Multiobjective risk-based optimization for real-time interbasin water diversion under decomposed chance-constrained total water use

The eastern route of the South-to-North Water Diversion Project in Jiangsu Province, China, a critical national interbasin water diversion system for alleviating water shortages. This study proposed a risk-based multiobjective optimization model for interbasin water diversion, with chance constraint on total water use. Probabilistic forecasting of local streamflow and water demand was adopted to identify operation risks. Multiobjective stochastic optimization was then introduced to minimize the risks of water shortages and spillages. Furthermore, a decomposition method was proposed to investigate the regime of water use under different hydrological conditions, and the decomposed chance constraint was incorporated into the optimization model. Finally, two indices were designed to assess the value of forecasts and water utilization efficiency. Developing a robust and efficient water diversion strategy based on forecast information is crucial. The proposed method with case study provides the following new hydrological insights: (1) conflict occurs between water diversion, spillage, and shortage, with water shortage and diversion representing major contradictions. (2) high-skilled forecasting helps reduce water diversion (22.3 %), spillage (over 60 %), and shortage (approximately 10 %), indicating considerable value for promoting the benefits of water diversion operations. (3) water use constraint focuses restricting excessive water diversion (30.8 %), exploiting the potential of local water supply, increasing in local water utilization efficiency from 92.8 % to 93.4 %. • Identified conflicts between diversion benefits and costs under complex uncertainties. • Evaluated probabilistic forecast skills in multiobjective water diversion operations. • Proposed decomposition method on total water use constraint considering uncertain forecasts. • Revealed that effect of water use constraint on improving water utilization efficiency.