Dynamic simulation of industrial synergy optimisation pathways in Beijing-Tianjin-Hebei region driven by water...

China is promoting the coordinated development of the Beijing-Tianjin-Hebei region as a national strategy project; however, water scarcity and water quality problems will become a bottleneck restricting high-quality development. This study aimed to explore a feasible industrial synergy optimisation pathway to realise the collaborative development of economic growth and water environment improvement, combined with incentives for environmental efficiency improvement and reclaimed water utilisation. Research methods integrate input-output modelling, system dynamics, and multi-objective programming to construct a complex multi-region model. A dynamic simulation measure was adopted to simulate the economic and environmental impacts of different approaches that mix from 2020 to 2030 under water resource environment constraints. According to the simulation results, the annual economic growth rate of the entire region can exceed 6.1%, and the emission intensities of water pollutants decrease by more than 60.0%. In addition, traditional manufacturing industries that achieve cross-regional synergy can still release location advantages without negative environmental impacts. Furthermore, regional collaborative development optimises the allocation of water resources and alleviates water stress. Moreover, the pollutant emission reduction effect of source control in Hebei was more effective than in other cities. Finally, reclaimed water, as the end treatment measure, has the largest marginal effect on improving the trade-off between economic and environmental improvement in the long run. This study provides a new approach for multi-regional industrial synergy development and optimal allocation of resources and contributes to the high-quality development of the watershed.