The development of and access to freshwater resources in East Africa is fundamental to the region's sustainable development goals. Following vision documents for regional development and working with local stake-holders, we developed water scenarios up to 2050 that inform the hydro-economic modeling analysis of the extended Lake Victoria Basin, the headwaters of the Nile River. Water scenarios that take an integrated approach to assessing the combined effects of climate change, land use, and increasing human water use suggest that the flow regime of the Nile may remain relatively stable. However, if this stability is to be achieved, while at the same time sufficient water is preserved for healthy freshwater ecosystems, a large fraction of water infrastructure must rely on advanced, often costly technologies and management. Interconnected analyses of both upstream and downstream water resources over time, guided by co-developed scenarios, are indispensable for planning sustainable water-development pathways.

Food security has long been a challenge for East Africa region and is becoming a pressing issue for the coming decades because food demand is expected to increase considerably following rapid population and income growth. Agricultural production in the region is thus required to intensify, in a sustainable way, to keep up with food demand. However, many challenges face the sustainable intensification of the agricultural production including low productivity, inadequate management, small scale operations, and large climate variability. Several pilot initiatives, that involves a bundle of land and water management practices, have been introduced in the region to tackle such challenges. However, their large-scale implementation remains limited. In the framework of a research project which is jointly implemented by the International Institute for Applied System Analysis (IIASA), the Lake Victoria Basin Commission (LVBC) and the International Crops Research Institute for Semi-Arid Tropics (ICRISAT), we analyse up scaling opportunities for water and land management practices for the sustainable and resilient intensification of rice and fodder production systems in the extended Lake Victoria Basin in East Africa. The expected outcome of this project is to provide an improved understanding of up scaling of such practices through model simulations and integrated analysis of political economy aspects, governance and social and gender dimensions. This paper presents an integrated upscaling modeling framework that combines biophysical suitability analysis and economic optimization. Several production system options (i.e., management practices) for rice intensification are examined at high-spatial resolution (0.5°x0.5°) in the extended Lake Victoria basin. The suitability analysis identifies suitable area for the production system options based on a combination of various biophysical factors such as climate, hydrology, vegetation and soil properties using the Global Agroecological Zones (GAEZ) model and the Community Water Model (CWaTM). The economic optimization identifies the optimal combination of those production systems that maximizes their overall contribution to agricultural economic benefits having satisfied various technical and resource constraints including commodity balance, land availability and suitability, water availability, labor availability and capital constraints. A set of socioeconomic (e.g., impact of population and income growth on food demand and agricultural productivity) and climate change (e.g., impact on water resources availability) scenarios based on combinations of the Shared Socioeconomic Pathways (SSPs), Representative Concentration Pathways (RCPs), and co-developed bottom-up policy scenarios, through stakeholders’ engagement with the Basin Commission (LVBC), have been utilized to simulate the modeling framework. Results of this study show the existence of significant opportunities for the sustainable intensification of rice production in East Africa. Moreover, the study identifies the key biophysical and economic factors that could enable the upscaling of sustainable land and water management practices for rice production in the region. Overall, this study demonstrates the capacity of the proposed upscaling modeling framework as a system approach to address the linkages between the intensification of agricultural production and the sustainable use of natural resources.

The development of and access to freshwater resources is fundamental if East Africa aims to achieve its goal of increased economic growth. Following vision documents for regional development and working together with local stakeholders, we developed water scenarios up to 2050 that inform the hydro-economic modelling analysis for the extended Lake Victoria Basin, the headwaters of the Nile River. Results indicate a 4-5 fold increase in water demand, especially for expanding irrigation and domestic water needs. Together with climate and land use change, the discharge and flow regime of the Nile will remain relatively stable. However, if this is to be achieved, while sufficient water is preserved for environmental needs, a large fraction of future water infrastructure must rely on advanced, often costly, technological, and management options. The interconnected analysis, between up-stream and down-stream water resources and sectoral water demand, guided by co-developed scenarios, supports planning of sustainable water pathways.

Water scarcity has become a crucial environmental issue worldwide. It has increased substantially in the last decades in many parts of the world, and it is expected to further exacerbate in the future driven by socio-economic and climatic changes. Several solution options could be implemented to address this growing water scarcity, including supply and demand-side management options that span the water, energy, and agricultural sectors. However, these options involve tradeoffs among various societal objectives, especially when the interactions between these objectives are not properly considered. This paper provides a review of the impending water scarcity challenges and suggests assessing water scarcity solution options using a nexus modeling framework that links well-established sectoral-oriented models.

This study presents the development of a new bottom‐up large‐scale hydroeconomic model, Extended Continental‐scale Hydroeconomic Optimization (ECHO), that works at a subbasin scale over a continent. The strength of ECHO stems from the integration of a detailed representation of local hydrological and technological constraints with regional and global policies, while accounting for the feedbacks between water, energy, and agricultural sectors. In this study, ECHO has been applied over Africa as a case study with the aim of demonstrating the benefits of this integrated hydroeconomic modeling framework. Results of this framework are overall consistent with previous findings evaluating the cost of water supply and adaptation to global changes in Africa. Moreover, results provide critical assessments of future investment needs in both supply‐ and demand‐side water management options, economic implications of contrasting future socioeconomic and climate change scenarios, and the potential trade‐offs among economic and environmental objectives. Overall, this study demonstrates the capacity of ECHO to address challenging research questions examining the sustainability of water supply and the impacts of water management on energy and food sectors and vice versa. As such, we propose ECHO as useful tool for water‐related scenario analysis and management options evaluation.