This review broadly follows a hydrogeological terrain concept that combines classification of groundwater occurrences and their tectonic and geomorphological setting with specific climatic zones as this approach conveys an idea of what type of groundwater system or occurrence to expect. Thus the term "large sedimentary basin and arid" conveys the prospect of extensive stratiform sandstone aquifers largely containing "fossil water" and that only receives modern recharge along the mountainous rim of the basin. Similarly "Basement complex and arid zone" conveys a mountainous terrain with widespread exposures of crystalline metamorphic and batholithic rocks that are cut by numerous faults, fissures and stress joints. Preferentially erosion along these lines of weakness results in a heavily incised surface water drainage pattern with the fissure and fault zones below the valley floors are ideally located to receive indirect recharge as are the large tracts of outwash deposits (colluvial deposits) along the mountain front piedmont.