Multi-objective Collaborative Optimization of Water Resources in Hebei Irrigation Areas: Maximizing the Benefits of the Water-energy-grain Nexus Driven by the NSGA-III Algorithm and Verified by Digital Twins

Peng Huang^1*Mengdi Jia²Fuxing Gu³

• ¹City University of Hong Kong, Hong Kong, Hong Kong, SAR China
• ²School of Civil Engineering, Zhengzhou University, Zhengzhou, China
• ³Guangdong Zhonghao Survey, Design and Consulting Co., Ltd., Guangdong, China

Hebei's irrigation districts, critical for China's grain security, face severe water-energy-food nexus challenges with 72% of groundwater areas being over-exploited and 60% of total energy consumed by pumping systems. This study develops a digital twin-enabled framework integrating three innovations: an enhanced NSGA-III algorithm achieving 18.5% water conservation and 1285 kWh per hectare energy reduction through dynamic reference points and hybrid constraints, a four-dimensional nexus model capturing nonlinear economic returns with 0.913 determination coefficient and 0.07-meter groundwater recovery in droughts, and a real-time verification platform demonstrating 0.03-meter groundwater prediction accuracy and 186-millisecond decision latency.Empirical validation using multi-year data from 32 meteorological stations and 48 soil sensors confirmed 0.48% yield simulation error and 0.85 robustness under 30% electricity price fluctuations. The framework's scalability was proven in Hexi Corridor with 15.3% water savings and 77% decision acceptance through adaptive calibration. Comparative analysis showed 22.3% higher solution diversity than industrial benchmarks while reducing monthly optimization cycles to 15-minute intervals.This paradigm shift resolves the water-saving versus energy-cost dilemma, providing actionable solutions for 89% of China's water-stressed farmlands. Implementation costs of 485,000 USD are offset within 6.2 years through 19% pumping cost reductions, demonstrating technical and economic viability for global arid regions.