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| Titel |
Effect of hydraulic parameters on sediment transport capacity in overland flow over erodible beds |
| VerfasserIn |
M. Ali, G. Sterk, M. Seeger, M. Boersema, P. Peters |
| 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 ; 16, no. 2 ; Nr. 16, no. 2 (2012-02-27), S.591-601 |
| Datensatznummer |
250013185
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| Publikation (Nr.) |
 copernicus.org/hess-16-591-2012.pdf |
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| Zusammenfassung |
| Sediment transport is an important component of the soil erosion process,
which depends on several hydraulic parameters like unit discharge, mean flow
velocity, and slope gradient. In most of the previous studies, the impact of
these hydraulic parameters on transport capacity was studied for
non-erodible bed conditions. Hence, this study aimed to examine the
influence of unit discharge, mean flow velocity and slope gradient on
sediment transport capacity for erodible beds and also to investigate the
relationship between transport capacity and composite force predictors,
i.e. shear stress, stream power, unit stream power and effective stream power. In
order to accomplish the objectives, experiments were carried out in a 3.0 m
long and 0.5 m wide flume using four well sorted sands (0.230, 0.536, 0.719,
1.022 mm). Unit discharges ranging from 0.07 to 2.07 × 10−3 m2
s−1 were simulated inside the flume at four slopes (5.2, 8.7, 13.2 and
17.6%) to analyze their impact on sediment transport rate. The sediment
transport rate measured at the bottom end of the flume by taking water and
sediment samples was considered equal to sediment transport capacity,
because the selected flume length of 3.0 m was found sufficient to reach the
transport capacity. The experimental result reveals that the slope gradient
has a stronger impact on transport capacity than unit discharge and mean
flow velocity due to the fact that the tangential component of gravity force
increases with slope gradient. Our results show that unit stream power is an
optimal composite force predictor for estimating transport capacity. Stream
power and effective stream power can also be successfully related to the
transport capacity, however the relations are strongly dependent on grain
size. Shear stress showed poor performance, because part of shear stress is
dissipated by bed irregularities, bed form evolution and sediment
detachment. An empirical transport capacity equation was derived, which
illustrates that transport capacity can be predicted from median grain size,
total discharge and slope gradient. |
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