The Influence of Coastal Wetlands on Hurricane Surge and Damage with Application to Planning under Climate Change

Coastal storm surges from hurricanes are one of the most costly natural disasters in the United States (US). Current research arguably indicates a mean sea-level (MSL) increase due to global warming, as well as an increase in damages caused by hurricanes under climate change. The objectives of this research are: 1) to develop a framework that integrates Geographical Information Systems (GIS) with hurricane storm surge numerical models; 2) to quantify the uncertainty derived from coastal land cover spatial data on hurricane storm surge; and 3) to investigate the potential impacts of SLR changes on land cover to hurricane storm surge and coastal damages.

Numerical analysis is an important tool for predicting and simulating storm surges for coastal structure design, planning and disaster mitigation. Here we proposed a framework to integrate Geographical Information Systems (GIS) with computational fluid dynamic (CFD) models used to simulate hurricane storm surge. The geodatamodel "Arc StormSurge" is designed to store geospatial information for hurricane storm surge modeling and GIS tools are designed to integrate the high performance computing (HPC) input and output files to GIS; pre-process geospatial data and post-process model results, thereby, streamlining the delineation of coastal flood maps.

Georeferenced information of land cover is used to define the frictional drag at the sea bottom and to infer modifications to the momentum transmitted to the water column by the winds. We investigated uncertainties in the surge response arising from land cover for Texas central bays considering several land cover datasets. The uncertainties were quantified based on the mean maximum surge response and inundated area extent.

Considering projected SLR, wetland composition and spatial distribution are also expected to change with coastal environmental conditions. Our results showed that wetland degradation by SLR increased the mean maximum surge for coastal bays. Direct damage to buildings and businesses was also significantly increased by the loss of wetlands due to SLR. Here, we demonstrated the importance of considering the effects of land cover and SLR to hurricane storm surge simulations for coastal structure design, floodplain delineation or coastal planning.