Analysis of impacts of large dams on river ecosystems

摘要

Large dams are one of the symbols of civilization. Nowadays, dams play an important role in river basin management and flood control. In addition, they are used to generate electricity and get clean and cheap energy. At the same time they will affect the river system significantly. Unlike rivers, reservoirs greatly reduce the flow velocity of water. Although builders and managers of dams do their best to alleviate the negative effects of large dams on river ecosystems, they cannot restore the original state. In this study, several cases of long term effects of dams on physical, chemical and ecological characters of river system (downstream, estuary and estuary wetland and so on are discussed). The effective strategies and critical points are summarized to protect river ecosystem in dam construction.