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| Titel |
Sub-daily variability of suspended sediment fluxes in small mountainous catchments – implications for community-based river monitoring |
| VerfasserIn |
C. Duvert, N. Gratiot, J. Némery, A. Burgos, O. Navratil |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 15, no. 3 ; Nr. 15, no. 3 (2011-03-02), S.703-713 |
| Datensatznummer |
250012675
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| Publikation (Nr.) |
 copernicus.org/hess-15-703-2011.pdf |
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| Zusammenfassung |
| Accurate estimates of suspended sediment yields depend on effective
monitoring strategies. In mountainous environments undergoing intense
seasonal precipitation, the implementation of such monitoring programs
relies primarily on a rigorous study of the temporal variability of fine
sediment transport. This investigation focuses on seasonal and short-term
variability in suspended sediment flux in a subhumid region of the Mexican
Volcanic Belt. Intensive monitoring was conducted during one year in four
contrasting catchments (3 to 630 km2). Analyses revealed significant
temporal variability in suspended sediment export over various time scales,
with between 63 and 97% of the annual load exported in as little as 2%
of the time. Statistical techniques were used to evaluate the sampling
frequency required to get reliable estimates of annual sediment yield at the
four sites. A bi-daily sampling scheme would be required at the outlet of
the 630 km2 catchment, whereas in the three smaller catchments
(3–12 km2), accurate estimates would inevitably require hourly
monitoring. At the larger catchment scale, analysis of the sub-daily
variability of fine sediment fluxes showed that the frequency of sampling
could be lowered by up to 100% (i.e. from bi-daily to daily) if a
specific and regular sampling time in the day was considered. In contrast,
conducting a similar sampling strategy at the three smaller catchments could
lead to serious misinterpretation (i.e. up to 1000% error). Our findings
emphasise the importance of an analysis of the sub-daily variability of
sediment fluxes in mountainous catchments. Characterising this variability
may offer useful insights for improving the effectiveness of community-based
monitoring strategies in rural areas of developing countries. In regions
where historical records based on discrete sampling are available, it may
also help assessing the quality of past flux estimates. Finally, the study
confirms the global necessity of acquiring more high frequency data in small
mountainous catchments, especially in poorly gauged areas. |
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