Ribolzi, Olivier and Karambiri, Harouna and Bariac, Thierry and Benedetti, Marc and Caquineaux, Sandrine and Descloitres, Marc and Aventurier, Alain (2007) Mechanisms affecting stormflow generation and solute behaviour in a Sahelian headwater catchment. In: Journal of Hydrology, 337 (1-2). pp. 104-116.
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Abstract
Summary The aim of this study was to analyse stormflow processes and the behaviour of solutes therein $(Ca^{2+}, Mg^{2+}, Na^+, K^+$, alkalinity, $NO^-_3 , SO^{2-}_4, Cl^-, Si)$, during flood events in tropical semi-arid conditions. The study site was a small Sahelian catchment (1.4 ha) located in northern Burkina Faso. Runoff and rain water was sampled over a 2-year period (1999 and 2000). In addition to dissolved load, suspended load was measured in the stream water collected at the outlet of the catchment. Isotopic tracing using $\delta^{18}O$ was also conducted during two very different flood events. The results indicated that: (i) event water was by far the major contributor to the stream stormflow, with Hortonian overland flow being the main stormflow process at work; (ii) a small fraction of pre-event soil water may have contributed during the recession of heavy flood with wet antecedent conditions; (iii) solute concentrations were higher in runoff compared to rainwater. With the exception of $NO^-_3$ and $Cl^-$, the highest concentrations were measured at the onset of floods, and almost always decreased during the rising stage of the hydrographs; (iv) a good correlation was found between sus-pended load and the concentrations of $Ca^{2+}, Mg^{2+}$, alkalinity and Si. It was concluded that fast physico-chemical interactions between event water and reactive suspended phases may explain most of the chemical changes between rainwater and floodwater.
Item Type: | Journal Article |
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Publication: | Journal of Hydrology |
Publisher: | Elsevier |
Additional Information: | Copyright of this article belongs to Elsevier. |
Department/Centre: | Division of Mechanical Sciences > Civil Engineering |
Date Deposited: | 14 Aug 2007 |
Last Modified: | 19 Sep 2010 04:39 |
URI: | http://eprints.iisc.ac.in/id/eprint/11713 |
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