Urban Biomimicry for Flood Mitigation Using an Ecosystem Service Assessment Tool

Abstract: Many cities are vulnerable to flooding due to their high proportion of impervious sur-faces and lack of vegetated land cover. This vulnerability will often be exacerbated by changing rainfall and storm patterns due to climate change. Using the principles of urban biomimicry, this study aims to show an ecosystem service-based approach to designing an urban green infra-structure network for stormwater management in densely built areas that more closely emulates natural hydrology processes. Nature Braid (formerly LUCI) is an ecosystem services assessment tool that was used to simulate flood mitigation ecosystem services in a 13.7 km2 urban water catchment in Wellington, Aotearoa New Zealand. The simulation results revealed that 59% of the catchment does not contain or benefit from flood-mitigating land cover features. Adding 0.6 km2 (4% of the catchment) of green roofs alongside major stormwater flow paths resulted in a nearly three-fold decrease (-11%) in the non-mitigated flooding area. These results suggest that green roofs could help manage stormwater and mitigate flooding in the densely built areas of the catchment. Ecosystem service assessment tools, like Nature Braid, can help inform the design of more regenerative and resilient urban green infrastructure networks that help mitigate climate change impacts on urban residents