Calculating highly fluctuated suspended sediment fluxes from mountainous rivers in Taiwan

Shuh Ji Kao*, Tsung Yu Lee, John D. Milliman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Small drainage basins, highly fractured rock, high relief, and steep gradients make Taiwan watersheds particularly sensitive to episodic events such as typhoons and earthquakes, and to various types of anthropogenic disturbance. Here we analyze the characteristics of a long-term hydrological dataset from Taiwan and re-evaluate methods used to calculate sediment loads for Taiwan's event-driven rivers. We suggest using the rating curve method stratified down to seasonal levels to reflect the rapid changes in the relationship between water discharge and suspended sediment load. A program is developed to determine the optimal time-interval for constructing rating curves, and is used to calculate hourly, daily, yearly, and long-term mean suspended sediment loads. Seasonal rating curves applied to hourly discharges are particularly critical to calculate sediment fluxes and concentrations in response to episodic events, particularly typhoons. The calculated cumulative long-term mean sediment fluxes for the Jhou-Shuei and Bei-Nan Rivers are considerably smaller than those calculated using monthly weighted average (MWA) method (Dadson et al. 2003). The MWA method likely over-estimates the mean load due to more frequent sediment observations during high-flow events.

Original languageEnglish
Pages (from-to)653-675
Number of pages23
JournalTerrestrial, Atmospheric and Oceanic Sciences
Volume16
Issue number3
DOIs
Publication statusPublished - 2005 Aug
Externally publishedYes

Keywords

  • Rating curve
  • Suspended sediment flux estimate
  • Taiwan

ASJC Scopus subject areas

  • Oceanography
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)

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