Impact of Sea Level Variation on Coastal River Flooding Caused By Extreme Rainfalls

Hurricanes Joaquin (2015), Matthew (2016) and Irma (2017) and their associated extreme rainfalls hit South Carolina and caused extensive flooding in three consecutive years. These extreme weather events have caused more interest in coastal flooding mechanism under the impact of climate change. The Intergovernmental Panel on Climate Change projects that global mean sea level will continue to rise during the 21st century. Under all representative concentration pathways scenarios, the rate of sea level rise (SLR) will very likely exceed that observed during 1971 to 2010. And accompanied by the SLR, extreme rainfalls will likely increase too. With more than 39% of U. S. population living in coastal regions, it is important to understand how coastal river systems response to the sea level rise and extreme rainfall. It has been hypothesized that coastal sea level rise could affect river flooding by altering the river water head slope and thus the pressure gradient force, which may cause more flooding in the estuary regions. In this study, a physics-based hydrological model is employed to simulate coastal river systems and the effects of sea level rise and extreme rainfall on river flooding are tested. The results of these numerical studies will be presented.