a "common theory" is that "kingdoms and empires" emerged in river valleys, "because agriculture there involved the maintenance of complex irrigation systms, which in turn required some form of administrative coordination and control"
Bali, a "small volcanic island which manages to support one of the densest populations on earth by a complex system of wet-rice agriculture," would seem a good candidate for this kind of emergence, and indeed, "[f]or most of its history Bali was divided into a series of kingdoms, endlessly squabbling"
However, "the kingdoms seem to have had no role whatsoever in the management of the irrigation system. This was governed by a series of 'water-temples,' through which the distribution of water was managed by an even more complex system of consensual decision-making, according to egalitarian principles, by the farmers themselves"