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| Titel |
The role of reservoirs in global sediment budgets |
| VerfasserIn |
G. Verstraeten, W. Renwick, J. Poesen, J. De Vente, N. Vinogradova, P. Bazzoffi, A. Lajczak, M. Radoane, F. Rey |
| 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 |
250021197
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| Zusammenfassung |
| Man-made reservoirs are an important sink for sediment eroded from the land and thus constitute an important
aspect of the sediment budget. Their impact has mostly been assessed at the scale of an individual river basin but
rarely on a continental or even a global scale. Although there are recent estimates of global sediment retention by dams,
these studies have solely focussed on the role reservoirs play in controlling sediment fluxes to the oceans, thus
on their net impact for global sediment budgets. However, the net impact of reservoirs is much larger than the
gross amount of sediment stored within all reservoirs on the globe. Furthermore, the impact of smaller waterholding
structures is mostly neglected. In this paper, we present a first comprehensive assessment of global annual
sediment storage within reservoirs based on sedimentation rates obtained from over 3700
reservoirs, representing nearly 25% of the global storage capacity. We argue that at least 27 petagrams (Pg)
sediment are stored annually in all larger reservoirs, with possible sediment retention of an additional 27 Pg in
smaller man-made water bodies. These values are 2 to 4 times larger than the estimated sediment mass transported
annually to the global coastal ocean, and 8 to 15 times larger than the net reduction of sediment flux to the oceans
attributed to reservoirs. These estimates provide minimum annual continental erosion rates and comparison with
soil erosion data suggest that soil erosion on agricultural land is not the dominant source of sediment deposited in
reservoirs or exported to the ocean. In recent decades, reservoir sedimentation has become as least as important
as floodplain sediment storage and can nowadays be considered as one of the most important sediment sinks in
continental sediment budgets. |
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