A new approach for linking event-based upland sediment sources to downstream suspended sediment transport

Peng Gao, James Puckett

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

In this study, we proposed a new approach for linking event sediment sources to downstream sediment transport in a watershed in central New York. This approach is based on a new concept of spatial scale, sub-watershed area (SWA), defined as a sub-watershed within which all eroded soils are transported out without deposition during a hydrological event. Using (rainfall) event data collected between July and November, 2007 from several SWAs of the studied watershed, we developed an empirical equation that has one independent variable, mean SWA slope. This equation was then used to determine event-averaged unit soil erosion rate, Q S/A, (in kg/km 2/hr) for all SWAs in the studied watershed and calculate event-averaged gross erosion E ea (in kg/hr). The event gross erosion E t (in kilograms) was subsequently computed as the product of E ea and the mean event duration, T (in hours) determined using event hydrographs at the outlet of the studied watershed. Next, we developed two linear sediment rating curves (SRCs) for small and big events based on the event data obtained at the watershed outlet. These SRCs, together with T, allowed us to determine event sediment yield SY e (in kilograms) for all events during the study period. By comparing E t with SY e, developing empirical equations (i) between E t and SY e and (ii) for event sediment delivery ratio, respectively, we revealed the event dynamic processes connecting sediment sources and downstream sediment transport. During small events, sediment transport in streams was at capacity and dominated by the deposition process, whereas during big events, it was below capacity and controlled by the erosion process. The key of applying this approach to other watersheds is establishing their empirical equations for Q S/A and appropriately determining their numbers of SWAs.

Original languageEnglish (US)
Pages (from-to)169-179
Number of pages11
JournalEarth Surface Processes and Landforms
Volume37
Issue number2
DOIs
StatePublished - Feb 1 2012

Keywords

  • Event gross erosion
  • Event sediment yield
  • Sediment connectivity
  • Sediment rating curve
  • Sub-watershed area
  • Suspended sediment load

ASJC Scopus subject areas

  • Geography, Planning and Development
  • Earth-Surface Processes
  • Earth and Planetary Sciences (miscellaneous)

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