This thesis aims to assess the applicability of the CRCTool for evaluating the effectiveness of NBS for mitigating tropical urban floods in the city center of Paramaribo. Assumptions related to urban flood mitigation were tested, a sensitivity analysis for the most sensitive parameters was performed, and the hydrological behaviour of groundwater processes, evapotranspiration, and percolation were critically assessed. In addition, the model outcomes were compared to a hydrodynamic model, developed in D-HYDRO, to determine the importance of spatial effects such as flow routing and elevation. It was found that the current state of the CRCTool restricts its applicability to areas with low rainfall and runoff volumes. The continuous modelling capabilities are limited due to the way hydrological fluxes are implemented. Minor model adjustments can be made to make the tool more suitable for areas with larger rainfall volumes. This research recommends implementing these adjustments and thoroughly testing the tool's performance. Additionally, to minimize the impact of flow routing and elevation, it is advised to test the tool on smaller areas where the hydrological conditions are more clearly defined.