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| Titel |
Water flow pathways and the water balance within a head-water catchment containing a dambo: inferences drawn from hydrochemical investigations |
| VerfasserIn |
M. P. McCartney, C. Neal |
| 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 ; 3, no. 4 ; Nr. 3, no. 4, S.581-591 |
| Datensatznummer |
250001193
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| Publikation (Nr.) |
 copernicus.org/hess-3-581-1999.pdf |
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| Zusammenfassung |
| Dambos, seasonally saturated wetlands, are widespread in
headwater catchments in sub-Saharan Africa. It is widely believed that they play
an important role in regional hydrology but, despite research conducted over the
last 25 years, their hydrological functions remain poorly understood. To improve
conceptualisation of hydrological flow paths and investigate the water balance
of a small Zimbabwean catchment containing a single dambo, measurements of
alkalinity and chloride in different water types within the catchment have been
used as chemical markers. The temporal variation in alkalinity is consistent
with the premise that all stream water, including the prolonged dry season
recession, is derived predominantly from shallow sources. The proposition that
dry season recession flows are maintained by water travelling at depth within
the underlying saprolite is not substantiated. There is evidence that a low
permeability clay lens, commonly present in many dambos, acts as a barrier for
vertical water exchange. However, the highly heterogeneous chemical composition
of different waters precludes quantitative hydrograph split-ting using end
member mixing analysis. Calculation of the chloride mass-balance confirms that,
after rainfall, evaporation is the largest component of the catchment water
budget. The study provides improved understanding of the hydrological
functioning of dambos. Such understanding is essential for the development and
implementation of sustainable management strategies for this landform. |
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