『Abstract
Taiwan's natural setting creates highly vulnerable watershed
whose rivers discharge disproportionately large quantities of
sediments to the coastal ocean. The 16 Taiwanese rivers analyzed
in this article discharge 〜180 Mt yr-1 of sediment
to the coastal ocean, although totals over the past 20 years have
varied between 16 and 440 Mt yr-1. The mean annual
sediment yield of 9500 t km-2 yr-1 for the
16 rivers is 60-fold greater than the global yield of 150 t km-2
yr-1, but mean yields for the individual rivers vary
by more than 2 orders of magnitude, from 500 to 71,000 t km-2
yr-1. Most sediment erosion and delivery occur in response
to typhoon-generated floods, as evidenced by the fact that >75%
of the long-term flux occurs in <1% of the time, about one-third
of which reaches hyperpycnal concentrations. Detailed analysis
of the 16 watersheds reveals little evidence of any single environmental
factor that controls sediment load. The Erren, the highest-yield
river on Taiwan, drains an erodible but low-gradient watershed
with relatively low runoff. In contrast, three east coast rivers,
the Hoping, the Hualien, and the Beinan, have high sediment yields
that may be explained by relatively frequent earthquakes coupled
with high runoff. Farming and urbanization also have elevated
sediment yields in eastern watersheds, whereas Holocene sediments
buried in the Taiwan Strait suggest that present-day sediment
loads of the western rivers may be no higher than prehuman levels.』
Introduction
Taiwan rivers
Calculating sediment discharge
Role of seasonal fluctuations and episodic events
Deriving a meaningful sediment rating curve
Sediment discharge from Taiwanese rivers
Controlling factors
Episodic events
Hyperpycnal events
Human activities
Concluding remarks
Acknowledgments
References cited