Seasonal forecasting of the flood volume of the Senegal River, based on results of the ARPEGE Climate model

From the end of August to the beginning of October, the support of the annual flood of the Senegal River by the multipurpose Manantali Dam requires high release volumes, which can be problematic for its hydro-electric production. To facilitate the programming of this objective by predicting reserves available in the reservoir at the end of the monsoon, attempts are made to predict in August the natural flood volume of the river for September-October, starting from an index of pluviometric anomalies calculated at the end of July for these two months by the model "ARPEGE Climat". After a principal components analysis of these indexes produced on a 300 x 300 km grid covering West Africa, a 1200 x 1200 km zone may be determined shifted to the east of the basin, where the eigenvectors of the indexes are related to the natural discharge of September-October by linear regression with five parameters (R-2 = 0.651). This statistical relationship calculated for the period 19792000 is validated for the period 2001-2005.