Classification Approaches to Assess Groundwater Quality (Wadi El-Natron, Egypt)

Environmental management of the groundwater is based on three axes; (1) safe water use that grantee the equilibrium between water consummation and refeed of well groundwater (2) elaboration of chemical and magnetic water to improve water quality, and (3) characterization and classification of water types to achieve the most efficient water use. The third axe of environmental management groundwater is the core of the current research that classified the groundwater (Wadi El-Natron, Egypt) by multiple approaches (1) water quality indices (2) Wilcox and Riverside plotting classification, and (3) groundwater hydrochemical classification. EC index classification, of wadi El-Natron groundwater, indicated that 90.90% of shallow wells samples (SW) were good and permissible class, 90.90 % of moderate deep wells samples (MDW) and 68.75 % of deep wells samples (DW) located in permissible salinity class. The averaged pH values of the groundwater related to their moderate alkalinity. The assessed grade quality of water irrigation varied according to the used sodicity indices. The averaged values of sodium percentage (SP), sodium adsorption ratio (SAR), and permeability index (PI), residual sodium carbonate (RSC) designated the majority of wadi El-Natron groundwater as permissible category. Contrary, most of studied water samples located in not recommended class according to Kelly’s ratio (KR) and chloro-alkaline index (CAI1). All studied groundwater samples are situated in the acceptable class according to magnesium hazard (MH) and total hardness (TH). Plotting of EC-Na% analytical data on Wilcox diagram indicated that generally, groundwater of (SW) and (DW) had higher quality waters than (MDW).

EC- Na% Wilcox Diagram: Plotting of EC- Na% analytical data on Wilcox diagram indicated that waters of the shallow wells were distributed excellent (45.46%), good (18.2%), permissible (27.3%) and doubtful (9.09%) water quality. According to EC- SAR Riverside diagram, groundwater in the study area falls within the medium EC-low SAR, high EC–low SAR, and high EC–medium SAR. For groundwater wells, the hydrogeochemical classification indicated the abundance of Na and K cationic facies, while the waters of (MDW) and (DW) were characterized by high contribution of strong acidic anionic (SO42−). Generally, NaCl water type was dominant in wadi El-Natron groundwater.