Towards an improved understanding of free-riding in collec- tive irrigation systems: proposition of a basic system dynamics model

A basic system dynamics model for collective irrigation management is proposed, which is aimed at improving the understanding of dynamic processes in collective irrigation systems. In particular, the problem of free-riding on water in irrigation systems is addressed. A feedback system is introduced, which builds on the concept of a critical mass and integrates a number of influence factors that have been identified to play a key role for farmers’ motivation for co-operation in irrigation. The base run corresponds to the relatively frequent situation of deteriorating irrigation infrastructure and unsuccessful co-operation. Yet, by varying initial conditions and parameters, the model also describes successful co-operation. Lines of further development are suggested, including a generalisation of the proposed model for collective natural resource management.