ASSESSING GROUND WATER QUALITY USING GEOSPATIAL MODELING IN CENTRAL GONDAR ZONE, ETHIOPIA

Abstract

Ground water quality assessment using geo-spatial modeling in the Central Gondar Zone of Northwestern Ethiopia, for the majority of the study areas, springs and pumped water wells are the main sources of drinking water. In order to better comprehend the spatial distribution of groundwater quality characteristics, the study's objective is to provide groundwater spatial data in a GIS environment. In this study, 157 improved water sources were chosen at random from a 21,791.83 km2 study area. PH, Electrical Conductivity (EC), Total Dissolved Solution (TDS), Total Hardness (TH), Magnesium (Mg), Fluoride (F), Nitrate (NO3), Sulfate (So2-4), and Chloride (Cl) were evaluated and compared to national and World Health Organization (WHO) guideline values. For exploratory data analysis, semivariogram model selection, cross validation, and the creation of a distribution pattern for groundwater quality metrics, the geo statistical analyst extension module of ArcGIS was utilized. The spatial patterns of groundwater quality were produced using the Ordinary Kriging (OK) approach. The outcome of the OK interpolation shows higher pH values in the NE and SW, higher EC in the N and NE, higher TDS, TH, and Mg in the CE and CW, higher fluoride in some areas of the SW and N, higher nitrate in the C and CE, higher sulfate in the W and E, and higher chloride concentrations in the study area's eastern parts. The best-fit model for PH, Electrical Conductivity (EC), Total Dissolved Solution (TDS), Total Hardness (TH), Magnesium (Mg), Fluoride (F), Nitrate (NO3), Sulfate (So2-4), and Chloride (Cl) was a spherical model with Mean Error (ME) values of 0.013, 0.004, 0.001, 0.003, 0.007, 0.004, -0.010, and 0.004 and with Root Mean Square Standardized Error (RMSSE) values of 0.99, 1.020, 1.045, 0.91, 0.98, 1.10, 1.06, 0.92, and 0.95, respectively. The results of the statistical analysis of the data indicated that the concentrations of PH, Electrical Conductivity (EC), Total Dissolved Solution (TDS), Total Hardness (TH), Magnesium (Mg), Fluoride (F), Nitrate (NO3), Sulfate (So2-4), and Chloride (Cl) were within the acceptable ranges for drinking water set by both the national and WHO standards.