Sensitivity Analyses of Environmental Impact Factors for Songyuan Backwater Dam, Jilin Province, China

The main environment impact factors (EIFs) to the normal water level of Songyuan Backwater Dam, in Jilin Province, China, were identified through principal component analysis for managers to develop a more rational, comprehensive decision support. This research is based on a comprehensive ecological index system, including land resources utilization, water occupancy of the city, reservoirs sediment deposition, reservoir temperature structure and water reservoir structure. The results obtained are as follow: Significant sensitive EIFs were contributed from the land resource utilization and the water occupancy of the city (Songyuan); insignificant sensitive EIFs were recognized as the reservoir temperature structure and backwater reservoir length; and those factors uncertain for sensitivity were found to be the reservoir silt accumulation. This information is very helpful for Songyuan Backwater dam, especially for the environmental impact assessment of the project construction.