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| Titel |
Sensitive analysis of low-flow parameters using the hourly hydrological model for two mountainous basins in Japan |
| VerfasserIn |
Kazumasa Fujimura, Yoshihiko Iseri, Shinjiro Kanae, Masahiro Murakami |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090592
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| Publikation (Nr.) |
 EGU/EGU2014-4846.pdf |
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| Zusammenfassung |
| Accurate estimation of low flow can contribute to better water resources management and
also lead to more reliable evaluation of climate change impacts on water resources. In the
early study, the nonlinearity of low flow related to the storage in the basin was suggested by
Horton (1937) as the exponential function of Q=KSN, where Q is the discharge, S is the
storage, K is a constant and N is the exponent value. In the recent study by Ding (2011)
showed the general storage-discharge equation of Q = KNSN. Since the constant K is
defined as the fractional recession constant and symbolized as Au by Ando et al. (1983), in
this study, we rewrite this equation as Qg=AuNSgN, where Qg is the groundwater runoff and
Sg is the groundwater storage. Although this equation was applied to a short-term
runoff event of less than 14 hours using the unit hydrograph method by Ding, it
was not yet applied for a long-term runoff event including low flow more than 10
years.
This study performed a sensitive analysis of two parameters of the constant Au and
exponent value N by using the hourly hydrological model for two mountainous
basins in Japan. The hourly hydrological model used in this study was presented by
Fujimura et al. (2012), which comprise the Diskin-Nazimov infiltration model,
groundwater recharge and groundwater runoff calculations, and a direct runoff
component. The study basins are the Sameura Dam basin (SAME basin) (472 km2)
located in the western Japan which has variability of rainfall, and the Shirakawa Dam
basin (SIRA basin) (205km2) located in a region of heavy snowfall in the eastern
Japan, that are different conditions of climate and geology. The period of available
hourly data for the SAME basin is 20 years from 1 January 1991 to 31 December
2010, and for the SIRA basin is 10 years from 1 October 2003 to 30 September
2013.
In the sensitive analysis, we prepared 19900 sets of the two parameters of Au and N, the
Au value ranges from 0.0001 to 0.0100 in steps of 0.0001 and the N value ranges from 1.0 to
100.0 in steps of 0.5. The analysis was evaluated by the Average of Daily runoff Relative
Error (ADRE). The results showed that the minimum value of the ADRE is 32.199% using
N=100.0 and Au=0.0003 for the SAME basin, and is 38.058% using N=0.0003 and
Au=70.0 for the SIRA basin. Log-log plot for optimal sets of Au and N suggested
accurate simulation of low flow can be achieved when relation of Au and N are in
exponential form. The equations are Au=1/{26.91N1.041} and Au=1/{34.55N1.060} for
each basin, which have similar gradients, but have different intercept on the log-log
graph. From this study, it is found that the optimal sets of Au and N, which obtained
lower relative error in the hydrological analysis, are formulated using the exponent
equation.
Acknowledgements
This work was supported by the Research Program on Climate Change Adaption
(the RECCA Project) of the Ministry of Education, Culture, Sports, Science and
Technology.
References
Ding, J. Y. (2011) A measure of watershed nonlinearity: interpreting a variable
instantaneous unit hydrograph model on two vastly different sized watersheds. Hydrol. Earth
Syst. Sci., 15, 405–423.
Fujimura, K., Shiraha, K., Kanae, S. & Murakami, M. (2012) Development of the hourly
hydrological model for mountainous basins using the storage function method and the
Diskin–Nazimov infiltration model. In: Models – Repositories of Knowledge, IAHS Publ.
355, 338–344.
Horton, R. E. (1936) Natural stream channel-storage. Trans. Am. Geophys. Union, 17,
406–415.
Ando, Y., Musiake, K. & Takahasi, Y. (1983) Modelling of hydrologic processes in a
small natural hillslope basin, based on the synthesis of partial hydrological relationships.
Journal of Hydrology, 64, 311–337. |
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