QUANTITATIVE SEDIMENT INFILL MODELS OF JACKSON LAKE, WY (USA)

Lakes and reservoirs host critical ecological, environmental, and socio-economic services; their central role in water security in the face of ongoing climate change cannot be overstated. Erosion and siltation affect water capacity and reservoir pool, yet robust, quantitative models of sediment infilling timescales are rare. Here, data-rich infilling models were completed on Jackson Lake, WY (USA), an important reservoir for the Upper Snake River system. A multi-disciplinary approach combined basin-wide CHIRP seismic reflection profiles and a suite of radionuclide-dated (²¹⁰Pb, ¹³⁷Cs) sediment cores (n = 23) to showcase the importance of lake-wide sampling design for accurate determination of lake volume and variability in sedimentation. Three infill models were developed, including: (1) a 1-D linear infill model derived from radionuclide-dated sediment cores, (2) a 3-D mass-based infill model derived from radionuclide-dated sediment cores, and (3) a model derived from seismic reflection data centered on sediment volumes and assumptions of basin age. All three models exhibited strong agreement on an infilling time of ~30 ka from present. The adaptability of the infilling models is highlighted, with estimates modelled for both the current state of Jackson Lake as well as a “natural condition” model derived from the pre-dam morphology of the lake. Development of data-rich infilling models would advance global lake/reservoir research, and their application to critical waterbodies could help guide conservation and management practices to ensure their long-term sustainability.

Presentation Preference: Oral

Primary Presenter: Samuel Whitehead, University of Kentucky (samuel.jw@uky.edu)

Authors:

Samuel Whitehead, University of Kentucky; Old Dominion University  (samuel.jw@uky.edu)

Kevin Yeager, University of Kentucky; Old Dominion University  (kevin.yeager@uky.edu)

John Dilworth, University of Kentucky  (john.dilworth@uky.edu)

Michael McGlue, University of Kentucky  (michael.mcglue@uky.edu)

Ryan Thigpen, University of Kentucky  (ryan.thigpen@uky.edu)

Kimberly Schindler, University of Kentucky; Old Dominion University  (kimberly.schindler@uky.edu)

Edward Woolery, University of Kentucky  (ewoolery@uky.edu)