Vulnerability assessment of Malayer plain groundwater by SINTACS, DRASTIC and SI models

In order to prepare the aquifer vulnerability map of Malayer plain which is the water resource of agricultural and industry activities as well as rural consumptive waters of the region, the DRASTIC, SINTACS and SI models were used for exploration of Malayer plain groundwater as following steps: first, by development of aquifer media, vadose zone media, water table, net recharge rate, soil media, hydraulic conductivity, topography and land use maps, the initial layers of the models were prepared. In the second step, the available nitrates layer of the groundwater was also prepared based on 32 measurements of wells during spring 2010. In order to evaluate the performance of the models, the correlation between the initial layers and available nitrates layer was calculated. Based on the calculated coefficient correlation and its significance, DRASTIC, SINTACS and SI models were calibrated and than theirs parameters were modified. Third, using overlap of the and correlated aquifer vulnerability maps, contamination danger map of plain which called agricultural DRASTIC map was produced. At last, by comparing the vulnerability potential map, modified SI map, modified DRASTIC model, agricultural DRASTIC model and neuro fuzzy inference map with the available nitrate layer, the best model was distinguished. The result illustrated that the agricultural DRASTIC method (r=0.81) is identified as the best method to evaluate the vulnerable points of Malayer plain. According to this map, 15.5, 71.66 and 12.84% of the area are located in the less, medium and high vulnerable points, respectively.