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| Titel |
Variation in turbidity with precipitation and flow in a regulated river system – river Göta Älv, SW Sweden |
| VerfasserIn |
G. Göransson, M. Larson, D. Bendz |
| 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 (2013-07-08), S.2529-2542 |
| Datensatznummer |
250018921
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| Publikation (Nr.) |
 copernicus.org/hess-17-2529-2013.pdf |
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| Zusammenfassung |
| The turbidity variation in time and space is investigated in the downstream
stretch of the river Göta Älv in Sweden. The river is heavily
regulated and carries the discharge from the largest fresh water lake in
Sweden, Lake Vänern, to the outflow point in Göteborg Harbour on the
Swedish west coast. The river is an important waterway and serves as a
fresh-water supply for 700 000 users. Turbidity is utilised as a water
quality indicator to ensure sufficient quality of the intake water to the
treatment plant. The overall objective of the study was to investigate the
influence of rainfall, surface runoff, and river water flow on the temporal
and spatial variability of the turbidity in the regulated river system by
employing statistical analysis of an extensive data set. A six year long
time series of daily mean values on precipitation, discharge, and turbidity
from six stations along the river were examined primarily through linear
correlation and regression analysis, combined with nonparametric tests and
analysis of variance. The analyses were performed on annual, monthly, and
daily bases, establishing temporal patterns and dependences, including;
seasonal changes, impacts from extreme events, influences from tributaries,
and the spatial variation along the river. The results showed that there is
no simple relationship between discharge, precipitation, and turbidity,
mainly due to the complexity of the runoff process, the regulation of the
river, and the effects of Lake Vänern and its large catchment area. For
the river Göta Älv, significant, positive correlations between
turbidity, discharge, and precipitation could only be found during periods
with high flow combined with heavy rainfall. Local precipitation does not
seem to have any significant impact on the discharge in the main river,
which is primarily governed by precipitation at catchment scale. The
discharge from Lake Vänern determines the base level for the turbidity
in the river, whereas local surface runoff and tributary discharge induced
by rainfall govern the temporal variability in turbidity. Autocorrelation
analysis indicates a temporal persistence in turbidity of about 10 days. The
results also show that erosion along the main river, from the river bed and
banks, is not a dominant contributor to the suspended sediment transport in
the river under normal conditions. Further studies on the correlation
between turbidity and suspended sediment transport and its relation to
erosion processes are suggested. |
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