This chapter presents an application of a novel operational approach for designing and assessing the impacts of Watershed Investments, developed in Chap. 3, to the Asmara and Toker Watershed case study. Assuming urban water security and rural poverty alleviation as two objectives for Watershed Investments, the case study application explores all the steps of the proposed approach. The results of the application include spatially explicit data that allow quantitatively assessing the performance of different Watershed Investment scenarios in terms of changes in a selected ecosystem service, answering to important planning and management questions. The application to the Asmara and Toker Watershed case study also highlights the challenges of addressing stakeholders’ concerns through relevant boundary work strategies.