Modeling green infrastructure as a flood mitigation strategy in an urban coastal area

Urban areas can be seriously disrupted by flooding after heavy rain events. Therefore, several strategies based on grey infrastructure have been implemented over the years to mitigate the impact of significant rainfalls and make urban areas more resilient against flash floods. Green Infrastructure (GI) is an environmentally appropriate alternative which can reduce the amount of stormwater delivered to a drainage system within an urban area while mitigating the contamination carried with it. To date, however, relatively little attention has been paid to the public acceptance and the presence of shallow aquifers before the implementation of GI measures. This paper presents a framework to assess the social and technical feasibility of GI in a coastal urban area prone to severe flooding. The method consists of the assessment of potential scenarios upon the evaluation of government acceptance coupled with a stormwater management model.The city of Hoboken (NJ) located near the estuary of the Hudson river was selected as an urban laboratory given its vulnerability to flooding and the availability of data.A stormwater management model was developed and used to simulate various GI options to minimize stormwater runoff.Outcomes from the interviews indicate positive feedback for GI implementation, but no specific alternatives could be identified. Based on generally accepted GI measures, i.e., right-of-way storage, resiliency parks, and green roofs, urban hydrology models were implemented. Simulation results show that all of the considered alternatives are effective in reducing runoff volumes for rainfall events of less than 1-year recurrence interval. However, they do not mitigate the negative impact of heavier rain events due to the limited storage as a consequence of site size and the shallow aquifer within the coastal urban area.