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| Titel |
Runoff and Sediment load of the Yan River, China: changes over the last 60 yr |
| VerfasserIn |
F. Wang, X. Mu, R. Hessel, W. Zhang, C. J. Ritsema, R. Li |
| 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 ; 17, no. 7 ; Nr. 17, no. 7 (2013-07-05), S.2515-2527 |
| Datensatznummer |
250018920
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| Publikation (Nr.) |
 copernicus.org/hess-17-2515-2013.pdf |
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| Zusammenfassung |
| Runoff and sediment load changes are affected by climate change and human
activities in an integrated way. Historical insight into these effects can
not only improve the knowledge of river processes, but also promote more
effective land and water management. In this study, we looked at runoff and
sediment change in the Yan River basin, Loess Plateau, China, using data sets
on land use and land cover (LUC), monthly data of precipitation and
temperature, and observed data on runoff and sediment load from 1952 to 2010
at the Ganguyi Hydrologic Station. Available data on soil and water
conservation structures and their effect were also studied. Five main
findings emerged from the data analysis. (1) The annual runoff and sediment
load varied greatly during the last 60 yr, and both had coefficients of
variation that were much larger than those of precipitation and temperature.
(2) Annual runoff and sediment load both showed a significant trend of linear
decline over the period studied. The climate data showed a non-significant
decline in precipitation over the same period, and a very significant
increase in temperature; both can help explain the observed declines in
runoff and soil loss. (3) Based on a mass curve analysis with anomalies of
normalized runoff and sediment load, 4 stages in the change of runoff and
soil loss were identified: 1951 to 1971 (Stage I), 1972 to 1986 (Stage II),
1987 to 1996 (Stage III) and 1997 to 2010 (Stage IV). (4) When years were
paired based on similar precipitation and temperature condition (SPTC) and
used to assess the impacts of human activities, it was found that 6 sets of
paired years out of 12 (50%) showed a decline in runoff, 8 (67%) a
decline in sediment load, and 9 (75%) a decline in sediment
concentration. The other sets show an increasing change with time. It showed
the complexity of human impacts. (5) Human impacts relating to LUC change and
soil and water measures in this basin were significant because of both the
transfer of sloping cropland into non-food vegetation or terraces, and the
siltation in the reservoirs and behind check dams. Data indicated that about
56 Mt of sediment was deposited annually from 1960–1999 as a result of the
soil and water conservation structures, which is significantly more than the
average 42 Mt, leaving the Yan River basin as sediment load each year.
Although the effects of climate change and human action could not be
separated, analysis of the data indicated that both had a significant impact
on runoff and sediment load in the area. |
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