Galveston Island, TX, has a storied history of vulnerability to hurricanes. A 28-billion-dollar coastal spine which acts as a linear storm surge barrier paralleling the has been proposed to increase inland protection. Coupling ADCIRC flood models with 3D urban analytics, this research asks, how will the coastal spine protect Galveston Island across different storm scenarios? We assess the impacts across different storm scenarios with and without the coastal spine in place including 100-year and 500-year storms, storm surge, and a 2.4ft sea level rise. Multiple indicators are assessed including percent inundated area, water depth, household units submerged, people flooded, underwater streets, flood damage, effected land uses, and building inundation. The coastal spine will significantly protect Galveston Island across all storm scenarios. In a Hurricane Ike-scaled surge, the spine will reduce 59.8% of inundated area, 87.3% of inundated households, 105% of flooded population, $6.65 billion in property damage, and 48.8% of inundated buildings. When considering sea level rise, the bay side of the island will eventually flood regardless of the coastal spine.