DATA INTEGRATION FOR MAPPING GROUNDWATER IN THE ARID WADI QENA REGION, EGYPT

Wadi Qena is one of the most important valleys to national development in Egypt from agricultural and hydrological viewpoints. It is also a uniquely large geomorphic feature in the Egyptian Eastern Desert that covers approximately 18,000 sq km. Remotely sensed data such as Landsat Enhanced Thematic Mapper (ETM+) and Shuttle Radar Topography Mission (SRTM) data have been employed in the preparation of groundwater prospection map. Integrating slope, drainage, geology-geomorphology, and lineament density maps through GIS techniques were applied. These maps were integrated after assigning weight factors to identified features in each thematic map depending upon infiltration properties. The resulting map classified the region into six categories of groundwater potentiality being from excellent to very low. The alluvial and flood plains consisting of thick sand and gravel are favorable prospect zones for groundwater exploration and represent 22 % of the study area. Field observations and existing geophysical data validated the groundwater potentiality map, and show that most water wells fit in the excellent to the very good zones. In addition, these areas have a very gentle slope < 5 and are characterized by highly porosity sediments. Most of the infiltrated water is confined in the shallow quaternary aquifer that is underlain by impermeable silt and clay layer, which prevents the water from passing to the deeper aquifers. Field data show that water depths of these wells range from 4 to 120 m, and increase northward, which is the reverse of slope. In addition, the aquifer is affected by sub-basins. The overall results demonstrate that data integration of remote sensing and GIS with the aid of the field surveys provide a powerful tool for better assessing, planning, and monitoring of groundwater resources in such an arid region.