Relationship Between River Flow, Rainfall and Groundwater Pumpage in Mikkes Basin (Morocco)

This paper investigates the relationship between river flow, rainfall and groundwater pumpage in the mikkes stream during theperiod 1968-2009. the mikkes basin is located in the north center of morocco and consists of three different zones that representdiversified geologies. this basin includes a phreatic and confined aquifer in saïs basin and a shallow aquifer in the tabular middleatlas. analysis of monthly medium flows between 1968 and 2009 shows an approximate oceanic system which is characterized bytwo hydrological seasons. first a period of high waters in winters which is conditioned by the pluviometric contributions and thesecond is a low water period in summer which is conditioned by evapotranspiration. the mode of this river can be called a pluvioevaporaltype. the high deficit of the mikkes stream (between 1968-1979 and 1980-2009) is about 76% and could be the combinedeffect of drought and groundwater pumpage. water table variations could be conditioned by climatic changes and regional geology.actually, the annual water table variations show a drop in ground water levels, which is due to the combined effect of reduction inprecipitation that has reduced the natural recharge of groundwater, and the increase in pumping which is increasing year by year formore than 80 years in this region. in addition, free-water tables are much more susceptible to pumpage when compared to theconfined aquifer. thus, the water table and piezometric heads of the mikkes basin do not demonstrate a uniform sensitivity to thedrought. high rainfall between 1995 and 1997 had affected the groundwater levels of mikkes with an increase in piezometric level. themonthly piezometric variations of free-water table are characterized by a seasonal operation: groundwater recharge and discharge.