A Framework for Modeling Tropical Cyclone‐Induced Compound Flooding of the Continental US: Demonstrated in New Orleans

Compound flooding involves the interaction of multiple flood processes (e.g., coastal, fluvial, and pluvial) and is modulated by several factors (e.g., weather, climate, topobathy, morphology, time-lag). In tropical and subtropical regions globally, Tropical Cyclones (TCs) are a primary cause of compound flooding as they generate substantial rainfall runoff and elevated river discharge, in combination with strong winds and low-pressure systems that produce storm surges and waves. In this study, we develop a novel 30 m resolution compound flood modeling framework centered around Lisflood-FP, SCHISM-WWIII, SFINCS, FUSE, and MizuRoute to simulate compound coastal-fluvial-pluvial flooding across the continental US. This framework is demonstrated by simulating compound flooding associated with 9 historical TC events in the Greater New Orleans Metropolitan Area and the surrounding Mississippi River Delta. Findings reveal several regions that regularly encounter compound flood interactions during TC events, with the most prominent being Lake Maurepas, Lake Pontchartrain, and surrounding coastal estuary basins. For all TC events, the average maximum flood disturbance (water level increase from baseline conditions) across sites of nonlinear compound interactions is found to be underestimated by 60% or more if flood drivers are simulated separately and summed. Relationships identified between TC characteristics and compound flood magnitude (extent and intensity) for 9 events suggest that greater compounding correlates with intense (low minimum center pressure, high rainfall rate, and high maximum wind velocity) but concentrated (low maximum wind radius) storms. Lastly, suitable performance is observed by the model framework given the complex study area, which can be replicated for future research.