Subak is the name of water management (irrigation) system for paddy fields on Bali island, Indonesia which was developed in 9th century. For Balinese, irrigation is not simply providing water for the plant's roots, but water is used to construct a complex, pulsed artificial ecosystem. The system consists of 5 terraced rice fields and water temples covering nearly 20k ha. The temples are the main focus of this co-operative water management system of canals and weirs, which are known as Subak.