Abstract
Coastal communities are under increasing threat from extreme flood events, resulting in substantial economic, social, and ecological impacts as well as causalities, especially among socially vulnerable communities. These flood events are driven by riverine and coastal flood hazards, and are exacerbated by expansions of impervious cover and poor planning practices. Attempts to manage urban coastal flooding and reduce its impacts are confronted by inadequate funding for infrastructure investments, geospatially and temporally limited local observations, and insufficient public engagement and flood risk awareness.
This dissertation advances our understanding of 1) the advantages, challenges, and opportunities afforded by online community engagement for stormwater management, 2) how socioeconomic, climatic, and physical environment factors influence community flood reports, and 3) the sensitivity of flood hazard mapping to stormwater infrastructure modifications evaluated through hydrodynamic modeling. The first study uses a thematic analysis of interviews conducted with local, state, and federal stakeholders to understand facilitator perspectives on community engagement practices in the case study region of Harris County and the City of Houston, Texas around stormwater infrastructure pre-, during, and post- COVID-19 pandemic-mandated social distancing measures. The second study analyzes five years of 311 service requests for flooding stoppages in Norfolk, Virginia, employing a logistic regression model to identify statistically significant predictors for flooding stoppage reports. The third study evaluates how changes in conveyance capacity within stormwater pipe networks propagate through hydrodynamic simulations to alter flood extent and depth distributions across varying return periods.
Key findings from this dissertation are (i) virtual engagement strategies can provide communities access to non-local experts, foster resilient communications through diversified communication streams, and capture community input and other relevant data efficiently, (ii) the frequency of 311 flood reports are strongly influenced by climatic conditions, thus outweighing differences in reporting that may occur across socioeconomic variables; however, differences across racial groups persist suggesting a need for a multilingual reporting system and possibly successful outreach methods (iii) evaluation of stormwater pipe network modifications under combined precipitation and surge forcing across multiple return periods demonstrates that flood hazard representation is sensitive to targeted conveyance capacity enhancements, providing a quantitative basis for prioritizing infrastructure investments under future climate conditions. By integrating community engagement analysis, statistical modeling of flood reporting behavior, and hydrodynamic sensitivity testing of stormwater infrastructure upgrades, this dissertation advances a coupled social and physical framework for urban flood risk management and supports more equitable, data-informed flood resilience planning.
