Evaluation of low impact development approach for mitigating flood inundation at a watershed scale in China

• Published in: Journal of environmental management 2017-05, Vol.193, p.430-438
• Main Authors: Hu, Maochuan, Sayama, Takahiro, Zhang, Xingqi, Tanaka, Kenji, Takara, Kaoru, Yang, Hong
• Format: Article
• Language: English
• Subjects: China; Flo-2D model; Floods; Hazard level; Humans; Inundation area; Inundation depth; Modeling; Models, Theoretical; Urbanization
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2017.02.020

Low impact development (LID) has attracted growing attention as an important approach for urban flood mitigation. Most studies evaluating LID performance for mitigating floods focus on the changes of peak flow and runoff volume. This paper assessed the performance of LID practices for mitigating flood inundation hazards as retrofitting technologies in an urbanized watershed in Nanjing, China. The findings indicate that LID practices are effective for flood inundation mitigation at the watershed scale, and especially for reducing inundated areas with a high flood hazard risk. Various scenarios of LID implementation levels can reduce total inundated areas by 2%–17% and areas with a high flood hazard level by 6%–80%. Permeable pavement shows better performance than rainwater harvesting against mitigating urban waterlogging. The most efficient scenario is combined rainwater harvesting on rooftops with a cistern capacity of 78.5 mm and permeable pavement installed on 75% of non-busy roads and other impervious surfaces. Inundation modeling is an effective approach to obtaining the information necessary to guide decision-making for designing LID practices at watershed scales. •Inundation modeling was applied to evaluate LID effectiveness on flood hazard mitigation at an urbanized watershed.•LID practices can reduce urban flooding and waterlogging hazards in terms of reductions in water depth and hazard area.•Permeable pavement has better performance than rainwater harvesting on inundation mitigation in the study area.•The findings are useful for decision-making of urban stormwater management and increasing public awareness of LID benefits.