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| Titel |
Improved unit hydrograph characterisation of the daily flow regime (including low flows) for the River Teifi, Wales: towards better rainfall-streamflow models for regionalisation |
| VerfasserIn |
I. G. Littlewood |
| 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 ; 6, no. 5 ; Nr. 6, no. 5, S.899-911 |
| Datensatznummer |
250003773
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| Publikation (Nr.) |
 copernicus.org/hess-6-899-2002.pdf |
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| Zusammenfassung |
| An established rainfall-streamflow
modelling methodology employing a six-parameter unit hydrograph-based
rainfall-runoff model structure is developed further to give an improved
model-fit to daily flows for the River Teifi at Glan Teifi. It is shown that a
previous model of this type for the Teifi, which (a) accounted for 85% of the
variance in observed streamflow, (b) incorporated a pure time delay of one day
and (c) was calibrated using a trade-off between two model-fit statistics (as
recommended in the original methodology), systematically over-estimates low
flows. Using that model as a starting point the combined application of a
non-integer pure time delay and further adjustment of a temperature modulation
parameter in the loss module, using the flow duration curve as an additional
model-fit criterion, gives a much improved model-fit to low flows, while leaving
the already good model-fit to higher flows essentially unchanged. The further
adjustment of the temperature modulation loss module parameter in this way is
much more effective at improving model-fit to low flows than the introduction of
the non-integer pure time delay. The new model for the Teifi accounts for 88% of
the variance in observed streamflow and performs well over the 5 percentile to
95 percentile range of flows. Issues concerning the utility and efficacy of the
new model selection procedure are discussed in the context of hydrological
studies, including regionalisation.
Keywords: unit hydrographs, rainfall-runoff modelling, low flows, regionalisation. |
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