Klimatanpassade urbana växtbäddar : ett samlat kunskapsläge

Sammanfattning

In the light of increased urbanization in combination with climate change, there is an increased need to deal with torrential rain and heat islands in our urban space. One method to address these issues is through urban plant beds. In order for the urban plant beds to be able to address both issues, it is required that they can facilitate robust vegetation growth while also managing stormwater. In addition to climate change, there is also a variation in climate conditions to consider depending on where the urban plant bed is intended to be located. For instance, while the concept of rain gardens was developed in 1989 in Malmö by Peter Stahre, the facility type has mainly been used in Maryland and Portland, USA, where the average annual precipitation is significantly higher than in eastern Sweden, but more similar to the average annual precipitation in western Sweden. This raises the question of whether urban plant beds should be designed differently based on regional climate conditions, especially since in several parts of Sweden there are facilities with a failed vegetation establishment today. The aim of this work is to research which principles for urban plant beds that need to be considered to promote good vegetation development and stormwater management. Moreover, the work aims research if urban plant beds need to be designed differently in western and eastern Sweden, which is done to visualize whether regional differences in climate conditions affect the design or establishment management. Initially a literature review and inventory of technical manuals is performed to obtain sufficient knowledge to implement the primary method of the study; Semi-structured interviews with industry experts. The collected information from the literature review, the manuals and interviews are compiled and concretized in the form of a principle-based design proposal to clarify how the results of the study can be used in the design of urban plant beds. According to the results, it appears to be possible to combine vegetation development and stormwater management in urban plant beds. However, there may be a conflict in enabling moisture retention and water diversion capability, depending on the degree of stormwater management that is requested. The results also indicate that in order to enable both good vegetation development and stormwater management, the following aspects need to be considered: substrate composition, homogeneity, particle size, dimensioning, terrace characteristics, catchment area, vegetation interception capacity, establishment management and adaptation to local conditions. The result indicates that the differences in design, based on the climatic conditions, are primarily limited to the dimensioning. It was also noted that more research is needed into substrate composition and whether it should differ between regions. It appears that the design of the urban plant beds mainly differs depending on local factors instead of regional ones.