Ecological security evaluation for Changtan Reservoir in Taizhou City, East China, based on the DPSIR model

Reservoirs supply drinking water to many major cities in China, and their ecological security ensures the economic development, drinking water safety and ecological balance of cities. Based on Driver-Pressure-State-Impact-Response (DPSIR) model, this study evaluated the ecological security of Changtan Reservoir in Taizhou City, East China. The ecological security evaluation system was constructed, including 17 s-level evaluation factors, which included 36 third-level evaluation indices. By combining the expert scoring method with the entropy method, the weights of each index can be calculated effectively. Finally, the ecological security index (ESI) was obtained according to the DPSIR model. The results show that the ESI of the Changtan Reservoir is 75.78, which suggests that the Changtan Reservoir is in a relatively safe state. However, the soil erosion intensity index is in a poor state in most areas. Therefore, soil and water conservation management should be strengthened. The aquatic biodiversity in the watershed of the reservoir is also poor, especially the benthos with a single species. Hence, the ecological conservation of the reservoir watershed should also be enhanced. The study also proposes that centralized treatment of urban domestic sewages and rural domestic sewages around the reservoir should be greatly improved by enhancing the sewage treatment facilities and pipelines.