What a shame to have all this water pass by and not to put it to work! The topography of the island is already well suited as a water management system. With the mountain lakes and ground water as the source, and the rivers as the delivery system, an irrigation system is already half finished.
To complete the task, countless generations of farmers have carved into the hills and plains to complete what nature had started. The end result is a massive water management system complete with tunnels through the hills, aqueducts, dams, canals, and finally the rice terraces themselves. Its like an island with its plumbing exposed. Taken as a whole it is a beautifully articulated sculpture in the earth which could stand alone as a work of art in its own right. But this is just the beginning, this system is just the framework for something even more intricate. The water enters at the highest point and is directed and carefully coordinated to slowly flow through the different pathways to irrigate specific fields at specific times. Sometimes a field needs to be wet, at other times it needs to be dry. The different requirements of the rice plants at the various stages of their growth needs to be carefully monitored. If this is not done, the rice plants will fail due to lack of water, or be destroyed by pests and disease because of too much water.
There is a social organization in Bali called Subak. Year after year it functions to provide a stable and orderly environment that coordinated the farmer’s needs. Subak was formed as long as 1000 years ago and remains the latest word in agricultural sustainability. This group and its work are arguably he crowning achievement of Balinese culture.