Graduation Year


Document Type




Degree Name

Master of Arts (M.A.)

Degree Granting Department


Major Professor

Jennifer Collins, Ph.D.

Committee Member

Kevin Ash, Ph.D.

Committee Member

Mark Rains, Ph.D.


Vulnerability, Risk, Flooding, GIS, Environmental Justice


Flooding has become a problem of national proportion and many scholars have started to take note of the human impacts in this area. This study will focus on the social vulnerability framework in tandem with the environmental justice theoretical frameworks being applied to Polk County Iowa so that information can be added to the body of works within a Midwestern U.S. context. This research will contribute to the current geographical knowledge in natural hazards, environmental justice, and vulnerability to flood hazards. Taking into consideration the scarcity of county or sub-county studies in the Midwest U.S. measuring spatial tendencies in hazards vulnerability, this thesis is fitting. This study examines Polk County Iowa for social vulnerability factors present today to the natural disaster of flooding and then looks longitudinally back to 1990 to see if similar individual variables were also prominent historically. This study utilizes block group census level data and creates from it a social vulnerability index (SoVI) following Cutter et al. (2003). The study then used FEMA flood risk level boundaries and the 100-year floodplain to create a comparison of vulnerability of higher flood risk areas and lower risk areas to see if exposure to flood prone areas coincides with an increase or decrease in social vulnerability. Findings of statistical tests and the bivariate choropleth map of the study area suggest that Polk County exhibits a spatial vulnerability paradox, where the persons most socially vulnerable do not necessarily always preside in the source area for flooding. Interestingly enough the study suggests that risk capable and risk resilient populations live in some of the most physically risky places. An examination of specific individual vulnerability factors from the present and historically in 1990 give the same picture of spatial paradoxical vulnerability, leading many variables to be inconclusive. However, four variables (QFAM, QMOBILE, QEXTRACT, and AVGTRVL) did show correlation to prolonged historical disenfranchisement within the flood boundaries. It is crucial to take this information and widen the spatial location of risk from the present immobile boundary set forth and perpetuated by government entities, to a realistic flexible range of spatial locations that consider historical cultural forces and formulate new mitigation policies from these understandings. This thesis further highlights the need to use multiple interdisciplinary methods to understand what is happening within our space, place, and time. This thesis adds to the ever-growing literature in social vulnerability, and environmental justice but in a U.S. Midwestern context instead of a U.S. coastal context to a flood hazard situation.