“Groundwater Vulnerability Assessment and Comparison of Existing Methods"

Abstract This thesis presents a comprehensive assessment of groundwater vulnerability through the application and comparative analysis of five distinct methods: DRASTIC, SINTACS, GOD, SI, and a remote sensing-based approach. The primary objective is to evaluate the effectiveness of these methodologies in identifying and mapping areas at risk of contamination, thereby providing a robust framework for groundwater vulnerability assessment. The DRASTIC method, which stands for Depth to water, Recharge, Aquifer media, Soil media, Topography, Impact of the vadose zone, and Hydraulic conductivity, utilizes these seven hydrogeological parameters to generate detailed vulnerability maps. Widely recognized for its comprehensive approach, DRASTIC has been extensively used in various hydrogeological studies. The SINTACS method, an adaptation of DRASTIC, is specifically tailored for Mediterranean regions, modifying the weightings and ratings of the same seven parameters to better reflect the environmental conditions typical of these climates. This aims to enhance the accuracy of vulnerability assessments in these specific regions. The GOD method offers a more simplified approach by focusing on three key parameters: Groundwater occurrence (G), Overall aquifer class (O), and Depth to groundwater (D). Despite its simplicity, the GOD method provides a quick and effective means of evaluating vulnerability, making it valuable in resource-limited settings. The SI method, standing for Susceptibility Index, integrates a range of relevant factors impacting groundwater vulnerability, ensuring a comprehensive evaluation by considering multiple influences. In addition to these traditional methods, a remote sensing-based approach is employed, leveraging advanced satellite imagery and geographic information systems (GIS). This approach offers dynamic and scalable assessments, with high spatial resolution and real-time monitoring capabilities, representing a significant advancement in the field. A comparative analysis of these five methods was conducted using a case study of a groundwater system. Factors such as ease of application, data availability, cost-effectiveness, and sensitivity to regional variations were considered. The results highlight the strengths and limitations of each method, demonstrating significant variations in vulnerability predictions. Notably, the remote sensing-based approach provided enhanced spatial resolution and real-time monitoring capabilities, proving particularly beneficial for large-scale assessments. This research underscores the critical importance of selecting appropriate methods for groundwater vulnerability mapping, tailored to specific regional conditions and data availability. The findings contribute to optimizing groundwater management strategies, ensuring the sustainable use and protection of vital groundwater resources. By providing a comparative analysis of multiple methods, this thesis offers valuable insights into the best practices for assessing groundwater vulnerability, ultimately supporting more informed decision-making in water resource management.