Research on two-way ecological compensation strategy for transboundary watershed based on differential game.

Water pollution control in transboundary watersheds can improve the water environment quality, alleviate water resource conflicts, and is an important guarantee for achieving healthy and stable development of watersheds. Ecological compensation is an important measure to solve the problem of water pollution in transboundary watersheds and has been widely applied in China. We constructed differential game models for water pollution control in transboundary watersheds under four scenarios: (1) no ecological compensation scenario, (2) upstream one-way ecological compensation scenario, (3) downstream one-way ecological compensation scenario, and (4) upstream and downstream two-way ecological compensation scenario. We studied the optimal water pollution control strategies and ecological compensation strategies under different scenarios, and compared the results obtained under different scenarios to explore which scenario has better water pollution control and ecological compensation, as well as the applicable conditions for different one-way ecological compensation. The results indicate that both upstream and downstream one-way ecological compensation can promote water pollution control, and the optimal one-way ecological compensation should be determined based on the cost and benefit parameters of upstream and downstream water pollution control. The upstream and downstream two-way ecological compensation can reduce the pollutant reduction furthest and improve the social welfare extremely, making it the best ecological compensation. Finally, it is necessary to actively promote the formation of two-way ecological compensation in the upstream and downstream of transboundary watersheds to achieve long-term sustainable development of the watershed.