ABSTRACT
Efficient utilization of the limited water, energy, and food resources in stressed transboundary river basins requires understanding their interlinkages in different transboundary cooperation conditions. The Blue Nile Basin, a transboundary river basin between Ethiopia and Sudan, is used to illustrate the sensitivity of water-energy-food nexus (i.e. hydro-energy generation, irrigation, and reservoir evaporation nexus) to cooperation between riparian countries. This sensitivity is quantified and evaluated for the Blue Nile reach between the Grand Ethiopian Renaissance Dam and Khartoum using a simulation model (see the figure below). The model covers 27 years (from 1983 to 1996 and from 2000 to 2012) and simulates hydrological processes, irrigation water requirements, and water allocation. The model is developed using RiverWare, a generalized river and reservoir simulation tool, HEC-HMS, a rainfall-runoff modeling tool, and CropWat, which is an irrigation water requirements calculation tool. The model is used to determine changes in the long-term economic gain of Sudan, Ethiopia, and the Blue Nile Basin from water, energy, and food in 120 scenarios. Those scenarios result from combinations of cooperation states (unilateral action, coordination, and collaboration) and infrastructure development settings (the Grand Ethiopian Renaissance Dam and planned irrigation schemes in Sudan). The results show that the economic gain of the Blue Nile Basin from water, energy, and food decreases with raising cooperation level between Ethiopia and Sudan from unilateral action to coordination and increases with raising cooperation level from coordination to collaboration. However, the economic gain of each riparian country does not necessarily follow the same pattern as the economic gain of the basin. The evidence from this study points towards the idea of sharing benefits between riparian countries which implies the need for integrated management strategies of water, energy, and food that reach beyond political boundaries, sectors, and institutions.