A robust decision analytic framework to design sustainable development pathways in transboundary river basins: the Omo-Turkana case study

Global trends in population growth and rising economic prosperity are expected to increase energy, food, and water demands, with severe impact particularly in fast-growing African economies. Significant investments on large dams are likely increasing in the next decades and assessing their social, economic, and environmental impacts, especially on local stakeholders, is crucial for promoting sustainable development pathways. In this work, we contribute a decision-analytic framework to explore the effects of alternative development pathways on the water-energy-food nexus. Our approach is demonstrated onto the Omo River–Lake Turkana basin. Lake Turkana is an endorheic lake in the Kenyan Rift Valley, with its northern end crossing into Ethiopia in correspondence with the delta of the Omo River, which contributes most of lake inflow volume. As part of the Ethiopian energy- security strategy, a number of dams are being constructed along the river. Yet, hydropower development in the basin is impacting on several water-related sectors both in Ethiopia and Kenya, yielding to social and international tensions. Besides, in the incoming years the Lower Omo region is going to be exploited also for large-scale agricultural production. To support the design of sustainable development pathways, we first design the optimal operations of the existing infrastructures to provide an initial baseline of the system tradeoffs, including hydropower production, indigenous recession agriculture, ecosystem services in the Lower Omo, and fish yield in Lake Turkana. Then, we enlarge the system by considering the planned system expansions, either in terms of new dams, irrigation projects, or combination thereof, and quantify their potential benefits and risks. Finally, we test the robustness of the designed solutions against a wide range of potential changes in both flow regimes and irrigation demands. Results show that our approach allows discovering solutions able to address the water-energy-food nexus tradeoffs and perform robustly under changing climate and society.