In the dry zone of Sri Lanka, human-made reservoirs (locally called tanks or wewas) have served for the collection, storage and distribution of rainfall and runoff and provided irrigation water for the cultivation of paddy for 2400 years. This water management system is deeply inscribed in the rural communities utilizing and maintaining it. Local knowledge connected to the utilization of this system is regarded as a substantial part of the intangible cultural heritage of this unique cultural landscape. In the dry zone of Sri Lanka this system had spread from the fifth century BCE onwards from the hinterland of the ancient capital Anuradhapura throughout the entire dry zone and provides a prerequisite for paddy cultivation. From approximately the 13th century onwards, written sources give evidence, that a weakening of state bureaucracy led to a decline of the water management system. In the Colonial period, numerous reservoirs were restored and the implementation of new governance structures lead to a diminishing of water supplies and conflicts at a local level. In post-Colonial times, since the 1950s, the system had undergone rapid changes triggered by governmental and economic developments (e.g., land use change, migration). The rich local knowledge, serves in line with a high degree of adaptation to local conditions, as a corner stone for its resilience. A future sustainable management requires the integration of local knowledge in combination with modern techniques in education, planning, and application.
