160 Advances in Fluvial Processes and Sediment Transport, Part I

We encourage submissions on fluvial geomorphology, fluvial processes, and sediment transport including field studies, numerical modeling, physical modeling, and spatial analyses.

Tuesday, 21 October 2025
8:00 AM - 12:00 PM
HBGCC, 212AB

A catchment-wide assessment of the impacts of Hurricane Helene on the Wilson Creek Drainage along the Blue Ridge Escarpment, North Carolina

Paper number: 160-9
Program: Technical Sessions
Time: 10:20 AM – 10:35 AM

Authors

Abstract

Hurricane Helene was a generational event in the Blue Ridge Mountains of North Carolina in terms of precipitation intensity and accumulation, flooding, catastrophic mass movements, and forest loss. Assessing the cumulative impacts of Helene on the landscape involves both quantifying the geomorphic work done during the storm and understanding the ways in which these direct consequences have now primed the geomorphic system for evolution over the coming decades. Here we present preliminary field data collected in the Wilson Creek drainage where basin-wide geomorphic mapping was completed immediately before Helene. Following Helene, we conducted preliminary landslide mapping, inventories of large woody debris for 1st through 4th order streams, discharge estimates for various sub-basins, qualitative descriptions of changes to the fluvial system, and detailed hillslope tree-throw surveys. This holistic approach across the continuum from landslide initiation zones to stream channels sheds light on the sources and sinks for both sediment and large wood across the hillslope and fluvial process domains. For example, we are able to estimate tree density within landslide tracks and approximate the number of trees recruited by the river for landslides of various sizes. We compare these recruitment estimates to actual logjam volumes to determine the relative degree of wood recruitment from landslides versus stream banks. We also present tree throw hole volume ranges to better understand soil displacement on hillslopes with large blowdown events.  Our field data and detailed observations provide an important ground truth for interpreting subsequent differencing of pre- and post-event lidar and vegetation change detection as we seek to better understand the geomorphic impacts of Helene across the Blue Ridge Mountains more broadly.

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

doi: 10.1130/abs/2025AM-413366

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