302-3 Using numerical models to quantify supply and transport limiting factors of river-sourced aeolian dunes.

Session: Aeolian Systems in Time and Space (Posters)

Poster Booth No.: 156

Presenting Author:

Madeline Kelley

Authors:

Kelley, Madeline M¹, Sankey, Joel², Cohn, Nicholas³, Kasprak, Alan⁴, East, Amy⁵, Caster, Joshua⁶, Fairley, Helen⁷, Van Westen, Bart⁸

(1) U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, Flagstaff, AZ, USA, (2) U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, Flagstaff, AZ, USA, (3) US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, Field Research Facility, Duck, NC, USA, (4) Oregon State University, College of Earth, Ocean, and Atmospheric Sciences, Corvallis, OR, USA, (5) U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA, USA, (6) U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, Flagstaff, AZ, USA, (7) U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, Flagstaff, AZ, USA, (8) Deltares, Resilient Ports and Coasts, Delft, Netherlands,

Abstract:

Aeolian sediment transport in dryland landscapes is shaped by the interaction of supply- and transport-limiting factors; Understanding both is essential for predicting landscape change. In river-sourced aeolian systems, such as those along the Colorado River in Grand Canyon National Park (GRCA), aeolian dunes develop adjacent to sandbars that act as fluvial sources of aeolian sediment supply. However, the operations of the upstream Glen Canyon Dam have reduced fluvial sediment loads, dampened seasonal variability of river flows, and, in turn, promoted riparian vegetation growth, all of which can decrease subaerial sandbar volume and limit the availability of aeolian sediment supply. We apply the coastal morphodynamic model AeoLiS to simulate site-specific changes in surface conditions and transport processes for sandbar-fed aeolian dunes, many of which contain culturally significant archaeological material. The modeling framework allows us to explore how variations in supply and transport conditions interact to shape sediment transport pathways and dune morphology across the landscape. By running targeted scenarios—such as including or excluding riparian vegetation growth, altering sediment supply through changes in sandbar exposure, or adjusting drying times—we can isolate the individual and combined effects of these processes on sediment flux and dune evolution. These experiments reveal how shifts in key controls can fundamentally change dune formation and evolution, providing a more complete understanding of sediment connectivity in fluvial-aeolian systems. We present results that demonstrate the contributions of different processes and further highlight the model’s capability for evaluating experimental management actions and assessing long-term landscape evolution in the Grand Canyon region.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-5156

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.