Evaluation of a Monitoring Network of Seawater Intrusion in the Coast of El Jadida District, Morocco

Abstract

The coastal area of El Jadida District contains one of the most important monitoring networks of seawater intrusion along the Moroccan Atlantic coast. This network is constituted of six boreholes lies at about 1km from the coast and arranged with space between 10 and 13km. Boreholes are drilled by the mixed drilling technique using two different methods; the rotary rock bit in the mud and the down the hole hammer drilling. The drilling has allowed us to recognize an unconfined aquifer formed by Quaternary sandstone and two confined aquifers formed by Cenomanian limestone and Paleogenian sandstone. A measurement campaign of the electrical conductivity by multi-parameterics probe had allowed locating a seawater intrusion into each borehole, the high value of the electrical conductivity reached its 56 mS/cm allowing concluding that Ghyben-Herzberg relationship was improved. The calibration of the geophysical data by the networks allows us to highlight the seawater extension in the Sahel.