Akhavan,S., Mousavi,S.-F., Abedi-Koupai,J. and Abbaspour,K.C.(2011): Conditioning DRASTIC model to simulate nitrate pollution case study: Hamadan-Bahar plain. Environ. Earth Sci., 63, 1155-1167.

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wAbstract
@One of the major causes of groundwater pollution in Hamadan-Bahar aquifer in western Iran is a nonpoint source pollution resulting from agricultural activities. Withdrawal of over 88“ of drinking water from groundwater resources, adds urgency to the studies leading to a better management of water supplies in this region. In this study, the DRASTIC model was used to construct groundwater vulnerability maps based on the gintrinsich (natural conditions ) and gspecifich (including management) concepts. As DRASTIC has drawbacks to simulate specific contaminants, we conditioned the rates on measured nitrate data and optimized the weights of the specific model to obtain a nitrate vulnerability map for the region. The performance of the conditioned DRASTIC model improved significantly (R2 = 0.52) over the intrinsic (R2 = 0.12) and specific (R2 = 0.19) models in predicting the groundwater nitrate concentration. Our study suggests that a locally conditioned DRASTIC model is an effective tool for predicting the region's vulnerability to nitrate pollution. In addition, comparison of groundwater tables between two periods 30 years apart indicated a drawdown of around 50 m in the central plain of the Hamadan-Bahar region. Our interpretation of the vulnerability maps for the two periods showed a polluted zone developing in the central valley requiring careful evaluation and monitoring.

Keywords: Groundwater vulnerability; SUFI2; Conditioning; Optimization; Indexing method; Iranx

Introduction
Materials and methods
@Description f the study area
@DRASTIC model and model calibration
@Model parameterization
Results and discussion
Conclusions
Acknowledgments
References


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