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Titel |
A three-component hydrograph separation based on geochemical tracers in a tropical mountainous headwater catchment in northern Thailand |
VerfasserIn |
C. Hugenschmidt, J. Ingwersen, W. Sangchan, Y. Sukvanachaikul, A. Duffner, S. Uhlenbrook, T. Streck |
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. 2 ; Nr. 18, no. 2 (2014-02-12), S.525-537 |
Datensatznummer |
250120275
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Publikation (Nr.) |
copernicus.org/hess-18-525-2014.pdf |
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Zusammenfassung |
Land-use change in the mountainous parts of northern Thailand is reflected by
an increased application of agrochemicals, which may be lost to surface and
groundwater. The close relation between flow paths and contaminant transport
within hydrological systems requires recognizing and understanding the
dominant hydrological processes. To date, the vast majority of studies on
runoff generation have been conducted in temperate regions. Tropical regions
suffer from a general lack of data, and little is known about runoff
generation processes. To fill this knowledge gap, a three-component
hydrograph separation based on geochemical tracers was carried out in a
steep, remote and monsoon-dominated study site (7 km2) in northern
Thailand. Silica and electrical conductivity (EC) were identified as useful tracers and were applied to
calculate the fractions of groundwater (similar to pre-event water), shallow
subsurface flow and surface runoff on stormflow. K+ was a useful
indicator for surface runoff dynamics, and Ca2+ provided insights
into groundwater behaviour. Nevertheless, neither measure was applicable for
the quantification of runoff components. Cl- and further parameters
(e.g. Na+, K+, and Mg2+) were also not helpful for
flow path identification, nor were their concentrations distinguishable among
the components.
Groundwater contributed the largest fractions to stormflow (62–80%)
throughout all events, followed by shallow subsurface flow (17–36%) and
surface runoff (2–13%). Our results provide important insights into the
dynamics of the runoff processes in the study area and may be used to assess
the transport pattern of contaminants (i.e. agrochemicals) here. |
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