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| Titel |
Regional analysis using the Geomorphoclimatic Instantaneous Unit Hydrograph |
| VerfasserIn |
M. J. Hall, A. F. Zaki, M. M. A. Shahin |
| 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 ; 5, no. 1 ; Nr. 5, no. 1, S.93-102 |
| Datensatznummer |
250002258
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| Publikation (Nr.) |
 copernicus.org/hess-5-93-2001.pdf |
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| Zusammenfassung |
| The construction of design flood hydrographs
for ungauged drainage areas has traditionally been approached by regionalisation,
i.e. the transfer of information from the gauged to the ungauged catchments in a
region. Such approaches invariably depend upon the use of multiple linear
regression analysis to relate unit hydrograph parameters to catchment
characteristics and generalised rainfall statistics. The concept of the
geomorphological instantaneous unit hydrograph (GIUH), in relating the shape and
scale of the catchment transfer function to stream network topology and channel
characteristics, offers an alternative methodology. GIUH derivation depends upon
a series of assumptions, including that of estimating a "characteristic
velocity"; these continue to attract attention and debate. However, if this
velocity is expressed in terms of the kinematic wave approximation, the peak and
time-to-peak of the IUH may be expressed in terms of a group of catchment and
channel characteristics and the intensity of rainfall excess, giving the
so-called geomorphoclimatic IUH (GCIUH). Previous studies involving the GCIUH
have developed a single IUH relating to the total duration of rainfall excess.
In this study, the rainfall excess duration was divided into several (equal)
time increments, with separate IUHs being generated for each interval. This
quasi-linear approach was applied to 105 storm events from nine catchments in
the south-west of England, ranging in size from 6 to 420 (km)2 . The
results showed that, providing the time interval chosen is fine enough to
capture the shape of the runoff hydrographs, a comparable level of
goodness-of-fit can be obtained for catchments covering a range of about 1:75 in
area. The modified GCIUH approach as described is therefore recommended for
further investigation and intercomparison with regression-based regionalisation
methods.
Keywords: floods; geomorphology; rainfall-runoff modelling |
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