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| Titel |
Comparison of different base flow separation methods in a lowland catchment |
| VerfasserIn |
A. L. Gonzales, J. Nonner, J. Heijkers, S. Uhlenbrook |
| 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 ; 13, no. 11 ; Nr. 13, no. 11 (2009-11-04), S.2055-2068 |
| Datensatznummer |
250012048
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| Publikation (Nr.) |
 copernicus.org/hess-13-2055-2009.pdf |
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| Zusammenfassung |
Assessment of water resources available in different storages and moving
along different pathways in a catchment is important for its optimal use and
protection, and also for the prediction of floods and low flows. Moreover,
understanding of the runoff generation processes is essential for assessing
the impacts of climate and land use changes on the hydrological response of
a catchment. Many methods for base flow separation exist, but hardly one
focuses on the specific behaviour of temperate lowland areas. This paper
presents the results of a base flow separation study carried out in a
lowland area in the Netherlands. In this study, field observations of
precipitation, groundwater and surface water levels and discharges, together
with tracer analysis are used to understand the runoff generation processes
in the catchment. Several tracer and non-tracer based base flow separation
methods were applied to the discharge time series, and their results are
compared.
The results show that groundwater levels react fast to precipitation events
in this lowland area with shallow groundwater tables. Moreover, a good
correlation was found between groundwater levels and discharges suggesting
that most of the measured discharge also during floods comes from
groundwater storage. It was estimated using tracer hydrological approaches
that approximately 90% of the total discharge is groundwater displaced by
event water mainly infiltrating in the northern part of the catchment, and
only the remaining 10% is surface runoff. The impact of remote recharge
causing displacement of near channel groundwater during floods could also be
motivated with hydraulic approximations. The results show further that when
base flow separation is meant to identify groundwater contributions to
stream flow, process based methods (e.g. the rating curve method; Kliner and
Knezek, 1974) are more reliable than other simple non-tracer based methods.
Also, the recursive filtering method (proposed by Eckhardt, 2005) can be
calibrated well using the results of tracer investigation giving good
results. Consequently, non-tracer based base flow separation methods that
can be validated for some events may provide a powerful tool for groundwater
assessment or model calibration/validation in lowland areas. |
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