Anthropogenic alluvial sediments in North Carolina Piedmont gullies indicate swift geomorphic response to 18th century land-use practices

ABSTRACT

Gullies are common erosional features in the Piedmont of North Carolina that have often been studied as indicators of poor land-management practices. However, the timing of gully formation, and thus the specific practices that caused their formation, has been largely overlooked in the literature. Here, we use the timing of gully formation to examine the geomorphic and anthropogenic triggers for erosion in the Piedmont. To do this, we mapped 74 gullies in the landscape and found that most contained alluvium within the gully or in alluvial fans. Soil pits were dug at a subset of the gully sites (16 in alluvium, 1 in colluvium, and 1 upland comparison) and examined for soil development, organic content, and particle size. Seven charcoal fragments were sampled from the soil pits and were radiocarbon dated. Radiocarbon ages cluster in the late 1700s, which suggests that early European settlers had an immediate impact on the landscape through deforestation and agriculture. The swift response of the landscape to deforestation and agriculture indicates that the argillic Piedmont soils are pre-disposed to erosion. Our results highlight the importance of erosion prevention as reforested farmland is cleared during urban expansion.

Graphical Abstract

KEYWORDS:

• Gully formation
• alluvium
• anthropogenic erosion
• soil development
• radiocarbon dating
• sediment dating

Acknowledgments

We would like to thank the Town of Davidson for providing research access to town parks. Thanks also to K. Kempthorn and N. Kuntz for their assistance in the field and to Amanda Schmidt for providing preliminary Cs-137 analysis. Two anonymous reviewers significantly improved this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here

Additional information

Funding

This work was supported by the Davidson Research Initiative [NA].