Ancient Reservoirs of Sri Lanka – ශ්‍රී ලංකාවේ පුරාණ වාරිමාර්ග

Parakrama Samudraya

Parakrama Samudraya

Irrigation systems of ancient Sri Lanka consist of a large number of village tanks, gigantic reservoirs and a intrinsic network of water cannals connecting these tanks while supplying water to farming land. There about 30,000 tanks in Sri Lanka of which the majority was built form 3rd century BC to 12th century. This compared to the Sri Lankan dry zone land area of about 40,000 sq. kilometres (where almost all the tanks are located), is almost equivalent to one reservoir for each sq. kilometre.

The first large tank to be built in recorded history is Abaya Wewa in 3rd century BC. From that day onwards Sri Lankan tank builders developed a remarkable expertise on controlling large bodies of water which allowed them to built massive reservoirs which no other civilisation ever could have dreamt of.

The breakthrough which made the Sri Lankan Irrigation Engineers build such massive tanks was invention of the “Biso Kotuwa” of valve pit as early as 3rd century BC which could easily regulate the out flow extremely large water bodies. Europeans stared using the valve pits in their resoviors only in the mid 18th centuary, 2100 years later according to H. Parker, an Irrigation Engineer who was in charge of restoring many ancient iIrrigation tanks in late 1800’s, in his book ‘Ancient Ceylon’

He goes on to say,

……..At first, only the simplest works of the smaller class, with very low embankments, would be undertaken; but when a better knowledge of the art of raising such banks of earth to hold back greater depths of water was acquired, schemes of a more comprehensive character would be attempted, until at last no reservoir was looked upon as too great to be constructed, and the lengths of the embankments extended for any distance up to a maximum of nine miles, while their heights in a few instances rose to more than fifty feet…………..

……… It may appear to be such a simple matter to raise a long bank of earth in order to hold back a certain quantity of rain water for bathing purposes or for watering an adjoining rice field after the rains have ceased, that any people living in hot countries where the rains are only seasonal and are followed by several almost rainless months might be expected to be struck by the idea of making these little reservoirs for themselves, without its transmission from another country ; but as a matter of fact the notion of reservoir-making appears to have been originated in only one country, and never to have been invented independently elsewhere, at any rate in the Old World. …………

Another development of the ancient irrigation systems is the remarkable instrumentation precision. When king Dathusena (459-477 AD) built Yodha Ela, also known as Jayaganga, the ancient irrigation engineers first found out that the Kala Wewa in Pollonaruwa was built on a slightly elevated ground compared to Tissa Wewa in Anuradhapura. Then he built the 54 mile ( 87 Km ) Yoda Ela with a gradient of 6-12 inches per mile ( appox 10 to 20 cm per kilometre) to carry excess water in the Kala Wewa to Tissa Weva. How these engineers could achieve such precision still baffles experts today.


Ancient Reservoirs in Sri Lanka

  1. Bandagiriya Tank – Pallemalala
  2. Basawakkulama ( Abaya ) Wewa
  3. Bathalagoda Tank
  4. Debera Wewa – Tissamaharamaya
  5. Ehelapola Wewa
  6. Girithale Tank 
  7. Kaudulla Tank
  8. Lenabatuwa Tank / Wilpita Tank (natural lake)
  9. Mahagala Tank - Hambantota
  10. Minneriya Tank 
  11. Nachchaduwa Wewa - Anuradhapura
  12. Nuwara Wewa  - Anuradhapura
  13. Nuwara Wewa ( Kandy Lake )Kandy
  14. Palavi Tank
  15. Panda Wewa – Panduwasnuwara
  16. Parakrama Samudraya ( Ocean of Parakrama) – Pollonnaruwa
  17. Siyambalagamuwa Reservoir
  18. Sorabora Weva – Mahiyangana
  19. Thabbowa Tank – Puttalama
  20. Thuruwila Irregation Tank – Anuradhapura
  21. Tissa Wewa – Anuradhapura
  22. Tissa Wewa – Tissamaharamaya
  23. Urusita Wewa – Monaragala District
  24. Vavunikulama Tank – Vavunia
  25. Weerawila Wewa – Wellawaya
  26. Yoda Wewa – Mannar District
  27. Yoda Wewa – Tissamaharamaya



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