A millennium of divine engineering
For over 1,000 years, the volcanic landscape of Bali has been shaped by a cooperative water management system called Subak. This network of canals, tunnels, and terraced rice paddies, first recorded in an inscription from 1072 AD, is an irrigation method; it's a complex adaptive system managed by farmers and priests. The entire structure, which today includes roughly 1,200 water collectives irrigating over 20,000 hectares, was inscribed as a UNESCO World Heritage site in 2012.
In the Subak are water temples. The system operates on a hierarchical basis, with water and information flowing from the supreme water temple, Pura Ulun Danu Batur, located on the edge of a volcanic crater lake. This temple is dedicated to Dewi Danu, the goddess of the lake, who is believed to control the water for the entire island. Priests at this temple and smaller local temples coordinate planting schedules and water allocation for the collectives of farmers, which can range from 50 to 400 members each. This management is guided by a philosophy known as Tri Hita Karana, which seeks harmony between the spiritual, human, and natural worlds.
The Green Revolution test
In the 1970s, the Indonesian government's "Green Revolution" introduced new high-yield rice varieties and mandated that farmers plant them continuously, using modern fertilizers and pesticides. The government ignored the traditional synchronized schedules set by the water temple priests. The results were disastrous. Without coordinated fallow periods, pest populations exploded, and water shortages became common, leading to lower yields than before.
In the 1980s, anthropologist J. Stephen Lansing and ecologist James Kremer investigated the traditional system. They created computer models of the Subak network, simulating the flow of water and the effects of different cropping patterns on harvests and pest populations. The models demonstrated that the priests' system of coordinated planting and fallow periods across entire watersheds was highly effective at controlling pests and managing water. Their simulations showed that the traditional management by the temple network achieved a near-optimal balance, producing higher yields over time than either the continuous, centrally planned Green Revolution model or a scenario where each farmer acted independently. Following Lansing's work, agricultural officials acknowledged the effectiveness of the Subak system.