This article describes the cultural ecology of terraced tank clusters (Cascades) in the Dry Climatic Zone (DCZ) of Sri Lanka. As recognized by Julian Steward in 1950s, Cultural ecology is a theoretical approach that attempts to explain the similarities and differences in the culture in relation to the environment (Tucker 2013). The traditional settlements linked with small tanks called ‘Wew gam’ (Tanks villages) and the interrelationships between human activities and the natural ecosystems of the cascades are good examples of the cultural ecology in Sri Lanka. According to the study, the ecology and the and culture sustainably go together and ecology deals with patterns of relations of plants, animals, and people to each other and their surroundings, and culture deals with all products of human thoughts. There are however certain aspects of both ecology and culture that have very interesting and intimate relationships. The Sri Lankan cultural and water heritage is one of the richest and most colorful heritages in Asia. Therefore, there are much to be re-learned from our ancient hydraulic civilization. In history, the people of agricultural communities lived sustainably, respecting the environment, dealing well with wild animals, and coping with natural hazards. A village tank cascade ecosystem exemplifies a sustainable system. Concerning the historical behavior and the contribution to make a sustainable environment in drought prone areas of the DCZ of Sri Lanka, the village tank system was recognized on 19th April 2020 by FAO as one of the “Globally Important Agriculture Heritage System” in the world. It is an ancient, widely used, and unique traditional agriculture system. The system provides water for irrigation, domestic purposes, animals, and ecosystems.