Understanding the Coupled Effect of Upland Hydrology and Ocean Hydrodynamics During Extreme Events Along the East and Gulf of Mexico Coasts of the US

Recent literature suggests that climate change is altering both inland and ocean storm characteristics in a way that could amplify the combined effect of ocean hydrodynamics and inland hydrology to create extensive flooding. However, we currently lack models that account for the combined effects of ocean (tides, surges, waves) and inland hydrological (precipitation and streamflow) processes due to their complex interactions and mismatched spatial and temporal scales.

To address how upland hydrologic processes and their interaction with ocean hydrodynamics impact coastal flooding, we built new capabilities into the widely-used 2D ocean circulation model ADCIRC that allow a one-way coupling with inland river discharge and precipitation. We developed our model on the North Atlantic Ocean basin with a channel-to-ocean basin scale grid whose nodal distribution along the coast resolves the majority of the inland channels in the continental US up to 10 m above sea level. We connected the rivers with streamflow estimates from the National Water Model (NWM) and incorporated precipitation data from the NSSL Program Multi-Radar/Multi-Sensor System (MRMS). In this presentation, we will show results that reveal how the coupled effects of tides, storm surge, waves, rainfall, and river discharge during historical storms resulted in amplified flooding effects. By simulating hurricanes Sandy (2012), Irma (2017), and Harvey (2017), we quantify the impact of hydrology on water levels and velocities with respect to time and space. Ultimately, we seek to implement our coupled model to characterize how near-coast hydrodynamics responds in various regions and under changing meteorological conditions.