Vulnerability Assessment of Groundwater Resources in Qazvin Aquifer with DRASTIC, Modified and Fuzzy Methods

Concept of vulnerability used in order to determine the pollution risk of Qazvin plains aquifer. Vulnerability map of the aquifer was developed by qualitative rating, and then pollution risk map was provided. Results shows, some part of the plain and south eastern part has high pollution risk, because of the high electric conductivity (EC) and the high groundwater level respectively. Some parts were in the low risk region and due to the high ground water level the confirmation based on the chemical analysis is unexpected. By using Nitrate data the vulnerability maps reveal dramatic changes. In the corrective drastic method, areas which were in low risk region in conventional drastic moves to the moderate risk region. Also, results from the fuzzy drastic was close to the corrective drastic. Major parts of the plane were in the moderate risk region. From the experts point of the view the results from the corrective drastic was realistic. Results from sensitivity analysis shows that weight of the aquifer depth layers and feeding decreased, unsaturated slop layer's weight and hydraulic conductivity increased. Also, the weight of the ambience of the aquifer layers and soil was remained constant.