The missing link between cross-sectoral resource utilisation and management, and full-scale adoption of the water-energy-food (WEF) nexus has been lack of analytical tools to support policy and decision-making. This paper defined WEF nexus sustainability indicators and developed a methodology to calculate composite indices to facilitate WEF nexus performance, monitoring and evaluation. WEF nexus indicators were integrated through the Analytic Hierarchy Process (AHP) in a multi-criteria decision-making (MCDM). Data were normalised to determine composite indices. The method established quantitative relationships among WEF nexus sectors to indicate resource utilisation and performance over time, using South Africa as a case study. A spider graph of normalised indices was used to illustrate WEF nexus indicator performance and inter-relationships, providing a synopsis of the level of interactions and inter-connectedness of WEF nexus sectors.
The shape of the spider graph is determined by the level of the interdependencies and interactions among the WEF nexus sectors, whose management is viewed either as sustainable or unsustainable depending on the classification of the developed integrated index. The spider graph produced for South Africa shows an over emphasis on food self-sufficiency and water productivity at the expense of other sectors, which results from the sectoral approach in resource management. Although the calculated integrated index of 0.203 for South Africa is classified as lowly sustainable, the emphasis is on the quantitative relationships among the indicators and on how to improve them to achieve sustainability. The developed method provides evidence to decision makers, indicating priority areas for intervention. The analytical model is another niche area for the WEF nexus, as it is now capable to evaluate synergies and trade-offs in a holistic way to improve efficiency and productivity in resource use and management for sustainable development.
This study developed a WEF nexus analytical model, firstly by defining WEF nexus indicators, and secondly calculating the indicator composite indices for South Africa. Although the procedure uses data for South Africa, it can be replicated anywhere and at any scale. Thus, the procedure presents an inclusive and multi-scale analytical framework that defines and quantifies the interconnectivity of water, energy and food. The composite indices assess the interactions between the natural environment and the biosphere in a given context and at any scale, and the methodology presents the WEF nexus as a unique tool that can be used to (a) quantitatively assess the cross-sectoral linkages among resources and indicate performance of resource utilisation and management, (b) leverage an understanding of WEF linkages to promote coherence in policy-making and enhance sustainable development, and (c) guide and promote cross-sectoral collaboration. The indices provide a clear overview of the level of interactions, inter-relationships and inter-connectedness among sectors. The relationships are demonstrated in the form of interdependencies, constraints, synergies and trade-offs that arise when changes in one area affects others, and they are viewed as either positive or negative. When shown through a spider graph, the indices indicate areas needing immediate attention to create a balance in resource utilisation, increase efficiency and productivity, improve livelihoods and build resilience. The WEF nexus analytical framework simplifies the understanding of the complex and dynamic interlinkages between the issues related to the securities of water, energy and food and it provides evidence for decision-making and policy formulation.
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Nhamo, L., Mabhaudhi, T., Mpandeli, S., Nhemachena, C., Senzanje, A., Naidoo, D., Liphadzi, S. & Modi, A. T. (2019). Sustainability Indicators and Indices for the Water-Energy-Food Nexus for Performance Assessment: WEF Nexus in Practice – South Africa Case Study