Comprehensive Assessment of Environmental Impact of Large-Scale Water Conservancy Project: A Case Study of Yintao Irrigation Project on Tao River in Gansu, China

Yintao Irrigation Project (YIP), aiming to handle the drought and water problem in the middle part of Gansu, improve its impoverishment and backwardness, and change the deterioration of ecological environment, is a large-scale trans basin diversion water project. This project has a profound impact on environment, not only covering an immense area for a long time, but also including a great number of complicated influential indices. In order to conduct a systematic and comprehensive assessment to the environmental impact level of this project, Analytic Hierarchy Process (AHP) is used to determine the important weighted value of environmental impact under each assessment index, and to conduct a comprehensive evaluation of environmental impact in different districts. The results give evidence that effectuation of this project will significantly improve the living standards of those people who has benefited from this project as well as the ecological environment, and will promote a sustainable development of regional environment and economy. In the mean time, the results also show that AHP is better than the general qualitative analysis. As is expected, the assessment results coincide with the actual ones.