Gravimetry Contribution to the Study of the Bahira Aquifer (Morocco) - Hydrogeological Implication

This study, based on analysis of gravity data, is aimed to improve the knowledge of the geological structures of the plain of Bahira (Central Morocco) that control the groundwater flow through the basin. A residual gravity anomaly map was first calculated from Bouguer anomaly map by subtracting a regional trend. This map provides information on the variation of the rock densities under the plain of the Bahira. Several gravity highs and lows which indicate the presence of horts and grabens structures in the basin basement have been highlighted. The superposition of the piezometric surface map of the plain of the Bahira and the residual anomaly map showed that groundwater flows from recharge areas of Ganntour, Jbilet, and Rehamna to closed depressions of Sed El Mejnoun and Lake Zima. In order to delineate the main faults contributing to the structure of the study area, horizontal gradient and upward continuation techniques have been applied to determine gravity lineaments that represent the location of the density contrasts limits. Three families of fractures that control groundwater flow have been highlighted.