Evaluation of Groundwater Vulnerability and Susceptibility to Pollution in Erbil City Using the DRASTIC Model

This study employed the DRASTIC model to assess groundwater vulnerability and sensitivity to contamination. The model's accuracy is attributed to its quantitative analysis of seven hydrogeological parameters: depth to groundwater (D), recharge rate (R), aquifer media (A), soil media (S), topography (T), impact of vadose zone (I), and hydraulic conductivity (C).

The primary objective of this research was to investigate the influence of natural factors on groundwater contamination, characterize its quantitative and qualitative properties, map its spatial distribution within the study area, and evaluate its suitability for various uses. A geographic information system (GIS) (ArcGIS 10.8) was utilized to generate thematic maps representing the groundwater characteristics of the study area.

Data from 128 groundwater wells were collected and used to develop final models illustrating contamination levels, which were classified into three categories: high, moderate, and low. A masking technique was applied based on groundwater sensitivity to contamination, with each parameter assigned a weighting factor. The results indicated that low-contamination areas constituted 31% of the study area, while moderate-contamination areas accounted for 34%, and high-contamination areas comprised 35%.

Several factors contributed to the observed contamination levels. Industrial activities in the eastern part, such as block, furniture, and automotive manufacturing, released pollutants during floods. Unregulated well drilling adversely affected aquifer geology. The topographic gradient facilitated the movement of contaminated water from higher to lower elevations. Additionally, pesticide use in parks and external pollution sources, including industrial emissions, oil field leaks, and untreated wastewater, significantly impacted groundwater quality.