Synergistic management mechanism of water pollution in near-shore waters under the background of land-sea integration: A quadrilateral evolutionary game model

The impact of land-based sources of pollution on near-shore seawater pollution has intensified. However, current governance pressure is concentrated in coastal areas, lacking a scientific governance model for upstream inland watersheds and near-shore seas to collaborate in managing transboundary water pollution. This study used a quadrilateral evolutionary game model to discuss the evolutionary mechanism of collaborative transboundary water pollution management among higher-level governments, inland and coastal governments, and scientific institutions in China and explore the key influencing factors affecting decision making. The combination of stabilization strategies and conditions for land-sea synergistic management of offshore water pollution are also clarified through case-based numerical simulations. The results show that the cost of effective governance is the key influencing factor for decision-making in coastal and inland areas, with incentive payments significantly influencing higher-level government decision making. Monitoring cost is the key influencing factor for decision-making of scientific institution. Meanwhile, the bidirectional compensation payments and government incentives and penalties have a driving effect on effective governance in inland and coastal areas, respectively. In contrast, monitoring by scientific institution only has a binding effect in coastal areas. For the optimal strategy, the ecological benefits of inland and coastal areas must make up for the excess governance costs. This study enriches the theoretical system of water pollution synergistic management model in near-shore waters and proposes implementable policy recommendations for policy formulation and synergistic management.