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| Titel |
Geostatistical prediction of flow–duration curves in an index-flow framework |
| VerfasserIn |
A. Pugliese, A. Castellarin, A. Brath |
| 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 ; 18, no. 9 ; Nr. 18, no. 9 (2014-09-30), S.3801-3816 |
| Datensatznummer |
250120481
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| Publikation (Nr.) |
 copernicus.org/hess-18-3801-2014.pdf |
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| Zusammenfassung |
| An empirical period-of-record flow–duration curve (FDC) describes the
percentage of time (duration) in which a given streamflow was equaled or
exceeded over an historical period of time. In many practical applications
one has to construct FDCs in basins that are ungauged or where very few
observations are available. We present an application strategy of
top-kriging, which makes the geostatistical procedure capable of predicting
FDCs in ungauged catchments. Previous applications of top-kriging mainly
focused on the prediction of point streamflow indices (e.g. flood quantiles,
low-flow indices, etc.); here the procedure is used to predict the entire
curve in ungauged sites as a weighted average of standardised empirical FDCs
through the traditional linear-weighting scheme of kriging methods. In
particular, we propose to standardise empirical FDCs by a reference
index-flow value (i.e. mean annual flow, or mean annual precipitation
×
the drainage area) and to compute the overall negative deviation of the
curves from this reference value. We then propose to use these values, which
we term total negative deviation (TND), for expressing the hydrological
similarity between catchments and for deriving the geostatistical weights. We
focus on the prediction of FDCs for 18 unregulated catchments located in
central Italy, and we quantify the accuracy of the proposed technique under
various operational conditions through an extensive cross-validation and
sensitivity analysis. The cross-validation points out that top-kriging is a
reliable approach for predicting FDCs with Nash–Sutcliffe efficiency
measures ranging from 0.85 to 0.96 (depending on the model settings) very low
biases over the entire duration range, and an enhanced representation of the
low-flow regime relative to other regionalisation models that were recently
developed for the same study region. |
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