POWERFUL HURRICANE STRIKES SERVE AS GEOLOGIC AGENTS ON THE MCFADDIN NATIONAL WILDLIFE REFUGE, TEXAS

This study investigates the spatial extent of two recent hurricane storm surge sediment deposits on coastal marshes on the McFaddin National Wildlife Refuge (NWR) in Southeastern Texas. Twenty-three hurricanes passed within 300 km of the study area between 1950 and 2017, however, prior research in 2014 discovered that only the storm surge sediment beds deposited by Hurricanes Audrey (1957), Carla (1961), Rita (2005) and Ike (2008) had been preserved in the marsh substrate during that time frame. The aforementioned research was conducted on a transect 90 to 1230 m inland from the Gulf of Mexico coastline and revealed that hurricane-derived sedimentation had increased nearshore marsh surface elevation by up to 0.68 m since the Hurricane Rita strike in 2005. Further inland, the sediment deposits gradually thinned and tapered out. Research conducted in summer 2017 involved digging shallow trenches on a transect about 760 m west of the transect in the previous study. Preliminary results indicate that the Hurricane Ike deposit has been identified at five trench sites in the current transect, and that the deposits thin out further inland. Future research will involve work on three more transects stretching from High Island, Texas to McFaddin NWR, Texas. The goal of this study is to discover spatial variations in recent storm surge sediment deposits in relation to the landfall locations of Hurricane Rita and Hurricane Ike. The results of this study should provide valuable knowledge about the sedimentary response of coastal marshes subject to storm surge deposition and useful guidance to public policy aimed at combating the effects of sea level rise on coastal marshes along the northern Gulf of Mexico coastline.