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Wind and Waves- Lessons in Resiliency from Hurricane Hydrodynamics

January 30, 2019

In late summer of 2004, Civil and Environmental Engineering Professor Jim Chen was traveling to New Orleans for a work conference. His stay was short-lived; Hurricane Ivan, one of the strongest of the 2004 season, was barreling down on the city after rampaging across the Caribbean. Chen and many others in the city evacuated to nearby towns and states outside the path of the storm. With the highway jammed bumper to bumper, Professor Chen set out to escape the storm in nearby Mobile. The journey to Alabama, normally a two hour drive, took Chen eleven hours to complete. The city did not offer sanctuary, however. No sooner had he arrived than he was forced to evacuate again. Ivan had abruptly changed course, placing Mobile in its sights. The unpredictable storm was devastating to the region. Just one year later, the infamous Hurricane Katrina made landfall on the still-recovering Gulf Coast, ripping the roof off of Prof. Chen’s Alabama home.

The experience was a motivating one for Chen. He had seen first-hand the chaos and devastation caused by extreme storms. Governments needed better tools and methods to understand hurricanes, predict their impact on shorelines, and fortify cities against them. While many know hurricanes by their distinctive swirling cloud formations and powerful winds, knowledge of the movement of the water below is equally important to understanding a hurricane’s destructive power.

As a coastal engineer, Professor Chen has focused his research on exploring this issue. At Northeastern University, he runs the Department of Civil and Environmental Engineering’s Coastal Hydrodynamics Lab out of the Nahant Marine Science Center, where he and his team study the development and application of state-of-the-art computational models to address coastal resiliency and sustainability.

The behavior of a hurricane is notoriously difficult to forecast. Their paths and intensities are determined by variables arising worldwide, from the dry air of the Sahara Desert to the moisture rising off the Atlantic Ocean current. To compound the problem, their extreme wind speeds and waves make it difficult to deploy instruments to study the hurricanes in real-time.

Because of these challenges, mathematical modeling is crucial to understanding the ways in which hurricanes will impact coastal communities. Through grants from agencies such as the National Science Foundation, the U.S. Geological Survey, the U.S. Army Corp of Engineers, and the Department of Treasury, Chen collects data from sites on the East and Gulf Coasts and creates comprehensive mathematical models to understand ocean movement during storms and the ways in which vegetation and natural barriers can be used to mitigate their effect on coastal communities.

His research often involves innovating new methods. In a grant through the Treasury Department RESTORE Act, Professor Chen integrates computer modeling and innovative remote sensing techniques to understand storm impacts on Louisiana’s shoreline and deltaic systems. The grant involves international collaboration with engineers from Deltares, a Dutch research institute.

Chen is working with the Army Corp of Engineers to assess the effectiveness of “living shorelines” in combating water surges and waves caused by coastal storms. Living shorelines are a form of green infrastructure that utilize natural and natural-based solutions to engineering problems, such as maintaining vegetated coastal wetlands and growing oyster castles to disrupt wave movement. A challenge with using living shorelines to fight storm surges and waves is that no reliable methodology currently exists to evaluate their capacity to do so. Chen’s team is developing the necessary numerical models to calculate the benefits of vegetated shorelines. Through a separate award from the U.S. Geological Survey, Chen collects ecological and hydrodynamic data from living shoreline projects in Maryland, New Jersey, New York and Virginia to calibrate and validate computer models of wave behavior.

Chen was recently part of a team led by the Woods Hole Oceanographic Institute to be awarded a $992K NSF grant entitled “Convergence: RAISE Nearshore Water-Land Interface During Extreme Storms”. He will develop cyber-enabled coastal resilience research and continue to study the role that natural landscapes play in attenuating storm surges and waves. Chen was also awarded an $866K National Science Foundation CyberSEES grant to lead the “Coastal Resilience Collaboratory: Cyber-enabled Discoveries for Sustainable Deltaic Coasts.” In collaboration with Louisiana State University and Texas A&M University, the project will foster cooperation among coastal engineers, earth scientists, computer scientists and cyberinfrastructure specialists towards building sustainable deltaic communities and help coastal regions address flooding hazards.

Hurricanes Ivan and Katrina caused immense damage to the Gulf region with their powerful storm surges and high waves. As climate change accelerates and storms become more powerful, research like Chen’s to understand the hydrodynamics of extreme storms will be crucial to building resilient coastal communities.

Qin Jim Chen, Ph.D., is a Professor in the Department of Civil and Environmental Engineering and the Department of Marine and Environmental Sciences at Northeastern University.