Environmental and livelihood impacts of dams: common lessons across development gradients that challenge sustainability

The economic benefits of dams have been assumed to outweigh the costs, thus providing rationale for construction of dams around the world. However, the development of these structures can be accompanied by negative biophysical, socio-economic, and geopolitical impacts; often through the loss of ecosystem services provided by fully functioning aquatic systems. Moreover, impacts of dams can be involuntarily imposed on marginalized peoples whose livelihoods are dependent on riverine resources. In this review, we examine the impacts of dam projects in regions of the world that are at different stages of development, using the USA, China, and Southeast Asia to represent a development gradient from developed to developing, respectively. Case studies for each region illustrate the environmental and livelihood impacts of dams in each region, while also providing a basis to better understand how environmental degradation is directly related to economic growth. We conclude that a distinct temporal component related to development mediates the relationship between policies and governance mechanisms and the mitigation of environmental and social costs of dams. The role of affected individuals to influence the political will behind dam projects and the importance of environmental advocacy is emphasized as a fundamental approach towards more sustainable development.