Assessment of ground water vulnerability to pollution in Jinja district using modified drastic model

Abstract

It is estimated that approximately 80% or more of the low-income peri-urban population in developing nations uses groundwater for drinking water (Croni et al., 2006). Because of the high rates of pollution generation per unit area and insufficient waste management systems, urban groundwater quality in these peri-urban and urban communities is a growing problem (Pegram et al., 2009). The MODIFIED DRASTIC model has been used to assess the amount of groundwater sensitivity to pollution in Jinja district and to identify regions of possible groundwater vulnerability to pollution in Jinja. This study created a map of groundwater vulnerability that shows areas of possible pollution. The vulnerability index is calculated in the analysis by taking the eight model factors, which are water table depth, topography/soil slope, vadose zone material, aquifer material, soil media, Recharge, Hydraulic conductivity, and Landuse/Landcover. All study parameters were prepared, categorised, weighted, and integrated into the Geographic Information System (GIS) environment. The vulnerability index ranged from 60 to 229 points. Low vulnerability areas have an index ranging from 60 to 110, covering approximately 46% of the district; moderate vulnerability areas range from 110 to 157, covering approximately 44% of the district; and high vulnerability areas range from 157 to 229, covering approximately 10% of the district. The results suggest that the majority of Jinja is in the intermediate vulnerability zone, with a moderate potential for ground water pollution. According to the single parameter sensitivity analysis, Landuse/Landcover has the greatest influence on the vulnerability index, with an effective weight of 20.28% versus the theoretical weight of 17.86%. Its elimination has a significant impact on the index map. With an effective weight of 2.95% vs a theoretical weight of 3.57%, slope has the least influence on the vulnerability score. Its elimination has the least impact on the vulnerability index. This study suggests that Environmental Management decisions be implemented to reduce the hazard of contaminants to groundwater. According to the research, this model can thus be a helpful tool for local governments in groundwater assessment planning and preservation, as well as the design of efficient groundwater management policies.