Flooding, Sociospatial Risk, and Population Health

Area of Science:

• Environmental epidemiology
• Public health
• Climate change impacts

Background:

• Climate change and settlement patterns exacerbate flood risks.
• Existing research links flood exposure to health but often lacks causal inference.
• Sociospatial factors like floodplain delineation are understudied determinants of flood-related health outcomes.

Purpose of the Study:

• To causally assess the impact of flood exposure on population health using Hurricane Harvey as a case study.
• To investigate the role of sociospatial risk determinations, specifically floodplain coverage, in modifying flood-related health effects.
• To examine the mechanisms through which floodplain coverage influences health outcomes.

Main Methods:

• Utilized novel, repeated cross-sectional health survey data from Houston (predisaster and postdisaster).
• Linked survey data with local flood inundation and floodplain delineation data.
• Employed difference-in-differences and triple-difference estimators to establish causal links and test moderation effects.

Main Results:

• Flood exposure significantly increased psychological distress and fair/poor health.
• Mixed evidence was found for unhealthy mental health days; no change was observed for unhealthy physical health days.
• High floodplain coverage buffered mental health adversity in flooded areas, potentially by increasing disaster preparedness and evacuation.

Conclusions:

• Flood exposure poses significant risks to population health, particularly mental health.
• Sociospatial factors like floodplain delineation are critical vulnerability dimensions that can stratify health impacts.
• Findings offer empirical insights into the climate-health nexus and highlight the importance of considering spatial risk factors in public health interventions.