Floods are a burden to both individuals and communities. Since individual, community, and governmental decisions and actions for hazard reduction are interrelated, they depend on regional culture, identity, perceptions, resources, and the capacity to act against floods. Unbalanced decision-making often causes inequitable distributions of information and resources, exacerbating the vulnerability of specific populations. In response to natural disasters, hazard mitigation strategies have been undertaken to reduce harmful environmental impacts on affected neighborhoods. A floodplain buyout program, as a non-structural mitigation strategy, has been a common practice in the United States since its emergence in the 1970s. Despite the growing interest in floodplain buyouts, little research on the long-term neighborhood change in affected areas after buyouts has been done. Many existing studies have examined individual-level factors of residential mobility decisions after disaster events, but research on buyout impacts at the neighborhood level is scarce. Furthermore, few studies have considered a longitudinal approach in a comparison between the treatment and the control group to investigate the outcome of buyouts. Moreover, few studies have utilized mixed methods for floodplain buyouts so that the impacts of buyouts on households and neighborhoods have not been holistically investigated. To fill these research gaps, this dissertation examines how floodplain buyouts have changed neighborhood characteristics compared to the normal trend of neighborhood change over time, especially in terms of racial composition, economic status, and housing stock. Focusing on changes from 1990 to 2015 in 2,144 block groups in Harris County, Texas, how buyouts implemented between 2001 and 2010 have altered neighborhood characteristics compared to the normal trend of neighborhood change over time was examined. This study used a mixed-method approach, including longitudinal multilevel analyses for the quantitative study and a phenomenological qualitative approach. In the quantitative research, a piecewise discontinuity model was developed to compare trajectories of neighborhood change between the pre-buyout and the buyout phases. Questions derived from the statistical results were posed to residents who participated in the buyouts and those who opted out. Findings suggest that neighborhoods with a significant number of buyouts experienced white flight, increased rental units, more frequent residential turnover, and disinvestment. In buyout neighborhoods where residents remained, flood risks still exist, especially in the poorer neighborhoods. Buyouts intensified neighborhood decline for communities left behind. Moreover, even though the shift is more intense in wealthier buyout neighborhoods, there have been structural mitigation strategies for flood protection. In contrast, residents in the poorer buyout neighborhoods are still at risk. By reviewing the local buyout practices over the long term and analyzing the consequences in neighborhoods, this study sheds light on the neglected long-term impacts of floodplain buyouts on the remaining communities. It also suggests a better-designed floodplain buyout program to promote hazard mitigation and community resilience.
