The Three Gorges Dam in China is one of the world's largest hydroelectric dams, providing energy for millions of people. However, the dam's construction forever altered the Yangtze River ecosystem and the lives of local residents. In this case study, students explore the complex and inter-related issues associated with large ecosystem-altering projects like dams and develop a persuasive argument for or against their construction. Do the benefits from a dam outweigh the ecological, economic, and social costs? Answering this question is difficult, since the benefits and costs are not directly comparable. How do you compare the loss of endemic species to the increased safety from flooding? How do you weigh a relocated family's social and economic costs in comparison to the benefits of a sustainable and renewable energy source? Although this case was developed for an undergraduate course in fisheries management, it would also be directly applicable to courses in ecology, environmental engineering, or global issues.