Geomatics-Based Modeling and Hydrochemical Analysis for Groundwater Quality Mapping in the Egyptian Western Desert: A Case Study of El-Dakhla Oasis

Abstract

Groundwater is the single source of water in El-Dakhla Oasis, western desert, Egypt. The main objective of this study is an assessment of groundwater in the area for agriculture and drinking compared to Egyptian and World Health Organization criteria. Most the contamination of water in the study area comes from human and agricultural activities. Thirty soil profiles were studied in the area and we assessed soil quality. Seventy-four samples were taken from the area’s groundwater wells to assess the chemical characteristics of the groundwater. Moreover, the contamination of groundwater by farming and anthropogenic activities was assessed using a land use/land cover (LULC) map. Nine standard water criteria were determined to assess groundwater quality for agriculture. Furthermore, the resulting risk to human health and agricultural crops has been addressed. Therefore, the drinking quality of groundwater samples is graded as low as the hydrochemical study showed high TH, EC, TDS, Ca2+, Mg2+, Mn2+, and Fe2+ contents of 40.5%, 2.7%, 1.4%, 3.8%, 1.6%, 86.5%, and 100%, respectively. Human health is risked by drinking this water, which negatively affects hair, skin, and eyes, with greatest exposure to enteric pathogens. Using these criteria, the majority of groundwater samples cause harmful effects on soil types and are toxic to sensitive crops (vegetable crops). In conclusion, the output of this research is a map showing groundwater suitable for consumption and agriculture in El-Dakhla Oasis based on all indices using the Geographic Information Systems (GIS) model. Additionally, there was evidence of a linear relationship between soil quality and irrigation water quality (R2 = 0.90). This emphasis on tracking changes in soil/water quality was brought on by agricultural practices and environmental variables.