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Intense rain a threat to the urban water systems

Published: 18 December 2012

Future scenarios of global and regional climate models predict more intense rainy seasons. Precipitation in the form of rain has great significance for how stormwater systems, and the pollutants washed into them, affect the environment.

PhD student Matthias Borris uses an urban hydrological model to study how climate change affects the amount of pollutants carried by stormwater in urban environments. The model can also be used to test different strategies for adapting stormwater systems to climate changes affecting rainfall.

- The global climate models that are required to scale down to the local conditions, for example, to areas of Luleå's size, he said. My model uses climate data from SMHI that reflects both current and future scenarios. The model makes it possible to see how the urban environment surfaces - asphalt, metal roofs, buildings etc. that water accumulating on - can adapt to changing rainfall, rain intensity and proportion of dry periods. Using scenarios can change rain properties, and study how changing rain conditions affect the levels of pollutants in storm water as sediment, heavy metals or bacteria from traffic, buildings and other flushed away

Rain in winter is likely to be common. When the ground is frozen the runoff is affected. Biofilter, instead of asphalt, or green roofs, instead of metal roofs, are options that can improve the runoff of storm water and management of contamination. The project Hydro Impact - Stormwater Quality in a Changing Climate financed by Formas and conducted in collaboration with SMHI and Lund University.

Text: Åsa Svedjeholm