Urban, pluvial flooding : Blue-green infrastructure as a strategy for resilience

Abstract: This thesis investigates urban, pluvial flooding and if blue-green infrastructure, for handling of stormwater in urban green spaces, can be used as a strategy for resilient flood risk management. Spatial analyses of flood claims from insurance companies and the water utility company of Malmö are used to better understand the mechanisms and characteristics of pluvial flooding and how blue-green infrastructure impacts flood risk. It was found that flooding during intense rainfall often is located closely to the main overland flow paths and the main sewers, while flooding during rainfall with longer duration seem to be more randomly distributed. Combined sewers are more affected by flooding than separate sewers. Blue-green infrastructure can reduce urban, pluvial flooding. The large-scale spatial distribution of flooding with respect to urban flow paths and drainage system are discussed in relation to the small-scale impact of surface water detention in e.g. detention basins and concave green spaces. Based on transition theory, socio-technical transition towards wide-spread implementation of such measures are examined through interviews with municipal and water utility officials. Legal, organisational and financial changes are suggested. A framework for management of spatial data in the strategic planning of blue-green infrastructure is also presented. The thesis consists of a summary and five appended papers, where the first paper serves as a background for the thesis.