SOME IMPACTS OF CLIMATE VARIABILITY IN THE TENSIFT WATERSHED (MOROCCO)

Morocco is a country located in an arid to semi-arid climate zone. Surface water resources in Morocco are becoming increasingly limited and difficult to exploit. They are related to precipitation and the whole region is characterized by a highly irregular distribution of rainfall in space and time.

In this context, a study of the evolution of precipitation and temperature allows assessment of some impacts of climate variability on the Tensift watershed (central Morocco). A slight decrease of precipitation has been noticed in the piedmont regions of the High Atlas and near the Haouz plain. In other areas of the basin, especially in the area of Marrakech, the amount of precipitation increased to an average of 40 mm. Preliminary results indicate that temperature in the watershed became higher during the last two decades. Paradoxically, it increased towards mountainous areas.

De Martonne’s aridity index was calculated based upon the mean annual values of precipitation and temperature. Generally, the aridity index is decreasing from upstream to downstream in our study area. However, during the past two decades, the aridity index is advanced in areas of the piedmont and decreases towards the Atlantic Ocean, north and south of the Tensift watershed.