Sustainable regional water allocation under water-energy nexus: A chance-constrained possibilistic mean-variance multi-objective programming

It is important to manage water resources under water-energy nexus considering both steady economic development and environmental needs. In this study, a water resources management modelling framework of regional water use sectors was established by combining the water resources value theory with the uncertainty theory. The water resources value of different water use sectors was calculated through Cobb-Douglas (C-D) production function and emergy theory to estimate the benefits of water resources accurately. On this basis, a chance-constrained possibilistic mean-variance multi-objective programming (CPMMP) model was established by integrating the classical mean-variance model based on investment portfolio, chance-constrained programming (CCP), possibilistic mean and variance of fuzzy number with multi-objective programming framework. This model can not only deal with the risks of inaccurate water-supply prediction and the fluctuating water supply benefits but also achieve compromise resources consumption, and environmental protection under uncertainty. Taking Shiyang River Basin as an example, the validity of the proposed framework and solution method were verified under different hydrological years, 60%WSB (best water supply benefits) and 90%WSB scenarios. The calculated average water resources value in agricultural, industrial and domestic were 1.92, 109.67 and 20.71 CNY/m³ respectively, and the standard deviation were 0.21, 15.68, 2.60 CNY/m³ respectively. The variability of water resources value in industrial sector were far greater than those in agricultural and domestic sectors. These fluctuations of water resources should be paid attention to in the water resources allocation. The established CPMMP model can effectively reduce the system risks, net carbon emissions and energy consumption under the premise that the system benefits are equivalent to the status quo. Optimal results can provide decision makers energy-saving and emission-reducing water resource management strategies, which are conducive to the sustainable development of the system. Besides, the established framework can also provide a scientific basis and technical support for other resource management in other regions.