SECHERESSE METEOROLOGIQUE AU BASSIN HYDRAULIQUE OUM ER RBIA DURANT LES DERNIERES DECENNIES

Abstract

Morocco has often been known for the past periods of severe drought. The situation is critical for the four watersheds in the country (especially for the most important hydric basins: Oum Erbia, Sebou, Moulouya, Souss Massa). In the case of Oum Erbia hydraulic basin, the rainfall situation was characterized by a global deficit, due to the combined effects of drought and overuse. The gap reached in some resorts 50%. The data series reconstructed by drought indices most commonly used in Morocco for the monitoring and prediction are:  The deviation from the precipitation index,  The deviation from the average, compared to the normal standardized precipitation index and precipitation (SPI). These indices allowed us to show that the hydraulic basin OUM ERBIA experienced dry spells from 1980-81 to 1985-86, from 1991-92 to 1994-95 and from 2000 - 2001 to 2002-2003 in the last twenty years. A review of drought years revealed a higher frequency and spatial extent of the largest drought are at the moment longer, more frequent and they succeed. The hydraulic basin has experienced an increase in average temperature by about 1°C, providing information on the phenomenon of global warming.