Authors: Kam-biu Liu*, Louisiana State University, Alejandro A. Aragón-Moreno, Louisiana State University, Junghyung Ryu, Louisiana State University, Qiang Yao, Louisiana State University, Joanne Egan, Edge Hill University, United Kingdom, Harry Williams, University of North Texas
Topics: Coastal and Marine, Geomorphology, Hazards and Vulnerability
Keywords: Hurricane Harvey, storm deposit, multi-proxy analysis, paleotempestology
Session Type: Paper
Presentation File: No File Uploaded
Hurricane Harvey brought up to 2-3 m of storm surge along the Texas coast and up to 152 cm (60 inches) of rain to southeastern Texas in August 2017. This “wind and rain” event offers an excellent opportunity to study the evidence of both fluvial flooding and storm surge in the sedimentary records of coastal wetlands by means of multi-proxy techniques. A 2.56 m core taken from an estuarine lake near the mouth of the Trinity River (about 60 km east of Houston) yielded multiple storm deposits. Harvey's impact was registered by a 9 cm-thick sand layer at the top marked by a slightly elevated Cl/Br ratio and a pollen assemblage marked by increased upland tree and herb pollen percentages, increased pollen concentrations, and absence of foraminifera. The Harvey layer also contained a diverse assemblage of diatoms dominated by freshwater taxa, although marine and brackish water types were also present. Four other clastic layers below the Harvey deposit (possibly representing Hurricanes Ike, Alicia, Carla, and Audrey) were identified down to about 70 cm, but they were each characterized by a sharp peak in the Cl/Br ratio, implying that storm surge-driven seawater intrusion was the primary depositional mechanism in these older storm events. Our study shows that multi-proxy techniques including sedimentological, XRF, palynological, and diatom analyses can be used to assess the relative contributions between freshwater and saltwater flooding in hurricane sedimentation.