I bought J. Stephen Lansing's book (subtitle: "Technologies of Power in the Engineered Landscape of Bali") to learn how water temples manage water in Bali. Initially, I thought (see this post) that the priests in these temples told farmers how to share water across their rice fields, threatening divine retribution upon those who did not obey.
After reading this book, I have a better understanding. Although my first impression is more or less true (the water temples regulate water flows), it was also a little too superstitious. It turns out that the "priests" (or guardians) of the water temples are more like bureaucrats. Water temples on the lower level (of the subak, or irrigation district of 20-100 farmers) coordinate their labor for common infrastructure and rotation of water deliveries. (They use a "wheels within wheels" system of multiple calendars that cycle every 7, 15, 28, 45 days or on irregular but repeating patterns (7-7-3-1 day patterns); these calendars match various crop and logistical schedules, and they allow various activities to be scheduled independently without losing track of interdependencies.)
Above the subak level are one or more levels of temples, each of these receiving "tax" payments from subaks (offerings) in exchange for continuing water delivery (lest the goddess be angry). On a terrestrial level, the superior temples coordinate larger water flows, crop patterns, infrastructure and water rights. Each of these roles explains how the Balinese have been able to grow two crops of rice per year for around 1,000 years. Regulation of water flows is straightforward -- sometimes there is not enough water, sometimes infrastructure constraints require that water go to some subaks but not others, and so on. Crop patterns turn out to be VERY important. Farmers monocropping rice must worry about pests and diseases, and the water temples facilitate coordination of fallowing times and types (flood/rot or dry/burn) so that pests and diseases are "starved out" in an entire area. Infrastructure is also straight-forward in the sense that guardians of the temple provide technical advice (put a weir/diversion here or of this shape), amass funding for big projects, and ensure that infrastructure is maintained. Finally, the temples arbitrate between old and new claims to water, with the goal is maintaining sustainability while developing any and all resources for irrigation use. Elaborate and constant rituals coordinate these activities and the flow of information (up and down) among farmers of various subaks, with "coffee breaks" during rituals functioning as informal information exchanges and coordination.
Perhaps the most important part of water temples is their contribution to sustainability. Lansing gives an excellent description of how colonial Dutch bureaucrats had no idea of how the temples worked. (They assumed that the king had controlled water and taxes for infrastructure; that assumption allowed them to impose a "traditional" tax on farmers.) Even Indonesian bureaucrats had no idea of the temples' roles. Thus, they totally screwed up when they introduced "green revolution" rice that required fertilizers, pesticides and three crops/year. The "modern" system that they rolled out (with the assistance of the typical World Bank technicians) ignored the role of the water temples. Although yields rose in the first few years, water shortages quickly appeared and -- worse -- pests and diseases rose up to destroy up to 100 percent of the "modern seed" crops. In the end, the Bankers and others realized that the temples played a critical -- not superstitious -- role. They allowed the old system to be re-introduced, and the farmers rejoiced!
Besides these interesting facts are Lansing's very thorough description of how water temples evolved and worked (i.e., what Lin Ostrom would call the "institutions of water management") and the way that this "primitive" set of institutions was fully matched to modern challenges.
Bottom Line: I give this book FIVE STARS for its complete and clear description of sustainable water management in Bali.