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Communication incl. Poster: BibTeX citation key:  Dieme
Dieme, Y., Sambou, S., Touré, A. K., Badji, A. M. & Malanda-Nimy, E. N. 2009. Man made structure and climate change effect on hydrological regime through a statistical approach: case of the Manantali dam, upstream Senegal river. Work presented at Third International AMMA Conference, July 20—24, at Ouagadougou, Burkina Faso.
Added by: roussot 2009-11-24 20:28:47
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Categories: Society-Environment-Climate interactions
Keywords: Adaptation and Mitigation, Water - Energy - Resources
Creators: Badji, Dieme, Malanda-Nimy, Sambou, Touré
Publisher: African Monsoon Multidisciplinary Analyses (Ouagadougou, Burkina Faso)
Collection: Third International AMMA Conference

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Abstract
Analysis of hydroclimatic variables time series such as rainfall and runoff is a prior step to know the trend in water resources for management and planning and for reservoir operations. Runoff time series are often affected by climate through the hydrological cycle and by modification induced by man made structures in rivers, such as dams.
A statistical approach is used to determine the modification of the Senegal river hydrological regime due to the Manantali dam effect upstream Bakel. Time series of runoff observed between 1961 and 2006, upstream and downstream of this dam are used, at annual and monthly scale. Statistical tests for independence and homogeneity popular among hydrologists in African context are applied: Kendall test rank correlation, autocorrelogramme analysis, turning point test for independence, and Buishand test, Ellipse of control, Pettitt test, Lee and Heghinian procedure, and segmentation of series of Hubert for homogeneity.
At the annual scale, the null hypothesis of independance is accepted for all runoff series. The null hypothesis of homogeneity has been rejected for all runoff series. The rupture generally occurs before the year of commissioning of the dam (1987). At monthly scale, the null hypothesis of independence of time series is accepted for all stations and for all months, except the month of May for Bakel station. The null hypothesis of homogeneity is also rejected for all stations and for all times series. Upstream of Manantali dam, rupture always occurs before the dam commissioning. Downstream of the dam, for rupture occurs before dam commissioning during high flows, and after dam commissioning during low flows.
The time series we are analyzing contains two kinds of signals: climate one, and dam one. The results we have obtained show that statistical approach detect always the strongest signal between the two one.
Added by: roussot