Authors: Tyler Dearman*, University of South Carolina, L. Allan James, University of South Carolina
Keywords: Geomorphology, Legacy sediment, Sedimentology, UAV-based modeling
Session Type: Paper
Start / End Time: 8:00 AM / 9:40 AM
Room: Balcony K, Marriott, River Tower Elevators, 4th Floor
Presentation File: No File Uploaded
Anthropogeomorphic changes vary across time scales and indicate contemporary processes. The arrival of European settlers into the Americas in the 1700s provides an example of intensive landscape alteration caused by destructive agricultural practices up through the 1930s. The Piedmont physiographic region was particularly affected and these impacts can still be seen in the landscape today. This research examines anthropogenic impacts of land-use change on valley bottom sedimentation in the Chicken Creek Watershed. Soil stratigraphic and sedimentologic evidence are presented, alongside UAV-based and traditional modeling techniques, to contrast patterns and rates of pre-settlement and post-settlement (legacy) sediment delivery, deposition, and storage on the floodplain and the environments in which this occurred. Legacy sediment deposits between 2 and 4 meters thick throughout the stream corridor rest on top of exposed pre-settlement soils, on average 1 meter thick above bed rock. Thin pre-settlement soils suggest modest erosion and sedimentation rates prior to European arrival. This geomorphic stability is supported by the occasional presence of a well-developed epipedon on the pre-colonial floodplain soils. Contrasts in grain-size and sedimentary structures between the pre- and post-settlement alluvial units document a change in post-settlement sedimentation styles, sediment sources, and floodplain depositional environments. Abrupt contacts between pre-settlement soils and a thick overburden of legacy sediment are common throughout the study reach and provide clear evidence of sudden, massive post-settlement sedimentation.