Urbanization alters the hydrological cycle increasing surface runoff water volume and peak flow. the traditional approach on urban drainage is being updated to an integrated approach of managing the water on its source. This study proposes a strategy based on urban retrofit of impervious surfaces using an infiltration-exfiltration linear system of runoff collection. the proposed system is based on street side channels and is composed by a porous asphalt top layer, aggregates base and drainage underdrain. The aims are to promote infiltration, filtration and adsorption of stormwater. Storm water management model was used to simulated pre and post-retrofit response for extreme single events on the city of Milan from 2006 to 2015. The system has positive effects on runoff reduction and hydrograph attenua- tion reaching from 18% reduction to full infiltration of runoff volume.
stormwater, SUDs, sustainable drainage, floods
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