Environmental Effects of Aquifer Overexploitation: A Case Study in the Mitidja of Algeria

The Mitidja plain, in northern Algeria, has experienced a very significant socio-economic development in recent decades that has been manifested by a population growth, urban expansion and an intensification of agricultural and industrial activities. This situation has impacted the environment primarily through the increased use of natural resources, especially groundwater, and production of wastes. This study focus on the long term piezometric evolution levels of the Mitidja groundwater and evaluate the influence of aquifer exploitation over a large observation period of 47 years. For this goal, we collected, homogenized, and analyzed piezometric data recorded from March 1968 to May 2015 in wells almost homogeneously distributed in the study area. A total of 1536 water table depth measurements were used at 212 monitoring points. The results indicated that the intensive exploitation of the Mitidja alluvial aquifer to supply urban, agricultural and industrial water demands began in 1976 and is responsible for a steady decline of piezometric levels of about 25 m in some localities. Other effects of this overexploitation caused serious environmental impacts such as the fall in flow and drying up of several wells, formation of cones of depression at some wellfields, marine intrusion and early drying up of certain tributaries in Mazafran. Authorities must undertake several actions in order to reduce overexploitation and preserve the availability of water resources in this important region.