Electricity is the fastest growing source of end use energy worldwide. In order to meet the increasing energy demand, whilst reducing greenhouse gases, the role of renewable energy sources is getting more and more significant. Of course, the production of electricity with dams is classed to the renewable energy sources as well. Usually water power is thought to be a sustainable energy source, but within the last decades the voices against water power stations and their potential environmental effects rose. The question appears how sustainable the construction of dams is and what their contribution to a sustainable development can be.The aim of the thesis is to proof the qualification of chosen instruments for the evaluation of the sustainability of dams and the identification of deficits of each method that occur in practice. In order to make this observations, the stakeholder analysis, the product line analysis and the environmental impact assessment have been applied on the dam project "El Diquís" in Costa Rica. Due to the equality of social, ecological and economical aspects, the evaluation of sustainability is based on the tripple bottom line of sustainability. It turned out that the stakeholder analysis with the identification of the needs of affected humans is a substantial part of the sustainability evaluation. With the product line analysis a good overview of the positive and negative effects of the dam project could be made. The environmental impact assessment has been identified as the most important analysis method for the effects of projects in practice. It was not possible to make a clear statement about the sustainability of the dam project "El Diquís".