sub system including distributary canals and field of the irrigation scheme with financial support from Irrigation Department.