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A Paleoflood Assessment of the Greenbrier River in Southeast, West Virginia, U.S.A.

Thurkettle, Sara
http://orcid.org/0000-0002-9436-1813
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1554904220305813

Abstract Details

2019, Master of Science (MS), Ohio University, Geological Sciences (Arts and Sciences).
Slackwater deposits and hydraulic modeling were used to extend the historical record of floods and determine the critical threshold of sediment entrainment in the Greenbrier River of southeastern West Virginia (SE WV). The southward flowing bedrock river incises Paleozoic sandstones, limestones, and shales. The river has experienced three catastrophic floods since 1985: the 1985, 1996, and 2016 floods, which caused extensive damage in communities alongside the river with the most recent flood destroying roughly 1,200 homes in the Greenbrier River watershed. This study better constrains the frequency of floods that have the potential to cause similar damage, which is a matter of urgent need. Paleostage indicators (PSIs) found in Greenbrier River Cave were used as proxies for extending the historical record and reconstructing recurrence intervals of floods. Radiocarbon dating was used to determine ages of pre-historic slackwater deposits (floods) in the cave. Wolman counts were performed in the river channel to determine stream competence and sediment transport thresholds. Known discharges and recoverable paleostages were used to calibrate channel roughness in a 1-dimensional modeling program, HEC-RAS. Channel roughness (Manning’s n) during large floods was determined to be 0.029. Discharges and clast entrainment velocities were calculated using a Shield’s critical shear stress equation and clast size data, then compared against velocities determined in HEC-RAS. HEC-RAS was used to back-calculate discharges for the pre-historic flood deposits which allowed for the 100-year flood frequency to be re-evaluated. Recurrence intervals were assigned to discharges, calculated from clast size data and critical shear stress equation, using the existing flood frequency analysis. The reliability of using paleostage indicators and HEC-RAS to create flood chronologies is discussed.
Gregory Springer (Advisor)
Gregory Nadon (Committee Member)
Dorothy Sack (Committee Member)
Geology; Geomorphology; Paleoclimate Science
Paleoflood Hydrology; Paleoflood; Geomorphology; HEC-RAS; Hydraulic Modeling; Channel Roughness; Paleostage Indicators; Wolman Count; Critical Discharge

Recommended Citations

Citations

  • Thurkettle, S. (2019). A Paleoflood Assessment of the Greenbrier River in Southeast, West Virginia, U.S.A. [Master's thesis, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1554904220305813

    APA Style (7th edition)

  • Thurkettle, Sara. A Paleoflood Assessment of the Greenbrier River in Southeast, West Virginia, U.S.A. 2019. Ohio University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1554904220305813.

    MLA Style (8th edition)

  • Thurkettle, Sara. "A Paleoflood Assessment of the Greenbrier River in Southeast, West Virginia, U.S.A." Master's thesis, Ohio University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1554904220305813

    Chicago Manual of Style (17th edition)

ohiou1554904220305813
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