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| Titel |
Attribution of climate change, vegetation restoration, and engineering measures to the reduction of suspended sediment in the Kejie catchment, southwest China |
| VerfasserIn |
X. Ma, X. X. Lu, M. van Noordwijk, J. T. Li, J. C. Xu |
| 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 ; 18, no. 5 ; Nr. 18, no. 5 (2014-05-26), S.1979-1994 |
| Datensatznummer |
250120369
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| Publikation (Nr.) |
 copernicus.org/hess-18-1979-2014.pdf |
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| Zusammenfassung |
| Suspended sediment transport in rivers is controlled by terrain, climate, and
human activities. These variables affect hillslope and riverbank erosion at
the source, transport velocities and sedimentation opportunities in the river
channel, and trapping in reservoirs. The relative importance of those factors
varies by context, but the specific attribution to sediment transfer is
important for policymaking, and has wide implications on watershed
management. In our research, we analyzed data from the Kejie watershed in the
upper Salween River (Yunnan Province, China), where a combination of land
cover change (reforestation, as well as soil and water conservation measures)
and river channel engineering (sand mining and check dam construction)
interact with a changing climate. Records (1971–2010) of river flow and
suspended sediment loads were combined with five land-use maps from 1974,
1991, 2001, 2006 and 2009. Average annual sediment yield decreased from
13.7 t ha−1 yr−1 to 8.3 t ha−1 yr−1 between the
period 1971–1985 and the period 1986–2010. A distributed hydrological model
(Soil and Water Assessment Tools, SWAT) was set up to simulate the sediment
sourcing and transport process. By recombining land-use and climate data for
the two periods in model scenarios, the contribution of these two factors
could be assessed with engineering effects derived from residual measured
minus modeled transport. Overall, we found that 47.8% of the decrease
was due to land-use and land cover change, 19.8% to climate change,
resulting in a milder rainfall regime, 26.1% to watershed engineering
measures, and the remaining 6.3% was due to the simulation percent bias.
Moreover, mean annual suspended sediment yield decreased drastically with the
increase of forest cover, making diverse forest cover one of the most
effective ecosystems to control erosion. For consideration of stakeholders
and policymakers, we also discuss at length the modeling uncertainty and
implications for future soil and water conservation initiatives in China. |
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