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| Titel |
Investigation on extreme runoff characteristics in major German river basins |
| VerfasserIn |
Rohini Kumar, Luis Samaniego, Matthias Zink |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051198
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| Zusammenfassung |
| Identifying trends of extreme runoff characteristics is one of the major research
areas in the contemporary hydrology. This is mainly because of the compelling
evidence that the anthropogenic disruptions of the environment are significantly
modifying the likelihood of occurrence of floods and droughts. Changes in the
characteristics of extreme events may have both socioeconomic and environmental
consequences. In Germany, for instance, major river basins have frequently experienced
catastrophic floods and droughts situations leading to enormous losses during the last
decades. The objective of this study is to identify changes and trends of extreme runoff
characteristics in major German river basins during the last 60 years. Daily streamflow data
from more than 200 runoff gauging stations obtained from EWA database were
used to estimate extreme runoff characteristics. Among these characteristics were:
specific volume, total duration and frequency of high flows, and cumulative specific
deficit, total drought duration, and maximum drought intensity of low flows. The
peak over threshold method (at threshold levels of 90, 95, 99th percentile of daily
streamflow data), and the truncation level method (at truncation levels of 5, 10,
20th percentile of daily streamflow data) were used to derive high and low-flow
characteristics, respectively. All these characteristics were systematically analyzed for
winter and summer to better comprehend seasonal variability. Mann-Kendall and
Spearman tests were conducted to detect either monotonically increasing or decreasing
patterns whereas the Pettitt test was used for detecting change-points in the mean
and variance of the extreme runoff characteristics. A bootstrap resampling process
will be used to determine the field significance of the trend results. Results of this
study agreed with recent findings regarding the positive trend (in winter) and the
negative trend (in summer) of low flows across many rivers in Germany. We are
currently investigating possible explanatory reasons for changes in extreme runoff
characteristics. |
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