Sustaining Coupled Irrigation Infrastructures: Multiple Instruments for Multiple Dilemmas

In order to smooth the availability of water and address water scarcity, shared irrigation infrastructure is constructed in many irrigation systems. However, maintaining contributions to shared infrastructure has grown increasingly challenging as private infrastructure, such as groundwater pumps, have become attractive substitutes. This problem is especially acute in the semiarid regions of South Asia. We model South Indian tank irrigation systems as an example of a coupled infrastructure system that captures these real-world challenges. We developed a replicator dynamic model to analyze the interactions of multiple policy instruments to address interlinked appropriation and provisioning dilemmas in a coupled infrastructure system. We demonstrate that a fixed fee levied on groundwater users combined with highly differentiated fees on tank users can improve the provision of the shared tank significantly, yield higher profits, and greater equality of livelihoods. However, the presence of private infrastructure limits the ability to credibly implement sufficiently high fees. This institutional complexity is decidedly “second best” – falling well short of the outcomes available if the substitution to private infrastructure were more effectively managed.