African Journal of Geography and Regional Planning

African Journal of Geography and Regional Planning ISSN 3627-8945 Vol. 7 (11), pp. 001-013, November, 2020. © International Scholars Journals

Full Length Research Paper

Groundwater vulnerability and risk mapping of the Quaternary aquifer system in the Northeastern part of the Nile Delta, Egypt

Saad Mogren and Mohamed Shehata^*

Geology and Geophysics Department, King Saud University, PO Box 2455, Riyadh 11451, Saudi Arabia

Accepted 06 May, 2020

Abstract

As the most valuable natural resources, protection and management of groundwater is vital for human evolution, socio-economic development and ecological diversity. This paper presents the groundwater vulnerability mapping of the Quaternary aquifer system in the northeastern part of Nile Delta using Weighted Multi-Criteria Decision Support System model (WMCDSS). This model has been implemented using Geographic Information System to delineate groundwater zones and to suggest a protection and improvement plan for major groundwater wells in the area. Six thematic layers were digitally integrated after assigning different weights (W_f) and rates (R_f) to them. These GIS layers have been created to adopt the most indicative criteria for investigating the groundwater degradation trends from sea level rise and seawater intrusion. The chosen layers are: total dissolved solids (TDS), rCl/rHCO₃ ratio, sodium adsorption ratio (SAR), groundwater type, hydraulic conductivity (K) and well discharge (Q). Weights have been assigned to all these layers according to their relative importance for groundwater vulnerability, whereas their corresponding normalized weights were obtained from their effectiveness factors. The groundwater vulnerability map indicates four classes ranging from very low to high. According to this map, the promising localities for groundwater usage are located in areas where very low to low vulnerability has been observed. These localities are distributed over 4080 Km² area, covering 53.68% of the total study area. The areas having moderate to high groundwater vulnerability are more than 3520 Km², indicating a deterioration of groundwater quality in 46.32% of the study area, which need special treatment and cropping pattern before use.

Keywords: Nile Delta, Egypt, groundwater, vulnerability, Quaternary aquifer, sea level rise.