Sediment transfer in an extremely low-gradient, low-relief and highly buffered system: Darwin Harbour catchment, northern Australia

Nawaz, M., and Wasson, R. (2020) Sediment transfer in an extremely low-gradient, low-relief and highly buffered system: Darwin Harbour catchment, northern Australia. Australian Journal of Earth Sciences, 67 (3). pp. 351-359.

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Abstract

Sediment yields from and sediment transfer within catchments of very low relief and gradient, which make up about 50% of Earth's surface, are poorly documented and their internal sediment dynamics are poorly known. Sediment sources, their proportionate contributions to valley floors and sediment yield, and storage are estimated using fallout radionuclides ²¹⁰Pb₍ₑₓ₎ and ¹³⁷Cs in the catchments that drain into Darwin Harbour, northern Australia, an example of this understudied catchment type that appears to be globally at the extreme end of this category of catchments. Unchannelled grassy valley floors (dambos, or seasonal wetlands) trap ~90% of the sediment delivered from hillslopes by sheet and rill erosion. Further down valley, small channels transport ~10% of the sediment that escapes from the dambos, and the remaining sediment comes from erosion of the channels. In this case, the fractional sediment storage is very high as a result of the existence of dambos, a landform that depends for its existence on low gradients.

Item ID: 60871
Item Type: Article (Research - C1)
ISSN: 1440-0952
Keywords: sediment transfer and yield, low-gradient catchments, dambos, fallout radionuclide tracers
Copyright Information: © 2019 Geological Society of Australia.
Funders: Charles Darwin University (CDU)
Projects and Grants: CDU Tropical Rivers and Coastal Knowledge project
Date Deposited: 06 Nov 2019 07:53
FoR Codes: 04 EARTH SCIENCES > 0403 Geology > 040310 Sedimentology @ 100%
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