The impacts of climate change and urbanisation on drainage in Helsingborg, Sweden: Suburban stormwater

Assessment of the potential impact of climate change on water systems has been an essential part of hydrological research over the last couple of decades. However, the notion that such assessments should also include other changes is relatively recent. In this study, the potential impacts of climate change and continued urbanisation on stormwater flows to a suburban stream, Helsingborg, south Sweden, have been assessed using drainage simulations for present conditions as well as two climate (medium and high gas emission) and two water management storylines for subdivision. Climate change was simulated by altering a high-resolution rainfall record according to the climate-change signal derived from a regional climate model. Subdivision and urbanisation was simulated by altering model parameters chosen to reflect current trends in demographics and water management. The simulations were run for a 15 month period. It was found that city growth and projected increases in heavy rainfalls, both together and alone, are set to raise peak flow volumes and increase flood risk. Conversely, installation of a sustainable urban drainage system (SUDS) has a positive effect on the urban environment in general and can largely allay the adverse impacts of change road.