Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : GROUNDWATER SALINIZATION IN THE COASTAL AREA OF JIFARA PLAIN, NW-LIBYA

Auteur : Alfarrah Nawal Khalifa

Université de soutenance : Universiteit Gent

Grade : Master of Science (MS) Physical Land Resources 2006

Résumé
Large increases in water demand with very little recharge have strained Libya‟s groundwater resources resulting in serious declines in water levels and quality, especially along the Mediterranean coast where most of the domestic, industrial and agricultural activities are concentrated. This project presents results of the hydrogeological investigation of groundwater salinization in the Jifara plain upper aquifer system. The unconfined coastal aquifer of Jifara plain, NWLibya, is characterized by the presence of saltwater. By means of the available hydrogeological and hydrochemical information, the sources of salinization have been identified : seawater intrusion is the main reason for groundwater salinity in the study area. In the western part of the study area the brine of coastal sebkha is the contaminant. The origin of salinity whether (sea or sebkha) is shown by comparing the chemical composition and the conservative mixture of fresh and seawater end members. Seawater intrusion is a result of overexploitation of the aquifer, its shape and position is illustrated by 12 hydrogeochemical profiles perpendicular to the coast from 8 to 15 km long. In this study the Jifara plain is divided into 3 study zones, Az Zawiah area, Tripoli area and Al Kumes area according to various key consideration factors, notably, the geological formation, water supply and the topography. Water samples were collected from 160 sampling points in these study zones and analyzed for the major cations and anions (Na+, K+, Ca2+, Mg2+, SO42-, Cl-, HCO3-, CO32- , Fe2+). Piezometric maps, TDS and EC maps have been drawn. Lithological and hydrological cross sections have been established. Most of area has a CaCl and MgCl groundwater type, with some profiles having a (Mg+Ca)Mix groundwater facies

Source : Pedon 18 - Physical Land Resources - Universiteit Gent