Towards an Active Living Environment: Evaluating the Impact of Stream Daylighting on Pedestrian Networks in Zurich

Abstract

The burial and culverting of urban streams to make way for twentieth-century urbanization has disconnected nature from the built environment and led to the loss of ecosystem services. As waterways are inherently lateral obstacles to movement that must be overcome, it can be understood that reintroducing water features into the urban landscape through daylighting may contribute to a loss in route network connectivity and a negative impact on active mobility. However, reintroducing streams through the practice of daylighting has demonstrated benefits associated with active mobility by re-establishing urban environment connections with nature and place-making for residents. To better understand if stream daylighting can support the development of an active living environment, despite urban streams being traditionally understood as barriers to movement, the City of Zurich, Switzerland is used as a case study because of its widespread stream daylighting initiatives. Specifically, this study evaluates how stream daylighting impacts active mobility by focusing on route network connectivity change at stream sites before and after daylighting. This is done using metric reach, a measure of connectivity that utilizes a configurational approach computed in a GIS platform. To facilitate such a study, waterways and route centerlines were digitized using a georeferenced historic map of Zurich from 1984 (pre-daylighting). These were compared with 2020 open-access spatial data for the City of Zürich (post-daylighting). Spatial data results are complemented using photography to better understand how urban design choices involved in daylighting projects influenced route networks. Findings reveal that in most cases daylighting streams did not negatively impact connectivity. On the contrary, this study’s finding reveals that daylighting in Zurich is commonly part of broader urban design interventions that improve or create new spaces for pedestrians while maintaining existing route connections through the incorporation of small footbridges. While stream daylighting is well established as a nature-based solution that supports infrastructure resilience and effective stormwater management, these findings help demonstrate the cultural ecosystem services the practice of urban stream daylighting can contribute.