Co-development of transformation pathways for the integrated management of water-energy-land resources in the Zambezi basin

Abstract:

The Zambezi basin is one of the largest river basins in Africa, spanning over eight countries, with growing population and economy, large potential for agriculture and hydropower development, and high climate variability. Water demands are expected to increase in the coming decades, while available surface and groundwater resources are projected to remain at the present level or even decline. As such, basin policymakers need to anticipate how to adapt management practices to secure reliable future water supply for the different sectors. The choice of water management options is often associated with trade-offs across multiple water-related systems such as drinking water supply, food production, energy generation, and ecosystem services, and it requires the development of a system approach, depicting the interactions among the different sectors to identify most cost-effective solutions.

This study presents a coupled modeling framework that combines, in a consistent way, various sectoral water, food and energy (WFE) models. This integrated modeling framework has been applied to co-develop a number of model-based scenarios that can serve as a basis for discussing cost-effective solutions to jointly meet sectoral and transboundary development goals. These scenarios integrate stakeholder-driven regional pathways that have been co-developed with basin stakeholders and global scenarios obtained from Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs). Results of this study show that there are multiple opportunities to expand food and energy production and related benefits over the coming decades. However, these developments will increase considerably water use, exacerbating local water stress problems in the most populated areas of the basin. They could also create negative environmental impacts, in the absence of environmental protection policies. Overall, the study identifies a broader solution space and demonstrates the capacity of the proposed modeling framework as a system approach to address challenging issues related to the WFE nexus.