Storm flooding sensitivity to sea level rise for Galveston Bay, Texas

The combination of sea level rise and population growth in coastal regions makes it essential to continue improving flood management strategies. Flooding estimates must take into account both local vertical land motion and estimated rates of sea level rise linked to global climate change. Several extreme value distributions are compared using multiple statistical measures for the modeling of maximum annual storm surges based on the 105-year record of Galveston Pier 21, Texas. Increases in inundation frequencies are computed based on two possible sea level rise scenarios, a conservative linear continuation of the past century trend, and a scenario based on the upper limit of the sea level range in the IPCC AR4 report, i.e. the A1FI scenario. The research shows that by the year 2100 exceedance probabilities may double for the impact of the largest storms such as Hurricane Ike, but may increase by 6–7 times for the smaller surges associated locally with the impact of storms such as Hurricanes Cindy, Alicia, and Rita. While individually not as devastating or costly as large hurricanes, the cumulative and regular cost of smaller surge events could well be a bigger threat to coastal communities as sea level rises.

► Several extreme value distributions were examined to model storm surges. ► Impact of sea level rise on inundation was evaluated for Galveston, Texas by 2100. ► Variation in probability of inundation caused by different size storms was found. ► Probability of inundation caused by largest storms may be about to double or more by 2100. ► Probability of inundation caused by smaller storms may increase by 7 or more by 2100.