Comparative Assessment of GroundwaterVulnerability to Pollution in a Semi-AridArea Using DRASTIC, SINTACS, GOD,and SI Methods: A Case Study of the AnkDjamel Watershed, Northeastern Algeria

This study focuses on the Ank Djamel watershed, a semi-arid region located in northeastern Algeria, with the objective of mapping vulnerability to pollution to enhance groundwater management.To achieve this, a comprehensive database was compiled from various sources, including geological, hydrogeological, geomorphological, climatic data, and satellite imagery.Four different methods are applied using a geographical information system (GIS): DRASTIC, SINTACS, GOD, and SI.The SI and SINTACS methods revealed three main vulnerability classes: low, medium, and high.The GOD model identified three classes as well: very low, low, and moderate.In contrast, the DRASTIC model identified four classes: very low (18.47%),low (26.38%),moderate (38.46%), and high (16.28%).The accuracy of the models was assessed through a comparison of nitrate observation value with the estimated pollution vulnerability in the measured wells.the DRASTIC and SI methods emerged as the most reliable for assessing groundwater vulnerability in the Ank Djamel watershed, while the SINTACS method provided complementary information.The GOD model was found to be less suitable for the studied area.