The mighty Susquehanna-extreme floods in Eastern North America during the past two millennia

• Published in: Geophysical Research Letters
• Main Authors: Toomey, Michael R., Cantwell, Meagan, Colman, Steven, Cronin, Thomas M., Donnelly, Jeffrey P., Giosan, Liviu, Heil, Clifford W., Korty, Robert, Marot, Marci, Willard, D. A.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Geophysical Union 2019
• Subjects: Hurricane; Flood; Holocene; East coast; River; Chesapeake; Zimmerman; North Atlantic; North Atlantic oscillation
• Online Access: https://hdl.handle.net/1912/24132

Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 46(6), (2019):3398-3407, doi:10.1029/2018GL080890. The hazards posed by infrequent major floods to communities along the Susquehanna River and the ecological health of Chesapeake Bay remain largely unconstrained due to the short length of streamgage records. Here we develop a history of high‐flow events on the Susquehanna River during the late Holocene from flood deposits contained in MD99‐2209, a sediment core recovered in 26 m of water from Chesapeake Bay near Annapolis, Maryland, United States. We identify coarse‐grained deposits left by Hurricane Agnes (1972) and the Great Flood of 1936, as well as during three intervals that predate instrumental flood records (~1800–1500, 1300–1100, and 400–0 CE). Comparison to sedimentary proxy data (pollen and ostracode Mg/Ca ratios) from the same core site indicates that prehistoric flooding on the Susquehanna often accompanied cooler‐than‐usual winter/spring temperatures near Chesapeake Bay—typical of negative phases of the North Atlantic Oscillation and conditions thought to foster hurricane landfalls along the East Coast. This work was supported by the USGS Land Change Science Program and Northeast Region. We appreciated the assistance of Brian Buczkowski, Andrew Zimmerman, and John Bratton in locating archived core materials and data sets. We thank John Jackson and Bryan Landacre for assistance with XRD and pollen analysis, respectively. We thank two anonymous reviewers, Lynn Wingard (USGS), and Rob Stamm (USGS) for their helpful feedback on earlier versions of this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Data generated for this report can be found in the accompanying supporting information. 2019-08-19