The tank-based irrigated agricultural system in the Dry Zone of Sri Lanka is one of the oldest historically evolved agricultural systems in the world. The main component of the system consists of a connected series of man-made tanks constructed in shallow valleys to store, convey and utilize water for paddy cultivation. Up to 10,000 tanks originating from the heydays of ancient kingdoms are still integrated in the current agricultural landscape. During the last two millennia, this indigenous system has undergone many changes in technological, management and socio-cultural norms.