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| Titel |
Assessing reservoir siltation by means of sediment budget techniques |
| VerfasserIn |
J. A. López-Tarazón, T. Francke, G. Mamede |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250019456
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| Zusammenfassung |
| Research on sediment transport is especially important in catchments draining highly
erodible sediments that eventually cause the siltation of downstream reservoirs. Reservoir
siltation leads to several problems such as reduction of storage capacity, obstruction of water
intakes, and water quality problems, which may threaten domestic water supply and related
economic activities (e.g. irrigation, hydropower production, nuclear power production).
Siltation is a severe phenomenon in areas under variable climatic conditions, such as the
Mediterranean mountains, with long dry periods and storms of high rainfall intensity,
and where runoff occurs over highly erodible unconsolidated sediments on bare
slopes (i.e. badlands on marls, mudstones or shales). Under such conditions, erosion
rates are very high, creating high suspended sediment concentrations in the river
network that reach the lowland areas and the reservoirs. This is the case of the River
Isabena, a 445 km2 drainage basin located in the Southern Central Pyrenees, whose
suspended sediment yield has historically threaten the water storage capacity of
the 92.2 hm3 Barasona Reservoir located at the catchment outlet. To assess the
sediment contribution of the catchment to the reservoir an integrated sediment budget
research has been carried out during the last 3 years considering three different
scales: i) sediment yield from the badlands (main sediment source); ii) water and
sediment transfer within the river system from the badlands to the reservoir; and iii)
sediment dynamics and retention into the reservoir. Specific sediment yield of up
to 6⋅103 t km-2 y-1 were observed at the monitoring badland area, yielding an
specific yield of 414 t km-2 y-1 at the catchment scale, a value that represents
550,000 t of exported sediments during the monitoring period. This value equals
to 0.36 hm3, a value that represents more than the 0.4% of the original reservoir
capacity, in accordance to the bathymetrical surveys carried out in the reservoir. |
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