A growing number of cities are investing in green infrastructure to foster urban resilience and sustainability. While these nature-based solutions are often promoted on the basis of their multifunctionality, in practice, most studies and plans focus on a single benefit, such as stormwater management. This represents a missed opportunity to strategically site green infrastructure to leverage social and ecological co-benefits. To address this gap, this paper builds on existing modeling approaches for green infrastructure planning to create a more generalizable tool for comparing spatial tradeoffs and synergistic ‘hotspots’ for multiple desired benefits. I apply the model to three diverse coastal megacities: New York City, Los Angeles (United States), and Manila (Philippines), enabling cross-city comparisons for the first time. Spatial multi-criteria evaluation is used to examine how strategic areas for green infrastructure development across the cities change depending on which benefit is prioritized. GIS layers corresponding to six planning priorities (managing stormwater, reducing social vulnerability, increasing access to green space, improving air quality, reducing the urban heat island effect, and increasing landscape connectivity) are mapped and spatial tradeoffs assessed. Criteria are also weighted to reflect local stakeholders’ desired outcomes as determined through surveys and stakeholder meetings and combined to identify high priority areas for green infrastructure development. To extend the model’s utility as a decision-support tool, an interactive web-based application is developed that allows any user to change the criteria weights and visualize the resulting hotspots in real time. The model empirically illustrates the complexities of planning green infrastructure in different urban contexts, while also demonstrating a flexible approach for more participatory, strategic, and multifunctional planning of green infrastructure in cities around the world.
Abstract. Megacities are predominantlyconcentrated along coastlines, making them exposed to a diverse mix ofnatural hazards. The assessment of climatic hazard risk to cities rarely hascaptured the multiple interactions that occur in complex urban systems. Wepresent an improved method for urban multi-hazard risk assessment. We thenanalyze the risk of New York City as a case study to apply enhanced methodsfor multi-hazard risk assessment given the history of exposure to multipletypes of natural hazards which overlap spatially and, in some cases,temporally in this coastal megacity. Our aim is to identify hotspots ofmulti-hazard risk to support the prioritization of adaptation strategies thatcan address multiple sources of risk to urban residents. We usedsocioeconomic indicators to assess vulnerabilities and risks to threeclimate-related hazards (i.e., heat waves, inland flooding and coastal flooding) at high spatial resolution.The analysis incorporates local experts' opinions to identify sources ofmulti-hazard risk and to weight indicators used in the multi-hazard riskassessment. Results demonstrate the application of multi-hazard riskassessment to a coastal megacity and show that spatial hotspots ofmulti-hazard risk affect similar local residential communities along thecoastlines. Analyses suggest that New York City should prioritize adaptationin coastal zones and consider possible synergies and/or trade-offs tomaximize impacts of adaptation and resilience interventions in the spatiallyoverlapping areas at risk of impacts from multiple hazards.
more » « less- Award ID(s):
- 1737626
- NSF-PAR ID:
- 10110654
- Date Published:
- Journal Name:
- Natural Hazards and Earth System Sciences
- Volume:
- 18
- Issue:
- 12
- ISSN:
- 1684-9981
- Page Range / eLocation ID:
- 3363 to 3381
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Coastal urban areas like New York City (NYC) are more vulnerable to urban pluvial flooding particularly because the rapid runoff from extreme rainfall events can be further compounded by the co-occurrence of high sea-level conditions either from tide or storm surge leading to compound flooding events. Present-day urban pluvial flooding is a significant challenge for NYC and this challenge is expected to become more severe with the greater frequency and intensity of storms and sea-level rise (SLR) in the future. In this study, we advance NYC’s assessment of present and future exposure to urban pluvial flooding through simulating various storm scenarios using a citywide hydrologic and hydraulic model. This is the first citywide analysis using NYC’s drainage models focusing on rainfall-induced flooding. We showed that the city’s stormwater system is highly vulnerable to high-intensity short-duration “cloudburst” events, with the extent and volume of flooding being the largest during these events. We further showed that rainfall events coupled with higher sea-level conditions, either from SLR or storm surge, could significantly increase the volume and extent of flooding in the city. We also assessed flood exposure in terms of the number of buildings and length of roads exposed to flooding as well as the number of the affected population. This study informs NYC’s residents of their current and future flood risk and enables the development of tailored solutions to manage increasing flood risk in the city.
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.5194/nhess-18-3363-2018
