Quantifying human impacts on rates of erosion and sediment transport at a landscape scale
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Quantifying human impacts on rates of erosion and sediment transport at a landscape scale

  1. Dylan Rood2,3

+ Author Affiliations

  1. 1Rubenstein School of Environment and Natural Resources, and Department of Geology, University of Vermont, Burlington, Vermont 05405, USA
  2. 2Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
  3. 3Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California 94550, USA


Establishing background (geologic) rates of erosion is prerequisite to quantifying the impact of human activities on Earth's surface. Here, we present 10Be estimates of background erosion rates for ten large (10,000–100,000 km2) river basins in the southeastern United States, an area that was cleared of native forest and used intensively for agriculture. These 10Be-based rates are indicative of the pace at which the North American passive-margin landscape eroded before European settlement (∼8 m/m.y.). Comparing these background rates to both rates of post-settlement hillslope erosion and to river sediment yields for the same basins, we find that following peak disturbance (late 1800s and early 1900s), rates of hillslope erosion (∼950 m/m.y.) exceeded 10Be-determined background rates more than one-hundred fold. Although large-basin sediment yields during peak disturbance increased 5–10× above pre-settlement norms, rivers at the time were transporting only ∼6% of the eroded material; work by others suggests that the bulk of historically eroded material remained and still remains as legacy sediment stored at the base of hillslopes and along valley bottoms. Because background erosion rates, such as we present here, reflect the rate at which soil is generated over millennial time scales, they can inform and enhance landscape-management strategies.

  • Received 13 September 2014.
  • Revision received 23 November 2014.
  • Accepted 8 December 2014.

(Source: http://geology.gsapubs.org/content/early/2015/01/07/G36272.1.abstract)

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