Many rivers in Switzerland have in the past been managed by means of channelization, which had negative impacts on their morphological state, biodiversity and in some cases on river water quality and flood risk. Nowadays there are plans to return rivers into their more natural state through river rehabilitation measures. The objective is to rehabilitate 4000 kilometers of rivers in the country until 2090, which corresponds to approximately one third of the total river length in Switzerland. The Federal government has allocated 40 million CHF annually for this purpose. However, no assessment of the benefits of river rehabilitation measures in monetary terms or cost-benefit analysis of a river rehabilitation project has been conducted until now. This project aims at closing this gap by assessing the economic values of improvements in river ecosystem services resulting from river rehabilitation. Thur and Töss Rivers thereby serve as case studies. A survey with stated preference methods (choice experiment and contingent valuation) will be conducted among the relevant population to elicit their willingness to pay for river rehabilitation projects. This will allow estimating the total economic benefits of improvements in river ecosystem services. The benefits will subsequently be compared with the costs of rehabilitation measures in a cost-benefit analysis. From a methodological perspective, the substitution effect between the two rivers is captured directly in the choice experiment design, where unlabeled and labeled choice experiments are framed as a valuation exercise of a single and multiple (substitute) rivers. In addition, we test for differences in distance decay effect, stated preferences and welfare measures by comparing single- and multiple-site choice experiments.