Hydro-Chemical Study with Geospatial Analysis of Groundwater Quality Illizi Region, South-East of Algeria

Abstract

For the aim of evaluating the physical and chemical groundwater quality of six layers (the Lower Devonian, Mio Pliocene, Infero Flux, Cambro Ordovician, Albian, and Zaraitine in Illizi, and to identify the sources of its chemical composition and detect the suitability for drinking and irrigation purposes, 44 samples were collected during tow years 2018-2019 to measure pH, T°, Electrical Conductivity (EC) and Total Dissolved Salts (TDS), major elements concentrations were analyzed in the laboratory. The suitability of groundwater for irrigation and other uses was assessed by determining the sodium adsorption ratio (SAR), Soluble-Sodium Percentage (SSP), Permeability Index (PI), Kelly Index (KI), and Total Hardness (TH) of water samples. The spatial distribution of key parameters was assessed using a GIS-based spatial gridding technique. This analysis indicated that the Zaraitine groundwaters used to have the worst chemical quality, while the Infero Flux, Cambro Ordovician and Albian groundwaters have suitable water for drinking. Based on Sodium Absorption Ratio (SAR), Solubility Sodium Percent (SSP), Kelly Index (KI), Permeability Index (PI), Residual Sodium Carbonate content (RSC), and Magnesium Hazard (MH). we find that the Lower Devonian, the Infero Flux, and Cambro Ordovician have suitable water for irrigation, on the other hand, all of Mio-Pliocene, Albian, and Zaraitine consider as unsuitable for agriculture practice. PCA analyses with the comparison between Lower Devonian wells in Illizi town and Lower Devonian wells in Fadnoun town in groundwater quality confirm that the local environmental conditions are a more important factor for groundwater quality than geographical distribution. Geospatial mapping of hydro-chemical parameters shows that the southeast of Illizi and the western part of Djanet are the best sub-areas for agriculture practice.