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| Titel |
Use of deuterium to understand runoff generation in a headwater catchment containing a dambo |
| VerfasserIn |
M. P. McCartney, C. Neal, M. 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 ; 2, no. 1 ; Nr. 2, no. 1, S.65-76 |
| Datensatznummer |
250000394
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| Publikation (Nr.) |
 copernicus.org/hess-2-65-1998.pdf |
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| Zusammenfassung |
| Dambos, seasonally saturated wetlands, are widespread in
headwater catchments in southern Africa and play an important role in the regional
hydrological cycle. However, the processes influencing runoff from these catchments are
poorly understood. This paper reports an isotopic investigation of runoff-generating
mechanisms within a Zimbabwean catchment containing a dambo. Hydrograph separation using
deuterium reveals that, once the dambo is saturated, up to 70% of total storm flow can be
considered "new" water (i.e. derived directly from rainfall generating the runoff event).
However, both the total proportion and the instantaneous maximum amount of "new" water in
hydrographs are sensitive to rainfall characteristics and antecedent conditions. These
results are (1) compatible with observations made in catchments in temperate climates when
wetlands are present, and contrast with results obtained when wetlands are absent and (2)
consistent with saturation overland flow, generated in saturated regions of the dambo,
being the major storm runoff mechanism. To reconcile these observations with past
perceptions that dambos attenuate flood flows, a dual role for dambos in storm flow
production is postulated. |
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