Economic losses due to weather-related natural hazards (Extreme rainfall and droughts) continue to rise rapidly in urban areas. For example, the extreme rainfall event in Amsterdam in July 2014 caused a huge impact and economic losses, and these impacts will increase in the future through climate change The current sewer systems in urban areas are often not designed to cope with (future) extreme events, and novel adaptation measures are needed. In Resilio project, the City of Amsterdam will develop smart system of blue-green roofs on different pilot locations. These smart blue-green roofs are essentially a layer of vegetation and water on top of an existing roof with the ability to store or release water depending on weather conditions. The vegetation layer is able to absorb rainwater, evaporate a part of the rainwater, and slows down the discharge of rainwater into the sewer-system. Another advantage is the ability of blue-green roofs to insulate a building, keeping the building warm in winter, and maintaining lower temperatures in summer time. This latter aspect is important in the future, when cities are faced with increasing droughts and heat waves.
VU Amsterdam has the task to assess the effectiveness of green roofs with a Postdoc research, and to scale up the blue-green roofs at the scale of the whole City with a computer model. This model shows the (a) the effect of smart blue-green roofs on the hydrological cycle of the Amsterdam and (b) the model supports to calculate cost and benefits of reducing risk from extreme rainfall by scaling up green roofs to the City level.
- design a model to analyze the performance of a smart blue-green roof.
- set up a hydrological model for the Amsterdam with Waternet, include scenarios with different numbers of blue-green roof surfaces, and calibrate the model using the hydrological data from the three pilot sites
- perform a societal cost-benefit analysis for the blue-green roofs
- discuss simulation results with stakeholders such as Waternet and the City of Amsterdam