Designing Storm Strength Simulations to Predict and Mitigate Coastal Flooding

abstract of lab and field work

MES/CEE Assistant Professor Samuel Muñoz and CEE/MES Professor Qin Jim Chen, in collaboration with Jeffrey Donnelly from Woods Hole Oceanographic Institution, were awarded a $590K NSF grant for “Morphodynamic Simulations of Coastal Storms and Overwash to Characterize Back-Barrier Lake Stratigraphies.” This project continues work based on seed funding from the Global Resilience Institute (GRI).

Modeling Hurricanes of the Past to Predict the Climate Change-charged Storms of the Future

In a new grant from the National Science Foundation, Department of Civil and Environmental Engineering and Marine and Environmental Sciences Professors Samuel Munoz and Jim Chen will combine their expertise in paleoclimatology and hurricane modeling to understand past storm behavior in southern New England. They hope their research can be used to understand the behavior of severe storms in a variety of historic climate conditions, and thus help us predict the effects of Climate Change on future hurricane frequency, intensity, and behavior.

The grant, titled “Collaborative Research: Morphodynamic simulations of coastal storms and overwash to characterize back-barrier lake stratigraphies,” will involve collaboration between Principle Investigator Munoz and co-principle investigator Chen and focus on the study of historic overwash in the New England area. “We will study the process of coastal overwash (i.e., when sand from a beach overtops a barrier during a storm) and deposition to understand (1) the sensitivity to overwash deposition to geomorphic (i.e., landscape) change and (2) how overwash is influenced by storm magnitude and track,” said Munoz. Barriers are common coastal landforms that consist of sandy ridges that form parallel to the shoreline.

Prof. Munoz, a geoscientist with expertise in sedimentology and paleoclimatology, will collect sediment samples from lakes and ponds and analyze their age and texture. For his part, Jim Chen, a leading expert in hurricane modeling and coastal hydrodynamics, will build morphodynamic models to simulate overwash in the areas. Munoz’s work will be used to inform Chen’s models. “We will ultimately apply this information to develop reconstructions of landfalling hurricanes in southern New England over the last 2,000 years or so,” said Munoz.

As the planet faces a shifting climate caused by human activity, it is crucial for coastal communities to understand how the frequency, severity, and behavior of severe storms shifts in response to changes in climate. “Overwash deposits are often used by geologists to understand the history of coastal storms in a region. This information is useful for hazard assessment and mitigation, but has been limited to qualitative assessments of storm occurrence,” Munoz explained. “Overwash is also a critical process that shapes coastlines through erosion and deposition; our project will clarify the controls on overwash along the heavily populated coastline of southern New England.” Their work could help coastal communities better prepare for coastal storms as the planet’s climate changes and sea levels rise.

Abstract Source: NSF

Hurricanes constitute major hazards to coastal communities of the eastern United States, generating strong winds and waves, coastal flooding, and erosion. These storms often induce overwash, a process where water and sediments flow over coastal barriers, erode the beach, and deposit sediments atop and behind the barrier. Geoscientists often use deposits of overwash in coastal ponds to infer when hurricanes occurred in the past, prior to written and satellite records of hurricanes. These sedimentary records of past hurricane activity are useful for constraining the probability of a hurricane making landfall on a stretch of coastline, or for understanding changes in hurricane frequency in response to past changes in climate, and are commonly integrated into hazard assessments. However, these sedimentary records are limited to reconstructing the frequency of past storms, while inferences into the magnitude or track of these events remain preliminary. In this project, the investigators will harness recent advances in computer simulations of coastal sediment transport to develop a new approach for reconstructing storm strength and track from overwash deposits.

This project will integrate field-based observations of overwash from sediment cores with state-of-the-art simulations of observed and simulated hurricanes to: (i) evaluate the influences of storm properties on overwash deposition in back-barrier settings, (ii) diagnose the sensitivity of depositional patterns to geomorphic change, and (iii) relate storm strength and track to the properties of overwash deposits. This work will deliver quantitative reconstructions of hurricane magnitude for southern New England — a heavily-populated region that is vulnerable to tropical cyclones — extending the historical record of hurricane activity in this region back centuries to provide insight into strengths and tracks of prehistoric hurricanes that made landfall in this region. The investigators anticipate that the integrative and scalable approach developed here will be applicable to other coastlines in the United States and abroad that are vulnerable to tropical and extratropical cyclones, and will facilitate the critical challenge of predicting and mitigating against coastal erosion and flooding.

This award reflects NSF’s statutory mission and has been deemed worthy of support through evaluation using the Foundation’s intellectual merit and broader impacts review criteria.

Related Faculty: Samuel Munoz, Qin Jim Chen

Related Departments:Civil & Environmental Engineering