The impacts of tidal wetland loss and coastal development on storm surge damages to people and property: a Hurricane Ike case-study

Coastal wetlands protect communities during hurricanes by reducing storm surge flooding and damages. Previous studies have quantified surge reduction benefits of wetlands, but there is less understanding of how the combination of wetland loss and coastal development influences the spatial distribution of flood extents and damages. In this study we integrate a high- resolution 2-D hydrodynamic model with land-use/land-cover change analyses to assess the effects of total wetland loss, decadal wetland loss, and coastal development on storm surge damages in Galveston Bay, Texas. We measure storm surge flood extents from Hurricane Ike for three scenarios: (i) 2008 Baseline; (ii) 2008 No Wetlands, and (iii) 2019 "Present-day H. Ike". We find that during Hurricane Ike in 2008, the total loss of coastal wetlands would have increased damages by a net similar to USD $934 million or 12.8% of baseline damages. For the 2019 Present-day H. Ike scenario, we found very few wetlands were lost between 2008 and 2019. If Hurricane Ike had occurred in 2019, damages would have been higher by similar to $2.52 billion or 34.6%, almost entirely due to increased real estate value and new coastal development. Our findings suggest that, while increase in economic exposure is a key driver of storm surge risks in Galveston Bay, effective wetland conservation continues to reduce these risks.