Revealing the Vulnerability of Urban Communities to Flood Hazard in Tanzania: A Case of the Dar es Salaam City Ecosystem

Losses from environmental flood hazards have escalated in recent decades, prompting a reorientation of emergency management systems away from simple post event response. There is a noticeable change in policy, with more emphasis on loss reduction through mitigation, preparedness, and recovery projects and programs. Effective mitigation of losses from flood hazards requires hazard identification, an assessment of all the hazards likely to affect a given place and people, and risk-reduction measures that are compatible across a multitude of hazards. The degree to which populations are vulnerable to flood hazards, however, is not solely dependent upon proximity to the source of the threat or the physical nature of the hazard—social factors also play a significant role in determining vulnerability. This paper presents a participatory disaster risk method for assessing vulnerability in spatial terms using both biophysical and social indicators. The results revealed that the most physically vulnerable places do not always spatially intersect with the most vulnerable populations. This is an important finding because it reflects the likely “social costs” of hazards on the city. While economic losses might be large in areas of high physical risk to floods, the resident population may also have greater safety nets (insurance, additional financial resources) to absorb and recover from the loss quickly. Conversely, it would take only a moderate hazard event to disrupt the well-being of the majority of city residents who are more socially vulnerable, even though they might reside in the highest areas of physical risks to floods. This paper advances theoretical and conceptual understanding of the spatial dimensions of vulnerability. It further highlights the merger of conceptualizations of human-environment relationships with geographical techniques in understanding contemporary public policy issues.