Measurment and analysis of collaborative governance efficiency of water environmental pollution transfer in river basins under environmental regulation

Based on the shift-share analysis model, the study identifies the transfer paths of water environmental pollution in river basins. Combined with synergetics theory, the three-stage SE-DEA-Malmquist index model and coupling coordination degree model are employed to measure and evaluate the collaborative governance efficiency of water environmental pollution transfer across the seven major river basins in China from 2006 to 2018. The results indicate that: from 2006 to 2018, the upper and middle reaches of the river basins were mostly pollution discharge transfer-out areas, while the lower reaches were mainly transfer-in areas. Compared with the upper reaches, the water environmental quality in the middle and lower reaches improved more significantly. Specifically, the lower reaches achieved effective improvement in water environmental quality due to the optimization of production structure, but the total amount of water pollution discharge still showed an expanding trend. In the process of undertaking industrial capacity transfer from the lower reaches, the local pollution discharge level in the upper and middle reaches increased to a certain extent. Under the influence of the water environmental pollution transfer mechanism, the collaborative governance efficiency of river basins exhibited temporal and spatial differentiation characteristics. The coupling coordination degree of total factor productivity (TFP) in transfer-out areas was significantly higher than that in transfer-in areas, with the difference fluctuating around 0.085. The collaborative governance efficiency in the upper and middle reaches was relatively similar-both the coupling coordination degree of TFP and technical efficiency in transfer-out areas were significantly greater than those in transfer-in areas, while the gap in the coupling coordination degree of technological progress between transfer-out and transfer-in areas was relatively small. This study suggests constructing a differentiated environmental regulation system, optimizing the river basin collaborative governance mechanism, and strengthening the dynamic supervision of the water environmental pollution transfer process.