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| Titel |
Discharge estimation in a backwater affected meandering river |
| VerfasserIn |
H. Hidayat, B. Vermeulen, M. G. Sassi, P. J. J. F. Torfs, A. J. F. Hoitink |
| 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 ; 15, no. 8 ; Nr. 15, no. 8 (2011-08-30), S.2717-2728 |
| Datensatznummer |
250012937
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| Publikation (Nr.) |
 copernicus.org/hess-15-2717-2011.pdf |
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| Zusammenfassung |
| Variable effects of backwaters complicate the development of rating curves at
hydrometric measurement stations. In areas influenced by backwater,
single-parameter rating curve techniques are often inapplicable. To overcome
this, several authors have advocated the use of an additional downstream
level gauge to estimate the longitudinal surface level gradient, but this is
cumbersome in a lowland meandering river with considerable transverse surface
level gradients. Recent developments allow river flow to be continuously
monitored through velocity measurements with an acoustic Doppler current
profiler (H-ADCP), deployed horizontally at a river bank. This approach was
adopted to obtain continuous discharge estimates at a cross-section in the
River Mahakam at a station located about 300 km upstream of the river mouth
in the Mahakam delta. The discharge station represents an area influenced by
variable backwater effects from lakes, tributaries and floodplain ponds, and
by tides. We applied both the standard index velocity method and a recently
developed methodology to obtain a continuous time-series of discharge from
the H-ADCP data. Measurements with a boat-mounted ADCP were used for
calibration and validation of the model to translate H-ADCP velocity to
discharge. As a comparison with conventional discharge estimation techniques,
a stage-discharge relation using Jones formula was developed. The discharge
rate at the station exceeded 3250 m3 s−1. Discharge series from a
traditional stage-discharge relation did not capture the overall discharge
dynamics, as inferred from H-ADCP data. For a specific river stage, the
discharge range could be as high as 2000 m3 s−1, which is far
beyond what could be explained from kinematic wave dynamics. Backwater
effects from lakes were shown to be significant, whereas interaction of
the river flow with tides may impact discharge variation in the fortnightly frequency band.
Fortnightly tides cannot easily be isolated from river discharge variation,
which features similar periodicities. |
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