A differential game of water pollution management in the trans-jurisdictional river basin

Strengthening cooperation of water pollution management in the trans-jurisdictional river basin is of great significance for ensuring water security and deepening the construction of ecological civilization. Therefore, this paper established a dynamic differential game model of pollution management in the trans-jurisdictional river basins composed of upstream and downstream governments and sewage enterprises, calculated the strategic equilibrium solution of multi-stakeholders, analyzed the changes of strategy selection of different stakeholders under cost and non-cost sharing, and simulated strategy selection of stakeholders under multi-scenarios. The main findings are as follows: (1) Cost sharing policy enhances the governance efforts level of all stakeholders and increases social welfare. (2) The selection of governance strategies by multiple stakeholders has an interactive influence which is affected by the cost–benefit relationship of each stakeholder. The proportion of cost sharing and incentives affect the variation of the utility of the upstream government, downstream government, and sewage enterprises in cooperation. (3) The increase in the attenuation coefficient of governance utilities and the governance costs of the three parties will reduce the level of water pollution management efforts of the three parties. (4) The increase of marginal utility and social welfare effect will enhance the level of governance efforts. (5) The cost sharing ratio of the downstream government has an impact on the governance efforts of the upstream government. (6) Downstream government rewards, corporate social reputation, and external influence coefficient of regional river pollution management has an important impact on the level of governance efforts of sewage enterprises. Based on the above conclusions, this paper puts forward suggestions from the perspectives of cooperation strategies, reward and punishment mechanisms, and the application of advanced technology and equipment to help strengthen cooperation of water pollution management in the trans-jurisdictional river basin.