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Titel |
A contribution to improved flood magnitude estimation in base of palaeoflood record and climatic implications – Guadiana River (Iberian Peninsula) |
VerfasserIn |
J. A. Ortega, G. Garzón |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1561-8633
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Digitales Dokument |
URL |
Erschienen |
In: Natural Hazards and Earth System Science ; 9, no. 1 ; Nr. 9, no. 1 (2009-02-26), S.229-239 |
Datensatznummer |
250006622
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Publikation (Nr.) |
copernicus.org/nhess-9-229-2009.pdf |
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Zusammenfassung |
The Guadiana River has a significant record of historical floods, but the
systematic data record is only 59 years. From layers left by ancient floods
we know about we can add new data to the record, and we can estimate maximum
discharges of other floods only known by the moment of occurrence and by the
damages caused. A hydraulic model has been performed in the area of Pulo de
Lobo and calibrated by means of the rating curve of Pulo do Lobo Station. The
palaeofloods have been dated by means of 14C y 137Cs. As
non-systematic information has been used in order to calculate distribution
functions, the quantiles have changed with respect to the same function when
using systematic information. The results show a variation in the curves that
can be blamed on the human transformations responsible for changing the
hydrologic conditions as well as on the latest climate changes. High
magnitude floods are related to cold periods, especially at transitional
moments of change from cold to warm periods. This tendency has changed from
the last medium-high magnitude flood, which took place in a systematic
period. Both reasons seem to justify a change in the frequency curves
indicating a recent decrease in the return period of big floods over
8000 m3 s−1. The palaeofloods indicate a bigger return period for
the same water level discharge thus showing the river basin reference values
in its natural condition previous to the transformation of the basin caused
by anthropic action. |
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