Abstract: | This paper studies the intertemporal allocation of monsoonal water storage in village dam-based irrigation systems in the Dry Zone of Sri Lanka. The traditional water management practices observed in these villages are based on common property access and serve to minimise social conflict over water rights. They are also acceptably efficient in economic terms, given the water demands of the traditional rice production technology. Adoption of high-yielding variety (HYV) rice technology produces a dramatic increase in rice output, but the traditional water-management practices then become less efficient. The paper demonstrates a method for determining the nature of an efficient water-management system and for estimating the economic magnitude of the inefficiency arising from the traditional practices. In the case study, efficient water management increases the gains available from HYV adoption by a further one fourth. |