Date of Award

Fall 2026

Abstract

Flooding is the most perilous natural hazard in the United States. Flood risk has historically been mitigated by constructing flood defenses such as sea walls or levees that are designed to prevent flood waters from reaching developed areas. However, climate change is increasing the frequency and intensity of flood events beyond the magnitude for which many flood defenses were designed, and the presence of flood defenses has incentivized development within floodplains significantly increasing the consequences of flooding when these systems fail. Total annual flood risk in the U.S. has been estimated in the tens of billions of dollars; however such estimates are based almost entirely on economic losses to property. Floods can also cause significant environmental and social impacts, yet these effects are not accounted for in cost-benefit analyses supporting the implementation of flood risk mitigation projects. As a result, flood risk management agencies such as the U.S. Army Corps of Engineers continue to advance a paradigm that leads to inequitable distributions of flood risk and a failure to implement nature-based solutions which have been shown to be effective at reducing flood risk while offering additional ecological and social benefits. The purpose of this dissertation is to contribute to the literature in quantifying the so-called “hidden costs” of flood risk and assess the reduction of these costs as co-benefits of flood risk mitigation. In particular, this dissertation assesses the extent to which flood damages to buildings, the primary component of existing economic flood risk analyses, increase greenhouse gas emissions and impact the mental health of residents. Greenhouse gas emissions associated with flood damages are quantified through the application of a novel simulation framework combining component-level fragility functions and life cycle analysis data to generate damage curves which can estimate the quantity and social cost of greenhouse gas emissions caused by exposure of a building to a given depth of flooding. The effect of damage to residential structures on mental health are quantified through a systematic literature review and meta-analysis to produce odds ratios which can be used to estimate the incidence of depression and post-traumatic stress disorder following flood events. These methodologies are applied to an assessment of levee setbacks as a nature-based solution to addressing flood risk on the Mississippi River to show that in addition to reducing flood risk, levee setbacks can reduce greenhouse gas emissions and mental health risk, offering additional economic benefits worth millions of dollars per year. The findings presented in this dissertation will contribute directly to future efforts to conduct more comprehensive assessments of the benefits of flood risk mitigation projects and will add to the growing body of knowledge showing that nature-based solutions are socially, ecologically, and economically viable means of addressing the risks posed by future floods.

Document Type

Dissertation

First Advisor

Weiwei Mo

Second Advisor

Fei Han

Third Advisor

Erin Bell

Department or Program

Civil and Environmental Engineering

Degree Name

Doctor of Philosophy

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