Rivers.
The balinese hydrology is ancient. Carved into the volcanic soil is a matrix occupying the space between roadways and farms that is designed to flood any and every bit of the island's beautifully terraced agricultural plots. These are thin ribbons of water. If you look closely they have very little volume but during a storm the ribbons become torrents, sometimes spilling over, usually merging with streams and rivers. The scope of this infrastructure is mind boggling but when the floods happen, and they do, it becomes a masterful work borne of survival instincts planned eons ago to support the many generations who come to rely on the bounty of the farmland. Their principle yield being rice.