Abhaya Wewa is a reservoir built by king Pandukabhaya. This logs the earliest of irrigation works in ancient eras of Sri Lanka, dating back to 300 BCE. After constructing the city, this king ruled Anuradhapura from the period of 437 BC - 367 BC. Sri Lanka has no natural lakes yet, Dams on the Mahaweli River and other rivers, have created large reservoirs. In addition, a series of small reservoirs named as tanks can be found in the north-central plains. These are used to store water during the dry season. Some of these tanks were constructed 2,000 years ago.

Tissa Wewa is an artificial reservoir, built in the 3rd century BC by Devanampiya Tissa is 3.2km in length and 7.6m in height and was constructed in Anuradhapura. This reservoir was built in order to increase the water supply to the capital city. The Sinhalese people were among the first, to build these artificial reservoirs to store water. These were complex irrigation systems of the ancient world.