As a result of the climate change, showers of rain become more and more extreme. This results in water problems in dense build areas where large amounts of rain water are immediately discharged into the sewer system. Rotterdam is one of these dense cities that struggles with this problem. The water system of Rotterdam can’t handle the amount of water during extreme weather. The sewer is discharged into the city canals which results in large water problems. Rotterdam is solving the direct causes of the water problems but also stimulation solutions to solve the problem in a indirect way. This project is about solving the water problem at its cause: the 99% hard surface in the inner city. The location along the Hoogstraat is chosen because it is a part of the area in which the municipality of Rotterdam has planned an open water system to collect rain water. Also the location includes a new-construction project and is situated along a main route. The special charachteristic of this is location is the link between the quiet Grote Kerkplein, the bustle Hoogstraat and the Delftsevaart. The Waterplan of Rotterdam argues for more temporary rain water storage in the innercity of Rotterdam. In the Museumpark a new parking garage is combined with water storage and the same concept will soon be used for the Zuidplein. But what happens if we combine rain water storage and architecture in a visible way? Multifunctional use of space and construction becomes possible and the relation between water and daily use will become more and more important. We already know buildings that collect rainwater and re-use it in a self-sufficient way. It is a challenge to design a building that also collects rain water from its surroundings and provides the surrounding area with purified water. If architecture and rain water storage are combined in a visible way the architecture and shape of the building will change if it rains. Rain water can be an integrated part of the architecture and the functional design. The project will be designed ...