If Buddhism was the spiritual sustenance of the ancient Sinhalese civilization, then the wewa (Irrigation Reservoir) was its physical counterpart and, not surprisingly, the two principal symbols of our ancient kingdoms were the dagoba and the wewa.
Sri Lankan history is deeply connected with its hydraulic civilization. The history of this ecosystem leads back to the 4th century B.C. or before. Basawakkulama sometimes known as “Abhayawewa” was identified as the most ancient Wewa, which was done by king Pandukabhaya.
The Sinhalese Engineers are the first Inventors of both the Hydraulic Surge Chamber and Valve Tower and the first to incorporate both the principles in the same structure, called a Biso Kotuwa more than 2,100 years ago
The greatness of the irrigation systems of Sri Lanka is summed up in the University History of Ceylon: “the construction of reservoirs originated from the meager knowledge the Indo-Aryan settlers had. From this basic elementary knowledge, there developed later the greatest engineering skill exhibited in the ancient Sinhalese Kingdom namely the progressive building up of a colossal and complex system of interrelated dams, canals and tanks, mingling the waters of rivers flowing in different directions; no parallel system of the same magnitude or intricacy existed in contemporary India.”