The Netherlands will be facing more cases of extreme rainfall in the future. Meanwhile the Netherlands is also facing a large housing problem which requires a yearly construction of 100,000 houses per year to solve. Nature-Based Solutions can be used as one of the solutions to flooding due to extreme rainfall events in urban areas. The goal of this research is to asses the impact of the implementation of Nature-Based Solutions on stormwater flooding in new construction areas in the Netherlands under uncertainty of extreme rainfall due to climate change. This was investigated by running the flood model, the Arc-Malstrom model, for the case-study of Het Zand, Utrecht. Furthermore scenarios of 35, 70 and 140 millimeters of rain were used including the implementation of 50% and 100% green-roofs in the area. It has been found that green-roofs provide only a small improvement of 1 or 2% in flood problems overall in the area, but that the most severe floods have a reduced water height of 20cm. However the implementation of green-roofs can improve the flood problems in some areas significantly. Green-roofs will have the most improvement in flood problems in areas where 20 to 30% of the area consists of houses and thus houses are built more close to each other.