Bassawak reservoir
Sri Lanka · built -379
Abhaya Wewa (Sinhalese: අභය වැව), historically Abhayavapi (Sinhalese: අභයවාපි) or Bassawakkulama reservoir, is a reservoir in Sri Lanka, built by King Pandukabhaya who ruled in Anuradhapura from 437 BC to 367 BC, after constructing the city. It was constructed in 380 BC. The dam of the reservoir is 10 m high. The water of the reservoir is also accumulated in the Giritale and Kantalai. Currently, the reservoir is about 255 acres. The embankment of the reservoir is about 5910 feet long and 22 feet high above the sill level of the sluice.
Reservoir data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).