Bader Jean-Claude, Dacosta H., Pouget Jean-Christophe. (2020). Seasonal variations of the depletion factor during recession periods in the Senegal, Gambia and Niger watersheds. Water, 12 (9), 2520 [24 p.].
Titre du document
Seasonal variations of the depletion factor during recession periods in the Senegal, Gambia and Niger watersheds
The daily depletion factorKdescribes the discharge decrease of rivers only fed by groundwater in the absence of rainfall. In the Senegal, Gambia and Niger river basins in West Africa, the flow recession can exceed 6 months and the precise knowledge ofKthus allows discharge forecasts to be made over several months, and is hence potentially interesting for hydraulic structure managers. Seasonal flow recession observed at 54 gauging stations in these basins from 1950 to 2016 is represented by empirical and usual conceptual models that expressK. Compared to conventional conceptual models, an empirical model representingKas a polynomial of the decimal logarithm of dischargeQgives better representations ofKand better discharge forecasting at horizons from 1 to 120 days for most stations. The relationship between specific dischargeQsandK, not monotonous, is highly homogeneous in some sub-basins but differs significantly between the Senegal and Gambia basins on the one hand and the Niger basin on the other. The relationshipK(Q) evolves slightly between three successive periods, with values ofKgenerally lower (meaning faster discharge decrease) in the intermediate period centered on the years 1970-1980. These climate-related interannual variations are much smaller than the seasonal variations ofK.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
;
Hydrologie [062]
