Should more water be diverted to or from electricity generation? This timely question is addressed in this short volume. Two different approaches are introduced and compared: The first is a cost-benefit analysis, examining the case of re-regulating a Swedish hydropower plant in which water is diverted from electricity generation to the downstream dryway. The proposed scenario generates environmental and other benefits, but comes at a cost in terms of lost electricity. The second study introduces an approach very different from the one used in conventional cost-benefit analysis, and provides a set of measures designed so that most, if not all, affected parties will be better off. Thus, in contrast to a conventional cost-benefit analysis, which draws on hypothetical compensation measures, the new approach envisages actual compensation. Comparing two different theoretical frameworks on the basis of a real-world case, this study can be seen as a manual that can be used to evaluate reasonably small re-regulation of rivers.