Unlike in coastal and sedimentary basins, regional-scale exploration of groundwater resources using only geophysical methods is costlier in consolidated rocks such as volcanic rocks and crystalline basement complexes in Africa because of the highly heterogeneous structure of aquifers. Therefore, advanced analysis of remotely sensed images and an accurate assessment of groundwater resources are crucial before carrying out a geophysical prospecting survey. This study proposed a joint analysis of satellite images from optical sensors and synthetic aperture radar (SAR) which aimed to enhance potential mapping accuracy of groundwater resources in crystalline rock areas in a semiarid region. The backscattering coefficient of the SAR data analysis effectively detected the zones of relatively high weathering degree and thus having thick permeable regolith. In addition, a modified clay index calculated from the four band reflectances of the optical sensor imagered, near infrared, and two shortwave infrared bandswas applied to discriminate clay-rich zones from high vegetation activity zones. The clay-rich zones detected corresponded with the highly weathered zones estimated from the small SAR backscattering coefficients. The zones also corresponded with a large density of faults and lineaments and furthermore were verified by high potential yields from groundwater wells. The thickness of weathered zones was likely to increase with a decreasing backscattering coefficient and higher modified clay index values. Conversely, large backscattering coefficients in the narrow zones along the major lineaments from large volumetric scattering because of high vegetation activity, as confirmed by the large vegetation index values, suggested that high moisture content was retained in the soils. In fact, the potential yields of the groundwater wells tended to increase near the lineaments. Accordingly, shallow groundwater occurrence is plausible in those zones.