Green infrastructure is one part of the Nature-Based Solutions in addressing climate change in urban ecosystems. According to the European Comission (2013), green infrastructure refers to “A strategically planned and managed, spatially interconnected network of multi-functional natural, semi-natural and man-made green and blue features including agricultural land, green corridors, urban parks, forest reserves, wetlands, rivers, coastal and other aquatic ecosystems.”
Changes in land use due to urban development results in increases in impervious surfaces in an urban environment. From a stormwater management perspective, increased urban imperviousness results in decreased rate of infiltration and evapotranspiration and increased runoff quantity. The increased runoff quantity leads to disruption of in-stream biota, bank erosion, channel incision, and negatively impacts water quality in receiving water, negatively impacting overall watershed health.
There has been a paradigm shift in stormwater management practices in urban areas in recognition of the negative impacts discussed above. Green stormwater infrastructure (GSI) is increasingly adopted by municipalities as a complementary stormwater management plan to deal with urban stormwater. GSI is also referred to as Nature’s Solution for water management and mimics natural water cycle by capturing rainwater where it falls through infiltration and evapotranspiration, thus reducing the reliance on grey infrastructure like pipes to convey water away from imperviousness area. Types of GSI include bioretention cells, rain gardens, infiltration trenches, porous pavement, rain barrels, vegetation swales, green roofs, connected blue green roofs, and many others. These systems can be deployed in urban environments in an effort to reduce runoff volume and peaks, and improve runoff water quality.