Department Urban Water Management

There is growing evidence that heat waves are becoming more frequent under climate change. Heat waves associated with higher daytime temperatures and reduced nighttime cooling are exacerbated in urban areas due to highly impervious surfaces, limited air humidity, anthropogenic heat, and reduced ventilation. This presents a threat to public health, increased energy consumption for cooling, reduction in economic productivity, increased heat related damage to infrastructure and a reduction of overall people’s well-being.

Also associated with climate change and intensified by the increasing level of urbanization is the challenge of stormwater management. Urban pluvial flooding (or surface flooding) is one phenomenon that causes larger damages when compared to other natural hazards. In adapting and minimizing these natural hazards, cities have been adopting blue-green infrastructure solutions (such as green roofs, infiltration basins and rain gardens) and reducing the reliance on grey infrastructure (e.g. building underground reservoirs or pipelines. Blue-green infrastructure in cities, have been demonstrated to mitigate urban heat impacts.

However, with the exception of a few studies, the quantitative potential of these systems on urban heat mitigation and its relation to water requirements has not yet been thoroughly explored. The Heat-Down project goal is to understand how smart urban stormwater systems in the era of digitalization, together with blue-green infrastructure solutions can contribute to urban heat mitigation and improve urban thermal comfort. This objective is being addressed by means of the development of an integrated model to support urban planners to investigate the potential of urban water to mitigate urban heat impacts. The project combines expertise from Switzerland, Australia and The Netherlands on urban stormwater management, urban microclimate and blue-green infrastructure planning.

Jixuan Chen: “Urban water management for cooler cities – investigating different water sources and blue-green infrastructure”.

Jixuan Chen’s research aims to develop an integrated approach for evaluating the urban heat mitigation potential of different urban water sources together with blue-green infrastructure (BGI). She will work with existing and new models to investigate (i) the urban heat impacts of BGI and pavement watering, as well as (ii) the spatial and temporal stormwater availability for watering pavement and BGI. She will then explore scenarios of different urban heat mitigation strategies in two case studies where the different water sources will be evaluated based on their cooling benefits, reliability, economic and environmental costs.

Lucas Gobatti: “Street to city-scale Blue-Green Systems planning for human thermal comfort improvement: balancing evaporative cooling maximization and heat vulnerability mitigation”

Lucas Gobatti is currently working on microclimate computational simulations to investigate the evaporative cooling potential of blue-breen Infrastructure (BGI). The aim of his research project is to reduce the amount of people experiencing heat vulnerability during heat waves in cities. To do that, Lucas will model different scenarios of built environment, water availability, wind conditions and street canyon orientations to quantify the performance of BGI. Furthermore, these scenarios will be spatialized using Zürich as case study to investigate the potential of BGI planning for heat-vulnerability mitigation. The effect of the installation of a new single BGI next to neighboring BGIs in terms of change in thermal comfort performance is also part of his research plan.