The Ideas And Methods Of Post-evaluation On Environmental Assessment Of Cascade Hydropower Development

All cascade hydropower development is wide in range, large in scale and long in time duration. EIA and individual project environmental impact assessment in the early period of exploration plays a guiding role in mitigating the adverse environmental impact on the project. In the later development stage, systematic post-evaluation and reviewing the environmental problems that emerged in the construction and operation of hydropower will be of great significance in finding validity of EIA forecast, supplementing and improving environmental protection measures, improving the management of environmental protection and providing a reference for the environmental management and protection of other projects.This paper took the course of hydropower exploration for over half a century in the upper reaches of the Yellow River (from Liujiaxia section to Longyangxia section) as an example; classified statistical method was adopted to collect data of the 14 cascade hydropower stations that were planned in the basin at different periods of time; remote sensing data was employed to conduct comparative analysis of the environmental conditions at different periods of exploration; the study of the environmental impact caused by the operation of the already-built cascade projects in the section of the river was carried out in general; retrospective analysis, research and discussion was carried out concerning the major environmental problems that emerged and the nature, extent and scope of the influence; the correctness of the predicted result of the environmental impact on the part of individual project was evaluated synthetically, and the validity of the precautionary measures that were adopted and the appropriateness of the designing scheme of environmental protection were verified; the existing environmental problems were detected. All those mentioned above have an important meaning of guidance towards improving the environmental protection measures of hydropower development in the upstream areas of the Yellow River, optimizing the management of environmental protection and guiding environmental protection acts of those projects under construction. Meanwhile, on this basis, the exploration which could find the ideas and methodology of post-evaluation on EIA of river cascade hydropower development will have significant referential values towards the introduction of technological regulation or evaluating system of China's post-evaluation of environmental impact. It also has important reference value for the assessment of the environmental impact and environmental protection of other basins.