Modelling the Water-Energy-Food-Land Use-Climate Nexus: The Nexus Tree Approach

Abstract

Abstract:The United Nations Food and Agriculture Organization (FAO) has established the Water-Energy-Food Nexus, implying that the three commodities are inextricably linked forming a complex system of interrelations. Perceiving water, energy and food as a system variable with dependencies rather than a singularity suggests an approach of a more holistic view that can offer a sustainable plan for managing resources. In this article, the already established three-way Nexus is expanded to include two more dimensions, namely land use and climate and a framework for modelling the interlinkages among these dimensions is presented.

Towards Ranking the Water–Energy–Food–Land Use–Climate Nexus Interlinkages for Building a Nexus Conceptual Model with a Heuristic Algorithm

“…Water, energy, food, land use and climate, the five nexus components as defined in [7] are linked to one another, through numerous direct or indirect interrelations (Figure 1a). A direct interconnection between two variables (e.g., land use and water) is defined as the effect in a variable's status (e.g., water), generated by a change in the other variable's status (e.g., land use), assuming that all other components (e.g., food, energy, or climate) remained unchangeable and did not affect the state of the two variables.…”

“…It is noteworthy that in indirect interlinkages, such as the interlinkage of F to C in FLWEC, the intermediate one-to-one interlinkages that are taken into account to construct the indirect pathway (such as FL in FLWEC, LW in FLWEC, WE in FLWEC, and EC in FLWEC) are all direct. For a more in-depth analysis of this, the reader is referred to [7]. were interacting.…”

“…It is noteworthy that in indirect interlinkages, such as the interlinkage of F to C in FLWEC, the intermediate one-to-one interlinkages that are taken into account to construct the indirect pathway (such as FL in FLWEC, LW in FLWEC, WE in FLWEC, and EC in FLWEC) are all direct. For a more in-depth analysis of this, the reader is referred to [7]. For drawing and counting the multiple different interlinked pathways of all orders, the nexus tree was designed for one nexus dimension at the time (the water nexus tree is showcased as an example in Figure 2, showing all possible direct and indirect interlinkages of water).…”

“…Naturally, most high-order interlinkages may turn out to not be significant and may eventually drop out, allowing for the most important ones to shape up the total influence that water has on land use. A Table that lists all pathways for all nexus variables following the nexus tree approach is included in the Appendix in [7]. Following this framework, one can define all pathways that can lead to a change in one nexus component because of a change in another.…”

Simulation of a Water Distribution Network with Key Performance Indicators for Spatio-Temporal Analysis and Operation of Highly Stressed Water Infrastructure

“…An aspect that becomes increasingly interesting regarding the management of resources in general and specifically the management of water in an urban WSS is the resource nexus, which means the interlinkage of resources though a complex system of interrelations that may lead to synergies or trade-offs [41]. The water-energy nexus within the WSS can be found in the impact of leakage on head loss throughout the network [42] and the coupling of energy consumption and water withdrawals, since every cubic meter of SIV has used energy to be pumped, transferred and/or treated.…”