Mapping Urban Risk: Flood Hazards, Race, and Environmental Justice in New York

This paper applies a more nuanced method for mapping population data to estimate the number of people potentially impacted by flood hazards in New York City.  The authors find that the number of people living in the floodplain in New York City is undercounted by traditional mapping methods by 37-72% compared to their method, and that this undercounting was not evenly spread across racial and ethnic groups. The paper also provides a literature review that outlines: why and how various groups of people may be impacted differently by the same disaster event, a review of environmental justice more broadly, and an overview of flood hazards in the U.S.

The mapping method used in this paper is called the Cadastral-based Expert Dasymetric System (CEDS). This method seeks to overcome some of the challenges of relying on units of analysis (e.g. zip codes and block census groups) that do not perfectly intersect with other geographic boundaries (e.g. flood zone boundaries). In comparing the data outputs using the CEDS mapping technique to expected values - based on the total population - the authors find that people of color do not appear to be over-represented in the flood zones across NY City boroughs. However, traditional mapping methods undercount black, Asian, and Hispanic populations at nearly twice the rate at which it undercounts white populations. 

In their literature review, the authors describe a few disaster events that showcase environmental justice concerns. For example, after the Loma Prieta earthquake, shelters in well-off neighborhoods were over-staffed and were visited by the mayor, while shelters in low-income areas were not. Additionally, frontline communities tend to received less relief-aid. This is not only because frontline communities tend to have less access to information and are less likely to “work the system,” but also because “cultural ignorance, ethnic insensitivity, racial isolation, and racial bias in housing, information dissemination, and relief assistance” make it less likely frontline communities will benefit from programs (quoting Fothergill et al, 1999).


Publication Date: January 1, 2009

Authors or Affiliated Users:

  • Juliana Mantaay
  • Andrew Maroko


Resource Category:

Resource Types:

  • Academic research paper
  • Assessment

States Affected:


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