As the basis of quantitative research over water-energy-food nexus (WEFN), qualitative analysis is indispensable for depicting the systems and providing effective measures and policies. Preceding qualitative WEFN studies largely neglected the role of local stakeholder participation, which could only reflect fragments of the systems. Causal loop diagrams (CLDs) have been proven to be effective for supporting stakeholder participation in many other areas. Nevertheless, there was a lack of impartial methods that could make CLD analysis tractable without significantly impairing the WEFN systems integrity. To fill such gaps, a novel method based on merging and reduction rules was proposed to reasonably merge and downscale WEFN CLDs built by stakeholders. Based on this improved method, a CLD-based methodology was developed as a prototype for characterizing WEFN systems, prescribing the WEFN problem, exploring its causes and consequences, and identifying effective measures and policies for alleviating conflicts. To validate the applicability of the developed methodology, it was applied to a real case. The results indicated that total water consumption, water allocation among varied sectors, available surface water, and available groundwater, as well as indirect factors such as volume of diverted water and agricultural water consumption, were the keys to alleviate water scarcity problem under WEFN in the study area. Measures and polices focusing on the interactions between surface water and groundwater could be viable for alleviating the problem. Directions to enhance tradeoffs and synergies within WEFN systems were also obtained.
This paper initially put forward a coupled CLDs and WEFN methodology through integrating problem and boundary definition, stakeholder analysis, individual CLD construction, CLD merging and downscaling, and qualitative analysis of CLD. Based on this method, a CLD-based model was developed as a prototype for prescribing the WEFN problem, exploring causes and consequences of the problem, and identifying effective measures and policies for alleviating conflicts. The whole framework is a time-saving and cost-effective qualitative analysis method based on WEFN perspectives. This methodology can not only merge and downscale CLDs constructed by key stakeholders but also effectively analyze key variables of the problem and seek feasible options to alleviate conflicts within WEFN.
To validate the applicability of the developed methodology, it was applied to the City of Bayan Nur in China as a prototype for WEFN analysis, aiming at prescribing the problems within WEFN and identifying effective measures and policies for conflicts among water, energy, and food. Based on the constructed CLD prototype, qualitative analysis was carried out for exploring the causes and consequences of the WEFN problem and identifying the measures and policies to alleviate it. The results indicated that total water consumption, water allocation among varied sectors, available surface water, and available groundwater, as well as their indirect factors such as volume of diverted water and agricultural water consumption, were the keys to alleviate the WEFN problem. Also, the results revealed that the existing measures and policies, such as water rights transfer, the application of drip irrigation, were unable to alleviate the problem effectively. This was mainly attributed to a lack of systematic thinking, especially the neglect of social and environmental dimensions of WEFN systems. In addition, measures and policies that focus on the interactions between surface water and groundwater could be an effective way to alleviate the WEFN problem in the study area. Without loss of generality, the developed methodology is also applicable to analyze other kinds of complex systems that involve multiple and interwoven elements and factors.