Authors: Alejandro Antonio Aragón-Moreno*, Louisiana State University, Kam-biu Liu, Louisiana State University, Junghyung Ryu, Louisiana State University, Qiang Yao, Louisiana State University, Harry F. L. Williams, University of North Texas
Topics: Paleoenvironmental Change, Coastal and Marine, Hazards, Risks, and Disasters
Keywords: Hurricane Harvey, Trinity River, fluvial flooding, storm surge, storm deposit, paleotempestology
Session Type: Poster
Start / End Time: 3:05 PM / 4:45 PM
Room: Lincoln 2, Marriott, Exhibition Level
Presentation File: Download
Hurricane Harvey, a category 4 storm, caused up to 2 m of storm surge and over 152 cm of rain in southeastern Texas in August 2017, resulting in catastrophic flooding in the Trinity River valley. We retrieved a 2.56 m vibra-core from Round Lake, an estuarine lake near the Trinity River mouth, to study the sedimentary record of Hurricane Harvey by applying the principles and methods of paleotempestology. Loss-on-ignition, X-ray fluorescence, and grain-size analyses as well as palynological techniques were applied to identify storm deposits. Preliminary results show a 9 cm sand layer at the top of the core that is attributable to Hurricane Harvey. The XRF results show that the Harvey storm deposit is marked by a slightly elevated Cl/Br ratio below a finer, more organic alluvial sediment layer, which is consistent with the predominance of fluvial flooding following seawater intrusion during and after the Harvey event. Four other sand layers, each characterized by a sharp peak in the Cl/Br ratio, were visually distinct in the uppermost meter of the core, suggesting that storm surge-driven seawater intrusion was the primary depositional mechanism as would be expected from intense Hurricanes Ike, Alicia, Carla, and Audrey that impact the study area in the last 50 years. Radio-isotopic dating is being conducted to match these historical storms to the sand layers. Palynological analysis is also underway to assess the potential of using microfossils to differentiate between freshwater flood deposition and storm surge deposition caused by Harvey and other historical storm events.