Hydrological processes and water balance of a tropical crystalline bedrock catchment in Benin (Donga, upper Oueme River).

Hydrological processes and water balance of a tropical crystalline bedrock catchment in Benin (Donga, upper Oueme River). Hydrodynamic, geochemical, and subsurface geophysical investigations, for two consecutive years with contrasting rainfall 2 conditions, were used to characterize the hydrological processes occurring, and the water balance of a 586-km(2) watershed in Benin (Africa). The water table's monitoring shows that recharge occurs by direct infiltration of rainfall, and represents between 5 to 24% of the annual rainfall. Both surface water outflow, limited to the rainy season, and water chemistry indicate a weak groundwater contribution to river discharge. This implies that the calculated variations in annual runoff coefficients (of 14 and 28%) are mainly governed by surface and subsurface flows. To cite this article: B. Kamagati et al., C. R. Geoscience 339 (2007). (C) 2007 Academie des sciences. Publie par Elsevier Masson SAS. Tons droits reserves.