Strategies for Enhancing the Efficiency of Bioretention Swales and Basins for Urban Stormwater Management in Temperate Region

Among various schemes to reuse and recycle the limited urban fresh water resources, sustainable urban stormwater management, such as water sensitive urban design and rainwater harvesting, has been recognized as one of the most efficient and economically viable approaches. Storm runoff shall be treated as close as possible to its source before it is reused or discharged into public drainage network or receiving waters to enhance the water environment quality. Bioretention swale/basin, which has been commonly applied to treat runoff from roads, car parks, cyclist and pedestrian paths, rooftops, etc., is recognized to be the most efficient and aesthetic pleasing way to harvest rainwater in urban settings, and other longish shape runoff catchment area. This paper studied over 10 bioretention swales/basins applications in temperate region worldwide covering China, Germany, Norway, Austria, USA, and Australia. Key steps in bioretention swale/basin design and implementation in temperate region were investigated, such as strategic bioretention scheme selection, flow conveyance and hydraulic capacity design, filtering media profile, vegetation scheme selection and maintenance scheme, and suggestion and key design parameters. The critical path and parameters of bioretention swale/basin design which enhanced the effectiveness and efficiency of its application for rainwater harvesting in temperate regions were derived.