Water, energy, and food are vital for human wellbeing, poverty reduction, and sustainable development. The three resources are strongly linked as food production needs water and energy; water management (extraction, treatment, and redistribution) requires energy; and hydro-energy production (major source of energy in southern Africa) requires water [1
]. Any impact on one affects the other two. These interconnections are described as the water-energy-food (WEF) nexus [3
], which, when well implemented, leads to socio-economic securities and development [3
]. Formal published evidence of the three-way mutual interactions among the WEF nexus components only started in 2008 [6
], and has since emerged as an important concept for integrated resource management at various spatial scales [7
]. Due to the current and forecasted increase in global demand and pressure on the WEF resources, and the strong linkages between the WEF sectors and sustainable development, the WEF nexus is increasingly being recognised as an approach to effectively manage sustainable development [3
]. The WEF nexus is, thus, a framework that captures the inter-relations, synergies and trade-offs between the demand on water, energy, and food in the context of threats, and emerging constraints of sustainable development in particular regions or systems [7
]. WEF nexus thinking is a method based on a systems approach, for example, using the socio-ecological system as the primary point of reference, and is gaining recognition within the scientific community and among policy makers [4
]. It has grown to be an essential approach to achieve the Sustainable Development Goals (SDGs) on poverty alleviation, zero hunger, provision of water and sanitation, and access to affordable and reliable energy (Goals 1, 2, 6, and 7, respectively) [4
Despite the recognition of WEF nexus linkages, current approaches are such that management of the three sectors often falls under sector specific institutions, with sector driven mandates. This has been partly attributed to a policy environment that does not recognise cross-sectoral linkages and the general ‘silo’ approach to resource management, particularly in southern Africa [3
]. Sectoral policies and institutions are designed to operate in silos; this creates an imbalance and often duplication in resource allocation, which translates to failure to deliver and in inefficiencies in resource use, negatively impacting on sustainable development [3
]. Although the Integrated Water Resources Management (IWRM) concept embraces other resources, it is generally water centric, whereas the WEF nexus considers all resources in equal terms as they are interlinked, depending on each other. Thus, the WEF nexus is multi-centric.
In the case of southern Africa, where the region as a whole faces water, energy, and food insecurities, a WEF nexus approach could unlock positive synergies needed to catalyse regional development. This could be achieved through, for example, coordination among countries in joint investments in energy projects in one country and sharing the resource, while ensuring that the water saved by the other countries is freely released for agriculture purposes in other Member States. For example, South Africa is considering harnessing water from the Democratic Republic of Congo (DRC) in exchange for energy. This forms part of South Africa’s National Water Sector Plan currently being championed by the National Planning Commission (NPC). The region also faces increasing demand for water, energy, and food due to population growth, urbanisation, and economic development [14
], thus necessitating greater coordination of the WEF sectors to meet current and projected demands. The region has significant shared water (surface and groundwater) and energy resources and infrastructure [15
]. In addition, several sector specific regional institutions tasked with coordinating these regionally shared resources and infrastructure already exist and could provide a useful platform for embedding the WEF nexus [3
The fifteen transboundary river basins within the SADC region provide an opportunity for riparian countries to achieve short and long-term benefits through an integrated and coordinated operation of existing and planned hydropower facilities, cooperative flood management, and irrigation development [3
]. Cooperation among riparian countries in the Zambezi Basin has the potential to create a reasonable balance between hydropower and irrigation investment that could result in the stable energy generation of 30,000 Gigawatt hours (GWh)/year and 774,000 ha of irrigated land [16
]. Most large dams in the region remain underutilised as they were originally designed for single purposes. However, some, like the Itezhi-Tezhi Dam in Zambia, are being redesigned for multipurpose activities, such as hydropower and irrigation [17
]. The Kariba Dam was also originally commissioned only for hydropower generation, but it is now used for aquaculture, urban water supply, eco-tourism, transport, and mining activities [18
]. This highlights opportunities for WEF nexus pilot projects within the region that could be replicated elsewhere.
The recognition of the role that can be played by the WEF nexus in regional socio-economic security, cooperation, and integration, was highlighted by the WEF Nexus Action Plan, which forms part of the Regional Strategic Action Plan IV (RSAP IV) [19
]. The action plan recognises the role of the nexus in adapting to the challenges posed by population growth and climate variability and change, as well as in optimising resource use to achieve regional goals and targets. Despite the presence of the WEF nexus action plan, there is little or no evidence of cross-sectoral linkages between institutions, policies, and current projects. This highlights a challenge in implementing the WEF nexus approach and can be attributed to a lack of guiding frameworks for its implementation. There is also not much clarity on the spatial scale at which implementation should occur and how to quantify or assess such implementation. This further alludes to the need for WEF nexus indicators and metrics, which, when coupled to the frameworks, could allow for implementation.
The pressure to produce more food and energy under increasing water scarcity requires the WEF nexus to balance competing demands for water resources. While current developmental approaches have often negatively impacted on other sectors and sustainability thereof, a WEF nexus approach could contribute to sustainable socio-economic and inclusive development [5
]. Climate change projections which indicate increased pressure on water, energy, and food resources, further justify the need for a coordinated and integrated approach to sustainable development [20
] such as the WEF nexus approach. The resource rich transboundary river basins of the SADC region present opportunities to cement regional integration, promote inclusive sustainable development, and ensure socio-economic security.
This study thus explores opportunities for the WEF nexus in promoting cross-sectoral policy linkages among water, energy, and food sectors at a regional level to achieve regional integration and sustainable development. The study provides an appraisal of the region’s WEF resource endowment, climate change impacts, and policy and institutional arrangements. We further propose a regional nexus framework for implementing the WEF nexus, as well as possible tools for monitoring and evaluating WEF nexus implementation. Thus, the study recommends an integrated model and tools for WEF nexus implementation at a regional level to promote integrated regional development, ensure socio-economic and political security, and achieve regional integration.
The WEF nexus offers opportunities to effectively attain sustainability through interdisciplinary cooperation at a regional level, particularly in southern Africa, where resources are shared. The nexus offers inclusive, transparent, intergovernmental approaches for all stakeholders, and supports the UN SDGs, using scientific and evidence-based policy, monitoring, assessment, and cooperation models. The WEF nexus thus offers opportunities to promote peace, regional cooperation, and harmonisation of legislations, policies, and strategies in a region of transboundary resources. Sectoral policies that are not linked to each other promote unsustainability and unbalanced resource development. The regional conceptual framework and the given models present opportunities for developing comprehensive analysis approaches, identifying synergies in the nexus, and assessing multiple benefits and trade-offs across ecosystem service sectors. Challenges in southern Africa are generally similar in nature among Member States and an integrated approach to resource management at a regional level may bring the desired outcomes. As the vast and unexploited resources within the region are unevenly distributed within the transboundary river basins, the WEF nexus could be a pathway for resilience building and a reduction of vulnerabilities that permeate the region. However, successful implementation of the nexus at a regional level requires commitment from Member States, supported by technological innovations that allow the production of more food with less resources. Adoption of the nexus approach would be a step forward towards attaining the SDGs on poverty eradication, zero hunger, availing water to all, and provision of clean energy (goals 1, 2, 6, and 7 respectively). The shared and transboundary nature of SADC’s resources implies that there are greater gains and more prospects of success if developmental efforts are focused at the regional level as opposed to the national level. Unlocking development at the regional level would ultimately allow greater progress at the national level and allow for genuine integration and inclusive development. Incorporating the nexus thinking in the development of agriculture investment plans would be worthwhile for sustainability.