Groundwater potential mapping using GIS, linear weighted combination techniques and geochemical processes identification, west of the Qena area, Upper Egypt

摘要

The water demand in Egypt has risen due to limited surface water and varied uses. Geological and hydrological data, radar, optical remote sensing data, and Geographic Information System techniques delineate groundwater availability zones in the study area. Thematic layers (lithology, topography, slope, stream networks, lineaments, and rainfall) were integrated into the ArcGIS 10.4 using a linear weighted combination technique. The final groundwater prospective zones (GWPZ) map revealed six zones, very low, low, moderate, high, very high, and excellent, covering areas of 7.49%, 14.93%, 3.74%, 28.88%, 37.30%, and 7.62%, respectively. The GWPZ map was tested and compared to the abstraction rates, locations of existing wells, and thickness of the water-bearing formations. NDVI analysis revealed an increase in the area’s vegetation from 1984 to 2017. Geochemical analyses of 43 groundwater samples revealed water-rock interactions, ion exchange, evaporation, and the influence of irrigation-return flows as prominent processes influencing ion enrichment of the groundwater.