Sebastian Rowan

I am a PhD candidate in civil and environmental engineering at the University of New Hampshire and an ORISE Graduate Research Fellow at the U.S. Army Corps of Engineers (USACE) Coastal Hydraulics Laboratory. My research focuses on quantifying effects of floods and flood risk management activities that are typically excluded from project planning efforts. Specifically, my research focuses on estimating the greenhouse gas emissions associated with damages caused by flooding events and the emissions associated with the implementation of flood risk mitigation projects. Through my ORISE fellowship, I am also working on research to estimate the health impacts of floods and develop methods to incorporate such estimates into the USACE planning framework.

news

Dec 23, 2025	Happy to share that my paper “Quantifying the hidden carbon cost of floods: a stochastic and uncertainty-based valuation framework” has been accepted for publication in Environmental Research Letters! Floods cause billions of dollars in damages each year, but current methods to assess the value of flood risk typically only consider the financial cost to replace damaged assets. Making those repairs requires the extraction of raw materials, manufacturing of those materials into final products, and transportation from the extraction site to the manufacturer and the installation location. In this paper, we developed a Monte Carlo analysis framework to simulate flood losses to residential buildings that incorporates life-cycle environmental impact data for each component within a building that may be damaged by a flood. Using this framework we developed depth-emissions curves to estimate the life-cycle greenhouse gas emissions associated with repairing flood damages from a given flood depth, and after applying a social cost of carbon emissions estimate we found that incorporating GHG emissions into flood risk assessments can increase the total value of estimated impacts by over 6%.
Dec 23, 2025	While I was unfortunately not able to travel to New Orleans to be there in person, I was happy to have the opportunity to participate virtually and present two talks on my work to quantify aspects of flood risk beyond financial losses!
Apr 01, 2025	I was honored to receive third place in the 2025 UNH 3-Minute Thesis (3MT) competition for my presentation titled Measuring What Matters for Flood Risk Management. This was a great opportunity not only to share my research and develop my skills as a science communicator, but to hear from so many great researchers working on interesting and important research right here at UNH.
Dec 15, 2023	It was great to be able to attend this year’s AGU conference virtually and present the findings of our research into the socio-economic impacts of future floods!
Jun 23, 2023	I was happy to have the opportunity to present a poster at the AEESP 2023 conference in Boston this week! See the poster here.

latest posts

selected publications

Quantifying the hidden carbon cost of floods: a stochastic and uncertainty-based valuation framework

Sebastian Rowan , Erin. Bell , and Weiwei Mo

Environmental Research Letters, Dec 2025

Abs

Flood damage repairs to the built environment generate substantial greenhouse gas (GHG) emissions, yet these indirect climate impacts are rarely integrated into flood consequence assessments. In this study, we present a fragility-based modeling framework to estimate material replacement needs for building components damaged at specific flood depths. We develop fragility curves for each building component using a triangular cumulative distribution derived from expert judgement due to the lack of empirical data on flood losses, especially at the component level. By combining these estimates with life cycle GHG emissions for each component in a Monte Carlo simulation, we derive probabilistic, emissions-based damage curves for single-family residential structures which comprehensively account for uncertainty in the estimates. We then applied these damage curves to estimate the GHG emissions caused by a 100-year flood in two testbed regions in the Mississippi River Valley. Our results show that including the social costs of GHG emissions can increase the valuation of total flood damages by over 6%. Our results also show that flood impact estimates are highly uncertain Our model can be used by planners in cost-benefit analyses of flood risk management projects to show that such projects are more economically efficient than current methods would report.
Enhancing Resilience: Integrating Future Flood Modeling and Socio-Economic Analysis in the Face of Climate Change Impacts

Natalie P. Memarsadeghi , Sebastian Rowan , Adam W. Sisco , and Ahmad A. Tavakoly

Science of The Total Environment, Jul 2024

Abs

As climate change intensifies, future floods will become more severe in some areas with geographic variation, necessitating that local and regional governments implement systems to provide information for climate adaptation, particularly for vulnerable populations. Therefore, we aimed to develop a methodology to identify areas that are at an increased risk from future floods and independently socially vulnerable. In this study, 100-year recurrence interval flood extents and depths were estimated using an ensemble of six independent Coupled Model Intercomparison Project Phase 6 climate models for a past and future period under the highest-emissions climate scenario. The flood inundation results were related to social vulnerability for two selected study areas in the Mississippi River Basin. The range of flood extents and depths for both time periods were estimated, and differences were evaluated to determine the effects from climate change. To identify at-risk areas, the relationship between the spatial distribution of flood depths and vulnerability was then assessed. Finally, an analysis of the current and future damages on infrastructure from flooding on residential housing was performed to determine whether damages are correlated with higher vulnerability areas. Results show in every flooding scenario, flood extents and depths are increasing in the future compared with the past, ranging from an increase of 6 to 76 km2 in extent across both locations. A statistically significant relationship between spatial clusters of flooding and of vulnerability was found. The infrastructure analysis found that residential structures in the most vulnerable census tracts are 6 to 59 times more likely to experience moderate damage compared with the least vulnerable tracts depending on scenario. Overall, a framework was established to holistically understand the hydrologic and socioeconomic impacts of climate change, and a methodology was developed to use for allocating resources at the local scale.