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| Titel |
An empirical method for estimating future flood risks for flood warnings |
| VerfasserIn |
H. Hlavcova, S. Kohnova, R. Kubes, J. Szolgay, M. Zvolensky |
| 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 ; 9, no. 4 ; Nr. 9, no. 4 (2005-10-07), S.431-448 |
| Datensatznummer |
250006973
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| Publikation (Nr.) |
 copernicus.org/hess-9-431-2005.pdf |
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| Zusammenfassung |
| Since medium and long-term precipitation forecasts are still not reliable
enough, rough estimates of the degree of the extremity of forthcoming flood
events that might occur in the course of dangerous meteorological situations
approaching a basin could be useful to decision-makers as additional
information for flood warnings. One approach to answering such a problem is
to use real-time data on the soil moisture conditions in a catchment in
conjunction with estimates of the extremity of the future rainfall and
experience with the basin's behaviour during historical floods. A
scenario-based method is proposed for such a future flood risk estimation,
based on an a priori evaluation of the extremity of hypothetical floods
generated by combinations of synthetic extreme precipitation and previously
observed antecedent pre-flood basin saturations. The Hron river basin,
located in central Slovakia, was chosen as the pilot basin in the case study.
A time series of the basin's average daily precipitation was derived using
spatial interpolation techniques. A lumped HBV-type daily conceptual
rainfall-runoff model was adopted for modelling runoff. Analysis of the
relationship of the modelled historical pre-flood soil moisture and flood
causing-precipitation revealed the independence of both quantities for
rainfall durations lasting 1 to 5 days. The basin's average annual maximum 1
to 5 day precipitation depths were analysed statistically and synthetic
extreme precipitation scenarios associated with rainfall depths with return
periods of 5, 20, 50 and 100 years, durations of 1 to 5 days and temporal
distribution of extreme rainfall observed in the past were set up for runoff
simulation. Using event-based flood simulations, synthetic flood waves were
generated for random combinations of the rainfall scenarios and historical
pre-flood soil moisture conditions. The effect of any antecedent basin
saturation on the extremity of floods was quantified empirically and critical
values of the basin saturation leading to floods with a higher return period
than the return period of precipitation were identified. A method for
implementing such critical values into flood risk warnings in a hydrological
forecasting and warning system in the basin was suggested. |
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