272 - Effect of Sea-level Rise on Hurricane-induced Compound Flooding and Economic Damages

Tropical cyclone (TC) flooding has caused devastation for coastal communities in recent years, leading to loss of life and damage to homes, businesses, and critical infrastructure. The frequency and severity of compound flooding associated with TCs is projected to increase in the future due to sea-level rise. However, the extent to which TC-driven compound flooding has been altered in response to historical sea-level rise remains uncertain. Here, we apply a coupled coastal-fluvial-pluvial hydrodynamic model (Delft3D-FM) to investigate the impact of sea-level rise on compound flooding during three recent hurricanes in the Sabine-Neches Estuary, Southeast Texas: Harvey, Ike, and Rita. We elucidate how historical sea-level rise since 1920 affected damage estimation during these TCs using depth-damage functions. We find that sea-level rise exacerbated the damages caused by Harvey and Rita by $24 million and $27 million, respectively. However, the impact of sea-level rise was most pronounced during Ike, resulting in an increase of approximately $1.9 billion in damages and affecting an additional 7,550 structures (85% residential). Although sea-level rise caused the greatest increase in flood extent for Rita, the additional flooding mainly affected uninhabited coastal areas and thus caused limited damage. For Ike, flood extent remained relatively unchanged, but flood depth increased significantly in developed regions of Beaumont and Port Arthur, resulting in greater damage. The findings of this paper demonstrate the influence of historical sea-level rise on TC flood damages and highlight the need to incorporate future sea-level rise projections into floodplain management and adaptation planning.