Assessing the Sustainability of Cascade Hydropower Development Based on Complex Ecology System

Despite of the high utilization efficiency, cascade hydropower development in river basin may induce negative indirect and cumulative ecological impacts too, and sensitive ecological problems would therefore arise to restrict the sustainability of the river basin ecosystem. First of all, this paper treats the basin ecosystem to be a multi-layer complex system which is driven and influenced by cascade hydropower stations. Then, Environmental Impact Assessment (EIA) is chosen to be main instrument to measure the sustainability of this ecosystem. Finally, by taking the fundamental principles of sustainability into consideration, a multi-layer sustainability indices system is constructed. Specific results are listed below: by the first step, basin ecosystem is decomposed into three sub-systems such as environment, ecology and social-economy sub-system; by the second step, a set of impacts, especially the impacts which could reflect intra and inter generational equity are analyzed and described briefly in a table; by the third step, several diagrams are depicted to describe the specific hierarchical structure of the indices system. These results show, compared with the fixed indices or integrating methods, sustainability indices based on EIA are more pertinently and efficiently to reflect characteristics of the cascade hydro power development.