wAbstract
@Sediment flux to the coastal zone is conditioned by geomorphic
and tectonic influences (basin area and relief), geography (temperature,
runoff), geology (lithology, ice cove), and human activities (reservoir
trapping, soil erosion). A new model, termed gBQARTh in recognition
of those factors, accounts for these varied influences. When applied
to a database of 488 rivers, the BQART model showed no ensemble
over- or underprediction, had a bias of just 3 across six orders
of magnitude in observational values, and accounted for 96 of
the between-river variation in the long-term (}30 years) sediment
load or yield of these rivers. The geographical range of the 488
rivers covers 63 of the global land surface and is highly representative
of global geology, climate, and socioeconomic conditions. Based
strictly on geological parameters (basin area, relief, lithology,
ice erosion), 65 of the between-river sediment load is explained.
Climatic factors (precipitation and temperature) account for an
additional 14 of the variability in global patterns in load.
Anthropogenic factors account for an additional 16 of the between-river
loads, although with ever more dams being constructed or decommissioned
and socioeconomic conditions and infrastructure in flux, this
contribution is temporally variable. The glacial factor currently
contributes only 1 of the signal represented by our globally
distributed database, but it would be much more important during
and just after major glaciations. The BQART model makes possible
the quantification of the influencing factors (e.g., climate,
basin area, ice cover) within individual basins, to better interpret
the terrestrial signal in marine sedimentary records. The BQART
model predicts the long-term flux of sediment delivered by rivers;
it does not predict the episodicity (e.g., typhoons, earthquakes)
of this delivery.x
Introduction
A brief history
Development of the ART model
New global predictor of sediment load: The BQART model
Defining the global river database
Defining the B factors in the BQART model
@Glacier erosion factor (I)
@Lithology factor (L)
@Sediment trapping (1-TE)
@Anthropogenic factor (Eh)
Testing the BQART model
A word on sediment yield
Geology, geography, and humans
Acknowledgments
References cited