An integrated approach is carried out to study the hydrogeological conditions in wadi systems. In this chapter, the use of remote sensing and direct current (DC) resistivity techniques was considered to manage the flash flood and explore groundwater in desert lands. As case studies, two wadis at the Eastern and Western Deserts, Egypt, are presented to show the efficiency of using the suggested integrated study. Based on satellite images, remote sensing (RS) and geographic information system (GIS) techniques are used to identify the regional geology, geomorphological features, lineaments, and active channels regarding flash flood events in desert lands. Consequently, a hydrograph and runoff modeling can be estimated for wadi systems. Furthermore, the calculated flash flood total discharges and the storage capacity of existing mitigation measures can be recognized. From a geophysical point of view, the DC resistivity method can be applied to identify the subsurface layer distributions, image the near-surface lateral heterogeneities, subsurface structures, and potential groundwater zones. Based on geophysical data inversion results, this chapter shows that it is possible to recognize sites for successful dam construction and groundwater bearing zones exploration. Accordingly, the results of these case studies represent the importance of the integrated approach for the flash flood hazards management and its harvesting.