Towards measurable criteria for the equitable sharing of international water resources

Equity is key to the allocation of international water resources. Six possible criteria and allocation algorithms that operationalise the equity concept, are developed and applied to the Orange, Nile and Incomati rivers. The criterion that considers all (blue and green) water resources and that uses the basin population as the main allocation variable yields the most equitable water allocation. Two important variables are identified over which the riparian countries should reach consensus: 1. The value of green water relative to blue water. 2. The fraction of reserved water, which is defined as the basic entitlement of each riparian country. These findings are based on approximate data and have therefore a limited validity. With this caveat it is suggested that the approach developed in this article may help de-politicise negotiations between riparian countries and provide fresh perspectives that may unlock stalemates during negotiations.